Thiel Owners

Thank you all (I'm from Kentucky) for your participation here and via PMs. Here is a progress overview.
Indeed a high priority is to avert losses from aging electrolytic caps. New work will have ALL film caps for indefinite product life.
 
In broad overview, all series signal path caps are ClarityCap CSA-630 volt. They have excellent technical and sonic performance at justifiable prices. I am bypassing with the custom 1uF styrene that Thiel had made from best German film, now defunct. We will salvage your old ones.
I will be double-bypassing with 1% fractional value MultiCap styrenes. Thiel CS2, 3 and 3.5 used this trick with MultiCap's predecessor. Jim dropped out as of the 2.2. I'm back in for the quicker and quieter leading edge transient at what I judge as justifiable cost for this upgrade scenario.
Shunts to ground in Thiels (pre 3.7 and 2.7) are electrolytics bypassed via that 1uF styrene. I am going with a custom ClarityCap polypropylene having all CSA factors but with a 160 volt film for manageable form factor and cost.

As beetle has mentioned, all resistors are being replaced with Mills MRA-12, an excellent and cost-effective solution.

Note that I am aware that some might want to go farther afield with cost no object components and others may balk at the significant cost of my choices. My vision is to find affordable solutions that reach the next performance / cost plateau. This project is larger than may be obvious. This relatively major redrawing of the rules will require re-voicing both via measurements and listening. Beetle's 2.4s and my PowerPoints are the first line of that work. Our custom parts will arrive early June, when we'll engage the core work and begin substantive feedback regarding our judgements to date.  

Prof, thanks for the reference to Phil Bamberg. He is part of the picture and solution of the puzzle. Your quandary of 2.7 vs 3.7 shines a light on some design particulars of interest. The 3.7 has no electrolytics in any signal path, whereas the 2.7 has bypassed electrolytic midrange feeds and an unbypassed electrolytic in a tweeter shunt. Our target caps will surpass the 3.7 quality for both 2.7 and 3.7.

Of further interest is that later production 3.7s have Chinese made crossovers which seem to have some polyester caps where polypropylenes are specified. And those are built on printed circuit boards, whereas all 2.7s are Lexington made on point to point boards. I associate sonic "ease" with point to point implementation.

The purpose of this post is not to overwhelm with detail, but to share some parts of the emerging puzzle. I am hopeful of achieving significant improvements via parts quality and implementation improvements.

Best regards,
Tom

Most folks agree that DSP is the future. The DEQX site is very impressive as are their reviews. The cost do "do it" actively and especially digitally is a small fraction of analog costs. And precision can be had. I note that ATC gives no phase spec, nor do I see relevant claims from Lyngdorf, but I haven't looked very hard. DEQX may really be doing it. If I were starting a company today, I certainly wouldn't be going all analog/passive! When I find time I'll share the Lexus / Thiel story.

Robin, the CS series have enough internal enclosure volume to tolerate the added bulk of the upgraded crossovers. We'll produce upgrades both inboard and outboard.

Unsound, you raise a strong, well grounded germ of an idea.

But in my experience and knowledge, active crossovers are a fairly blunt instrument. Their downfall is that they generally assume a very simplistic model of the driver and therefore give a very generalized net filter effect without the necessary interactive nuances between the signal and reactive driver loads.

Those interactive anomalies can be addressed passively. My study of the progression of Thiel designs shows drivers that are better and better behaved as time goes on, requiring simpler crossovers. But they're still not perfect.

As I mentioned way back, Jim's first purest ideal speaker (never brought to market) included separate amps with active crossovers driving each driver with its Zoebel / Boucherot and other corrections attached to it. That hybrid of active / passive offers everything via control of the factors as well as control over or elimination of all the input variables that cause so much trouble (cable reflections, etc.) With the line level signal presented to the inputs, everything else happens "in the box". We decided, as a young, green, minimally capitalized company, that we couldn't afford to educate our customers, as well as the high risk of failure presenting such a wild-card to the market in 1976. Dealers hated the idea of an amp / speaker system that "just worked". Their very existence depended on addressing all those problems . . .

History validates our decision. Today, someone might pull off that feat. I offered this idea (indirectly) to the new Thiel ownership, who thought it quaint and idiosyncratic and didn't want to talk about it.

If a savvy group could buy Thiel's intellectual property (assuming it becomes available), and if the engineering talent could be assembled, I think this solution could make some real waves, especially in how it harkens back to the roots of the company. What if pro-audio / record-makers had such monitors? What if we didn't have to make excuses for poorly produced albums? What if the vast differences introduced by amplifier output particulars modified by cable variables . . . weren't in the picture at all? Just dreaming. 

Thank you for a walk down memory lane.

With very broadband response with steep slopes, a driver could operate in its sweet-flat-pistonic zone. I would need convincing that higher order slopes could be "corrected" to actually produce minimum phase additions through the crossover. I've seen failed attempts, but never a success to my standards. It must pass a square wave right through the crossover, to be phase coherent. If not, then not.

A complicating factor is that unbelievably small anomalies of resonance, less-than-accurate transient behavior and so forth, are readily apparent in a minimum phase system, whereas they aren't even noticeable with higher order crossovers. There's the two-edge sword that Thiel lived with during its entire run. I believe that acuity of perception is caused by the ear-brain interpreting the sound-source as "real" rather than an electronic reconstitution. 

Remember, I am not an engineer. I would appreciate being educated as to how the hybrid might alleviate the need for 6dB roll-offs.

In the late 80s Toyota was building their Georgetown Camry plant and Thiel, IBM, Trane, Square D and Toyota were core members of the University of Kentucky's Advanced Engineering Initiative. What a trip. Also, the CS5 was a big deal in Japan. The chair of the AEI stirred the pot and we began exploring with Toyota a premium audio system for the not-yet-introduced Lexus. Their key people, including Mr. Toyoda, visited our plant, and we developed a proposal. Jim insisted that the best solution was integrated amp / speakers. Toyoda wanted Thiel speakers under the Mark Levinson Premium Audio System umbrella.

The project could have put us in the big-leagues, but the costs and risks of development were beyond our capacity. In fact, we were developing new products at break-neck speed and were production self-limited at 30% year on year growth with qualified dealers waiting in the wings . We couldn't handle it, even if Toyota were interested in our integrated solution proposal.

After Thiel Audio, I was involved as a consultant in a couple of Japanese  co-development ventures, and am confident that we made the right decision. Big Japanese corporations are a different animal than small American technology companies. 

Hi guys. I'm not up to speed with which amps do and don't, but I do have lots of general Thiel experience. I have noted that current delivery capability is very important, especially in large rooms or loud volumes. If an amp doesn't double its 8 ohm current into 4 ohms, it will probably sound anemic, and its oomph into 2 ohms is relevant also. Ayre amps are good fits. Jim used big Krells. Of related importance is that cabling is more critical on Thiels than usual. One reason is that phase coherence is easily scrambled by cables. On most speakers that doesn't matter because they are already scrambling phase, but the degradation is significant on Thiels. Also, Thiels very low impedance load requires more current through the cable, exacerbating its anomalies. I highly recommend very short runs of speaker cable. Jim used Goertz flat cable in 3.7 development.

Prof, I love it. Which model number? I need some long runs for house sound with CS 2 2s. 

Prof, obviously you need a bigger room. Build to golden proportions at about 12'3 high x 20' x 32' with "vents" near the corners (windows or doors work) and you'll have a room like Thiel's listening / optimization room and you can keep your 3.7s and join the upgrade brigade for even more musical satisfaction. What's a second mortgage compared to such bliss?

Thieliste, I have used many previous Pass amps and think very highly of them. (I don't know the INT-250). Nelson is a superb designer with values commensurate with driving a Thiel. The simple fact that it is doubling down to 2 ohms speaks clearly to the factors involved in driving a Thiel elegantly.

Because Thiel speakers present a sub-4ohm across most of their spectrum, dropping to 3-ish over extended ranges, the behavior of the amp from 4 to 2 ohms tells more than 8 to 4 does.

Hi Guys, As Beetle mentioned, I have a system for identifying cabinet misbehavior that permits real-time experimentation and amelioration. I use Chladni Patterns in my acoustic guitar design, I love the method, and will summarize here as applied to enclosures. On each panel in sequence, sprinkle glitter (etc), drive the cabinet with variable sine wave, stop when glitter bounces. The physical resonance patterns are mapped via glitter bouncing off the moving anti-nodal areas and accumulating in the still nodes. A seismic map! Take a photo. Increase signal frequency and repeat. Do all the panels.
One neat part is that correlations are easy to make on all panels, allowing a 3-D visualization and suggesting direct intervention strategies. This method is low-tech and enormously informative.
I have identified some modes on my CS2 2s, which are easily addressed. We can quiet down all the cabinets.

On other fronts, good progress is being made. Parts are on order for Beetle's 2.4SEs and my PowerPoint 1.2s. 

Jay, the cabinets are very quiet, but some issues are present. The 3.7 sings a little where the side meets the cap, and so forth. I'm just saying that we can make incremental improvements beyond the original performance parameters. Such on-going improvements happen regularly in many high-end product lines. We intend to keep Thiel alive in that way.

Prof, I agree with you. The cabinets are extraordinary in both anti-diffraction and inertness. I regard Thiel's cabinet engineering as state of the art. The approach I am taking is to investigate all areas where additional input might make improvements. Various test reports, such as John Atkinson's thorough work in Stereophile, show various resonant anomalies which I may be able to minimize with minimal cost.

The drivers are fixed and excellent. The cabinets may benefit from small tweaks. The crossovers are the main focus. New improved parts quality throughout and optional outboarding are the main impetus. We are experimenting with 4-nines foil coils in the signal-path feeds and up-sized 4-nines round wire in the shunts, Mills MRA-12 audio resistors throughout and returning to point to point layouts. This undertaking is a labor of love for me and in no way meant to disparage the existing products.

Beetle, I haven't yet looked at the 3.5, but will look into it. The equalizer could indeed be ignored in an upgrade. The 3.5 has 6-nines coils and hookup wire and custom 1uF styrene bypasses. We could renew the 'lytics with best of class 'lytics, especially in shunts. But any 'lytics in Signal Path would benefit from our newly developing custom CSA-160 volt propylene cap. Mills resistors. Possible SP feed coil upgrade. Layout can be addressed by building a new midrange board to allow space on the main board for woofer and tweeter upgrade bulk. I'm settling to a system. I "did" the 3.6 today with our first-round assumptions which need confirmation with first-pair trials of 2.4 and PPs.

I can offer a general answer. For perspective, the difference between 33 and 35 Hz is barely academic, virtually identical. Thinking in half-octaves (15 Hz at 30 Hz) is more germane to performance class than is a few cycles. Low E1 on a bass is 40 Hz.

Differences are accounted for by technical particulars. Bass alignment is very specific to cabinet volume, rigidity, driver position, diaphragm mass, maximum excursion, suspension characteristics and motor factors. An alignment is optimized considering these many factors among others. 

As alluded to above via driver size, air-coupling is a factor in the experience of bass authority. The 3.7 10" woofer has 50% greater area to drive its wave-front, reducing compressive non-linearities of air. Bigger makes cleaner. The 3.7 cabinet is also more inert and its baffle is less compressive for attack transient integrity. Regarding prof's thought about bass voicing, the 3.7 was Jim's work, the 2.7 incorporated various outside engineering input. Jim tuned his bass alignment to Q.707. Many designers give a little slop for "bloom, bigness, warmth", etc. I heard the two speakers at Thiel at finalization and heard the 2.7 bass as tuned a little looser. Most designers try to second-guess popularity, expectations and so forth. Jim was fairly immune to those ways.

Also note that image is highly dependent on cabinet and driver edge effects. Prof mentioned the driver part. The 3.7 cabinet design (love it or not) is very highly functional regarding diffraction, even though the 2.7 might qualify for world-class, it is not as good. 

A factor that contributes to "great bass" is that of articulation which, in a first-order design, includes the low end of the mid-range driver. Jim's 3.7 XO treatment is much more sophisticated and uses better parts than the 2.7 due to budget constraints and designer choices. The 2.7 midrange is fed through a 400uF electrolytic cap, albeit with a PP and styrene bypass in parallel. The 3.7 uses a bank of 75uF polypropylene caps with a styrene bypass. Multiple smaller PP caps provide faster reactions and less distortion than a large electrolytic.

Unsound, the 3.5 equalizer addresses only the bass with a simple, shaped boost centered at 22Hz or 40Hz depending on selection. Our reference set-up during development was bi-amped with identical amplifiers and 4 identical wire runs providing no EQ pollution into the midrange-tweeter circuit. (We were subsequently amazed by how many ways users could screw things up with varying amp and cable configurations working at cross purposes. So the bi-wiring option went away.) The EQ circuitry is elegant enough, but the budget required utilitarian execution (and use of generally inferior interconnects) adding some grain and haze to the signal. Jim considered the ported solution (O2, O4, CS2) to be inferior to sealed-box bass and only grudgingly accepted the market necessity of the passive radiator rather than the equalized bass in aspiring products. We aired the possibility of an EQ for the CS5 (the CS5 followed the equalized 3.5) and we talked about a follow-up super edition with an equalized bass. But Thiel was a one-man development lab experiencing high growth, and there was not time to explore such niceties.

One intriguing reincarnation for a CS5 Super would be to add balanced equalizers to the CS5 bass driving a separate bass input. That bass section has three  woofers in two configurations loaded by two sub-enclosures. All bass frequencies up to 500 or so are covered by that subsystem.     

Unsound et al, Thiel's electronics were all developed and built in-house. Jim was a circuit guy before we took up loudspeakers. His first patent was a sweet phono head amp circuit which we built and shipped for Monster Cable to market. The various equalizers suffered from an identity crisis, being seen as such a valuable and viable solution to us, but being considered a pariah in the marketplace, in no small part via Bose's low-grade application of the idea, and therefore resented by many dealers and consumers as somehow unworthy, therefore limiting the budget to fund exemplary execution.

Regarding the CS5 bass drivers, remember the mid 80s were the Dark Ages. We were designing our drivers and Vifa was making some, such as the CS5 proprietary tweeter. Otherwise, we identified some driver manufacturers to customize appropriate drivers. Those CS5 Kevlar units incorporate Thiel magnet structures and copper shunt rings and long excursions. Those 8" Kevlar cones were extraordinary, much better than their 10" stable-mate, and crossed over superbly to the 5" low midrange. With their extremely long excursions, they moved lots of air. The CS5 bass alignment is different than it looks. The bottom and third subwoofer have mass-loaded cones to lower their natural resonance plus damp the upper breakup mode. The way they straddle the center woofer allows them to create a larger-than-obvious radiation pattern for the 20 to 50 Hz (plus first-order roll out) range. The center woofer is lighter and covers 50 to 400 Hz loaded by its own sub enclosure. Let's just say that drivers are chosen for many interacting reasons. These did the job very well.

As I mentioned, the CS5's Achilles Heel is the low impedance bass load and the delay lines required for proper time-alignment of so many drivers. As I mentioned some time ago, that speaker would do well via incorporating an SS2 powered bass driven through a custom Thiel external passive crossover for the two subwoofers. Above that we might drive the upper woofers via an equalizer and handle the top end with my imaginary driver that mounts a 3.7 coax within a 6.5" wavy cone triax. Let's make all those drivers with carbon fiber diaphragms while we're at it.

Jim's low-impedance choice is indeed a quandary. Even with a 4 to 5 ohm minimum, the voltage sensitivity would not have been too low. If Thiel were starting over today, I think we would settle on higher impedance not only to spare amplifiers, but to reduce cable interactions. Such speculation distinguishes imagination from history. 

Indeed, the inboard and outboard options are different beasts. Space / layout constrains parts selection inboard. Making progress every day.

Regarding spikes . . . my knowledge is rather primitive, since all my work was long ago, before any commercial products were available, so there is plenty I don't know. I'll tell what I know. We found hearable and measureable time-domain slurring caused by recoil-swaying of the "unanchored" speaker cabinet. The woofer moves the cabinet in amounts which are very significant to tweeter frequencies, especially their transient attack/timing/phase behavior. Over many years' experience I found the presentation to be more focused with spikes. And transient tests measure more cleanly when spiked. As usual, there are other considerations. Speakers on carpet usually sound smoother, mellower . . . more polite, "nicer". I judge that mellowness to be caused by subtraction of transient detail. And another thing: direct coupling to a wooden floor can cause coupling resonances in the under-structure, euphonic-harmonic and/or dissonant, which are not stimulated with the insulating carpet or isolation-type feet. Another note is that spikes that are not locked down can absorb energy via motion losses between the threads.

There are so many particulars and mitigating circumstances that I hesitate to comment. But you asked, and my comment is that rock-solid stability at the micron scale aids the speaker in its job of transient replication.

Fitter and all, the way the upgrade project is shaping up is to target the most mature iterations of separate-driver classic systems first (with exceptions.) There are many thousands of pairs out there approaching eventual electrolytic capacitor problems. The targets are PowerPoint 1.2 (because I use them in my recording /documentation work and think they have serious professional potential) CS1.6 (no expressed interest), CS2 2 (because I use my pair in my work and it is very special) and CS3.6 for the same reasons. These models use Thiel-developed drivers with proprietary and patented technologies, mature enclosure designs and considerable performance upgrade headroom. The CS5(i) is not on the list. Its fundamental upgrade option is to replace the huge bucket-brigade delay lines with a re-engineered baffle to place the drivers in correct offsets for time-coincidence and elimination of dozens of capacitors and resistors in the signal path. I have ideas and skills, but insufficient life-force to take on that project. Similarly the CS3.5. The CS x.7s will come later. They do have upgrade potential, but are stable in their present lives for now. CS2.4 is in the first tier because of broad interest, significant potential and beetlemania's willingness to collaborate.

All models will have an inboard and outboard option. Inboard space constraints limit some capacitor and coil choices, but all electrolytics will be replaced by high-functioning propylene caps, and feed coils replaced with 4-9s foil coils. Outboard applies same strategies with some larger, higher-voltage feed caps and larger gauge coils and optimized layouts. The cap choices settled on ClarityCap and Multicap RTX bypasses, after exhaustive research and correlation with Thiel history and values. All parts are ordered for first-round samples for PP inboard, PP outboard, CS2 2 inboard, and CS2.4 outboard. We'll be making music this summer.

I will be using an unconventional evaluation approach, rather than MLSSA and related lab development and measurement tools, which I don't have, but would love to find a collaborator for. I use Metric Halo SpectraFoo, a pro-audio tool for tuning rooms, performances and recording, mixing and mastering music, along with some precision meters and scopes. Our benchmark method will be the system I use for my professional instrument and music making. We'll record live in my studio direct to hard disc at 24x192kHz for playback in the same recording space through the same signal chain, through speakers under test. We have live thru playback (music or technical content) with very few unknowns and considerable control and documentation of bass, peak and mix levels. The results going in and coming out are all sampled and analyzed via technical measurements and simultaneous listening. Someone could build a speaker company on this methodology . . . 

You might notice that this scenario looks like more than an after-work undertaking. It is and I don't know how that will all settle. But I am enjoying this challenge and have high hopes for outcomes. Stay tuned.

The x.7 drivers are indeed breakthrough design. That said, the 2.4 drivers are very mature and made and tested in Lexington with significant, advanced technologies. The 2.7 cabinet is stiffer, but the 2.4 will come close in vibrational performance, especially after tweaking. Regarding passive component quality, the upgrades will leap-frog the stock x.7 series into pretty rarified territory. We can expect some veils to be lifted by applying technologies that were out of reach for the stock product line.

FYI: I have contacted the world leader in audio cryogenic immersion. I am previously familiar with what can go right and wrong in that process, and how to stay out of trouble. I will be comparing stock and cryo-treated crossovers to evaluate efficacy. 

Just for clarity, I think the CS3.5 is in many ways Jim's pure vision, especially the bass equalizer. I believe it to be a strong contender for an update / upgrade and I would be interested in addressing the crossover. However, I lack the chops and time to upgrade the equalizer, which would be required for system synergy, since in terms of sonic transparency, the EQ is already a performance limit. So many good ideas, so little time.

Rob, the passive parts quality will leap-frog present Thiel crossovers, plus we'll address other subtle issues.
Thielrules, since you have gear, give it a try. You can see the boost curve in John Atkinson's Stereophile review. That boost is designed to not overload the woofer on normal music content. Be careful with movies or other bombast.I among others here would be interested in what you learn.

Harry, the CS3.5 was introduced in 1988, but its lineage goes straight back to the O3 in 1978, updated to the O3a (equalized) in 1979, O3b and then CS3 in 1983 and the 3.5 in 1988, numbered such as the 5th incarnation of the fundamental "3" design. They all share the same design goal of full-range, accurate in all spheres 10"x 3-way reference monitors. One core value, early on, was sensitivity / efficiency. The O1 and O2 came in at 93+dB @1w/1m. The hard facts of physics relegated efficiency to a lower rung on the survival ladder, which haunted the brand furthermore.

A simple passive part update for the stereo 3.5 EQ might be feasible, depending on how much space is available in the chassis.

Wayne, from the beginning, before the O1 in 1976, we experimented with many wave-form paradigms before settling on the wide-dispersion point source that became synonymous with Thiel. A highly intriguing form was the sound-field created by two back-to-back speakers forming a bi-pole radiator. I have run a pair of CS1.5s backed against my CS2 2s with wonderful results. The back-firing pair can get by with less evolved amplification.

The designer's job becomes extremely easier by using 4th order Linkwitz Reilly crossovers which give you everything except phase coherence at the XO point. They introduce 360° / 1 full cycle, which is considered by some, including someone recently posting on this forum, to be zero. The full-cycle time error can be corrected with digital signal processing, if one is in the digital domain. The "new Thiel" pulled a AD-correction-DA jujitsu. It works except for that last truth of ultimate rightness of doing it right in the analog domain. I suspect the Magico to be doing in some fashion what I described, but I don't know anything about it.

Here's a little wood trip for those sort of folks. There is a wood in Bolivia of two principal species, Machaerium schleroxylon or acutifolium, the former upland and the latter lowland. Since mid twentieth century the Germans have exported it to Europe as Santos Rosewood, named for a port in Southeast Brazil as its "source". Lots of intrigue there, but not today. The Danish "Rosewood" finish has been this wood since the beginning. Not a Dalbergia (rosewood species) it acts and looks a lot like rosewood. In the 1980s I developed a direct Bolivian source including a substantial plantation project with the Chiquitano Natives. They distinguished between the upland and lowland types and I applied the names "Amberwood" to the lighter colored, more contrasty upland type and "Morado" to the darker, more purple, homogenous lowland type. Note that they are both photo-sensitive and lighten toward amber with exposure to ultraviolet. The photo tagged above seems to have a fairly dark stain, which looks like the "Dark Cherry" color, but Morado and Cherry are structurally different. Amberwood generally has no stain.

Jab, your lumber dealer will call the wood Pau Ferro, Bolivian Rosewood or Santos Rosewood. You may find some light colored boards, but the upland variety is more rare. You can bleach the darker wood to match your Amberwood.

Prof, Morado can be quite dark naturally. Thiel generally stained to match a standard sample, so some cabinets may be natural or some stained at varying levels of coverage to match the target.

Pau Ferro (Amberwood / Morado) is an excellent-sounding wood. My main business is supplying tonewood to guitarmakers. We introduced Morado to that world in the mid 90s and it is considered by many to be the sonically-preferred fingerboard stock, as well as highly regarded for acoustic guitar body wood. Like Maple, it has virtually no open pores and is a joy to finish. Be careful, about 15% of people exhibit a poison-ivy-like reaction to the dust. Wear gloves and a mask when working it.

Thielrules, your 3.5 performance is not normal. Perhaps Rob might supply guidance.

As you might surmise, I have been looking closely at the classic models to determine where to best expend resources for upgrades. A sad truth is that the 3.5 is old. Those drivers were modified commercial units and are no longer available. The tweeters and midranges are not rebuildable, but I believe Rob can rebuild the woofers. The 3.5 dates from 1988, so early serial numbers are approaching end-of-service-life for the electrolytic caps in the EQ and XO. Those are replaceable.

After considerable deliberation I have decided to not develop an upgrade kit for the 3.5. There are too many disqualifying factors recommending against spending significant money there. However, Rob at Coherent Source Service can help you keep them in service in stock or enhanced stock form.

Since I was behind the scenes, it is normal for folks to be confused. As Beetle says, I was part of the mix from the beginning. Before co-founding Thiel Audio in the mid 70s with Jim and Kathy plus two more indispensible players, I had been a singer-songwriter-guitarist at the college coffeehouse level, had done some recording and had a producing art-craft studio with Walter Kling, another of the founding members. We made various artifacts of our own design - I made about 500 stringed instruments by the time Thiel Audio usurped my life. Fred Collopy, a college friend of mine joined us as business manager and Kathy stepped up for marketing and we decided to give speakers a try.  The Strata-gee.com interview from earlier this year scratches the surface pretty well.

Regarding Jim's records; they were detailed and extensive. They are missing in action through the change-of-ownership. I hope to recover them, or access to them. I agree, they are foundational for any real progress going forward.

Jay, my songs included Dylan, Leonard Cohen and many of the more insight and art driven folk fare of the time with a focus on my own music and that of our folk trio built around a female vocalist-arranger. We applied the seriousness of youth without any thought of making a living at it. A huge lesson for me was the radical difference between any recording and the live event and that commercially produced music could not be counted on as a reference. Record-making is a deep jungle.

Batman, please remember that I was not involved with THIEL since the mid 1990s, so my observations reflect general approaches rather than specific product knowledge. Jim's approach was very analytical and different from many audio engineers. Jim chose to make the speaker's job that of translating its input signal into the room. A corollary is that preceding links in the chain were also required to do their part. A signal chain must be clean, which is a tall order. Most designers of my experience hedge their bets toward forgiveness. Jim went for truth.  When it came to amps and cable, Jim would measure and listen and determine how well a link, cable in this case, was performing its job transparently. I judge that Jim chose that Goertz wire because he determined that it did a better job of being wire and that silver, being a better conductor did it better, both measurably and aurally . . . and so forth. This determination is different from whether he preferred the sound of silver to copper, flat or round but rather that one was a better wire having less distortions. The lab amp lived under the measuring tower with cable runs of about a meter and the listening room had several highly regarded amps with short cable runs.

FYI, Gary Dayton, Thiel marketing and Jim's lab assistant, is working for Bryston and should have deep knowledge of Thiel-Bryston synergies. I imagine he can be contacted through Bryston or gary.dayton@gmail.com

Searching is a sweet part of finding.

Thosb, As Beetle mentioned, the 2.3 is not a front line candidate because more interested folks have 2.4s which have more evolved drivers. But 2.3s have potential and everything we are learning on other models applies to the 2.3. If you are so inclined, we could help you create a pair of well hot-rodded 2.3s that will definitely address the "tizziness / brightness" to a significant degree. 

Be aware that your room has a significant issue of the length being close to double the width. Your standing waves and timing reflections are likely the significant limitation to performance. Diffusion in the corners will help. If possible, consider orienting on an axis not parallel with any wall to spread out early reflections.

Welcome.

Dan, I have one SS1 and two SS2s (one working) in my studio. For my purposes of verity to the source, I've not heard anything close.

Jay, thanks for the Classe lead. I hope to identify and develop a solid electronics repair solution for EQs, SmartSubs, etc. that fall beyond Rob's grasp. Please keep that in mind for all of us.

Indeed, I came of age in the mid 60s and identified with the counter-culture and the folk resurgence, but from an unusual perspective. I avoided the drug thing and much of the dismissal of tradition. After high school I became a Brother in a teaching-social justice oriented religious order and continued studies in philosophy / social justice / human development until 1974 when I exited a PhD program to open my Conceptions Studio enterprise. My anti Vietnam War work and orientation underlay that time.
I formed a commune of sorts and bought land in the Cumberland Plateau of Kentucky to go "back to the land" and live outside the norms of mainstream society.  Thiel Audio was one of our community-cohesive work ideas that took root and "made it" to the exclusion of everything else. Have you ever ridden a wild horse?    

Ron, I likewise have noticed that except for the likes of us here, Thiel seems rather passé. I expect that attitude to change as we gradually and by degrees create new possibilities for these classic models via upgrade options. A quiet Resurrection is what I envision. I am investing considerable time in the ReXO project.  A full 2.7 XO re-envision is a way down the road, but to the extent it might interest you, there are some upgrades that you could perform yourself or with a handy friend. I guess my point is that rather than taking a beating in a soft market, you might change the terms of engagement.

Dan, I need my SmartSubs for my emerging guitar-making-research-recording-evaluation studio. One SS2 is being repaired. I'll report on the level of success.

350wpc is not too much. Too much really doesn't exist in my book, although there are small-amp aficionados who specifically want the wet sound of overdriven tubes. The amp you listed above @ 250-8 x 375-4 I judge to be inadequate (without ever hearing it.) If an amp doesn't double its output from 8 to 4, it is current limited and therefore producing distortion when driven hard. Thiel speakers drive hard, dropping below 3 ohms over extended ranges. That amp is likely to sound ragged / dry / conjested plus it could blow up drivers at high volume. Look for an amp that doubles from 8 to 4 and makes at least 1.5x its 4 ohm rating at 2.

In the long run, I believe the 2.7 (and 1.7) will become collectors' items. They were made in Lexington after Jim's death and before the sale, using old-Thiel type parts (high purity inductors, PP caps with PS bypasses, etc. on point to point boards. The 2.7 uses the 3.7 coax with a smaller woofer for a hypothetically "easier" crossover than the 3.7. I suspect that further tweaking, such as replacing the big electrolytics with PPs might make the 2.7 one for history.

Dan, if the MacIntosh amps deliver the same value into the three loads, the design is power-supply-current limited and will not do a good job. I have no current (ugh) knowledge of your best choices. Members here are quite well informed about best offerings. I have used Krell, Pass/Threshold, Ayre, Levinson, Conrad-Johnson and old (DR6 & 9) Classe. I have never heard a class D amp that I liked with Thiel. Whoever knows something definitive please speak up.

Jon, your experience coincides with mine and many, many more in my experience. The fact that the amp doesn't double into 4 ohms says that it is out of power as current demand increases. Thiel speakers have low impedance for high current appetite , especially in the bass. So, doubling your available current in the bass is germane. Your blown midrange was almost certainly caused by distortion which heated the midrange voice coil beyond its limits.

As an aside, the only driver failures I have seen have been burned voice coils, caused by overheating, caused by distortion. In all the years of heavy-duty, overnight, stress and show conditions, I am not aware of ever "blowing" a Thiel driver. We had big amps with high current delivery power supplies.

Harry, I have looked long and hard at which models to hot-rod. My choices center on Thiel-developed drivers and a long life horizon going forward. Although the 3.5 was a defining product in its time, it doesn't check enough boxes. The drivers are modifications of commercial units with little of Thiel's proprietary magnetics or cone materials and geometry. Those drivers are becoming obsolete. Same can be said for the equalizer. Redevelopment of a product is a substantial undertaking requiring custom component development and re-voicing via systematic measurement and listening, like when a new product is developed. I expect the results to be worthwhile.

The first-tier models are the PowerPoint1.2, CS1.6, CS2 2, 2.4 and 3.6. Next round includes the 2.7, 3.7, CS6 and 7.2 - in order of expressed interest and personal time availability. First tier hopes to debut before year's end. 

I agree with your "masking" comment, which can be attributed to various factors. Among them is the presence of electrolytic capacitors in the signal path which are at or nearing their end of life expectancy. Since you love the speakers and if you or someone you know is capable, I believe you can make a great improvement yourself by removing the crossovers and replacing the electrolytic caps and resistors with like-values. (Your coils, wire and layout are excellent.) If that prospect interests you, I can point you to brands and sources which have emerged from our upgrade project research. You are welcome to send a PM to explore this avenue.

Harry, I neglected to mention that Rob Gillum of Coherent Source Service is capable of doing the job if you prefer that route.

Regarding impedance, it is what it is. The designer chooses the nominal impedance for fundamental reasons and then optimizes all parameters around those dirver particulars. In particular, Jim needed low inductance drivers for high-end extension and low distortion, which is determined principally by voice coil turn count. Jim believed that if amp designers took their work as seriously as he took his, they would make amps that did their job of doubling their power into halved impedance loads to 2 ohms.

I have expressed a differing opinion here previously. IF the nominal impedance could have been 6 with minimum 4 ohms, the voltage sensitivity would be lower, but more amps could drive the load well. But, that's a big IF, because the laws of physics can not be suspended. So, we have 4 ohm speakers to contend with and the amplifier choice is of fundamental relevance to system performance. 

For the Record: Audio Consultants in the Chicago area was indeed as good a dealer as a manufacturer could ask for. Count on them for straight dealing. In those days of knowledgeable brick and mortar dealers, such questions of system pitfalls and synergy were a big part of the dealers' function. Nobody would be sold an anemic amp with a Thiel speaker and dissatisfaction and driver failures were a rare occurrence. 

Thiel has used the same internal wire since the 03 in 1978, before the time that wire became a component. We identified a high purity, long crystal, oxygen-free polished wire in teflon jacket, developed for the aerospace avionics industry. That wire, twisted at 2.5 per inch does the job in separate runs from input terminals to XO and XO to each driver, with no shared grounds, etc. The wire is a known component of the XO network, so all its factors are measured and listened to as system characteristics.

When ITT / Florida stopped making that wire, StraightWire developed an equally excellent source and Thiel used that exclusively going forward.

This internal wire is a different animal from amp to speaker cable runs which must be engineered without knowing source or load or ambient impedance, capacitance, length of run and so forth.

I have no actual knowledge of Goertz except that Jim used it in the lab as a reference quality cable. The industry works in many ways and each company develops its own value-style. Thiel valued long-term mutually sustaining relationships built on product, company and dealer synergies. In such relationships, the players share feedback and experience for mutual benefit. Thiel and SW worked this way for many decades. So it is no surprise they used each others' products or co-exhibited at shows.

I can't make product recommendations, because my personal experience is thin and very dated.

Indeed wire is a squirrelly stew. Considerable knowledge exists, much of it in the realm of very high tech-space research-at the fringe of measurement. High end audio "found" wire as a new frontier in the 1970s and some very good work has been done since. There also seems to be considerable borrowing of second-hand knowledge, repackaged with huge mark-ups attached - commonly called snake oil. But most oil has no snake in it and much wire technology is indeed real and crucial for ultimate performance. To the material dynamics of bare wire, add reactance of coatings and influence of geometry, and you see that complexity increases exponentially. We know much less than we don't know.

Exploration of these frontiers adds to the richness of our journey.

Presently I am comparing coil configurations as fed from the circumference or the core. The oscillation of the electromagnetic fields behaves differently in each layout. Opposing opinions exist among intelligent and qualified observers. Most say "it doesn't matter", which I interpret as "I don't wanna go there." Who knows where this road goes?

Hello folks; just letting you know that no grass is growing under my feet. I am making good strides toward first test samples. The CS2 2 development has dropped back till autumn and the PowerPoint and CS2.4 are now the first-tier projects. The big bundle of ClarityCaps is shipping in a week with lots of trial samples including the custom CSA-160 volt cap. This cap utilizes CSA technology with a 160 volt film to be small enough to fit inboard layouts. The outboard XO option seems to be dropping out via better inboard solutions.

On another front, I learned that Rob got the Klippel Analysis rig from ThielNashville, so it will likely find a place in this development project. World-class tool. Also, I have ordered the new, long-awaited update hardware for my Metric Halo SpectraFoo analysis rig which now sports 32bit x 192kHz ultra clean conversion and 64bit real-time multi-chip processing. This rig is used for recording and concert hall analysis, but applies well to speaker development. I am learning it.

Also, my Classé amps return this weekend from the rehab shop. While re-capping, I also upgraded the caps and added some bypasses. DR6 (late) preamp and 2x DR9 power amps. (100 w @ 8 ohms, 200 @ 4,  400 @ 2 ohms, one amp for each channel. They're old 1990 gear, but I know them well, and love what they do.

Additionally, some very knowledgeable and experienced folks are contributing to the project. By year's end I hope to have a version or two of upgrade crossovers for the 2.4 and PowerPoint. Stay tuned.

Tom

Dn, sounds like a wonderful setup. I don't know those amps, but can offer some general thoughts. This group might offer opinions of the Lyngdorf. Read between the lines, it might be class D and/or digital amplification, which you would have to sonically evaluate yourself: Get return privileges. It doubles from 200wpc@8 to 400wpc@4. FIND OUT how it behaves into 2 ohms. If at least 600wpc into 2 ohms, it will not distort under a Thiel load.

The Stellar M700 reads well too. Same suggestion regarding 2 ohm performance of at least triple the 8 ohm performance is required.

Regarding the PowerPoints: your dealer might help you through the power requirement equation. Your room and listening levels matter a lot. However, don't underestimate the PP and MCS. I am using PPs for my near-field and mastering monitors, and they are my first XO upgrade project. They and the MCS are in the same hi-end league as the floorstanders. If in doubt, and if you can, lavish amplification on them.

This is a long-shot including some hearsay. Jim began working with a very talented circuit designer at Vifa/Denmark in the mid 80s on what became the SmartSub amps. I have heard that he is or has worked with Lyngdorf. If true, that's a very good indication of excellence. They look excellent anyhow! Sorry that I've never heard them.

I love PS audio, but have not heard those amps either.

I notice that you use the plural for the SS2s. Congratulations. I know from experience that there is enough location information  in their signal to warrant careful positioning. Try putting them near the primary speakers and pay attention to arrival times. Avoid putting them out of sight or in a corner as is often done. Even though bass waves are long and therefore near omnidirectional, their leading edge transient component is intact and important. Everything matters.

Keep us posted.

For the record, the CS1.6 is on my  upgrade list, as it has sophisticated, all-Thiel drivers and represents the pinnacle of the 1-series (pre-coincident driver) and there were thousands of pairs produced. There has been no expressed interest in the 1.6 upgrade, nor do I have a pair. So it is on the back burner, but simmering nonetheless.