Thiel Owners

tomthiel 

These wood species tend to change hues with time and UV exposure. Wondering how the factory mitigated that?

Hi everyone, I am curious about the differences between CS5 and CS5i. I couldn't find the info online so I thought I'd ask here. CS5 are rare on the market and CS5i even more so. Thanks in advance!

@duramax747 Thank you for the explanation. 

I would like to own a pair of these speakers at least once, but they don't come up all that often so it's more of a wish list thing. Thank you! 

@tomthiel Thank you for this fantastic write-up of the differences between the two versions.

Most CS5 owners upgraded to the CS5i.

Great to know that some of the CS5 out there may actually be functionally equivalent to CS5i

The only visual difference between the 5 and 5i is the mass loading of the subwoofers. The original rubber mats proved troublesome via eventual corner lifting of of the mats. The 5i MDF center plugs perform the same loading function without the hassles.

I read this a few times and I am still a little confused. First thing that came to mind was a MDF brace at the back of the woofer motor, but you say the difference is visible so that couldn’t be it. If you could clarify what the difference looks like, that would be really great. Also, would that difference be there in CS5 that have been upgraded to CS5i spec, or just in factory CS5i? Thank you!

@tomthiel Got it, thanks for clarifying. Looking at pics of both subwoofer versions the difference is clear now. Thank you.

@jafant 

Thanks for the tip. I researched High Performance Stereo in FL around the time they started advertising these two pairs. The online feedback was not particularly confidence-inspiring: it painted a picture of a business where a knowledgeable audiophile would be comfortable doing business in person, but online buyers reported horror stories that sadly sounded all too credible. 

PayPal protects online purchases to some extent, but may require goods to be shipped to a third party after settlement, at buyer's expense. That would be an issue :)

I live in the Pacific Northwest btw.

A pair of CS7 showed up on USADM. They seem reasonably priced at $2.5k, if you happen to be in Nashville TN that is (local pickup only).

One wonders why anyone selling high-end speakers online would only show 3 vague pics of said speakers, none of which even gives a glimpse of the drivers.

Speaking of internal speaker wiring, I am currently working on two pairs of speakers:

Infinity RS-II (above, c 1982) use 24 AWG stranded conductor throughout, from binding posts to drivers, often tightly bundled together

ProAc Point Five (above, c 2004) use Straight Wire-brand dual twisted-pair cable that looks like 10ish AWG.

It strikes me as two extremes. The Point Fives’ selection of drivers nowhere near calls for such plus-sized cabling. Inversely, the RS-II love gobs of current to reveal their best, probably straining the electrical limits of its long runs of doorbell wire...

Interestingly, both speakers use the same gauge wire for all drivers, which also seems counterintuitive.

My apologies for the off-topic-ish post, it’s just that ever since I started delving into these speakers I’ve been really intrigued by how radically different their internal wiring is.

[EDIT] I attempted to insert pics obviously, and they showed fine in Edit and Preview modes but got stripped from the post. No time to solve this mystery right now :)  My apologies

@duramax747 

I keep keeping an eye out for a nice pair of CS5i, so maybe someday I'll have to deal with the question of what to drive them with.

I have Classé monoblocks that are 200w into 8 ohms and 400w into 4 ohms. I'm hoping they might be up to the task, and I'm curious - which Pass monoblocks clipped? Also which amps worked best in your experience? Thanks!

So CS5i are as hard to drive as big Apogees? How low do they dip?

Amp designs vary greatly in this area and likewise does the nature of the sonic malaise.Amp designs vary greatly in this area and likewise does the nature of the sonic malaise.

Sonic malaise, what a great phrase :)

Some Apogees (Scintillas?) were basically one-ohm loads with dips down to .5 ohm if I recall.

It sounds like CS-5 are difficult to drive in the low frequencies. Are they bi-ampable?

What amps did the Thiel factory use?

duramax747

My room is approx 32x16 with a 12’ listening triangle. My speakers are positioned halfway along the long walls, so about 15’ from the front wall.

Re your Nashville auditions, I would hazard a guess that someone at the first shop mistakenly wired the Thiels to the 8 ohm taps of the McIntoshs.

and tomthiel

I agree 100% with the importance of adequate amplification. I got my Classé monoblocks to drive my Infinity RS-II, themselves interim speakers to tide me over until I get my "perfect" ones (the RS-II are great speakers btw and, despite the fact that I’ve probably spent more time so far working on them than listening to them, I’m growing quite fond of them).

I am prepared to sell the Classés and get the amps to match whatever speakers I get eventually.

jafant

Thank you for the tip regarding the 3 CS5i in Florida.

I would consider buying speakers online from a well regarded seller, though I would much prefer to buy locally here in the Pacific Northwest so that I can audition prior to purchase.

I also want to say what a great source of high quality information this thread is! Thank you for creating and moderating it.

tomthiel

This is fascinating. A history lesson, a reflection on the consequences of decision-making, and a deep repository of product information all in one.

That necessitated electronic bucket-brigade delay on the upper and lower midrange drivers accounting for nearly half the component count in that huge crossover. Those coils and caps are all in the signal-feed path, which creates most of the sonic reticence experienced in the CS5.

My immediate thought reading this - and please forgive me if it sounds in any way sacrilegious as this is certainly not my intent - would be to yank out the passive crossover, amplify each of the five channels individually, and control the amplifiers via a 10-way active crossover, DSP-enabled speaker management unit, which in addition to crossover duties would allow for precise delay adjustment for each driver / driver pair, and room correction of course.

Was anything like this ever envisioned?

Most crossovers use film caps in the HF circuit from the factory. In LF / MF circuits, I tend to replace same with same when I rebuild crossovers, figuring that where the designer used electrolytics they took the latter's inherently higher ESR into account in their overall design, such that replacing them with low ESR caps might alter the voicing of the speaker.

beetlemania

I totally hear you :) Then again, you had the invaluable benefit of being guided by perhaps the most qualified person on Earth. This, I think you will agree, is an unusual circumstance.

I was on my own for my last rebuild, short of conjuring a séance with Arnie Nudell. I don’t have quite all the skills to modify / redesign 5-way, 7-driver crossovers with any expectation of actually improving them.

I stand by my earlier comment as it applies to most enthusiasts; barring an expert guiding us, I do believe replacing same with same is the course of action most likely to yield success.

To put things in perspective, 14 out of 14 electrolytics I replaced tested perfectly fine, both ESR and capacitance, despite being almost 45 years old​. I did find three bad resistors and one bad rheostat though, which I wouldn’t have expected.

Another safe and surprisingly effective tweak is replacing any electrolytic cap with 2 x half-value caps. The ESR and other anomalies are reduced by half, plus if you turn one cap backwards, end for end, other anomalies are cancelled.

tomthiel

Interesting, I think this is the first time I hear this. To make sure I understand, you are recommending replacing, say, one 100uF bipolar with two // 50uF bipolars, correct? So, when you say "turn one cap backwards" do you mean just physically, as in making sure the writings on the caps run in opposite directions? Since both caps are non-polarized anyway.

As far as cancelling anomalies, is that because bipolar caps are internally non-symmetrical?

I had to // caps in my rebuild because original values were unavailable. The pairs are not equal in value, but close enough that hopefully the smaller ones don't act as bypass. Also, I never thought of swapping ends because I hadn't read this post yet

Thank you again for sharing your knowledge.

vair68robert

12.5uF. Replaced with 8+4.7uF house-brand caps from Parts Express. Similar quality level as OEM as far as I can tell.

I did upgrade severely heat-damaged 10% sandcast resistors (one was open) with 1% wirewounds and bumped power dissipation from 10W to 20W and 25W to 40W respectively.

How resistors got that hot in a speaker crossover of all places is not something I can claim to understand, seeing that drivers appear original and in quite good shape without evidence of having been grossly overdriven in the past.

agdrago

tomthiel discussed electrolytics in his post dated 01-18-2025 at 07:45pm

agdrago

A capable amp's power specs should read something like:

- 100W @ 8 ohms, 0.1% distortion or less 20Hz - 20kHz, both channels driven

- 200W @ 4 ohms, 0.1% distortion or less 20Hz - 20kHz, both channels driven

- 400W @ 2 ohms, 0.1% distortion or less 20Hz - 20kHz, both channels driven

- Stable at 1 ohm

Amps whose specs diverge much from the above template may sound just fine, or even fantastic, paired with high-efficiency speakers.

But amps that will convincingly, authoritatively drive large, low-efficiency floorstanders with unforgiving impedance curves ought to be able to deliver 150A current peaks, not 15A.

agdrago

Specs are a quick way to whittle down dozens of possibilities, but they're just one factor in a complex equation. Nothing replaces an in-home audition, with your components, in your listening room.

Happy listening! 

Fascinating reading! Thank you, Tom.

You are right, there’s a biography in there waiting to be written. Until then, I look forward to your future posts.