Thiel Owners

While some might enjoy these Thiels with tube amps, ultimately I don't  believe tubes are the ideal match:

I can't comment on Pops current cable recommendations, and I know he's previously tried some of the following, but I'll put them forward any way:

Alpha-Core Goertz (w/ rc networks or zobels)

Ocos

Straightwire

Wire World

Enjoy!

^Interesting, your impressions of the MI 2's vs. the MI 3's were so different than mine. I found the MI 3's to negate the emphasis of the brightness region (mid to lower treble), centering  the sonic midrange, and though appearing contradictory; making the bass both tighter and richer . Perhaps it's due to different model Thiel's, with different amps, in different rooms through different ears. :-)

dar57, Most rooms vary enough, that there are no hard rules. My room is very similar to yours, though I do have a rather high ceiling.

I prefer the long wall placement when it can work. I have my Thiel's backs out 3' from the wall behind them, 10' apart center to center, >5' from speaker cabinet wall to side wall, with my listening position close up against the opposing wall with a large piece of thick foam with thick fabric covering, speakers are about 9' from the listening position firing straight ahead, without toe in.

Of course one could use other approaches, i.e., rule of thirds, etc.. With Thiels  do try to keep 8'-12' from listening position to speaker. Keeping the entertainment center cabinet well away from the speakers is a very good idea!

The bottom placement of the speaker terminals might be nuisance when auditioning cables, but once one's decided upon their favorite cables, I find their unobtrusive appearance and the hidden from children, pets, etc. a bonus. I would think again about raising the speakers.

BTW, why travel to get cables when cables can come to you;

http://fatwyre.com/

http://www.usedcables.com/

oblgny, At the risk of appearing petty, the 3.5's come with an external equalizer or bass booster not a cross-over. Though the smooth impedance rise with it's insertion mitigates its total demand on amplifiers, it does put added demands on amplifiers none the less. The point being, extra power can be quite beneficial with these particular speakers.

It appears as though you might be able to use the Primare i22 with the 3.5's if you aren't using the tape loop for anything else.

Though it was some time ago, and the state of Class D amps might have progressed since then, Jim Thiel once told me that Class D amps were only suitable for subwoofers, and not competitive with traditional amps further up the frequency range.

If you like to try different gear with your Thiel 3.5's, I suggest you consider some iron fists in a velvet glove old school high out
put big iron: Krell, Threshold, etc.

I suppose the MF200 would sort of qualify. I'm a fan of c-j ss. I ran an MF 80 with CS 2's (Thiel's easiest load) when I had a smaller room years ago. The c-j's don't quite double down the same way, and the bass isn't quite as tight. A small bit of c-j warmth coloration seeps through, but that isn't exactly unwelcome with these older Thiels. The c-j ss amps match very nicely with most tube pres as well. C-j's own ss pres are quite nice too. BTW, I found the Goertz Alpha-Core MI series cables to work beautifully with c-j and Thiel.

I keep an eye on Class D, though I haven't heard all the latest. Conceptually I love the idea,  and while there are differences amongst them, I find the treble curious on all of them. Is it because I'm not used to such a clean presentation, or are they lacking in harmonic extension? I'm not really sure. What little there is of published measurements are not especially encouraging. I hope I can look forward to your sharing  your impressions of them, especially with the 3.5's!

oblgny, I've heard the other arguments, but I steadfastly believe that "backasswards" is exactly how you should build a system! Starting with knowing how much of the contents of the billfold in your back pocket your willing to depart with, to the listening position in your room (where the sum everything before comes together), and the room (don't forget the treatment) is so important, then to speakers (the most colored of components, so make sure that those colorizations are the least objectionable possible) that will vary more in rooms more so than the vast majority of reasonably compatible electronics ever will, to the amplification needed to drive those speakers in that room, then keep going back to the source(s), then to the rack, finally fine tune with cables.

If you like Pass Labs, there's a good chance you'll like Threshold, some even prefer the Thresholds.

Curious that they list the doubling down 4 Ohm rating of their A60 amp (250/500 both channels driven) but not their A34.2. If it's not specified, I'd be hesitant to assume anything.

Unless the amp has lots of power to spare, if it doesn't double down, it will compromise frequency linearity with most dynamic speakers such as your Thiels.

tomthiel, I’m in complete agreement with your criterion, demonstration of proper square wave and step response would be required.

I could imagine a tri-amped Thiel with a 3.7’s mid/tweeter and 2 3.7’s 10" woofers above and below as in the MCS except in an hourglass shaped floor standing cabinet with separately adjusted/amplified
woofers to correct for floor reinforcement differences, designed to be placed directly against the back wall, or if particular room dimensions permitted in the corners then massaged with individual driver DSP room correction. Oh and it might be nice if the minimal impedance was kept to a minimum of 4 Ohms. The tube guys would like that! Heck, with the prospect of paying for six channels of amplification so would the ss guys.

The DEQX and Lyngdorf products look interesting.

^jimthiel, you hit exactly upon what I thought would be the main concern: driver/total loudspeaker correction. I would have guessed that with the co-axial drivers it might not have been too much of a concern with their mechanical cross-overs. The obvious advantage for those models with bass eq's is appealing of course. Perhaps a fusion of active and passive, or just going digital (which could probably reduce developmental labor hours) might be an option. Of course such an option could provide adjustable bass eq for one's actual room rather than perhaps an otherwise unused anechoic standard.

tomthiel,

There's another SS2 listed on e-bay. I have no knowledge of the particular item or seller.

The 3.5's and 3.6's used different drivers, similar but different cross-overs. The 3.5's used bass eq/boosted sealed boxes, and with the 3.6's a passive radiator.

IMHO, the 3.5's are more coherent, have deeper bass response, and are easier to amplify. The 3.6's are more refined and suave in the mid to upper frequencies, and are capable of more dynamic range.

The amplification requirements of both requires careful consideration, especially for the 3.6's. With that said, most seem to prefer the 3.6's and I seem to be I the minority of preferring the 3.5's.

https://www.stereophile.com/content/thiel-cs37-loudspeaker-specifications

https://www.stereophile.com/content/thiel-cs37-loudspeaker-measurements

Note that the sensitivity is spec'd as:

90 dB / 2.83 V/m (not 1 Watt)

the sensitivity is measured as:

90.7 dB 2.83 V/m (not 1 watt)

Note that the minimum impedance is spec'd as:

2.8 Ohms

the minimum impedance is measured as:

2.4 Ohms

This means that the equivalent "efficiency" as when using 1 Watt will probably closer to <86 dB.

Note that the only times the impedance rises above 4 Ohms (and then only in the deep bass region) it's met with rather challenging phase angles.

Note that through much of the bass and lower midrange that the impedance is below 3 Ohms.

Note that between 60 Hz through 20 KHz the impedance is always below 4 Ohms.

Note that Thiel recommended between 100 and 600 Watts per channel. That recommendation is based upon the standard 8 Ohm amplifier rating, with the understanding that the amp would double down as needed. If one wanted to do this comfortably without amplifier strain, being able to double down to 2 Ohms would mean between 400 and 2400 Watts into 2 Ohms. Why do you think Jim Thiel used 600 Watt Krell's with the 3.7's?  See Pages 16 &17 in the link below:

http://www.krellonline.com/assets/support/FPB_ORIGINAL_SERIES_MANUAL_V982.pdf

The more recent Thiel's are a bear to drive, limiting appropriate amplification to those well engineered products that are up to the task.

The job of the amplifier is to power the speakers. Limit the search to those amplifiers that are capable of the work required, and then choose your preferred sonic signature. Anything less is compromising the work that went into developing these speakers, and the potential to fully deliver what they're capable of.

 Something else to consider; underpowering speakers, and especially those with 1st order cross-overs might lead to damage.

^BTW, Class A is not a guarantee of high current. Consider SET's. And the Krell 600 Watter can deliver it in Class A. Well, it can deliver as much as the wall outlet gives it to work with.

Tomthiel, thankyou for your prompt and illuminating response.

Were the 3.5's eq's developed and/or built in house or contracted out?

Your recollections and future considerations of the CS 5's is most interesting. Perhaps my favorite Thiel model. If it weren't for the associated amplifier demands, I'd probably own a pair.

I've wondered why Jim used three 8" drivers rather than say a some combination of progressively larger bass drivers, and why he chose such a low impedance?

David, welcome! In answer to your question as to why more Thiel users don't use pure Class A amplification: cost. And heat.

To my ears, though typically advantageous, Class A is not the only criterion of the many upon which an amplifier's sound is determined. 

 Jim Thiel's power recommendations were based upon standard solid state 8 Ohm ratings (with a level of quality expected), where it could be assumed that the power doubled down as impedance halved, not the impedance load of the specific speaker.

Let's take your 3.7's

https://www.stereophile.com/content/thiel-cs37-loudspeaker-specifications

 for example: with power recommendations given as 100 - 600 Watts per channel. Of course actual power needs will vary with rooms and desired volume levels amongst other things. But, for the sake of this post, let's fall on the old audiophile axiom that one should first consider starting with double the minimum power recommendation, which in the case of the 3.7's would be 200 Watts per channel. 200 Watts per channel of pure Class A amplification comes with some expense.

Many high quality amps runs their bias towards Class A before sliding into Class AB. For example I run my 3.5's with their  recommend power of 50 Watts minimum 250 Watts maximum (with hints of 300 Watts max).  My Threshold amplifier is rated at 250 Watts (8 Ohm) per channel. The first 20% (50 Watts) biased towards Class A, then sliding into Class AB. Now into my 3.5's 4 Ohm minimum impedance; as the impedance is halved, the power doubles to 500 Watts per channel, but the Class A bias output is halved to 25 Watts per channel.

This not only true for some Class AB amps. Some amps that claim pure Class A output really only do so in their standard 8 Ohm rating, but as the impedance halves and the power levels double; their Class A outputs halve as well, with the increased power correspondingly sliding into Class AB.

https://www.stereophile.com/content/threshold-stasis-sa12e-power-amplifier-page-2

Of course some amps that tout pure Class A output, really don't. 

https://www.stereophile.com/content/krell-ksa-250-power-amplifier-when-class-class

We know that power consumption is not linear but rather exponential, and musical content can demand many, many times it's nominal power requirements. I haven't measured the bias output, but I suspect that much of the time my amp is behaving towards Class A bias. But now with the capability to cruise at 500 Watts per channel all day long (with short term headroom doubling that to 1000 Watts per channel).  

Now some might suggest that some of these power recommendations into actual impedances are outrageously high. To those may I remind them that with Thiel's and most typical speakers for that matter, that as impedances drop and power output increases that speaker sensitivity decreases correspondingly. So for general comparisons one might see the wisdom of the standard 8 Ohm ratings. Or not?

Would I prefer more Class A output? Probably, double that would be dandy. All 500 Watts per channel into 4 Ohms Class A? Sure! But, for my money I'd probably move up the line in speakers first, and settle on less Class A output with Thiel CS 5i's.
  

 Thiel's weren't made as cost no object super premium products, though in their time the CS 5's were knocking on the door. Given the cost of pure Class A with enough power to drive most Thiel's, some of which approach 2 Ohms (and some with challenging phase angles), I think many might find the money might be better off spent elsewhere. For example with the 3.7's, and given enough room, I can easily see someone spending the money on Thiel's own subwoofers before committing the funds towards up to 600 Watts of pure Class A amplification (if you could find it). As a general guide (and with adequate funds available), perhaps a reasonable starting point might be amplification meeting the minimum power recommendation with Class A and the maximum into power recommendation sliding into Class AB. If one could afford to provide the maximum power recommendation all in pure Class A output into actual minimum impedance load, perhaps all the better. But be prepared to pay!

Hi David, please accept my apologies if I wasn't clear in my previous post.

As for the Pass Lab users not using Pass Labs X amps instead of Pass Labs XA amps, every Thiel user I know that asked for guidance directly from Pass Labs has reported that Pass Labs has suggested that the X's would better serve Thiel's, with X250 and X350 with their various "." derivations most commonly recommended.

Yes, there are truly pure Class A amps that can double down while maintaining Class A all the while (the early Mark Levinson ML2 w/ 25 Watts output certainly jumps to mind). I was merely trying to make a generalized comment to a larger audience that might mistakenly believe that all amps that tout Class A, don't necessarily do so all the time. If I recall correctly the Aragon mono's dropped all Class A output below 8 Ohms despite being touted as pure Class A. I remember another manufacturer of a very highly regarded amp admitted when pressed that despite claims to the contrary, that his amps weren't really Class A and argued that it made no difference except in the market place perception. The current Pass Labs XA's aren't really pure Class A, as they provide extra Class AB Watts when power demands require it. To their their credit they only advertise the true Class A output, but unfortunately some leave thinking that these (advertised) relatively low output amps prove that extra power isn't necessary and/or that Class A is more powerful than Class AB.

Doubling the minimum recommended power is not my axiom. I've been at this for a few decades and it existed long before I became involved. Which is why I chose to use it previously. It is merely a long used generally accepted starting guide. I do believe that time has been kind to this guide, and though one might find less or more power might be required, and as difficult as it is find any specific guide I've found this one to be especially helpful as a general starting point. Heck, I can remember a time when 200 Watts was a broad brushed minimum recommendation for a serious system. That I think is an over simplification.

 As for an amp being able to handle a 2 Ohm load, keep in mind this is more of a prerequisite with some Thiel's (especially at lower power outputs) if one cares a whit for frequency and amplitude linearity. Despite what might appear to be technically true, the 200 Watts that your Accuphase puts out at 2 Ohms is really not so different than 50 Watts into 8 Ohms. Which really isn't all that much. Now in a smaller rooms playing music without much in the way of dynamic contrast such as much small choral works or chamber music 50 Watts might be more than enough, but for realistic symphonic music in larger rooms it might be lacking. There's a reason Jim Thiel allowed his loudspeakers to handle such big power inputs, Many other speaker manufactures discourage such power, as their speakers can't handle it. Sure one can get sounds out of most any Thiel with even the most low budget low powered amplifiers, but if one wants all that Thiel's are capable of, then more high quality Watts are needed.

The halving of Class A output with impedance drops isn't really all that much of a problem. I just pointed it out because many attribute the sound of some amps due to their Class A output, when if fact it might be due to something else. Most of the time our speakers really don't require that much power. It's really only when things get loud do the speakers drink up copious Watts. But then the demands really ramp up. The thing is that as things get loud our ears aren't as sensitive to all the delicacies', that is until real distortions start to rear their ugliness. Personally I'd rather deal with an adequately powered Class AB amplifiers cross-over distortion than even the impending clipping of an underpowered Class A amp. Especially with solid state amplification. That is not to say I'm suggesting tubes with Thiel's, I don't. Though some do.

I do think we're really much more in agreement than not. I was not specifically trying to tell you what to do, or what to use, but rather to offer a more generalized response to a larger audience for your rather good question. I used to often say that we all hear differently, but I now realize that it's probably more correct to say we all listen differently. I don't like to argue with success; if your happy, enjoy!

^please delete the first "not" in the second sentence.

 sorry

2018 will bring me to 30 straight years with Thiel's too!

not exactly the same thing :-)