Thiel Owners

hifi28 - Your room proportions aren't bad, and if you can get some insulation above your drop ceiling, it could be fairly good. Biggest limitation is the 11.5' dimension.

CS2s are wide-dispersion transducers, so your best bet is to put the speakers on the long wall. You also need them about 3' from the wall behind them, which puts your listening seat against the other long wall. That can be OK IF you can get a sonic hole behind your head, such as replacing drywall with acoustic tile to allow the back-wave to continue through the wall rather than reflect from it.

Can your room accommodate that?

The other option is short wall speaker placement which would require significant absorption / diffusion at the side-wall first reflection points. That could work.

hifi28 - your speaker positioning will be experimental with all things considered in your room.

An openable window can be a huge asset in that centered position. Sound waves through air accumulate as pressure zones in the corners and centers. Opening the window centered between the speakers might alleviate that pressure zone. Draperies between those cabinets might also be beneficial. The back end of the room benefits the most from absorption. Consider venting pressure from the corners, especially at the floor because the acoustic ceiling will reduce pressure up high. With care you can reduce standing waves to a small fraction of what they would be in an enclosed space. Well worth the effort.

For the record, most of the 'speaker problems' generally recited are not actually speaker problems, but rather room problems that may be excited more by some speakers than others. Thiel is capable of exciting problems due to their broad polar pattern and accurate response.

jafant - always a pleasure to connect some dots.

Summer is allowing use of an unheated artist's studio for my sound work. It's not much more than a shed, but the long wall behind the listening position is mostly open screens; so there is very little back-wall reflection. It sounds and measures well enough to be a useful space.

CS2 Chapter in Thiel History

CS2 development began in 1984 after the game-changing introduction of the CS3 in 1983.

The CS3 was the 4^th iteration of the model 3 – equalized sealed 10” 3-way with bass response to 20Hz. It demanded a fairly large room, robust woofer, and a midrange to cover 7 octaves including its long in and out ramps. The model 3 spent significant budget on those very capable midrange, woofer and the equalizer to take it low. Its right price was considerably higher than what Jim wanted to charge.

The model 4 filled smaller spaces with a bass limit in the mid 40s from a ported 6.5” two-way floor-stander. That format later became the CS1 series.

The company needed something for smaller rooms with less demanding bass at significantly lower cost than the CS3. The CS2 was born from those needs. From the beginning its identity included trimming costs without sacrificing performance beyond bass extension, which extended to 35Hz. In fact, its midrange could be cleaner than the CS3 since its crosspoint came in at 800Hz rather than the model 3’s 400Hz.

By this time we had established a strong working relationship with Vifa, who co-developed the 3.5” full-range driver for our midrange needs. Vifa and Jim also co-developed the woofer with some of his emerging motor geometries and techniques, even though it was still a conventional overhung design. A reflex woofer costs about half of a boosted sealed woofer because its low-frequency requirements stop at the port tuning.

In 1984 all cabinet work was still conventional tablesaw work along with our newly acquired inverted router. The CS3 baffle was being sculpted with hand tools, at considerable cost. We developed the routable CS2 grille board as a wave-guide and diffraction control mechanism with considerable success, at very low cost compared to the CS3 baffle. Later when we bonded the grille to the baffle with rubber tape, it became even more effective. The port was nearly free compared to the $ multi-hundred equalizer, which audiophiles wanted to be more transparent (and therefore expensive.) The CS2 load was a very resistive 6 ohms minimum, and moderate 87dB sensitivity, making it quite easy to drive. We focused our collective energies to cost-effectively producing this low-cost / nearly full range, coherent source for smaller spaces.

The introductory price was $1350/ pair against the CS3’s $1950. It met its market and sold consistently and well. Its 1991 replacement CS2.2 was driven by our developing CNC capability for a more sophisticated cabinet to support new driver technologies developed for the 1988 CS5.

The CS2 served as a sophisticated, elegant entry-level speaker for a broad audience. It sold about 7500 pairs over its 5 years, the most of any Thiel model.

hey prof - who remembers what’s been asked and answered?

We approached the speakers as part of the living / musc room; thus the veneer, hidden cable entries and grilles. All the later products used the grille frame and fabric as part of the design intent. The 01 had a foam grille, which was transparent enough not to matter much, but the foam did reduce diffraction a smidge. The fabric always knocks about 1/2 to 1db off the area about 4-8kHz. Many people gripe about Thiel’s being ’too bright’, while they use no grilles which indeed increases the brightness range above our intent. The 02 grille frame is counter-productive. It precedes our knowledge of diffraction and the frame increases edge diffraction. The 02 hotrod I am using to prove various technologies incorporates an elliptical rounded cabinet edge with no grille frame lip.

An exception was the later speakers such as the 3.7 and PowerPoint with  perforated metal grilles, which are claimed to be ’identical’ with or without the grille. The CS3 / 3.5’s stock grilles cause mild diffraction problems, which can be minimized with modifications.

I don't like the bright drivers either. Since they are anodized, any color would have been possible. My choice would have been charcoal to dark bronze with bronze hardware instead of gold. Maybe next time around . . .

hifi28 - good memory, with of course, a back-story for fun.

The crossover modification is at SN4901, May 1987, two years in. I don’t remember the exact change - I have only the revised layout from which I have derived the schematic. But I do remember the back-story.

Let’s start with the end: the modification was very slight, making a change in the roll-out of the upper midrange. Generally Jim revisited designs to tweak crossovers to accommodate driver tendencies and burn-in factors that become apparent as time passes. Or if a driver gets a production change (such as adhesive, etc.), slight engineering updates may correct it. The CS2 was uniquely a completely stable product, having no such driver changes and requiring no real tweaks. Jim was pleased that he had gotten it right the first time out.

Enter Larry Archibald, the fairly new publisher of Stereophile Magazine. Larry was supportive of our products, but always had the last word. He had written critically about the CS2’s upper midrange ’edge’ in various ways. It turned out, learned behind the curtain, that all of his listening to the CS2 had been without their (required) grilles because "he doesn’t listen with grilles". On a second round of review by one of his staff, Larry heard the CS2 with grilles and declared that "the problem had been fixed". Now enter Kathy Gornik, our co-founding marketing director whose job included press and public relations. Being an essentially political animal, she deemed fit to give Larry an ’out’ - by Jim ’fixing’ the crossover that Larry could point to as the remedy. Jim’s desire to have a product that needed no changes through its life took back seat to Kathy giving Larry permission to praise the upgraded performance without losing any face.

I don’t know whether it would be possible to reconstruct who did what when, the exact change and so forth. I do not remember changing our archived CS2 reference samples.

Bottom line: a small crossover change was made at serial number 4901 as well as adding the viscous rubber strips to mechanically unify the grille with the baffle. If anyone has access to an early CS2 and wants to send an XO photo noting component values, I’ll be glad to document the change. If anyone updates their CS2 crossovers, I’ll use the revised values. But the big deal is to use the grilles which include a tweeter wave guide and full baffle diffraction control which considerably upgrade performance.

jon - sending you a PM

prof - black paint is typically carbon pigment, which is light-weight as pigments go.

The issue would be added mass proportional to the extant moving mass. I suspect that in a woofer or midrange, the added mass would be functionally inconsequential, but in a tweeter it might matter.

I'm interested enough to try a light misting coat on my CS1.6 woofers. I can sweep before and after and compare output including all harmonics and time domain performance.

I'll use lacquer so I can wipe it off if necessary.

ydjames - I had seen the video before your notice, and didn't see the 3.7s.

But, George Cardas is said to have proclaimed the CS3.7 to be the best sound he ever heard at a show when it was introduced.

sdl4 - thanks for the tip; I hadn't seen them in the video. Cardas is a finalist in my hookup wire trials for Renaissance Upgrades. I'll be reporting in a couple of weeks.

Beetlemania - I'm interested in which Cardas hookup wire you used.

Thank you, Beetle. I'll be including Cardas 15ga chassis wire in an upcoming comparison. Quite a puzzle.

rop45 - can you provide a link, etc. A search of Audiogon says there are no listings for Thiel CS2. Or perhaps you could describe your offering here.

rop45 - I found it.

Prof - I ran the painted driver experiment; and I’ll call it a success.

I used Krylon ’Fusion’ because it claims ’5X the adhesion’ (of whatever?). Its solvent cocktail includes acetone, which makes a good scrub agent.Careful. I chose dark oiled bronze because it’s nearly black and so much more visually engaging than 'plain black'. I cut a cardboard mask, laid the speaker on its back and misted just enough paint to knock the aluminum down by perhaps 85%. First measurements were 1 hour later, which showed significant harm, especially in the mid bass and lower midrange with frequency erratica and time domain throbbing. After 4 hours it was much better and after 24 hours is hardly visible. The paint cure cycle is 48 hours.

At 24 hours, the top octave rolls off perhaps an additional 1dB at 20k and there are some harmonic differences. Generally, the 3rd to 7th harmonics are smoothed out and 3 to 5dB lower. On balance I would say the lightly painted cone is superior to the bare aluminum one. It is plausible that a crossover tweak might get that top octave air back, since the CS1.6 has a notch filter at its oil-can resonance. Note: there is none of the typical resonant peak at 28k (etc.) When using my Earthworks QTC40 into a 96kHz interface. The high end of the 1.6 just keeps rolling off around 12dB / octave out to 50k. That’s very nice.

I will experiment with a midrange driver when I get the 2.4s into the studio.

I suggest leaving tweaters alone, at least until we do some real homework.

If you paint cones, go easy. I certainly like the look better and it opens a door to using nylon window screen for a protective grille with far less resistance than Thiel’s polyester - plus a peek-a-boo allure.

By the way, the 1.6 grille shows differences in two areas. In the deep bass from 20 to 50 the grille introduces time domain throbbing, although I can't hear it. The FuzzMeasure sweep goes full power from 1Hz to 48kHz. This grille seems quite transparent up to about 7500Hz where it gradually rolls off the top to about 1-2 Hz at 20k. I like the sound better with the grille.

Tom D - welcome to the rabbit hole. Electrical and electromagnetic fields are a huge issue. In my opinion this issue deserved more attention than Jim gave it. As time went on, Jim's XO position moved farther from the drivers. Note the 3.7's location in a separate chamber in the bottom of the cabinet.

In the development of 1978's 03, we mounted the XO on the cabinet bottom, as far from the woofer field as possible. The interactions are significant. My clearest memory was noting the difference between the breadboarded 3 dimensional rat's nest crossover hanging in space / compared against the conglomerated XO on a board in relative proximity to the woofer (and other drivers) as well as closer to each other. The aural congestion was significant.

I had an aha similar to yours in my work on the CS2.2 a couple years ago using an EMF field meter which showed strong fields extending about 2' behind the woofer. I'm staying outboard when possible, and if not (such as a minimalist upgrade) it's going under or on the outside of the cabinet, in free air, far away from drivers.

Among the issues are vibration, which can be controlled via shock mounting.

Also, heat build-up changes circuit performance.

And there are proximity effects, both between components and in relation to the drivers. Those aspects interact because the coils (especially) must be positioned not only in relation to each other, but in relation to the flux lines of the driver fields, which can be a bigger deal than between the XO parts themselves.

MuMetal, etc. is quite technical and frequency and density related, generally requiring complete cages around components, which can exacerbate thermal considerations and reluctance interactions between the propagation fields in the coil wire. It's a jungle. I have found that physical distance and positioning geometry are more fertile avenues toward global solutions.

Regarding your preference for the sound of unbound coils - be very careful. Motion can induce various interactions with all other elements. Stillness is the goal (IMHO). As a generalization, many kinds of 'distortion' can be seductively appealing; sorting it out is a hard, complex problem. Where I've settled is that coils on rubber feet are strapped to the board. The feet increase and equalize thermal radiation , while mechanical motion is minimized as well as audio vibration frequency decreased to where the coils seem to not be stimulated into motion.

The position of coils can be optimized via listening to noise. The puzzle is hard because virtually all coils affect all others, and there are too many permutations to test (in a complex Jim Thiel crossover.)

There is another aspect that is real, but beyond my understanding, but here goes. Wire, at least new wire, has directional sonic properties. But I've found no reliable way (except Cardas wire) to track the directionality of wire. However, these effects seem to diminish with play-in time. I have chosen to ignore wire direction because I'm using played-in wire, and I can't do anything about it when re-using Thiel coils. In addition to spatial attitude, that leaves feed vs load of the coil. I have demonstrated to my own satisfaction (but contrary to common opinion) that coils are best fed from their circumference and tapped at their core with attention paid to lead wire dressing. I also note that as time passed, Thiel's crossovers tended to migrate toward this (outer to inner) feed direction.

Tom T.

Tom, I'm glad you've experiened Barkhausen noise - it is baffling on first encounter. Actually hearing effects from change of state electron spin is mind-boggling, until you grasp that the audio cortex can hear practically everything. My first exposure was in developing an electric pickup for acoustic instruments which sense geo-location of the string rather than acceleration or electromagnetic changes. We worked it out and the insights gained have remained, as yours have with you.

Isn't audio a trip?

hollowaudio - congratulations on your CS2s. First off, have you contacted Rob Gillum at Coherent Source Service? He knows everything about maintaining Thiel speakers. He may have moving systems for your speakers and/or help you test the viability of what you have. Try that first and come back for more.

trickydude - I’m not apprised of brands and models, but can paint a basic picture that might be helpful. Bluntly stated, Jim Thiel’s designs had impedances that were too low, making them suitable for only robust amps rated to deliver power into a 2 ohm load. Big discussion as to pros and cons, etc. but that more thorough investigation requires study beyond this answer.

There are two major aspects of speaker loads germane to your question: impedance magnitude and impedance reactivity. A: The 3.6 would properly be rated as a 3 ohm load. B: to its credit, it is an extremely resistive (non reactive) load. Amps love resistive loads, so if an amp can deliver the requisite power into 3 ohms, then it should work. See Stereophile’s measurements in its 3.6 review for reference.

There is another set of issues. Mainstream mid-fi amps rarely delivered such power, at least not gracefully. Japanese designers invariably chose to enhance specifications (TIM, etc.) at the expense of sound quality. In today’s market, you would probably be best served by an American design rated or reputed for operation into low impedance loads. On the used market, there are suitable amps that sell for a fraction of their new prices.

I’ll share some quite limited amp thoughts. At Thiel Audio we used Classé, Mark Levinson, Krell, and Conrad Johnson. Audio Research came and went, as did Classé, but they have models that work well. I still use my 1990 Classe DR6 preamp and a pair of DR9 power amps. I also have an Adcom GFA555 II which is adequate, but less than best of form. A friend has a PrimaLuna integrated which is an excellent sonic match, and an inexpensive candidate. The new Benchmark gear is magnificent at its price.

There are lots of folks here with lots of relevant experience; but it’s all been covered and kicked around. I suggest you might skim this thread to see what surfaces. I recommend that you try what you have, making sure you keep the gain below audible distortion. Distortion melts drivers. Assuming the speakers have been tested and are running without problems, the key to progress is to assume the amp, rather than the speakers, are limiting your sound quality. This world has many interacting variables which are not easy to learn, teach or understand. With an open mind and some patience you have a speaker that can be very, very good.

Happy Trails

ydjames - the breakup you describe can be caused by various things. Among them could be lose voice coil turns or other non-design-related phenomena. Let’s rejoice that the new drivers fixed the problem.

Last week I had a ’sound’ in a CS1.6 woofer similar to what you describe . I went looking for ’dirt’ in the voice coil gap, but instead found a steel washer resting on the ’top plate’. That little washer had fallen out of the driver mounting boss and stuck to the driver. It saturated and caused distortion in the magnetic flux field. In my case the ’fix’ was easy. Remove the washer and the distortion is gone.

Follow-on is that I am replacing the steel threaded inserts in the driver basket and the steel mounting bolts with brass, and the washers with fiber. I expect to hear the cleanup of a far lower level of that same distortion. That hardware is only an inch or so distant from where that single washer caused audible distortion. Speakers can have lots of low-level anomalies and sub-optimal implementations. Some get identified and fixed or improved during development, some are worked out during future product iterations. Some still remain to be addressed.

jafant - I do love the R&D and do appreciate the support and interactions I get with you guys. I’m glad Rob is pleased and hope we get those Purity caps sometime soon. The new order seems to run on snail time.

It is difficult and frustrating to be working against the current. But, progress is being made. The declarations here about Cardas Clear Beyond caused me to overcome my bias from earlier Cardas wire which I found to be warm and dark. I require neutrality and now have a sample of their 15.5 gauge internal hookup wire for comparison. Tests this week!

In the general news department, Bill Thalmann of Music Technolgy in Virginia has finished upgrading my Classé DR6 and is working on the DR9s. He is also upgrading the CS3.5 equalizer which has been upgraded to best professional specs by Jim Williams of Audio Upgrades in California. I’m looking forward to visiting Bill to compare JT stock against JW, against BT upgrades and finalize that project. I will say that in my trials here, JW’s upgrade is a significant improvement over Jim’s (budget constrained) 1987 design. JW used a bigger transformer, regulated power supply, faster and quieter transistors and a couple more bypass caps. JT’s design had all styrene caps and metal film resistors which came through unchanged. JW’s upgrade has a more authoritative bottom end as well as a cleaner, more transparent upper midrange. The previous ’sparkle’ was an artifact. Progress, slowly but surely.

jafant - Cardas makes heavy claims for its particular American copper mine source. I would suspend judgement based on rumors. We don't know what we don't know.

I have gotten more education around wire than I ever thought possible. Verifying claims is part of that education.

Regarding the ongoing discussion around integrated amplification - there is plenty of reason to keep 'it' in one chassis, to avoid another set of cables and their terminations.

When replacing a magnetic metal with a non-magnetic material, it's important to understand the function of the part. Often a chassis acts as a Faraday Cage where the entire envelope is engineered as a whole. Sometimes there are electrical value compensations for metals in proximity to circuitry.

I'm reminded of beetlemania's 2.4SE XOs, which turned out to be (late) made in China. The coils were different values to compensate for the electrical traces on the back side of the board. When we remanufactured his XOs on masonite, we returned to original coil inductance values to keep performance on spec.

Also, non-magnetic metals support electrical fields, which can be germane.

Just saying: everything is not always obvious.

Tom - that reflection is real. Shielded cable has a ’sound’ due to inward reflection of propagation field effects. Unshielded sounds better when it can be used in benign circumstances.

I’m reminded of Thiel’s early electronics. The 01 and 03 generations all had equalizers built in electromagnetically ’open’ enclosures. The sides were wood, the front was acrylic and the back was aluminum. The EQ required careful placement, away from transformers, etc.

I’m a big fan of distance rather than shielding. Outboarding the XO provides enough distance from the driver fields, and the opportunity to spread out the xo components. Thiel’s home theater products incorporated bucking magnets on the drivers (at least the woofers). In addition to containing stray fields regarding video interference, they focus the field in the gap and clean up the electromagnetic soup inside the speaker. Win-win.

trickydude - I’ll elaborate a little on Harry’s recommendation. I have and use and concur with him on that Adcom amp. But my experience with it taught me a few things. The original Adcom GFA555 was designed by Nelson Pass, as were many of Adcom’s amps. The MkII was not - it shared a chassis, but was otherwise a French design with somewhat different characteristics, far higher parts count and circuit complexity. (Reviewers and many users like the MkII better.)

Enter another twist of vintage gear - upgrading. There are folks who upgrade select vintage amps for better performance than was possible when that piece was new. One such upgrader is Jim Williams of Audio Upgrades in California, who concentrates on pro gear - rebuilding recording consoles, etc. Great work at very reasonable prices. JW offers an upgrade to Nelson’s original GFA555 which he considers a superior design to the MkII. I suggest that an original GFA555 might be found for very short money and my experience says that a JW AUDIO UPGRADE for it will produce stellar amplification for your Thiels. (Note: I’d love to trade my MkII for an original NP so I could do what I am suggesting.)

Note that Nelson and Jim were peers and each used the other’s products from the 1970s onward.

thieliste - maybe we should all have a music party at your house to hear what a Thiel speaker can do.

JAFANT - In my 20 years, we never had any Adcom in our factory. We were, however, familiar with it since many of our dealers carried it. Jim took the somewhat eccentric stance that it was other peoples' job to deliver 'proper' amplification. His job stopped at the input terminals. My assessment, at that time and continuing to the present, is that Thiel would have benefited from a more inclusive systems requirements approach. A $2000 pair of speakers is out of place, in my opinion, requiring a $10K amp to supply its peculiar needs. Jim felt that his highly resistive / non-reactive load characteristics made up for the very low impedances. But, the amp stable was severely reduced. In my opinion, many of the long-standing and ubiquitous criticisms of Thiel speakers as 'bright, in your face, aggressive', etc. are due to amplifier distress.

Anyhow, the first Adcom amp I personally heard / evaluated is the one I bought a couple of years ago with a pair of Thiel CS3.5s supplied from a member of this forum. I think the speaker needs 'better' to reach its potential, but it's better than most.

I'm having a 555 sent here to compare to the 555 II. Then the 555 goes to JW for upgrade. When it comes home I'll re-compare to the 555 II and let you guys know.

I have a pretty good idea how the mkII drives various Thiel models, so I'll develop an opinion (valid enough for myself) how the mkI compares to the mkII.

jon - hyperbolic figure of speech. But, Thiels do require care in setup. A consistent source of the brightness disparagement came from show-goers making judgements from standing in the doorway. Thiels baked-in design constraint requires sitting down for proper driver integration. Another aspect of driver integration is the 8' minimum listening distance requirement, which when subverted causes sonic problems.

Whether it was cable or amps, Jim chose to use very good ones, beyond a $-balanced norm.

Prof - the little critter has become a different animal. I began experimenting with the CS2.2 and 3.6 but migrated toward smaller models for practical reasons. I collected a few pairs of 02s to further simplify my learning experiments. I soon learned that I didn't want to live with the 2nd order XO due to higher reactivity and difficulty time-aligning the wavefronts. Jim had always (in every product from the start) kept onset transients arriving in same polarity. (Whereas most 2-ways flip polarity for one or the other driver.) Your stock tweeter signal arrives a full cycle before the woofer (which sounds 'normal' due to its ubiquity.) That's very non-Thiel to my ear and sensibilities, so I ended up using CS.5 drivers and a first order crossover, moving the woofer forward on a standoff and the tweeter backwards behind a waveguide for . . . Phase Coherence. 

Now, of course, diffraction and so forth become much more audible (you know my hypothesis) - not just to me, but to collaborators as well. So the cabinet edges are eased in an elliptical cross-section to meet the new (forward) super-baffle plane. Rear edge easing is also in the mix. Internal bracing (not visible) beefs up the panels. The diffraction-causing grille is gone, replaced by (most probably) a CS2.4 / 1.6 type arrangement, except I have no magnetic metals in my enclosure systems.

The crossover of the stock 02 is built on the rear input panel, right behind the woofer magnet, with audible and measurable distortion. In a portable speaker an outboard XO cabinet is a bit much, so I've mounted the XO on the exterior bottom of the cabinet in a plinth with ventilation holes. A chimney is under consideration to take heat through the cabinet and out a flared outlet in the top.

A big area of experimentation has been laminar wave-launch technology. It's not particularly visible, but no front or edge surfaces will be smooth or hard. Similarly the port looks like a 2" port, but it now contains patented and proprietary technologies that impart an uncanny realism. The increase in clarity, dimensionality and musicality are hard to describe and harder to explain, so let's not for now.

So, what's left of the 02 is the cabinet, the driver sizes and port, but everything is subtly to radically upgraded. I won't have a 'fix kit' for a normal 02. I know you love yours, but it is an ordinary if well-done second order 6.5" ported two way. My mission is to develop ways and means to improve performance beyond stock Thiel levels. The 02 emerged as my baseline platform due to its simplicity, flexibility and accessibility. My vision is for the Renaissance 02 to be a uniquely high-performance stand mount speaker with discrete drivers. It is fiction-ware in that no such product actually existed. I envision a limited edition inaugural run and that all this learning and solutions will be applied next to the CS3/3.5 which has gotten the bulk of my attention of late. Stay tuned, sorry to be so slow . . . 

Pictures aren't appropriate. They change constantly and aren't yet very pretty.

jon - thanks for your perspective. I can't say I understand what the naysayers actually object to.

JA - during my 20 years I don't remember any silver in the mix. For one thing, 'wire' wasn't really a thing yet in the early years. And also, we had very little spare cash, and 'wire' seemed over-priced for our sensibilities. The price of silver was a bridge too far. We were exposed and traded for those Kimber super expensive and magnificent speaker cables, but at that time those were copper. I've been told the later ("Black Swan"?) version, which became one of Jim's staples, may be silver, but that was in the 2000s. The Goertz that he used to develop the 3.7 was (I think) a copper version. (Someone on this forum may know for sure.)

Short answer is that from the mid 70s to mid 90s, silver wasn't in the picture. At that time we had found the 6-9s / aerospace wire which we brought to AcoustaCoil and Straightwire, which defined our approach to wire.

roxy - regarding speaker cables.

I've been out of the flow and the shows and the budgets to audition or live with 'serious' cables for some decades. But the first generation predecessors of those 'Black Pearls' from an 80s CES rings clear in my memory 40 years on. Also, I heard real Black Pearls in 2012 at the Thiel Listening Room when comparing CS3.7s to the newly finalized CS2.7s. The sound was the best that I've ever heard. I didn't peruse the gear, but I have found out that the Black Pearls were the speaker cables in use.

thieliste - while you’re waiting for hands-on experience to chime in, I can provide some history.

Early-on (1978 model 03) we discovered the deleterious effects of eddy currents, first in steel driver baskets and later in aluminum voice coil formers. Part of that exploration over the years included binding posts. Either in direct power transmission or the secondary effects of changing magnetic fields, back-currents are generated from reflections and discontinuities along and near the signal path. Best practice is to keep cross-sectional geometry and resistances as even and smooth as possible to avoid distortion. Thiel kept its plastic-capped binding posts a very long time, and reviewers consistently took pot-shots for their ’RadioShack cheapness’. Fact is they weren’t cheap, and they outperformed most bigger, bulkier, brass rigs.

Somewhere around the CS1.6, Thiel converted to big, brass, gold-plated posts to praise from reviewers. I haven’t directly compared their sound quality to the ’old style’, but I will. I did hear that Kathy deemed the change as more politically expedient than trying to educate reviewers, dealers and customers.

Note that some of the high end posts have plastic caps. Danny Richie of GR-Research invented and sells a tube connector for the reasons outlined above. Some amp companies tried and rejected big metal posts.

My recommendation is something with approximately similar cross-section and conductivity to your cables and/or internal speaker wiring to avoid electrical reflections and resulting eddy currents. Copper would be a plus. A disadvantage to gold is the typical nickel under-plating which many consider to sound bad. Simple, small and high conductivity are pluses of course.

As many of you know, I've been on a wire odyssey this spring and summer. The goal is finalizing internal wire upgrade options. But prior to those trials I have compared my various component and speaker cables to assure myself that I have a neutral and articulate signal feeding the speakers. More on that as things progress. Tonight I'd like to report on the digital S/PDIF from the CD player (Philips CD80 gone through by Bill Thalmann) to the DAC (Benchmark DAC3B). My digital cable stable includes Audioquest, BAV, Benchmark, StraightWire and Morrow. I consider the Morrow a cut above, and the rest basically equivalents with subtly different sonic shadings.

The good news is a sample which Iconoclast sent to me which ups the ante. The cable costs around $30 and appreciably outperforms the others in my trials, which are admittedly less than the league of many of you. The winner is Belden 4694R cable made for ultra high definition (12GHz) video, using high purity copper clad in silver. It's available from Blue Jeans cable. I'd love to hear from any of you who know it and are willing to share your opinions about it.

Agreed - since mine came from BJ as an unasked-for bonus. What a treat!

Along with a pair of mic cables with similar specs. Haven't yet put them to the test, but I have reason for high hopes.

JA - Things got complicated. I now have 2 matching amps coming this Thursday. I plan to send one to Jim Williams and keep the other for comparison when JW’s comes back. Both can be compared to the GFAII which I have in my stable.

JW’s approach is to identify weak links in fundamentally great designs and upgrade those weaknesses to new strengths. The upgraded GFA555s will have bandwith of 1Hz to 300kHz with decidedly lower noise and faster slew rate. Jim works in the pro world and doesn’t use ’audiophile’ parts, but rather best-of-form ’normal’, high-performance parts to achieve his results at minimal cost. His GFA555 upgrade costs $225 plus freight.

May I take a little side-trip here? I met Jim when I got two mic preamps from Tom Jung, founder of DMP. Tom used CS5s as his mastering reference speakers in his ground-breaking early digital label, and passed his STs along to me for my recording work. The Studio Technologies Mic-PreEminence was 1980s state of the art, but were a little noisy and had become less than best-of-form in some areas. Tom told me about Jim, who re-worked one of my STs with stellar results. I sold the other ST to a fellow audiophile recordist who had it upgraded. Subsequent upgrades included a reel-to-reel and recently the CS3.5 EQ. Jim doesn’t normally ’do’ power amps, but he uses GFA555 as his own amps, and has tweaked them to their best performance. I’m looking forward to his work on mine!

JA -

Here in New Hampshire we have different seasons than the USA. Winter starts in earnest in late December and through January and February we can get 10' of snow (12' in 2015.) Winter transitions to 'sap season' in late February / early March as the Maple sap runs and the sugar shacks boil it down to syrup. Temperatures can still be below zero at night. As daytime temps rise, we enter 'mud season' where a car can be mired to the axles on our gravel town roads, and roads are closed to vehicles over 6K#. Then comes 'black fly season' - biting insects that didn't exist in Kentucky > merging into 'mosquito season' in May. We say that spring weather keeps the riffraff at bay.

Then comes 4th of July when it turns to heaven and the 'summer people' come to fill their camps and lakes and villages. Varieties of glorious weather without appreciable insects continue into Autumn, sometimes 'till Thanksgiving. Even in the heat of August, night-time temperatures often drop into the 50s, and regularly the 60s, making the heat of the day more of a joy than a burden. September / October provide a glorious Autumn with forest canopy colors to rival anywhere and the arrival of the 'leaf peepers' bringing appreciation and tourism. Around Halloween to Thanksgiving, things turn rough and 'the bottom of November' can be quite deep. Christmas is more often fairy-book than not, and many older folks head south when snow starts piling up in earnest in January. Summer cars are stored and locals (year-rounders) hunker down for the very short days and long nights of winter.

For us, August is high summer, all month long. It shifts hard when school starts and families migrate to that reality. I came here in 1996, related to work, and feel fortunate to have found this village in this region. Northern New England seems more like England than the USA in its traditions and frame of mind.

Rob should be OK. He's in Lexington which is 100 miles west of the trouble, and on a high limestone dome - good surface drainage and underground caves. Plus my daughter in Lexington would tell me if they had problems.

harrylavo - from page 235.

I spent a couple hours this afternoon comparing the Benchmark AHB-2 to your recommended Adcom GFA555 II. Both amps are bridged, running the same CS1.5 (stock) in mono. I must say that the Adcom acquits itself nicely. The sonic signature of the two amps is quite similar as is the bass / treble balance. The Adcom presents slightly more upper end and a rounder low end. The AHB has a smoother texture. For the short money these used Adcoms command, it would indeed be hard to beat.

I’ll report on the 555 II vs the 555 (straight) in a day or two.

The reviewers loved them both and they sold boatloads in the 1990s.

The Adcom / Benchmark comparison was a response to trickeydude’s call for a good, inexpensive amp for Thiels. Plus, I have a personal interest in the journey of that GFA555 moniker from a Nelson Pass, simple, low parts count design to a different designer's complex, high parts count design. There’s a lot to learn there including the nature of the ’improvements’, what may have been sacrificed, and different solutions applied to that original amp.

At Jim Williams’ suggestion, I am exploring his solution of upgrading Nelson’s original design and comparing and contrasting outcomes between the three iterations, plus the AHB2 as reference. I'll keep you posted.

Adcom power amp comparisons

The two Adcom GFA555s arrived yesterday and I compared them to each other, to the GFA555 II, to Sennheiser HD800S headphones, and to the Benchmark AHB2. Brief report to follow.

A fair prior question is ’why’. My present odyssey includes long-standing riddles among which is why some users experience classic Jim Thiel products as some combination of hard or harsh, up-front, analytical, etc. while others hear little of these issues and love them. Among myriad interacting potential causes are:

• Room, listener position

• Inferior signal chain and/or recordings

• Cable/wire with time-domain problems exposed by phase coherent presentation

• Crossover location behind the woofer. Later progressed to behind passive radiator, cabinet bottom

• Less than best diffraction and wavelaunch control

• Other including high-frequency balance, driver and floor coupling, etc.

Today we’re examining Amplification. These Adcom amps were well-regarded and popular in Thiel’s mid-cycle product development. If some amps don’t like some cables or speakers (such as low impedance). Let’s say those issues are settled with the amps presently under consideration. Historically, Thiel graduated to top-tier amps because we got excellent dealers who used those amps. We never tested our speakers with anything less than the Krell-Levinson league. Even Audio Research and Classe washed out due to Jim’s assessment of off-neutral (AR) or less-than-best (Classé.) Bryston was our 'entry level' recommendation.

My present rack: Reference: All Benchmark stack with AHB2 power amp driven by HPA4 by DAC3B from Philips CD80. Benchmark interconnects. StraightWire Octave II speaker cables.

Known amp: Adcom GFA555 II

New amps: Adcom GFA555 (original) (2) All amps bridged mono

Speakers: Thiel CS1.5 stock

MO: Patty Griffin – Impossible Dream skipped through full album for 10-15 minutes total per amp under test. Album is pop vocal with simple to orchestrated instrumentation, and various pop production effects. Without apology, the Benchmark has become my reference. Adcom 555A is early production. Somewhat up-front, simple, direct, ’no mic windscreen’ sound Adcom 555B is late production. Slightly more ’refined’, ’mic windscreen’ sound. Adcom 555 II. More controlled, safe, less ultimate detail and dynamics. Differences are fairly subtle. Family resemblance is the over-riding quality. Family sound is very similar to HD800S headphones.

Benchmark AHB2. Solid, quiet, clean. Studio reference quality both technically and aurally. Note, the original 555 sounded closer to the AHB2 in their shared direct liveliness, than the MkII. I am sending 555B to Jim Williams for upgrade. Another comparison will ensue on its return. I support with Harry Lavo’s recommendation. The 555 II is the safer bet for unknown upstream components and source material, and within its power capabilities, should drive any Thiel speaker well.

TomD - I interpret what you're saying as decoupling the crossover from its environment via optimal tuning, such as the various mass/stiffness springs tend to quiet themselves quickly. That can work, but requires ongoing vigilance since the stiffness of the xo panel changes (creeps) over time. I realize that you understand the equation in other terms - transfer of energy and mechanical grounding. I don't have my mind around that, although I believe you may be onto something - your results are good.

We both agree that the xo functions better out of the box, and we understand that distance from EMF and reduction of mechanical vibration are beneficial - much more so than might be intuitively obvious. When the XO is in the box there are many assaults: the air is in episodic resonance and fluctuating pressure; the cabinet walls, the crossover panel, and the components themselves all vibrate causing microphonics and motor-currents via motion in the EMF. All considered our best production results (in the old days) were to mount the panel tightly to the cabinet and all the components tightly to the panel. The wires hung in free air, generally away from each other. In practice we controlled buzzing and rattling and considered the job accomplished when quiet was attained.

I have tried a different approach with more satisfactory results (although less good than the outboard XO.) The new approach is to isolate the various resonances, which spreads them out to various frequencies and reduces their resonance magnitudes because each individual part has far less mass than the combined whole.

Each capacitor or resistor is mounted on blue tack or mortite, held in place via its lead wires. Coils are mounted via zip ties against rubber donut standoffs. The driver leads are more carefully routed away from coils and seated in gooey tape to the cabinet walls and routed radially to the driver, avoiding the central flux axis. 

The crossover is broken into individual panels for each driver, and those individual XO panels are separated from each other as far as possible and as far from the driver magnets as possible, and mounted via fiber bolts isolated from the cabinet wall via rubber stand-offs and from the XO panel via rubber standoffs. These changes would not be very expensive in new construction - they're a bit more of a hassle in retrofit, but still far less cost than swapping out components. This description is of a level 1 upgrade, probably including replacement of any and all electrolytic caps with ERSE-level PPs, and some or all resistors with Mills. 

You may want to know the imput and output (source) impedances of the 3.5 equalizer, which are typical of line level devices. Input: 91kohms, Output (source) 130ohms.

stanleym9999 - I'll add a little to the cabling advice.

In my cabling comparisons I like StraightWire. It helps to use the ame product family that Jim used in designing the product. At this time, I asked Steven Hill for his recommendation. He supplied the following as incorporating all of his relevant technologies before climbing the cost wall to get in his words "different preferential sonic flavors". 

I use Rhapsody 3 RCA interconnects and Octave II (now I believe III) speaker cables.

oblgny - I'm a candidate.

jafant - yep, that's the idea. I have a pair on loan and like to keep one pair stock and modify the other. I have very little personal experience with the coax Thiels. The 2.4 is an elegant little thing and I'm looking forward to living with it.

Adcom amps - a fair question is why. In a world with new low-distortion amps and Benchmark’s AHB2 selling for $3K, why bother with vintage amps? We recently recommended an Adcom GFA 555 mkII as a viable, low-cost choice. I compared my 555mkII to an available 555 (straight), and bought a second 555 to keep while the original 555 was upgraded by Jim Williams of Audio Upgrades in Carlsbad CA. Turns out the newer 555 sounded a little more threadbare / forward than the older unit.

I got that older 555 back from Jim yesterday and did some listening. He replaced some caps and transistors with high-performance, low noise ones. I asked for a run-down of his upgrade (which hasn’t come yet). However we know he increased the bandwidth from its previous 3Hz-150KHz to 1Hz - 300KHz. The noise floor went from quite noticeable to hardly audible. The charge and decay speeds are faster.

As I’ve mentioned, Jim rebuilds / upgrades recording consoles and other pro devices. His parts choices are best-of-form ’conventional’ choices with a goal of improving the technical performance and sound quality toward ultra-clean at ’affordable’ cost. This upgrade cost $225 plus freight.

I listened via StraightWire Rhapsody 3 throughout. Speaker cable is Octave II. SW has survived my trials as extremely good, plus I know it from years of use. So I side-stepped the newer Iconoclast offerings in favor of familiarity.

The overall character of the GFA 555 (stock or upgraded) is similar to the BM AHB2, that is clean, clear, no-nonsense, factual and without editorial character. JW’s upgrade brought the 555 closer to the AHB2 by a lot. I could not claim to differentiate between the AHB and 555 in blind testing. However, I could easily blind-pick the stock vs upgraded 555. Stock is less definitive, less authoritative and less satisfying while having a slightly looser bass and slight upper midrange glare / shimmer that obscures detail.

I have not yet found time to compare the 555 mkII. I will report on that when I’ve put it in the mix. The only Adcom amps Jim upgrades are the GFA 555 and GFA 545.

Back to the question of why Adcom. Someone looking to supply a clean signal to any Thiel speaker would do well with the Adcom GFA555 with Jim Williams’ Audio Upgrade. Although Adcom was barely hi-fi, this may be its best amp, and this upgrade increases its performance considerably; and its high sales count supports multiple service and upgrade possibilities in the marketplace.

I’ll be sending my second 555 to Jim for more magic. Who knows, I might take one to Virginia when I visit Bill Thalmann at Music Technology in October.

Cheers, Tom