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Hoffman’s Iron Laws of Speaker Building
1) Bass Extension
3) Small Enclosure
The law is that you can only have two of these three attributes in speaker building. Ideally we would want all three, we want speakers with good bass, can play really loud, and are small. Unfortunately we cannot have all these. I run many SETs have owned dozs of 300b amps and they match up very well with horn systems. Size maters if you want efficiency running a inefficient loudspeaker off 300b is causing amp to produce far more distortion than a horn would.
There are many parameters if the goal is full-range and depending on budget. Efficiency, placement, design, budget, etc. Also depends on your definition of full-range. Among high sensitivity speakers. . . Audio Note would be a good match, but require corner placement to optimize bass extension. Zu Def 4s and Rethm have built in amplifiers for the bass drivers. Since you built your own 300bSET, you might consider one of the Audio Note kits.
Depending on room size and music choice, you will want high eff. speakers with a 300b amp. As Atmasphere and others point out (and I have heard w my own ears), once you start to push an SET amp, distortion increases dramatically. You will want at least mid-high 90's dB/w/m efficiency. In my 14' x 23' x 8' room, I could easily hear 8-9 wpc 300b SET starting to distort at moderately high volumes, even with relatively undemanding material. If you listen loud and/or full orchestral music, you are probably want to look at high 90 dB. Also 8 ohm or higher, flat impedance curves. Names that come to mind are Coincident, Horning, maybe some of the Ref 3As if you room is small enough, Deadelus, Rethm, Zu. Probably some of Duke's Audiokinesis line. If you actively bi-amp or use a sub with the signal high-passed to the mains, you can probably go down a bit in the efficiency department. As johnk points out, the laws of physics are a bitch!
The Pure Audio Project Loudspeaker is a excellent minimal crossover ,and is a open baffle design.95db dual woofers ,and the Excellent Voxativ driver , horn option , and the Crossover allows you to put in any capacitor combinations of your choosing. I have some excellent new combinations and Upgrade a Wire harness.
for around $8k and betters many speakers at 2x this and more.
Many owners of the Audio Note E type speakers (numerous versions of this model I realize)say they are well driven by 300b SET and similar power(8 to 10 watts) amplifiers. Have you found the Living Voice Avatar as easy to drive as the AN speaker? My understanding was that the Living Voice require a bit more power than the AN E type. The LV Avatar is reported to have exceptionally good sound quality.
Most 300b amps are good for about 7 watts.
The distortion goes up and begins to include the odd ordered harmonics at powers over about 20-25%. So you might have about 2-3 watts of really usable power- over that, you don't really get to experience what the amp is all about (despite many remonstrations you may hear to the contrary; keep in mind that many people with SETs often put them on speakers that lack the efficiency needed; this is **the most** common mistake made with SETs)!
So I would not consider any loudspeaker that does not involve either a high efficiency full range driver (like a Lowther or Feasterex) or horns. The exception would be if you are in a very small room or only doing near field listening. In most average rooms, you will want a speaker that is **at least** 98 db 1watt/1 meter.
I am about a month into owning my Heresys as well and they sound fantastic with my Quicksilver Mid Monos. I was running KT 66 and it was time to replace so I tried the Mullard EL34 repops and along with Mullard 12ax7 input tube and Volshod 6n23eb driver I have dialed it in exactly where I want it.
My amps don’t even break a sweat with them. Super easy to drive and have a huge soundstage along with good imaging. I love them now they are finally broken in and gel with my amp’s tube compliment. They are very revealing of changes of input or power tubes.
When you drive any single-ended amp hard, it starts to make odd ordered distortion. That distortion tends to be on the transients, and our ears use those harmonics to sense sound pressure. So the result is single-ended amps tend to sound very dynamic (REAL LOUD) but unless you actually have have high efficiency speakers (and I think a Heresy qualifies) if you measure the sound pressure you will see its really not all that loud. It just *sounds* that way due to the distortion.
I also have a 300b amp (Woo Audio WA-5). I did massive research on speakers for 300b amps and came across Tonian Labs TLD-1 speakers. They are no longer available new, but you can look for used ones. I have a pair and they are amazing! They won't sound super for hard rock, but for lighter, quicker music, even orchestra they sound great. They're a little light on the bottom end, but you don't really miss it unless you're listening to music made to highlight low notes (e.g. organ music). Do a google search on them for grins.
Altec 604 coaxials are quite stunning, and I get great pleasure out of them with my SET amp. There are vintage ones, and Great Plains Audio continues to manufacture them (and parts). If you have space for large speaker cabinets, then the 9 cu ft variants will deliver stunning bass response, as well as the rest of the spectrum. You do need sufficient drive to power the 15 in woofers, and I don't know if the 300b can go there. I think the 604 is rated at 98dB +, so there is hope.
I understand how tube amps distort (and I like it), and the amp isn’t working nearly as hard when driving the Heresy speakers so I can only assume there’s less distortion than previously (my Silverline Preludes are supposedly 91db but I think they’re less than stated), although I can hear immediately when the amp gets too greasy. In the volume range I’m generally using it’s unstressed…and by loud I suppose I mean loud enough! Regarding refinement, nuance, etc., the Heresy speakers are very musical and coherant…the titanium drivers are smooth and revealing and not bright or fatiguing…the Preludes are also great with the single ended amp but the efficiency of the horns in the Heresy design seem to let the amp sing with less effort (maybe I already said that). Heres a thing: The Heresy speakers came with an offer for free vinyl (there's a sticker on the side of the Klipsch boxes that I sort of forgot about initially)…so for 3 bucks each to cover shipping (one per speaker!) they sent me two 10" 33 1/3 reproductions of early mono vinyl from 1953…and both, a Monk and a Miles, sound astonishingly good…from a company called "The Sound of Vinyl" tied in with the Capitol Records edition of the speakers I wound up with...yeah man…I'm now the old dude with tube amps and horn speakers (we all knew that guy, right?).
Ditch the the lower octaves of bass, and let the 300b drive a medium efficiency speaker of your choice from 125-150 hz. On up. Do this by using a 4th order active xover unit, and subwoofer. I used a 300b amp with 89 db. Infinity Qb's with ribbon tweeters, and cut off everything from 150 hz. On down from the 300b. A Hsu subwoofer took over the bass from 150 hz. On down to about 30hz. It was amazing sounding. Relieving the 300b of producing low bass, allowed it to play at a reasonable volume, cleanly. Would probably sound even better with some better 88-90 db. Bookshelves of your choice, but the Infinitys and 300b filled the room wall to wall and front to back with "your are there experience." Etched in my brain is a day listening to so called "ambient music" with this. At one point in the "song", My room became the Amazon jungle, and I was surrounded by jungle noises, bird calls etc. A very ethereal experience, and no, I wasn't tripping or on drugs.
The Goldmund Dialogue has a reputation for being highly resolving yet natural in character. In my experience this type of speaker exploits the most of what a good quality SET amplifier has to offer. SETs need very good quality resolving speakers to fully uncover the musical beauty and nuance available.
+1 Audio Note happy AN/J owner here. The E recommended above is the floor standing version of my speakers and a bit more sensitive. I really do love horns also but can't accommodate them in my small space. A bit surprised to see the Goldmund Dialogue rec, never considered those in the context of low powered tubes. Also never heard them but what an intriguing and classic design.
Wolf, get this...
It looks like none of the Chicagoland brick and mortar dealers I’ve looked into so far (as listed on Klipsch’s website) stock the Heresys.
I’m down to Abt and am awaiting a response to this electronically submitted question "Does your Glenview showroom have the Klipsch Heresy III loudspeaker available to audition in the store? Thanks!"
Man I miss the days where brick and mortar shops with real humans were plentiful.
I powered a pair of Reference 3A MM DeCapo(i) speakers with various different SET amps (2A3, 300b, 45) in my small/medium room with excellent results. The DeCapo is 92 db eff. and a very easy load. I'm sure you've heard of this speaker and its excellent reputation as one of the great stand-mount bookshelf-sized speakers at its price point. It's a very good speaker and works well with a wide variety of amplifiers and music preferences. I really enjoyed the years I spent with the DeCapos in my room. I must say, I'm not a fan of the Nextel finish on the latest version - MM DeCapo BE. Mine were the MM DeCapo(i) and had the piano black lacquer finish.
Also, the fact that I auditioned Heresy IIIs in a shop but bought them elsewhere (Ebay) has interesting ethical baggage. I generally abandon that baggage in the overhead compartment in my brain (if it fits), but also like to point out that the "audio salons" around here sell everything at list price, and no pricing wiggle room is implied…that said, I like my money and prefer to keep as much in my pocket as possible, and although the dealer offered a deal that was below list for a pair of Heresys, the deal from Ebay was a THOUSAND BUCKS below list (although they sent me a higher list price "Capitol Edition" for the same cost as the regular black speakers I thought I was getting, so there’s that.). New with factory warranty. Guitar Center (sort of a musician’s necessary evil) had a thing where if you find whatever you’re considering buoying from them on the internet or anywhere else that’s cheaper, they’ll match the price (not sure if they still do this) thus they get something out of you! They had a dedicated computer in the store to facilitate this. It’s not that I expect "audio salons" to do that, but they should tell you to contact them if you get a better deal so they can counter it…if they got close at all I’d go local, but they don’t care and consequently, neither do I.
I am sick and tired of someone trying to promote his own amp by demoting other type if amps, specially singleended transform coupled low power high quality amps.
Eg. Transformless push pull amps produces extream high odd order distortions and extreamly sensitive to power supply quality,while he declaires single ended amp has high ODD order distortion,which is false statement at best.
Readers be warned of this guy.
Byang12…are you warning us about Atmasphere? I have to thank you for that as I've been enjoying his thoughtful and well stated comments for a while now, and had no idea about about when he "he declares (!) single ended amp has high ODD order distortion" as I sort of think he's never said that. But hey…we've now been warned in case he does! Good job.
Atmasphere has over a period of many years provided this forum with consistently very high levels of knowledge concerning audio and electronics. A lesion of members here are grateful and genuinely appreciative of his contributions.
People are willingly going to let him tout the merits of his own highly regarded products and be an advocate for OTLs in general. I believe that many here are perfectly fine with this situation.
I’ll assume the majority of members here rely on their own ears and judgement when deciding what Audio component is best for them.
Agreed Atmasphere is very transparent, no pun intended, and very helpful with many technical questions that arise. I've heard and enjoyed his gear at shows and he obviously know of what he speaks. And Charles your typo, "lesions of members" absolutely cracked me up and I will say no more on that subject. :)
I am sick and tired of someone trying to promote his own amp by demoting other type if amps, specially singleended transform coupled low power high quality amps.I have to chime in on this one, just to set the record straight. The text after 'Eg.' is false.
Transformerless push-pull amps (of which our are an example) do not produce 'extreme odd ordered harmonics', and in our case are actually less sensitive to power supply quality as opposed to single-ended circuits. This fact about balanced circuits is well known. This is easy to demonstrate- we can actually run one of our amps without any filter caps in the power supply of the output section and it will actually work fairly well. The topology does cancel even orders due to cancellation in the output (in our case, the cancellation occurs throughout the amp).
Because our amps are fully differential, like any fully differential amp, the primary distortion component will be the 3rd harmonic.
With single-ended circuits (tube or solid state) the primary distortion will be the 2nd harmonic.
The 2nd, 3rd and 4th harmonics are considered musical by the human ear and contribute to 'warmth', 'fulllness', 'bloom' and so on. The higher ordered (5th and above) do not. The 7th contributes to a metallic quality. The ear is far less sensitive to the lower orders. so if you are pragmatic, you design the amp so that higher ordered harmonic generation is avoided, while doing what you can to suppress the lower orders, as long as that does not hurt that lack of higher ordered content.
Our amps do generate higher ordered harmonics like any other amp does, but at a level that tends to be considerably lower than in a single-ended circuit. We suppressed the higher orders by simply keeping the signal path simple (one gain stage) and by separating the power supplies to avoid intermodulations. The idea was to get low distortion without feedback; at full power one of our amps properly set up will make about 0.5% THD, while IMD (which is highly audible) is less than 0.02% at full power. That's not bad for a zero feedback amp.
What I have said about SETs making odd ordered content is true (although I didn't mention anything about that on this thread), but I did not say that this is **all** they do... I've often pointed out that the distortion of SETs is primarily the 2nd harmonic, and that if you use them at low power their distortion decreases to unmeasurable (and also inaudible).
This is where the 'inner detail' of SETs derives as distortion can mask detail (and many push-pull amps actually have increased distortion at lower power levels). For this reason, you generally want a speaker for an SET that is efficient enough that the amp never makes over about 20-25% of full power; in that way you avoid the odd ordered harmonics that will show up at power levels above that (as well as higher ordered even harmonics, both of which are used by the ear to sense sound pressure). This is to maximize transparency.
When that guideline is violated and the speaker is of insufficient efficiency, the SET will appear to be very 'dynamic'. But its a false dynamic, simply occuring out of how the distortion interacts with our physiology, and transparency will suffer.
I prefer that any audio system sound like music, and that is how you go about it with SETs. If the speaker lacks the efficiency, the amp will fall right flat on its face. I have this idea that you want to honor your amplifier investment dollar as best as possible so the amp you bought can strut its stuff. I do apologize if anyone thinks that this sort of advice is intended to denigrate SETs, its not. Its just statement of fact so you can get the best out of the amp.