Zu Druid 6

TL; DR: VIVID! Sean finally built one for himself.

In amateur astronomy, we have orthoscopic eyepieces. Orthoscopic optics are designed for absence or near absence of dimensional distortions in the optical view, and they use relatively few glass elements for high light transmission, scant aberrations and low-to-no light scatter. Orthoscopic eyepieces are the standard for critical visual astronomy of planets, due to the undistorted detail, minimal glass and resulting contrast rendering fine details observable at high magnifications. Newer optical designs emphasize other characteristics, particularly wide fields of view for a more immersive experience in observing the night sky, but designing for wide fields trades away some orthoscopic properties to gain something more spectacular and useful in a different way, to the point where intentional spatial distortions are introduced or accepted in order to tame worse ones when field of view goes very wide.

Not wanting to go all the way down another hobby’s wormhole here, I’ll leave the matter of orthoscopics at that as a way of shifting your mindset to orthosonics for a similar agenda to design for authentic sound in hifi audio. It’s more difficult than it seems.

Last year marked 50 years elapsed since I spent my first dollar of my own money on gear to replay music. 2018 also marked 50 years elapsed since I spent the first dollar of my own money on guitars. I’ve been buying recordings longer than both. I mention this because one thing has remained absolutely consistent in all this time, and counting: at any given time, and for any given category of products, there are only a small handful that are worth buying. There’s always lots of choice, but choice isn’t the same as worth. I am aware of the full panoply of audio gear but am undistracted by most of it, because….well…..most of it at any price isn’t compelling.

Especially loudspeakers, which mostly remain very far away from representing music and the instruments (including the human one) that produce the sounds of music. If mid-to-high-end hifi buyers were primarily driven by music concerns rather than gear, or what’s cool, or whatever makes the best success statement, or whatever else you’ve got that isn’t strictly endorsing of objective music replay, the entire market could be served by just two speaker makers: Audience with their ClairAudient line, and Zu Audio. I wish I could say otherwise, but these are the only makers of speakers fully delivering authentic music fidelity today, i.e. replaying music orthosonically. There are a few additional contenders who nearly get it right, at various price strata: JohnBlue, Voxativ, 47 Labs’ Lens, Quad with their electrostatics, and Konus are some who cover between 270° and 330° of the full 360° circle of fidelity. Which is great, and that much completion of the circle can deliver beautiful sound. But only Zu and Audience have mastered making speakers that can effortlessly deliver altogether holistic music fidelity, authentically.

Send your Magicos, YGs and KEF Blades to the smelter. Torch everything Wilson, Focal, Devore, Maarten, Revel and Dynaudio, let alone those horrible JBL Century 100 reissues we see rising from the dead now. Throw every crossover-intensive speaker into the woodchipper and send the ground-up mulch to your local toxic waste facility. Fake news is mostly a trumped-up distraction, but fake fidelity – that’s real. The orthoscopic authenticity cornered by Zu and Audience is rooted in both companies having developed, within any practical considerations, uncompromised full-range drivers coupled to insightfully-engineered cabinets. In loudspeakers, adroitly-chosen materials, along with astute mechanical, resonance, acoustical, structural and construction decisions, preserve the essential simplicity of a full-range driver design, emitting music without exaggeration.

And that’s the whole distinction, because let’s face it -- most of the supply side of the hifi realm is in the exaggeration business. Moreover, much of the consuming public likes it that way! For every “hungry-ear” buyer who seeks the artificiality of being in the band or inside the piano, or gulped down by the singer to be a swallowed resident inside the body’s resonant cavity, there is a designer and manufacturer willing and eager to tilt the ratio of transient-to-tone, or the inverse, away from real and aggressively toward spectacle. It’s endemic, and buyers are as much at fault as the designers & sellers in the industry. For people who want more transient detail than is actually present in a performance or from an instrument, orthosonic speakers aren’t for them. If you want a Fender guitar amp running 6V6 tubes to sound like a Marshall stack, or if you think Johnny Cash sounding 12 feet tall is authentic, you don’t want a true-sound, orthosonic, hifi speaker.

If you need or want a surprisingly convincing speaker that can be held in one hand, buy a pair of ClairAudients. But if you want something with room-filling shove, you want Zu. So, I will leave Audience behind here, since this commentary is about Zu, particularly the Druid 6.

This year marks my 15th year of continual Zu in my hifi systems. I started with a pair of used Druids that had been updated by Zu to 2004 configuration. They turned out to be one of the first ten pair of Druids made back in 2000. Those Druids were the first convincing find in my then 30+ years quest for a convincing crossoverless speaker. The 2004-spec Druid was certainly not perfect, but it was a revelation. Imperfect because it was a bit of a narrowcaster, and was soft on the top end. A revelation for its completely coherent presentation, octave-to-octave balance, consistent transient behavior, striking intimacy, pinpoint imaging, absence of crossover-point pinching, plus it was a tone monster. Druid was effectively a dynamic driver Quad ESL-57 but with dynamic range, energy and willingness to be abused. It was the first speaker to ever pass my test for reproducing specific electric guitar/amp combinations with true fidelity. I immediately added an early pair of Definitions to another hifi system but kept those Druids on my secondary system until Druid 5 was introduced, along the way getting periodic upgrades installed, culminating in Druid 4-08.

In parallel, I made the Definition > Definition 2 > Definition 4 migration, yet the Druid never lost relevance. Definitions favored scale; Druids favored intimacy and they both overlapped on tone, coherence, speed, holistic transient and tonal behaviors and both excelled in delivering shove – that quality of musical dynamism that gives music projection and reach. In Zu’s case you get shove without gobs of power.

Druid 5 updated and expanded on the core Druid proposition but extended the top end for more harmonic completeness (courtesy of the Radian compression supertweeter replacing the older Zu tweet), deepened bass response, added greater agility and speed to the main driver, upped transparency, broadened the spatial presentation, boosted shove and put the Druid form factor in league with Definition by further killing cabinet talk. Druid 5 was the first Druid that had sufficient scale to double as a movie speaker, if the room wasn’t too big. Frankly, when Druid 5 debuted, it struck me as nearly perfect in practical terms, and about as much as one could expect from that form factor. Beyond Druid 5 lay incrementalism.

Or so I thought, then.

Enter Druid 6. Why has it taken me seven months to write this commentary? Because Druid 6 may as well be ground zero for a new vector of Zu. It completely unshackles the single-FRD / no-sub form factor of the Griewe – Druid configuration from the physical limits of its original form. Definition 1 had scale and a lot of cabinet talk. Definition 2 sacrificed some spatial scale to slay the cabinet talk. Definition 4 restored the spatial scale and tamed the cabinet talk to deliver a notably more objective speaker. Druid 6 has the spatial scale of Definition 1, which original Druids couldn’t come close to. It has the tone density trademark of all Druids and beyond what any Definition delivers. Snap and dynamic shove set a new Zu standard. Nuance and transparency Windex the entire presentation. Druid 6 is unbelievably quick, with the dynamic agility of Tiny Archibald confusing basketball opponents in his prime. And there is a fairly dramatic improvement in bass depth, character, impact and texture. I never had a real impulse to add subwoofers to any of my Druids, but then I had another system with Definitions and their powered sub-bass modules to satisfy deep bass cravings. Still, it just seemed counter to the simplicity and elegance of Druid to clutter the room with more boxes or towers to get bass fundamentals few recordings actually include. It’s probably only a half-octave further bass extension over Druid 5 but it sounds so convincing and fundamental that a sub is really only called for by a bass fetishist. All this adds up to a speaker that is a larger improvement over Druid 5 than Druid 5 was over v4-08. Which is saying quite a lot.

If you’ve traipsed through the Druids sequence as I have, that might not be your first conclusion, because on everything most obvious – high frequency response, neutrality, greater shove and improved bass, Druid 4-08 was left behind and there wasn’t a single aspect in which Druid 4-08 was better than Druid 5, other than you could buy a pair for much less cash. Druid 6 improves all these particular aspects over Druid 5 somewhat less so than the last generational shift, but that all sums, along with a specific and new Druid quality, to a new speaker that makes the greater leap over its predecessor. The new quality is “vividity." “ Yeah, that’s not a word, but I’m using it here. My TL;DR for this assessment is “Vivid.” And that is what slams your mind when you wire up Druid 6, especially after the 100 – 200 hours burn-in period needed when new.

Basil Hayden bourbon is 80 proof. Technically, that’s a little short for the category. But if I’m having whiskey before the sun is down, I often start there. It’s easygoing and doesn’t front load you for the evening. Druid 5 was like Basil Hayden. Forgiving, convincing, mellow. Works with almost any mood, music, room, aesthetic, amplification. Druid 6 is more like a 137 proof George T. Stagg bourbon. You need to be ready for it, and it’s going to seem a little loud on your palate. If you leave everything the same and just wire ‘em up, a pair of Druid 6 will hit you like a hot whiskey. Burning, flavorful….vivid. And unfailingly revealing. Druid 6 is a deity’s-honest truth of music presentation. So much so, some of you Druid aficionados out there might (will) prefer Druid 5. Depending on what you have today, Druid 6 will force upgrades, or at least changes in your system, upstream of the speakers. The most likely change Druid 6 will force is in amplification. Depending on how your DAC is voiced (don’t kid yourself, they’re all voiced) you’ll be contemplating a change there too. Phono cartridge? Could be, but less likely than DAC. Preamp, least likely to require a change unless a change in power amp argues for it. In my case, Druid 6 brought to a halt 15 years of Audion SET amplification with Druids, and really a total of 20 years of continuous SET listening in my secondary system. Why? Because the extra half octave or so of bass response is just a bridge too far for really clean, bloat-free bass from any zero-feedback SET amp I know of. SET works well with the deeper-plunging the Definition series because in the Def, a solid-state plate amp has a grip on the sub-woofer driver(s). The tonal qualities of the sub bass are derived from the power amp outputs (and characteristics) but the actual sub driver control is a product of the plate amp’s damping and grip. In Druid 5, the ~34 Hz bottom limit doesn’t reveal the limitations of low-damping factor, SET bass. My Audion Black Shadow 845 amps have excellent bass on Definitions and Druid 5. On Druid 6, bass extension is just enough further to bring SET deep bass control deficiencies to the forefront. Same with SET & PSET 300B.

So, I have to replace my beloved Audion Golden Dream monoblocks (300B PSET) to enjoy Druid 6 without distracting and illusion-undermining, zero-negative-feedback bass bloat. More on that near the end of this commentary.

But, if you’re forced into an electronics revision once in 15 years because of a significant loudspeaker advance, one can’t really complain. For the first time since first exposure to Zu Druid, I recommend alternatives to single ended triode amplification. As I will outline in a topical addendum at the end of this, I recommend single-ended pentode/tetrode, push-pull triode and some high-coherence push-pull tetrode and pentode amplifiers. Or if you’re tube-phobic, some solid-state amps one might want to consider include, Pass, First Watt, 47 Labs Gaincard, M2Tech Crosby, etc.

Druid 6 is the first Druid to serve as a convincing transducer for symphonic music. With the right amplification it will even play viciously intense metal without choking like you’re trying to squeeze toothpaste from its tube too quickly, forcing the tube itself to burst. No prior Druid could quite do that. On the other hand, Druid 6 loses nothing to prior Druids in the lone-performer-with-guitar genre, in fact drawing you into closer intimacy with the tone and textures of expression while maintaining the right spatial distance. It doesn’t exaggerate like the bulk of this industry’s loudspeaker offerings, inflating definition like you’re inside the instrument to feign intimacy.

Druid 6 is also easier to set up than any prior Druid. It might be more demanding of amplifier matching but the formerly-fussy floor-to-plinth gap height adjustment is much less hyper-critical now, for attaining correct bass. Because of its dispersive scale, getting a convincing soundstage is a less obsessive proposition in placement and toe-in. There will be rewards for taking the obsessive route, but you don’t have to. And one of the best small touches is that Druid 6 default footers are flat discs, layered with a thin polymer, and attached via a ball-mount that threads into the plinth. You can spec the plinth to be drilled through so the height of the feet can be adjusted from above with a hex wrench! Fantabulous. But the big advantage sonically is that the ball mount acts as a bearing for resonance dissipation. You can get spikes to anchor the speakers to a firm flooring under thick carpet, but for hard floors the default ball-mounted, top-adjustment, polymer-interfacing flat-disc footer is the bee’s knees, sonically and ergonomically. And it’s kind to your floors.

The design and execution emphasis on Druid 6 was the cabinet. The full range driver is improved and I won’t say that’s not important, but the complete revision to the cabinet materials, construction and the mounting of the drivers (including the FRD’s torque-tensioned anchoring to the rear of the cabinet, complementing the baffle attachment and its beefier surround), and the massive plinth are collectively a major advance in Druid resonance control, energy channeling and, by extension a murderous spree annihilating cabinet talk.

Figuratively Druid 6 wastes nothing from the signal in its transducing obligations. Of course it does waste something, but compared to what’s come before, it sounds like it doesn’t. Druid 6 is direct, declarative, clear, orthosonic. It snaps and crackles like real life sounds. Instruments and people have body and breath in correct proportion. Vocal fry sounds exactly like its coming from the Millennial voice behind it. Real acoustic guitar (if amplified, microphoned, not piezo-electric) sounds authentic in tone and in attack : resonance proportion. Voices, instruments and people are sized realistically. Everything is in high resolution in a natural way, without faked detail. Presentation is bursty and serene, strong and laid back, as is authentic to the performance.

It sounds perfect, but there’s a backside to the coin. Druid 6 is not forgiving of bad recordings, cheesy mixes, idiotic mastering. It lays bares faults in performance, recording decisions by the engineer, mastering, pressings (if vinyl). It is intolerant of runaway digititis. The manic sawing of digital compression loses the loincloth producers try to cover it with. The nasty bits of degraded fidelity traded away for expense reduction are naked for all to see.

You can ameliorate the relentless truthfulness of Druid 6 by choices upstream. A more forgiving phono cartridge or more sonically elastic phone preamp or DAC. Get the right tubes for your new configuration. Back off sheer resolution a trace with Zu Mission cables instead of Event 2. Or not. Go for the unmitigated, all-nude, vivid Druid 6 experience. Hear the beauty and the beast in modern recordings. You’ll thrill to music recorded in the pre-multi-track, pre-all-solid-state studio era. Recordings from the days of vacuum tube consoles and mics, with performers in the same room, have a holistic, tuneful sound mostly lost today, except for recordings from a few performers. Those recordings have a vividness perfectly transduced by Druid 6 and projected into your domestic space. With Druid 6, a modern, congested, over-processed, excessively-compressed assault is revealed for the noisefest it is. If you can’t handle that, you need Druid 5 or you need an obfuscating amp for poor recordings, and another amp for great ones.

Which means Druid 6 isn’t for everybody, and that’s a good thing. Because Zu can’t make as many of them as it can build Druid 5 in the same period of time. And Druid 6 costs about twice as much as its esteemed predecessor. Hence both are in the line concurrently. And this makes sense. In my TL;DR I noted “Sean built one for himself.” Sean has visited me often enough that I’ve had many hours of listening with him present. I’ve seen Sean spin vinyl of music he loves irrespective of recording or pressing quality, able to note the sonic offenses and still set them aside to let himself be infused by the tunes. And when the worst disk is done playing, he thinks about how to get more out of it.

This makes Druid 6 its own contradiction. It is the least forgiving Zu speaker ever, and yet the most fun. It’s seductive and off-putting in equal measure, depending on the quality of the source material. And yet its uncanny PRaT pulls you in to ignore what’s wrong with the source and revel in what’s right.

Zu’s finish quality is higher than ever, running with the best. The jewelry adorning the cabinetry is all functionally mandated, designed to look fab and is perfectly machined. While it sounds like this is as good as Druid can get, there’s no doubt Sean will take Druid further in coming years, but Druid 6 is a high plateau on which it can be parked, bought, enjoyed and admired while another speaker in the Zu line gets the new foundation of materials and build techniques laid down by Druid 6. In the meantime, in Druid 6, Sean Casey is making the one, true, full-range, orthosonic speaker. It doesn’t exaggerate, nor does it shade the truth. It neither spotlights nor romanticizes. It doesn’t make rough, wooly music silken, and it won’t make velvet sounds abrasive. Druid 6 presents Tom Waits and Maria Callas with equal authenticity. Yo Yo Ma and Joe Satriani are equally convincing. Frank Sinatra and Hound Dog Taylor are nothing but themselves.

A (lengthy) note on amplifiers for Zu.

If you’ve read anything prior I’ve posted here about Zu, you know I regard the amp-speaker interface and combination the fulcrum of fidelity for any Zu-based system. As I referenced earlier in having to abandon SET amps with Druid 6, buying this speaker requires careful consideration about the mated amplification. In the past 18 months another development required a complete revision to my power amplification in my Definition 4 system as well, so I have put extended effort into surveying alternate amps for both Zu systems over the past year or so.

In 2017 I had solar panels installed on my roof, and then later that year added Tesla Powerwall batteries. The panels were installed on the area of the roof directly over my living room where the Zu Definition 4 system lives. It’s a one-story rancher, wood construction house, so not much other than air, wood and sheetrock umbrellas my Definition 4 system from the shower of solar RFI. Apart from any RF emissions from the panels, the system has two wireless internet connections: a Wi-Fi connection to my mesh network by the Tesla Powerwall controller, and a cellular connection by the solar system inverter. At the same time, to accommodate the exterior Wi-Fi needs as well as prepare for wireless Roon endpoints to two separate systems, I changed my house Wi-Fi from a Google wireless router to an Eero mesh network.

The result was that my SET amps in the Definition 4 system proved perfect antennas for the shower of RFI bathing my living room, and no tactic for quieting that worked. The first step was to get an active preamp out of the system, so I sold off my crazy-good Melody p2688 tube preamp, which removed about half the problem. It was replaced by the splendid Luxman AT-3000 TVC from the early 1990s – a real work of magnetic art. Once that was added, I had quiet with push-pull tube and solid-state amps. At the time, I still had Druid 5 on the other system, and its location sharply contained the new RFI problem, so my Audion SET amps could still be used there. Then Druid 6 arrived to undermine my commitment to Audion SET. So, now what, for amplifiers?

About a year ago, after years of great difficulty finding a phono preamp that can make an Allnic Puritas phono cartridge sound correct (Allnic’s own phono preamps do not), I ventured a radical experiment to try the M2Tech Joplin Mk2 phono ADC, which I mated to the M2Tech Young Mk3 DAC, both powered by the Van der Graaf linear power supply. For this signal, The ADC converts analog to 24/192 digital and the DAC converts the processed phono analog digital signal to analog at 24/192 decoding. With RIAA done in the digital realm, and gain adjustable by 1 db increments, and a good range of options for cartridge loading, I finally got the Puritas to sound musically convincing. This led me to take a flyer on the M2Tech Crosby power amplifiers as a temporary fix to my Definition 4 power problem so I’d have something good to listen to while I took my time trying alternate tube amps. I bought two Crosby to run as bridged monoblocks. These are Class D amps using ICE modules with an M2Tech proprietary input section for better sound than most ICE-based amps. Into 8 ohms, one Crosby outputs 60w/channel. Run as a bridged monoblock, Crosby outputs 180w. Into the Def4’s 6-ohm load, Crosby should be good for ~270w each.

With a pair of Crosby amps and the Luxman TVC in the Def4 system, I had a quiet system again. In fact, dead-quiet. Quieter than ever! Without the RFI-induced gurgling, sputtering, spitting and whirring coming through my RF-antenna SET amps, I could listen in peace and embark on a tube amp odyssey as I had time.

Chalk up the M2Tech Crosby Class D amp as wonderfully-Zu compatible. This is the best Class D sound I’ve heard, period. Maybe only rivalled by the 47 Labs Gaincard, which has much less power. I prefer these to most bi-polar solid-state amps, only a few of which have somewhat better musicality, usually at less output. Such amps are generally associated with Nelson Pass. So if you are tube phobic or have any other reason to need or prefer a smooth, bursty, dynamic, musically-convincing, high-definition, solid state amplifier for Zu, consider the relatively affordable M2Tech Crosby.

Back to tube amps. At the same time I was considering tube amp alternatives to my long-time Audion SET amplifiers, I also have to note that I regularly am contacted for advice on affordable tube amps for Zu speakers as well. Now, I have a pair of Quad II Jubilee monoblocks, which were the last edition of Quad II amps produced in the UK. They sound quite good on any Zu speaker, so when I got Druid 6 and found them not ideal for SET in the bass region, it was easy to slip them in the Druid 6 system, or to move them over to Definition 4 when I wanted some tube-amplified music. The Quad II pair are always a great backup amp for me, and the closest-to-SET seamlessness I’ve heard in a push-pull amplifier, simple circuit and all that.

But Quad II is built for KT66, with 6L6 an alternative. I had mine pretty tweaked through tube selection: Tubestore Preferred Series 274B rectifier, Mullard mesh plate EF86, Sylvania NOS 6L6 long ago sourced from Mesa Boogie in the form of their legendary STR-415 power pentode. As an alternative I also used cryo’d Tube Doctor KT66. The Quad II sound seriously good but still only 12-15w and the pair could be more elastic. I would love them to have more of the Plasticman kaPow! reach & slam that my Audion Black Shadow 845 SET amps muster.

My system racks are setup for monoblocks, so all stereo amps are ruled out. Meanwhile, as I started my tube amps odyssey, more requests for affordable amp recommendations trickled into my email. Which is why I want to let you know about Ling Xiao Nan and his hand-built, affordable, amplifiers. Xiao Nan designs and builds his amps in the Guangzhou region of China. He is self-taught on the subject of vacuum tubes and amplification, and been building amps for over a decade. He’s also a guitar player, but he’s proud to point out that he is a “full-time amp builder.” You can find Xiao Nan offering amplifiers on eBay under his Tube Fantasy brand, but that’s only a fraction of what’s possible with him.

Online, Xiao Nan generally sells clones of vintage circuits, particularly pre-war and post-war German cinema amplifiers, the Quad II and the Williamson designs. The circuits are faithful with only a few component value deviations for modern speakers, particularly in cathode capacitors. When he is cloning an amp circuit, he builds his transformers to the original electrical spec but uses his own preferred winding techniques. Xiao Nan machine-winds his transformers on his least expensive amps, and hand-winds them in everything else not-very-much-more expensive. He keeps cost down first by building in China, but also by keeping to a Quad II-sized chassis for most of what he offers, in black or natural aluminum, or a similarly-proportioned upsize for designs with larger transformers. Ling Xiao Nan builds monoblocks.

I first learned about Tube Fantasy when I was out on my patio on a cold-for-Los-Angeles night in December with a glass of Corbin Cash Rye, Tidal on my iPhone through my i.am+ Buttons, idly flipping through tube amps on eBay. A listing for a Quad II clone pair at a ridiculously low price stopped me cold, especially since I had gotten a request to recommend a cheap tube amp for Zu earlier that day. They were so inexpensive I decided to do the Zu community a public service to evaluate them. If someone was selling a pair of Quad II clones for a few hundred bucks, I had to hear them, for better or worse.

I’m going to comment on those Quad II clones shortly, but in email correspondence about the sale and in asking some questions I had about the amps, I quickly got to know Xiao Nan beyond the usual eBay transaction, and in doing so I learned about other amps he makes. Perfect. I now had a custom amp builder to let me affordably tour circuits and tube types to bracket myself and zero in on where to finally land in replacing my Audion SET amplifiers. This led to me acquiring the following monoblock pairs in the span of 3-1/2 months: Quad II clone, Williamson push-pull, 2a3 triode push-pull, Klangfilm KLV-204 clone (F2a beam power tetrode-based) single-ended tetrode, LS50/GU50 single-ended pentode, 300B-or-2a3 push-pull. And I am considering getting a pair of Telefunken V69 clones.

At some point, some of these amp pairs will be sold, but the luxury of auditioning a range of circuits and tube types on a relatively modest cash outlay is considerable. And you know what? Xiao Nan might make you a pair of stepping-stone amps, or he might make you the last pair you need. He certainly can. Xiao Nan tends toward simpler circuits, high quality parts, emphasis on transformers and pentode/tetrode designs, though he builds triode push-pull anytime you want. He is quick to build, his soldering is clean and careful. Nothing is needlessly bulked up for faux masculine appeal.

Ling Xiao Nan and Tube Fantasy are in many respects the Sean Casey and Zu Audio of tube amps. Both represent strong points of view, are music-driven and constantly tinkering for better sound, and delivered value is high.

Here’s a sampling of Ling Xiao Nan / Tube Fantasy prices, monoblock pairs, shipped to USA (DHL), amps only, no tubes:

QUAD II Clone (18w), $499

Williamson Clone (25w wired triode / 45w wired pentode), $688

2A3 push pull triode (13w), $688

Klangfilm KLV204 Clone, single-ended-tetrode (10w), $688

LS50/GU50 Direct Coupled, Single-ended Pentode (13w), $1000

In cases where Xiao Nan supplies any of the tubes, he specifies so. Otherwise, you source tubes and stuff the amps when you get them. Every amp Xiao Nan builds gets burned in and listened to for five hours before shipping. All my amps have arrived trouble-free electrically. One had stripped transformer cover threads due to customs overtightening during disassembly-reassembly under inspection, and they also damaged a faceplate. Xiao Nan immediately ordered replacements for me.

Xiao Nan does not pot his transformers both for maintainability and because potting compromises high frequency performance. You may hear a trace more mechanical hum up close than from, say, a true Quad II. But music-on, this is irrelevant. The amps are quiet electrically. Common to all of Xiao Nan’s amplifiers is exceptional transparency, very high definition, fast transient speed, exceptional soundstaging and depth. For whatever reason, with any of his amplifiers, I am getting more spatial depth in the soundstage than with any amplifiers I’ve had connected to my Zu systems, regardless of price, and that includes the many amps visitors have brought to audition on Zu speakers. That fast, transparent, dynamic, tuneful sound I valued particularly in Audion SET is here. Further, in the push-pull amps, crossover notch grunge is vanishingly low. Some notes on specific amps:

Quad II Clone: Fast, open, dynamic sound. Because Xiao Nan winds the output transformer differently than Quad did, this also changes the feedback behavior somewhat. The result is greater audible difference between KT66, 6L6 and EL34 in the clone compared to genuine Quad II. With EL34, the clone is relentlessly revealing, hi-def and blindingly fast, which is great for excellent recordings/masters/pressings, but not forgiving of flawed wax or digitalis-digital. With KT66 the clone is closest to the original Quad II sound, which was not strictly romanticized but does possess some vintage warmth. The perfect balance is found with the NOS 6L6. With this power tube, the clone is smooth, defined, dynamic; delivering Druid-like tone density and lots of dynamic punch for its power. The amp takes some time to burn in and bloom. About 120 hours will do it. It will sound thin in the bass region until then, but progressively less so.

Williamson (Triode-Mode): Dynamically stronger than the Quad II or its clone. Refined, smooth, high definition, solid deep bass on Definition 4 or Druid 6. Same basic sonic difference between EL34, 6L6, KT66, as in the Quad Clone. Again, I settled on NOS 6L6. In the Williamson, the Quad II and QII Clone, my preferred rectifier is the Tubestore Preferred Series 274B. It gets the most tone, space, definition and dynamic punch from all three amplifiers. This is an exceptional tube amp, that lives up to the Williamson amp legend from shortly after WWII. In fact, it’s the best Williamson implementation I’ve heard and easily walks over a Marantz 8B.

2a3 Push-Pull: Inexplicably bursty and elastic for its 13 watts. And my pair have only 8 ohms windings. On 16-ohm Druid 6 they sound dynamically huge. Excellent bass discipline compared to any SET amp, while retaining all the triode magic, though still quite objective. No slow, lazy, old-school triode amp sluggishness. This amp, Xiao Nan’s custom circuit at my request, gives up nothing in definition, speed and punch to the tetrode and pentodes in his other push-pull amps. The rectifier you want is NOS 5v4.

Klangfilm KLV-204: This is an early post-war German cinema and studio amp. It was used as a monitoring amp in recording studios (so high definition required) and as a reserve amp for cinemas using the larger KLV-402 & 502 amplifiers. It lives up to its high definition requirements. I have known about the F2a tetrode tube for decades and never managed to get my hands on any of the Klangfilm or Telefunken amps that used it. I was excited to get a chance to hear the Shindo Cortese, which promptly disappointed me like most other Shindo amps I’ve heard. But this KLV-204 clone is exciting to listen to! Only 10 watts (I had my pair wound for 16 ohms to use with Druids), it sounds dynamic beyond its means. No detail gets past it. Midrange is tone-dense like a great triode but burstier. Among the quickest, most agile amps I’ve heard at any price. Like Druid 6, this KlangClone is vivid, tonally, dynamically, and spatially. With Druid 6 it is musically amazing on an excellent recording, but the x-ray truth of the combination can render a poor recording too distracting to listen to. Badly recorded or mastered bass, particularly, shunts the illusion of musicality. This is one of my favorite amps ever heard, but it is a specialist and Xiao Nan builds it affordably enough to use it selectively. The F2a tube, btw, is a German Post power tetrode built for 10,000 hours of life. They often go longer. As NOS and vintage tubes go, they aren’t cheap, but they aren’t ridiculously expensive, either, given how long they last.

LS50/GU50 Single-ended Pentode: More like the sound of the Klangfilm KLV-204 than any of the others. Crisp, clear, fast and transparent. Also dynamic beyond what’s expected from its mere 13 watts output. Clean top-to-bottom. A little bass shy compared to the push-pull amps but there’s a remedy. In most tube amps, particularly those with cathode bypass caps, there is a trade-off between ultimate bass performance, and ultimate top end. When faced with this, Xiao Nan prioritizes top end linearity over bass linearity. But making adjustments to the chosen values for cathode bypass caps can land you in your zone. You can do this after getting the amps or if you communicate to Xiao Nan your general preferences, he can reliably adjust for the right value. You just have to communicate effectively. Overall, Xiao Nan’s LS50/GU50 single-ended pentode monoblocks are sonically in the same realm as the F2a-based Klangfilm KLV-204 clones, but not quite so MRI in unsparing revelation. The LS50 has more latitude in acceptable recording quality than the KlangClone. Given the Definition 4 sub-bass extension, Xiao Nan suggest snipping the cathode bypass cap on the E180F driver tube to bring bass performance into better balance with the speaker. But I have to say before doing that, the intrinsic bass from this amp on Def4 maybe a little light, but it is very well presented in terms of character, definition and attack.

300B/2a3 Push-Pull: I commissioned Xiao Nan to build for me a pair of monoblocks that can use either 300B or 2a3 output tubes, in push-pull configuration. I have a quad of KR 300B Balloon tubes held back from my recent sale of my Audion Golden Dream 300B monoblock amps, which I wanted to use in push-pull configuration with either my Druid 6 or Definition 4 system to make continuing use of those magnificent tubes. Xiao Nan indulged me with a custom design. Those amps are arriving in the next day or two. Comments pending if anyone is interested.

Telefunken V69 Clone: Probably last in my series of bracketing amps from Xiao Nan will be a pair of clones of the legendary Telefunken V69 Cinema amp. This is a full Class A, push-pull, tetrode amplifier using a pair of the F2a tetrode tubes in each monoblock. Like the Klangfilm KLV-204, input and driver tubes are the equally-revered EF-12 small-signal pentode. Class A output is 25 watts per monoblock. I will decide in the next day or two whether I will order these, put them in the mix and then vet the whole shebang for what stays and what goes.

You can find Ling Xiao Nan on eBay as seller “fatkit83-8.” If you private message me, I can offer his direct contact information for amp inquiries.

Of course the genuine Quad II remains a highly-viable tube amp for any Zu speaker. It is coherent, musical and also delivers more dynamic shove than its diminutive specifications might lead you to expect. Ling Xiao Nan gives you alternatives, and plenty of them, for less cash. And similar to like-minded Asian originators like mhdt (DACs), Jasmine Audio (phono preamps and amplifiers), and Melody (preamps and amps), all of Ling Xiao Nan’s implementations are informed by music listening and in-depth inquisitiveness seeking more fidelity than he previously delivered at any given time. Just like Sean Casey.

Ask questions if you have them.



Showing 42 responses by 213cobra

So does mine.

The answer to this depends heavily on your PoV about what constitutes sonic fidelity and natural sound. I don't consider The B&W 800 Series listenable speakers for any music content compared to Zu but especially for symphonic orchestra. These are 88db - 90 db efficient multi-way loudspeakers. They force you into a restricted range of either relatively high-power solid state amps, or ganged tetrode or pentode push-pull tube amps. Tone-bleached, dynamically-clumsy engines for sound. Until you live with 101db/w/m Zu, crossoverless, you won't grasp how much of a burden the B&W and Revel approach imposes on amplifiers and compromises symphonic acuity.

If you think the B&W crossover-mangled sound is right, you won't cotton to Zu unless you use Zu's full 60 days eval period as a cold-turkey divorce from conventional "hifi" sound gaining you phase linear sonics. Otherwise stop reading now. Keep up? It's the other way around. Can the B&W and Revel keep up with Druid 6? Not really. They lack the agility, dynamic linearity and dynamic burstiness that preserves the life of a full orchestra performance. Listen to a B&W or Revel *after* a Zu, and you will be bothered by the crossover choke points and generally non-linear dynamics. But that's what most hifi consumers have been conditioned to hear as "hifi" in the modern, linearity-at-expense-of-everything-else era.

If full scale symphonic music is your raison d'etre for owning a hifi, in Zu, the Definition and Omen Def (at two distinctly dissimilar price points) are your first bets. The dual FRD architecture limits floor and ceiling effects, and spreads the horizontal scale. Prior Druids were biased to intimate or directly-channeled music, intentional or not. But Druid 6 broke this open so it does a good job of scaling for classical in most domestic rooms, in all dimensions.

From a resolution standpoint, Druid 6 does quite well. I think most speakers like B&W with their over-engineered crossovers and diamond tweeter, and Revel ,are actually *over-resolved* relative to what you will hear real-time in an audience-seat performance hall.  I have had dozens of correspondences with Zu owners who thought it isn't a "classical speaker," return after some coaching to say, "no, it's actually quite fabulous." Generally, when Zu owners claim compromised orchestral resolution, serious spelunking reveals the problem is other limitations in their system that Zu is actually resolving. Most of the time, mainstream hifi listeners are hearing in-your-face resolution hosing and event isolation you'd never experience hearing a performance live. It's ear-porn that has nothing to do with real music. I'll go so far as to say that Zu Definition 4 and Druid 6 have me listening to more recorded symphonic music than ever over the past 10 years. Before Zu, I'd just wait until I could attend symphonic to listen to orchestral music.

As I kid I regularly attended Philadelphia Orchestra concerts with Eugene Ormandy conducting. In college it was the Pittsburgh Symphony under Wm Steinberg. As I started my career in Boston, it was a subscription to the BSO under Seiji Ozawa for 10 years, and then the last 32 years in Los Angeles. I know vividly how an orchestra sounds and should sounc. For most of my 50+ years of hifi life I eschewed symphonic music via hifi because it wasn't convincing compared to my rich, live experiences. I revived my symphonic music listening via domestic hifi only after I found Zu, and I can do it on 25w amps.


A few further random notes:

1/ Bob Hovland offers an isolation transformer that improves the sound of amps I've tried with it. The design principle is that if an amp is fed power from a balanced power isolation transformer that is designed to operate close to its saturation point, the connected amp will sound, in Bob's words, "more relaxed." I auditioned a pair of Bob's proprietary isolators, found this to be true, and bought them. Each one is a simple black, crinkle-finish box, about 6.75"d x 5"w x 4.25"h. Using Bob's isolation xformers improves dynamic elasticity and removes an anxiety factor that you can put your finger on when you first remove Bob's iron after an initial extended listen. The effect improves further with burn-in. It's not dramatic, but it's musically beneficial. This is relevant to Zu owners, since most use relatively modest power amplifiers. The isolation xformers are rated for 2.5A at 120VAC, safely handling peak demands up to 4A. They are favorable to every tube amp I've tried them with, and with my M2Tech Class D monoblocks as well.

2/ Ling Xiao Nan can also make an upgraded Quad II Clone, using a higher-spec, larger output transformer. This also requires his larger chassis, so cost is higher than the standard true clone. I haven't heard it but he built a pair on a hunch, and reports that the uprated QII Clone now sounds better than the Williamson, and compared to the standard clone, delivers deeper, better bass with a more relaxed top end.

3/ I recently learned something new about the Quad II, explaining its particular synergy with Zu Druid. The Quad II has a multi-tap OPT but the chassis only has room for a pair of binding posts. Most Quad II have their outputs wired to the OPT 8 ohms tap. So why does the amp work so well driving the 16 ohms Druid? The curiosity of a gentleman in Australia answers the question. From the 8 ohm tap, measured at 1 kHz and driving 8 ohms, Quad II peaks at ~20.5w, THD < 1.5%. Peak power is actually produced at 10.5 ohms, reaching just shy of 22w. The 8 ohms tap driving 8 ohms makes up to 7 watts in Class A. However, if the 8 ohms tap is driving 16 ohms, peak power declines only slightly to ~18.5w, but ~14.5w are available Class A. If you use Quad II on Zu Druids, any version, don't have your output terminals wired to the OPT 16 ohms tap. If you did that so the 16 ohms tap drives 16 ohms, power would peak at ~21w but only ~7.5w would be available Class A.

You can get similar benefits for 6 ohms Definitions. There is an undocumented, "illegal" 4 ohms tap on the Quad II OPT. If you are driving Definitions with Quad II, make the change. The 4 ohms tap driving 4 ohms yields peak power just over 20w, but only 8w are available Class A. However, the 4 ohms tap driving 6 ohms causes only a modest peak power decline to 18w, but up to 12w are available Class A. If the 8 ohms tap drives 6 ohms, peak power is the same ~18w, but only ~5.5w are available Class A.

The author of the study does not recommend using the Quad II 16 ohm taps for any load less than 32 ohms, and there aren't many such speakers. But I have to point out that the QII 16 ohms tap would be sensational for double LS3/5a (15 ohms version) wired in series for 30 ohms, ala the mid-70s Absolute Sound Double Advent System. I had a Double LS3/5a system, powered by Julius Futterman OTL amps that peaked at 32 ohms, 40 years ago.

Here's the link on Quad II details, with lots more than I described above:


Hi Marc,

Well, at least you have it now!

SET well done is fine down to ~34Hz. It works in Definition deeper because the driver control is handled by the solid state amp. Druid 6 challenges the zero NFB SET bottom end discipline of SET directly controlling a driver. I didn't want to reach this conclusion, but the truth outs. The upside is that after all these years, it forces a new amplifier adventure in discovery!

>>So if Druids VI truly break the 35 Hz barrier in room, they may be a better choice for me than Definitions VI, Experiences I or Dominances II.<<


I don't think a Definitions owner will want to give them up for Druid 6. Especially after reading everything you've done to reach your current music equilibrium. But are you saying you essentially have the Def4 sub turned off? I can't explain your sub amp noise. They are absolutely silent in my Def4s. 

>>Check out the XTAC by Audiomachina and you will see most if not all of your concerns addressed properly and without compromise.<<

[Laughing hysterically...] No, that's exactly wrong what I don't want.

>>I have checked and "fatkit83-8" is NOT a seller on EBay. And "Tube Fantasy" produces nothing of audio worth on EBay.<<

Funny, he's right there on my eBay app. He doesn't always list his brand name.

>>So you read the actual description of these speakers and the white paper?<<

Yes, I read the white paper. I agree with most of the diagnostic observations about what's wrong with speaker types to-date. Further, the author's time-domain focus, and his dislike of crossovers parallel views I've articulated for decades.

OK, I was a little flip citing my amusement. This is a new thread, hence it might attract some folks who haven't read anything else I've posted here in the past. If you had, you'd already know that I don't agree that ganged drivers and amps in a line-array implementation are best advancements against the problems outlined in the Doctor's diagnostic summary.

This approach just introduces a new irritant or distraction to replace older ones it solidly attempts to eliminate. It's also for most people impractical. But it's also an honest effort and I don't question the designer's sincerity. If XTAC makes sense to you -- and your aural mind when listening -- enjoy the system.


I agree your vast suspended, older, flexy floor presents a special challenge for bass energy, especially for a down-firing sub arrangement. I don't think sub-bass performance is assured to be better with Class A/B than well-implemented Class D, but it's possible.

I've found it is impossible to know with certainty whether *any* power supply precursor will solve a noise problem, hum or otherwise. You just have to take an educated guess and try something, fully prepared to be disappointed. But Hovland's isolation transformer works and they aren't monstrously expensive.


Bob builds to order and he doesn't have a web site to order from. Email Bob at roberthovland@earthlink.net.

roberthovland@earthlink.net is definitely Bob's email address. Try it again and not it's not a .com, but a .net. Ancient email provider here.

If you have further trouble, I'll have Bob email you.
I've had no opportunity to hear the Cube Nenuphar. I'm aware of it. By all accounts, compared to comparable Zu it lacks bass foundation, and it is only93db/w/m efficient, 8db less than Zu. So for a given amp the burst factor will be reduced. On the other hand the driver is reputed to be quick and agile. So, no basis for a fact-based response. But once fully acclimated to Zu, I'd be very reluctant to give up 8db of efficiency in two speakers vying for crossoverless supremacy.

>> I didn't write a treatise on a particular speaker claiming it to be the second coming discounting other designs in the process. I didnt start a discussion on the XTAC. See if you see some similarities between your thread and the recent Tekton threads. <<

OK, I see what's eating you. I discounted other designs. Well, I surely did. I've been discounting, for example, crossover-based speakers for eons. I have no idea what's going on in Tekton threads and if there are similarities between this thread and those, it's entirely coincidental.

You are certainly welcome to write a treatise on Audiomachina. Somehow you seem bothered I wrote something long about Zu. It's just a review on an audio forum. What could be less consequential to the world at large? Put in the same time and effort I did with Druid 6 and lay out for us what you hear from Audiomachina. That's what the forum is for.

I don't make any claim to being neutral about speaker designs. You won't find me putting any real time and effort into reviewing crossover-based speakers because they are all seriously compromised and it's intrinsic, not just a matter of execution. I'm also on record long-term that the hifi industry broadly went off track a few decades ago, leaving very little of real value worth buying in the marketplace. So no one should be surprised by this Druid 6 commentary. If Audiomachina is a convincing speaker to you, make your case if you want, but otherwise certainly enjoy them!


>> Well these are not typical array speakers and the special amplification is critical. By using drivers and different size you open up a whole series of problems which are avoided by using multiple identical drivers. What I find so interesting are the speakers you tout as having solved the most problems. Now I havent heard some of the newer Zu speakers but the old ones were rife with problems some of which appear to have been addressed in the new lines. <<

I fully understand what they are. I also grok that the "special amplification" is critical to the design, if one believes it's critical to own that design in the first place. It's still an array speaker. I don't agree that ganged drivers and ganged amps are desirable. And in any case, the corners implementation is a serious limitation. And as asked elsewhere, why is this speaker relevant to a Druid 6 thread?

Yes, drivers of different sizes introduce or leave unsolved some problems. Druid 6 has one driver covering most of the musically-relevant frequency range, with a supertweeter for harmonic completeness. Simple, really. Is it perfect? Since it's a loudspeaker, no. It's just what I say it is.

Were 2004 Druids "rife with problems?" Perhaps. All speakers have been "rife with problems" compared to an ideal. Zu was just less-rife with problems than most of what else the market offered then. There are also differences between theory and practice. If you think another speaker is better, you should buy it. Any comments I made about Zu in 2004 and 2005 were made in that temporal context. Any comments made in 2010, 11, 12, 13, 14, same. Now it's 2019. A 2019 Zu Druid 6 has come a long way since a 2004 Druid Mk "2.5". It is theoretically possible to design a better speaker. In practical terms where are they? Very, very scarce, are these theoretically better speakers.

What I can say about the Audiomachina speaker is that a ganged array introduces its own problems, which I don't want in the mix. And in any case the corners implementation scheme is unusable to me even if I wanted to accept the results of a line array. The speaker might make someone else perfectly happy! Perhaps you, jsautter. As I wrote, Druid 6 isn't for everyone.

>> If Phil likes SETs on the Zus he really should hear your M-60s powering these speakers. <<

I have. Quite a good combination.
>> We used 300B amps by Audio Note and Mastersound. <<

With those amps representing SET, I concur with your assessment.

>> The PP amp was a VAC phi 200. <<

Oy. That's trouble.

I don't know who "we" are. but unless you were comparing M-60s to Audion Golden Dream, Black Shadow or Golden Night specifically representing SET, I don't really have an opinion. There are a limited number of good sounding SET alternatives. Audion really stand alone in SET, which I will go so far as to say that the Audion SET amps are much more like Atmasphere OTL in speed, neutrality, transparency and soundstaging, than they are to other SET amps. Similarly, there are great push-pull tube amps but many more are mediocre to just OK. So without knowing exactly what amps represented push-pull, it's hard to know what you heard. I like the M-60 on a variety of listenable speakers including any Zu Druid. For a long time I had Futterman monoblocks made by Julius himself -- I picked them up from the living, breathing maestro in 1975. They were my main amplifiers for close to 15 years. But I digress...

It is not for reasons of sound quality that M-60s are not in my hifi systems. But overall, if you heard push-pull tube amps as vague, and SET as homogenizing, then question first the p-p and SET amps you chose to audition. I certainly could select amps that commit those sins, but I wouldn't own them.

I have in the past made the observation that Zu is right and that makes most other speakers wrong prima facie, so I accept the postulate wrt Audiomachina. I don't know what you think "traditional arrays" sound like, as every array design I've heard over several decades sounds significantly different from one another. But an array of ganged drivers and amps is still an array, and still has the challenge of acting in true unity. Nevertheless, all of this is moot to me as the corner design is unimplementable in any dwelling I've ever lived in or expect to. And I think a lot of people are in the same boat.



I had a chance to listen to Nat 211 amps a few times in the past, even as far back as when I had Def2, and even earlier NAT amps using the VT4-C triode, well before I owned anything Zu. Certainly good sounding amps in the grand scheme of amplification choices; I just was not convinced of them relative to Audion Golden Dream and Black Shadow. I also didn't spend a lot of time with them because there were common QC complaints at the time. The range of choices in power tubes was also narrower for 211 than 845 and 300B. Overall, they didn't move me and did not sustain my attention. NAT have revamped their line since then and I haven't heard the current production. The Magma New using the GM100 certainly *looks* fantastic, and I'd be optimistic about its SQ if I were anticipating an audition.

No question cabinet talk was a noticeable flaw in early Zu, until the Definition 2 and steps taken with the Druid v4-08 upgrades. You got around that by limiting SPLs or just putting up with it when you wanted to hammer your skull. It wasn't that the cabinets were too thin, but that they weren't stiff enough for the early MDF construction.

Def2 and the briefly-made Presence went to birch ply and more bracing, and if anything, the cabinets were overdamped. Cabinet talk was gone but some of the Def1 projection was truncated. In Def4, the combination of mixed materials and more sophisticated internals laid a new foundation for how Zu thought about energy management. Druid 5 saw equal advancements to the drivers and the cabinet. Druid 6 has taken the mixed-materials laminates and cabinet internals to a new high, augmented by integrated energy management techniques.

Whereas a lot of designers would have just gone down the path of adding mass through thicker sidewalls, Sean put the time into developing a more sophisticated approach to make the cabinet much more inert and to channel spurious energy to ground while maintaining the external dimensions of the Druid form factor, while *also* keeping to the internal working volume needed for full Griewe function. Thus, Druid 6 looks like the original but it has evolved a sonic light year since inception.

In a few weeks I will complete my survey of amp circuits with Zu Druid 6 (and Definition 4). It will include evaluations of:

845 SET
300B Push-Pull
Quad II
Quad II Clone with transformer improvements
2a3 push-pull
Klangfilm KLV204 (F2 single-ended tetrode)
Telefunken V69 (F2 Push-pull)

There is certainly latitude in the matter of SET bass on Druid 6. I'll say that even with Druid 4-08, the relative lack of discipline in most SET bass was easily discernible, but it was a small enough error to be OK,; euphonic even. In Druid 5, it was a bit more noticeable still, but the Druid 5 FRD was quicker, and the floor-plinth-gap was much less fussy than with original Druid. WIth either 845 SET or 300B PSET, the lower bass limit of Druid 5 left bass performance with SET on balance, in equilibrium.

Druid 6 bass extension provides no cover. There's a guy on What's Best Forum that wants to fight me over this, claiming that I just need a better SET amp that isn't saturating the OPT core. But he's missing the point. Not only can I hear some compromises in even slightly-rising harmonic bass-region distortion in the best SET amps, an equal problem is the very low damping factor in SET topology. You can use very good SET amps for deep bass performance with Definition because the powered subwoofer is not not controlled by the SET amp. The bass character is derived from the SET power amp output signal, but the subwoofer is dynamically controlled by the solid-state Class D sub-bass power amp.

In Druid 6 all driver control not acoustically managed by the Griewe scheme or by the driver itself is left to the amplifier / FRD interface. And for this, SET is in my view suboptimal for Druid 6, whereas it is quite good with Druid 5. Now, if your tolerance for, or you have a preference for, euphonically rich bass, no one can say you are prohibited from enjoying it. And you may feel that the rest of SET benefits are worth accepting the deep bass compromise revealed with Druid 6. But I am noting for myself. SET bass is too distracting to be authentic and I cannot find a way to make it right. What does work very well is triode push-pull (I have had extensive hours with both 2a3 and 300B push-pull) and single-ended pentode/tetrode amplification. Does triode push-pull or SEP duplicate everything exceptional about SET? Not quite. But SET doesn't duplicate everything exceptional about good SEP either. I have had 20 years of continuous SET amplification in my systems, along with a couple of SEP amp in rotation during that time. So, it's not a matter of commitment to SET. It's a matter of commitment to objective, authentic sound. I will land on something not SET for Druid 6, and for different reasons (my solar installation RFI) on Definition 4 too. I'm not having any real difficulty finding successors.

If you read the amps survey I publish here later, the whole matter should be clearer.

Not sure about getting to RMAF this year. That show has an uncanny habit of overlapping professional obligations that, of necessity, eclipse it on my calendar. But maybe.

So far, so good. With the caveat that it's great specifically with the KR 300B Balloon Glass, same as was true in my Audion Golden Dream 300B PSET. Which isn't inexpensive. But the KR is the only 300B that gets bass right and everything else is objective and tone-dense; nothing sloppy anywhere in the frequency range. The Sophia carbon plate is pretty good. The Takatsuki is thoroughly disappointing; dynamically dead, old school rounded sound. Very well-made; just not musically credible by comparison, unless you like that over-smoothed sound.

I have no love for the Electro Harmonix 300B, but the EH 2a3 Gold Grid is quite good, especially for its moderate cost. The KR 2a3 is as good as their 300B, but the EH is an excellent 2a3 step-down in cost that gives up disproportionately much less in SQ relative to the KR equivalent. There is no equivalent value step-down in 300B, IMO. Shuguang also makes a large-glass 2a3 that is more dynamic and boisterous than the EH 2a3 Gold Grid. I give the EH an edge in refinement; the Shuguang gets the nod on energy and projection in 2a3.

I have had a series of amps made to explore circuits as alternatives to my longtime Audion SET amps. The builder is the same, the circuits are a mix of vintage designs cloned, and the builder's originated circuits, with some of my own specifications added. One thing I have to note off the bat is that I am getting more spatial depth from Xiao Nan's amps than *any* I've had through my home, ever. I haven't yet pinpointed why. I've always run monoblocks. But his amps (common element is his transformer winding technique) are either better preserving spatial information than any other amps I've heard on my systems (and when you add up all the amps people have brought over the years which which to listen to Zu, it's quite a range) or he has managed to add a spectacularly effective and musically-convincing distortion in precise measure to whatever he builds, irrespective of circuit. I'll say it's the former.

Right now, the custom 300B / 2a3 dual mode p-p triode pair are my favorites, running a quad of KR 300B balloon glass. I am using those on Definition 4, 20w with the 300B; 15w with 2a3. On Druid 6, I tip back and forth between the F2a SE-Tetrode Klangfilm KLV204 Clone, and the 2a3 push-pull (different from the dual mode amps). But next week I have three (and final) heavyweight contenders arriving: LS50 / GU50 Parallel Single Ended Pentode, Telefunken V69 Clone (F2a p-p for 25w full Class A), and EL-156 Single Ended Pentode. So no final assessments quite yet.

As for the practical matters: both triode push-pull and single-ended pentode/tetrode are immune to my solar RFI environment, for which SET amps have proven perfect antennas. And both push-pull triode and single-ended pentode/tetrode solve the bass quality / discipline problem otherwise heard with SET on Druid 6's extended bass response. More coming.

I have a semi-dedicated line for my main, Definitions 4 system. There are only a few other low-use sockets on the circuit. I have two Tesla Powerwalls supplementing my solar, and they are set up to power everything but HVAC for backup. To get the energy consortium subsidies on the Powerwall(s) you have somewhat narrowed implementation options for the first two years. They limit how much you can reserve for backup. They want to maximize the batteries' contribution to avoidance of domestic peak load consumption from the grid. And because the batteries' energy is returned through an inverter to your AC line, I haven't found a major sonic advantage in hifi. Maybe it pulls the quietest, best-sounding, wee-hours power earlier into the evening but it's not big, like when I have run audio gear off ganged motorcycle batteries in my past. Basically, if AC is coming out of the wall, it's coming via something grungy and noisy.

I have my power amps on dedicated Bob Hovland balanced power isolation transformers. They make more difference than powering AC from Tesla Powerwall, or not.

My original intent was to have Xiao Nan build several amp circuits on affordable economics to land on a direction that I'd then find established market equivalents for. Now I am not so sure I'll need anything more than what Xiao Nan can build. The two matched pairs of KR300B cost more than the tubeless amps. And that's the thing: a lot of people would feel better about paying four, six, eight, ten thousand dollar for amps, and then balk at buying $2400 worth of KR power tubes + NOS rectifier, input and driver valves. But most of those amps, with stock Shuguang, JJ, TJ or Sophia tubes will not sound as true as Xiao Nan's amps with crème de la crème glass. And the KR 300B and 2a3 are quite long-lasting, too.

Well, let's see when I next get to the UK. -Phil
I'm happy it's been helpful to you and others. More coming. -Phil
Which Whammerdyne? Would you spend the cash for the Parallel Single Ended model? I'm guessing not.

I haven't heard the Whammerdyne. And I have only an academic interest in it because a 2a3 SET amp just doesn't have enough shove, even for 101db/w/m Zu. They quote 4.6w of "peak power." Whatever that is. Remember those distant days of the RMS standard? That 4.6w of "peak power" is probably more like 1.5w of RMS power. You may not have clipped your Firstwatt SIT2, but you'll clip that Whammerdyne. Even a single piano note can drive exceedingly-fleeting transient clipping in more powerful amps, which can be subtly degrading. Plus the amp is built with 4/8 ohms terminals. Are you using with Druid? If so expect less at 16 ohms.

These amps are touted as the "finest 2a3 amps on earth." Which is a mindless claim, because who's heard all of them? No one. There are *many* good things about Whammerdyne's design principles and execution. Build quality is beyond reproach. But the power level is impractically meager unless you just don't care about dynamic realism. Maybe you don't.

Also note that the Whammerdyne amps are direct coupled. In principle that's a good thing, ensuring it sounds fast, transparent, clear. In practice, it can make a large percentage of recordings you actually want to live with and listen to somewhere between less listenable to unlistenable. I have a couple of d-c amps in my mix. I use them selectively.

If you are really only listening at 50-60 db, maybe you'll be happy with a 2a3 amp. I can't really say. Given the noise floor of even a reasonably quiet domestic environment, you are listening to a very limited dynamic range at that level. I don't recommend 2a3 (nor 45) SET for practical hifi. You don't need a lot of power for Zu, but 2a3 Push-Pull or PSET is preferable for that tube for all-purpose amplification. If you have multiple amps which you use selectively, then sure. There will be times when a 1.5w - 2w SET seems just right. Not enough times for me, though. If it works for you, Whammerdyne should be worth an audition.

Some catchup:

Our brainless administration's dumb trade war with China has slowed shipping of my last couple of custom amps. I expected them earlier this month but now it will be sometime in June. Shortly after I get them I will complete my amps survey. It's coming.

Correction: Audion Black Shadow monoblocks have been various rated for 24w and currently 25w, never 35w.

The Zu Submission is an excellent subwoofer but I only occasionally recommend separate subs, and would not generally use them in a "medium size room" with Druid 6, over going to Definition 4 or its coming successor.

Submission over-matches the acoustic scale of Druid, and most rooms have enough problems supporting deep bass as it is. Plus, the clutter! And the complications to maintaining coherence. The big advantage of Definition is having everything in a roughly one-square-foot footprint with bass coherence built in and just a pair of towers for stereo. Further, a pair of Druid 6 + a pair of Submissions becomes a $20,500 expenditure in basic finish. That's $3600 more than a pair of Definitions in basic finish, and the Druid + Submission still won't achieve the spatial and dynamic scale the Definitions will. Nor will Submissions make Druid 6 more intimate. Adding a pair of Submissions to Druid 6 pollutes what's most pure about Druid yet fails to achieve Definition's scale and balance.

I think Druid 6 + Submission is an interesting exercise, but ultimately a hifi curio someone might do just because they can. The configuration doesn't make sense to me. You would have four towers of clutter to get less spatial scale above the Submission's range, than a pair of Definitions. Given the economics, I think Druids -- any version -- should be enjoyed sans subwoofers, therefore at their most orthosonic. Definitions are the better way to get 16 Hz bass underpinning domestically, for the scant percentage of your recorded music that has it. Now if one has a love for complicating what was simple, blurring what was focussed, exaggerating what was objective, and / or has an unusually-accommodating room, I suppose go for it. But if you have a really large room, you'd go to Definitions in Zu's line anyway. Better to add true supertweeters to Druids, or buy better amplification.

No doubt that Druids + Submissions will make the initial impression of being altogether badass. Living with that over time and a full spectrum of music can be another matter. But it depends what drives your perception of convincing musicality. Or maybe that doesn't even matter. Some people simply go for an emotional response irrespective of whether what's inciting it is musically convincing. Put another way, I am not advising that Druid 6 + stereo subs is better than a pair of Definitions, but you can certainly find someone who will!


My amp observations weren't limited to less expensive push-pull examples. I started with Audion Golden Dreams and Audion Black Shadows, a Luxman Anniversary 300B SET and a host of others. What led to the amp circuits exploration was that I came to the conclusion that SET, even high end, is not ideal for Druid 6, notwithstanding the excellent synergy between SET and all prior Druid models. Now, certainly there will be Druid 6 owners who like what SET sounds like on Druid 6. And I suppose that if someone asked me, "What's the best amp for euphonic bass emphasis on Druid 6?" my answer might be "try a good SET amp."

In single ended, I think SE-Tetrode or SE-Pentode are more successful *with this speaker.* As soon as my remaining amps can thread the twin needles of the (ill-considered) trade war and the Hong Kong protests, I'll have a survey view of LS50 SEP, LS50 PSEP, Klangfilm klv204 SEP, 300B p-p, 2 different 2a3 p-p implementations, EL156 SEP, Williamson p-p, Quad II, Quad II Clone. From that I'll bracket a destination for myself that could even involve none of the above.

The V69 clones are rumored to have made it out of Hong Kong yesterday but I haven't yet gotten DHL notice or tracking. Xiao Nan took my batch of amps to Hong Kong to ship just as the protests were getting started back in late April and they've been trapped there. He's shipping others' amps from the mainland since. If the v69 got out, that leaves a pair of custom LS-50 PSEP and an EL156 SEP still to pry loose from DHL in Hong Kong. Expecting the v69 sometime in the next 5 days.

My essential point is that I am listening to circuits now, not brands; deciding on final implementations as a result. It just happens that I found (stumbled upon) an amp builder who can build inexpensively at quality execution to let me try many circuit options. 40 years ago I would have built these variants myself, but I no longer have the time. So I have a partner to accelerate this investigation and can experiment with some circuits not common in North America, among others. Xiao Nan's amps, if supplied by Euro or US companies. would cost much more but his executions are pure. So I am prototyping alternatives where high end SET is not longer ideal.

It's a journey; not quite yet a destination.

Xiao Nan doesn't just wind his transformers. He builds the cores too. Materials are very inexpensive, even copper, where he lives, compared to the West. He uses premium parts but on the other hand he is not going for overkill where it's not material. He also sells most of his amps tubeless unless a customer wants him to supply, so that cost isn't in his standard pricing. And he's using a spectrum of basic commodity chasses for his various amps and preamps. He tends toward simpler designs, but compared to his triode p-p and the Klangfilm klv204 clone, the Williamson and the Telefunken v69 are not so simple. They cost more but are still low by US standards, keeping in mind he also has no middlemen margin in his pricing, and he is acutely aware that he has no pricing power intrinsic to his brand so he prices to make a living but still get people who are music-first to take a chance.

My comments on SET compatibility with Druid 6 bass are not inclusive of using Undertone with them. I actually don't think Druid 6 is best with subs. Not that there's any harm in it, but doing so somewhat degrades the orthosonic character of the speaker and using a pair with D6 costs as much as Definitions. That's an aside. More to the point, Undertone works with SET for the same reason SET works with Definition: The SET amp is not controlling the driver. That's handled by the built-in solid state subwoofer amp, which maintains an electrical and dynamic grip on the driver that the scant-damping factor SET amp cannot. If you are feeding the Undertone from the output of the main SET amplifiers, you are getting the tonal and transient character of the main amp's bass input to the solid state sub amp, but the actual driver motor control is a product of that directly-connected Class D amp. Obviously, your AS M60s work equally well with Undertone for this reason, even though they would outperform the SET amp on bass discipline if driving a deep bass-capable driver directly.

If your preamp has dual outputs, have you tried driving the Undertone via line-level inputs so you are getting only the preamp's + Undertone amp's character in the sub output? I wonder which you'd prefer?

Now, the question then is, what are you doing to limit the Druid 6's bass response to 50 Hz or so when you tap the SET main amp for the sub input? Nothing? Then you are getting the Druid 6's lowest bass characteristics layered into or onto the the Undertone's output. Unless you set up the Undertone to roll in at or slightly below the Druid 6 roll-off, all you are doing with the Undertone is extending bass response deeper than the Druid 6 will go alone. You'll still have the Druid 6 bass / SET problem between about 45 to 28 Hz. Now, this isn't a problem in Definition because in that speaker, the lower response of the Zu main drivers are limited by the sealed chamber implementation. Turn off a Def's sub and you will hear that the Zu FRD as implemented there will not match the lower extension of the Zu FRD in Druid 6 with its Greiwe loading. I suppose you could limit the lower extension of the Druid 6 by closing off the bottom cabinet outlet and adjust Undertone upward accordingly, and that might actually be the best way to use the two together, seamlessly. I have to think about that.

I generally agree that moving a tube amp from D5 > D6 may require a change of one or more tubes. I have a wide selection of 845s for my Audion Black Shadows but in that case, I did not find a change to be useful. The two most objective 845 tubes in my stash have the same value to both speakers. What I did do is revert the driver tube from the very assertive Bendix 6900 to Tung-Sol NOS 5687 and that put the amps and speakers in the zone. Except for that portion of the D6's lowest response that extends beyond D5's.

As I wrote earlier, I fully accept that some people may like and prefer the sound of a good SET amp's bass with Druid 6. But I'm not advising it when anyone asks what will give them the most natural sound, and am hence on a trek to trial alternative topologies. So far, single-ended tetrode/pentode and push-pull triode are leading.

BTW, there's a price to every choice. I love great & objective SET amps but they give up some discipline that's natural to tetrodes, pentodes and triode-push-pull. So wherever I end up, I am not likely to contend that any of these alternate topologies will replicate every favorable SET trait. But I expect to make the holistic presentation better, regardless what I lose. I'll also say that using supertweeters with Druids (5 or 6) makes a broader spectrum of amps more suitable with the speaker, including right down to the bottom of bass performance.


I'll talk with Sean tomorrow or over the weekend. It's a simple procedure. You send him your Def sub electronics module + some money, he returns them upgraded. I speak with him. More on Def6 coming.

Before you commit to Takatsuki 300B in your Golden Dreams, I encourage you to listen to the KR 300B globe glass. The standard tube is half the price of the Takatsuki and in my view twice as good. There's a newer premium KR 300B for the US market only that is still cheaper than the Tak but more than the std KR - I haven't heard it. I tried the Takatsuki. I found it smooth but totally lackluster compared the the KR, especially in view of the price. The KR bass is far more disciplined and defined. The amps have more slam than with the Takatsuki and more spatial information. Top end is more extended, too. I got the same comparative results in the Luxman Anniversary 300B (true 70s-style Luxman audio art). The Takatsuki sounded quite old school triode to me. The advantages were magnified by Druid 6 compared to Druid 5 and very much laid bare by Definition 4. Having already been using KR for almost 10 years, I was not impressed with the Takatsuki at all. But given the native sound of many Japanese triode amps, I understand its sound, which is very well regarded there. It is a materially and structurally well-made tube. But then, feel and examine a KR!

The supertweeters I have atop my Druids are a JohnBlue model since superseded. They have multiple roll-in frequencies and extend to 45kHz. I have them set up to roll in at the highest point, 17kHz. I am probably going to try a pair of Townshends on my Defs, which extend out to 90kHz or thereabouts, but I may wait until I get my Definition 6s. The point of the supertweeter is not to duplicate the Radian's work but to extend the speaker ultrasonically. For me it's a one way street -- once the improvement is heard, you can't unhear it. It's subtle at first, then the longer you live with it, the more obvious are the penalties of removing them.

Sounds like you did a good job integrating the Undertone with your D6s. There is no right answer about running the Undertone line-in vs. speaker-in. Yes, you can run a second set of speaker cables from the Golden Dreams to the Undertone, or if Undertones are near the Druids just run a short speaker cable from the Druid speaker posts to Undertone. It's clean if you are using the Speakon connector with Zu cable to get from amps to Druids. There are good reason to expect the preamp line out to Undertone line-in to be better, but not always, and a lot depends on your pre.

Good news today: My Telefunken V69 clones popped out of DHL Hong Kong, to arrive Monday. Now he has to get them to shove the LS50 PSEP and EL156 SEP out the door, and I can get writing.

The Druid 6 reworked and improved every component in the Druid design, so the next Definition will leverage everything learned and developed in Druid 6. So expect the next Definition to be a "6" defining a common plane new generation for Zu's upper tier speakers. Druid 5 will remain in the line, but Definition 4 - now a ten year old design - will be superseded.

Telefunken V69 Clones arrived today. Listening now. Two more amps overdue and coming to complete the survey.


I did not have the same experience with 211 tubes as you describe, having listened for six or eight of various origin over the 15 years I've had various Definitions in my systems. I got what you describe through changes of caps and changes to the tubes in the input and driver positions in Black Shadows, as well as other 845s that passed through. The combination of the input and driver have interactive effects as well. For instance, did you ever try a NOS Siemens CCa in the input and Bendix 6900 in the driver? There are too many variables in play to know via forum or email why you prefer your NAT 211 and I prefer tweaked Audion 845 but in both cases we made conscious choices.

My remaining amps are alleged to get sprung from chaotic Hong Kong shipping Oct 31st or thereabouts. Xiao Nan can ship reliably now through the mainlaing. So I should be able to complete commentary within a few weeks. But in the next few days I'll update conclusions thus far, including v69.

The Hong Kong shipping fiasco seems unsolvable, so I am getting replacements in the next two or three weeks. Then I'll be done with my survey:

300B/2a3 push-pull (interchangeable power tubes)
Quad II Clone
Klangfilm KLV-203 clone (F2a SE)
Klangfilm KLV-403 clone (F2a p-p)
Williamson p-p
LS-50 SE
2a3 push-pull
EL-156 SE

Almost there. I should have the last few almost exactly a year after I started this mission.

Notwithstanding my amps that got hung up in Hong Kong last May, Xiao Nan is getting amps out to US customers from the mainland.


Since Zu Definition has come up in this thread, I am posting an update here, also including notes about a new Dominance, as the two are closely related. I may start a new thread on Definition 6 and Dominance II, as well, but let's start here.

Zu Definition 6 was to have been introduced at RMAF in Denver, in September. In a late-breaking development, that did not happen and it turns out there were some good reasons for the delay. The small, practical consideration was difficulty getting the Hypex sub amp working hum-free, worldwide. This was particularly troublesome in Singapore and the UK, but also sporadically in the US, without much rhyme nor reason. So, some more time had to be spent resolving the power amp choice for the sub. That was the minor reason for missing RMAF. The major reason was convergence of design thinking pertaining to a new Dominance as well as Definition 6. In a spasm of activity late summer, Sean crystallized his thinking about a new Dominance and built a pair for the owner of the original Dom.

The original Dominance from a decade ago was an imposing, 360 lbs. speaker with a vast, aluminum monocoque, faceted baffle. The speaker used three Zu FRDs with two Radian compression supertweeters, and IIRC two 15" sub drivers. The faceted baffle gave Dominance the combined focus and tonal purity of a Druid, with the scale (well, even more) and dynamic bloom of Definition (again, even more so). And deep bass performance beyond both. It was the best speaker I ever heard. At the time, it sold for $60,000 / pair.

As the audio business made its slow recovery from the Crash, an updated Dominance took a back seat to designs for two new Druids (5 & 6), along with steady improvements to the bread-and-butter lines. And a successor to Definition 4 was inadvertently put on a meandering design and delivery path. Now both are nearing resolution.

First, the common theme: Both Dominance II and Definition 6 will be missing the Radian 850 supertweeter. Instead, both speakers will use the latest Zu FRD with a new supertweeter in coax configuration, ala the diminutive Zu Cube, but with a much better supertweeter. This has sonic and packaging advantages, and requires a new level of custom assembly of the combined coax FRD. Sonically, combing in the existing Definition dual FRD design and larger original Dominance, is reduced, and the new supertweeter is flat out to 30kHz, whereas the smooth Radian's rolloff begins below 20kHz. Sean believes the new supertweeter is smoother still. The coax drivers can also be spaced more closely than in the past.

I think this is highly encouraging. If you've never heard nor seen the Zu Cube it is a 10"x10"x10" sealed box speaker with a basic Zu FRD stuffed with a coax supertweeter. It is a distinctly higher resolution speaker than the more popular Omen and Dirty Weekend speakers in its price realm, but one thing that cuts into its popularity compared to the others is that its resolving power demands a better amplifier than the more forgiving, easygoing Omen. The Cube also shows rapid falloff in low end response, below 60 Hz. But when you strap Cubes to, say, a Druid 6-worthy amp, they sing. This new coax Zu is crafting is far beyond Cube's.

Dominance II dispenses with the faceted baffle in favor of a flat front, to eliminate the original Dominance's too-tight sweet spot. The coax drivers and spacing achieve the Druid-like focus without faceting the baffle or fixing the sweet spot too narrowly. Dominance II retains the three-front-facing FRDs of the original, which means now three supertweeters. Powered sub duties are now split. 60Hz - 20Hz range is handled by four 10" drivers, side-mounted, two per side. Range below 20Hz is by two 12" drivers, side mounted, one per side. The 10" sub array will be on a low pass filter as in the past. Then the 12" array below 20 Hz will simply have an acoustic roll-off on its top end, to match the low end of the 10" array. So, 12 drivers per speaker, still sans crossovers. The Zu FRD shoulders the ~40Hz - 12kHz zone. Dominance II is about 13" wide in front, with the sides splayed 15° out from the front panel. Depth is 26 inches. The canted sides make the sub arrays visible from the face-on-view. I don't have a final height yet but it will be taller than Definition's 49" and somewhat shorter than original Dominance. The new speaker weighs 110-120 lbs. less than the original for around 240 lbs net. This will be a six figures speaker. Some final cosmetics are still being noodled, particularly wrt how the side mounted drivers are presented or masked, but the first pair have been built and are installed and in use in a home listening setting. That owner reports (as does Sean) the new Dominance is a serious leap forward from the original, which I would expect given what's happened to Druid now twice in the intervening decade. I am sure same will apply to Definition 6.

Definition 6 will keep its form factor, in the interest of keeping its product-brand proposition of "most performance possible in one-square foot of floorspace." It will gain all the cabinet construction advances in Druid 6, and the various noise and gain problems that cropped up in the powered sub module in Definition 4 are now eliminated in 6. Drivers will be the same 10" coax as in the new Dominance, so two supertweeters per speaker now instead of one with main drivers mounted more closely together. In another change, the high pass filter for the supertweeters will use a Jupiter oil capacitor instead of the long-standard Clarity cap. Definition may creep up in price a bit, but will remain under $20,000.

You can expect both of these speakers to gain (well, exceed) the advances in transparency, dynamic punch, speed and vividity evident in Druid 6 over Druid 5. The new extended-range supertweeter will also bring some of the benefits of true ultrasonic supertweeters. Dominance will likely have default wiring for 16 ohms impedance, as this will expand the population of amps that will sound good with it, compared to the alternative 4 ohms load. Sean is considering offering switchable impedance if he can find an appropriate rotary switch that isn't degrading to sound.

First availability of both speakers in final form is expected for April/May of this year, which I am reasonably confident of given that all the design and execution issues have been resolved, and an initial pair of Dominance II have already been built. I will be hosting a Zu listening event for both to be heard in a home environment in Los Angeles, around that time. All for now. More to come.


For a variety of reasons, doing a point release on Druid 6 with the concentric supertweeter FRD isn't just a matter of slapping the driver in a Druid cabinet where the hole for the Radian hasn't been cut out. So no comment yet on whether than can or should happen before a Druid 7.

In your expansive room, Marc, and given your music preferences, I don't think you will be happy with Druid over Definition. Druid 6 certainly has a much smaller delta in scale compared to Definition, than in prior Druids, but it's not a gap that's closed. Druid still tilts to focus. Definition tilts to scale, both dynamically and in terms of spatial projection. Plus, getting Definition sub-bass right is...well...just a matter of getting it right. Def6 will leverage all the tonal, speed, attack, resolution and dynamic factors present in the Druid6 driver, but in a Definition config that will still have it prevailing in scale, foundation and definition.

The other thing I have to mention is that Zu lets you order speakers, get them delivered, and have 60 days to evaluate whether you want to keep them. Yup, it's work to ship speakers that size back, but it is an honest way to know.