I happen to like Krell with Thiel quite a bit. |
The Krell dont match with Thiel, Iheard CS6 with
FBP, so fatiguing, I have not heard them with tubes,
but with the stratos extreme,sooo... musical,so natural,
instrument lovely,I was blown away when I heard the combo.
with tubes if you get the right power and synergy,I
would like to hear them.Not promoting stratos. |
Has anyone tried to increase the impedence of the Thiels as recently described in a home built journal. The author of the article was selling a transformer or choke coil that increased impedence and he claimed improved performance with tube low power amps? |
In as much as the 3.6's drop down to 2.5 Ohms, it's seems to be the most linear. I would imagine that would contribute to perhaps the most linear amplitude response of the group. |
In checking with Shari about impedance curves on the 2.3, 2.4 and 3.6, I found out some good data that I thought I'd post. It covers where in the freq. spectrum each model dips down and how far it goes....
"The CS2.4 speakers are the easiest to drive, with the CS2.3s being next, and the CS3.6 speakers being the most difficult load.
The CS3.6's impedance is at 4 ohms at 25Hz and then again at 55Hz. From there it drops to 3 ohms at 70Hz and on down to 2.5 ohms at 100Hz. It remains at 2.5 ohms until around 10KHz where it gradually rises to 4 ohms at around 36KHz.
The CS2.3's impedance is about 16 ohms at around 14Hz. It gradually drops to 4 ohms at around 100Hz. It continues dropping to slightly below 3 ohms at 500Hz, and the begins to rise back up to 4 ohms at 1000Hz and gradually increases to 8 ohms at 45KHz.
The CS2.4's impedance is at 14ohms at 20Hz. It drops to 5 ohms at 35Hz and rises back up to 12ohms at 50Hz. From there it gradually drops to 4 ohms at 100Hz and gradually drops down to a little above 3ohms at 700Hz. It gradually rises to 4 ohms at around 20KHz." |
About the 2.4 woofer, I did learn that is does not feature the oversized 3" voice coil introduced on the 1.6, although the cone is still larger than the net cone size of the nominal 6 1/2" driver used in the smaller model. (A measured cone size smaller than the nominal quoted driver size is typical of most manufacturers' drivers, with woofers usually being the most divergent due to their thicker suspension surrounds.) When I saw a 2.4 being tested for final assembly QC, they hit it with high-level low frequency signals that produced prodigous visible woofer excursion, I would guess on the order of about 3/4" foward-travel projection. Unfortunately for me, heavy demand resulting in back-orders kept me from being able to audition a pair of 2.4's in Thiel's listening room when I was there - they had to ship out the last set they'd had in there a couple of days before I arrived, and this despite the fact that almost all the current production at that juncture was devoted to that one model. |
Jazzdude, Thiel's 8" woofer cone is on the smallish side. I have no worries though. I've auditioned the CS2.4s three times now, and the quality and quantity of bass produced is impressive for the CS2.4's size. Anybody considering these for a small room should try them first. My CS2.4s will be arriving late this week or early next week. |
Tom_munro,
Thiel measures driver diameter by the size of the cage, not the cone. I am sure the cone is no larger that 6.5". I wouldn't be concerned, the woofer cones on the 2.3 are less than 6" and it has the best bass I've ever heard from a cone so small. |
That's interesting to know, Tmoran. I just got back from the Thiel factory where I took the tour, and it turns out that Thiel has, in the past, set up various models of their speakers in their own listening room with the same tube amps I use with my 2.2's, the VTL MB-185 Signatures. Shari (a 2.2 owner herself) thought the combination of this amp and their speakers was particularly outstanding among the many amps they've tried there (though she also thought the more expensive and powerful MB-450's did even better), a comforting report for me. She also plans to get herself a pair of 2.4's as soon as the factory can catch up with dealer demand, something she managed to resist doing with the 2.3's FWIW... |
I recently got a VAC PA100/100 tube amp and was hoping to be able to run Thiel 3.6's with it. But hearing everybody here recommend high current SS, I was nervous this combo wouldn't work well. So I talked to VAC's resident expert Kevin Hayes. Here's what he said.
"The CS3.6 is the speaker on which every VAC amp is auditioned before it is approved for shipment. In addition, it's the speaker that I'm using at home with my VAC Avatar Super. (I just bought another pair from Thiel
in January.)
Even the Renaissance 30/30 and the little Auricle can drive it; it's one of my benchmark requirements! The 3.6 is a fabulous match with our electronics, and I recommend it very highly. I prefer it slightly over their larger CS6, although that it also a good match with VAC.
I don't think I can say it any more strongly!" |
Thanks Tom for setting it straight - that's good news for 2.-series aficianados. Thiel's ads (unlike some others' I won't mention) are so carefully worded, it's hard to believe a boner like that could slip through the cracks... |
Sorry for that previous post. The most important correction being 100 to 400 watts. |
I called Thiel last week and they verified that the 2.4 has an 8" woofer. The 6.5" stated in the add is a typo. That's a pretty serious typo. I know I almost lost interest as a result. |
Zaikesman, the Thiel site indicates (for the 2.4) an 8" woofer and a nominal impedance of 4 Ohms impedance/ minimum impedance of 3 Ohms. Suggested power 100 to 40 Watts. Compared to the 2.3 bass response goes down a few Hz. Reads like a typical Thiel. |
It sure looks like good(?) bass response is getting expensive. My hopes of another sealed box from Thiel is looking less promising all the time. |
Well, that was just the ad, not the literature. And since this bass driver is smaller and seems to be the one from the 1.6, I wouldn't doubt that it presents a kinder load. But the fact that it is being called upon to extend lower in frequency range in the 2.4 would help explain why the speaker's sensitivity is rated at 87dB rather than 90dB as in the 1.6. Even though the cone diameter drops from 8" to 6.5", the 3" voice coil might well be bigger than was the case in the 2.3. Still, the smaller driven area might imply less dynamic range. I wonder if the 3-series replacement will go from the current model's 10" woofer down to an 8", leaving the 6-series with the 10". |
Zaikesman, as you know Thiel did something like this with the 3 series. The 3.5's went down lower than the 3.6's. There were of course different improvements that came with the newer more expensive model. I hope Thiel isn't trying to be cute with this less specific impedance information. It really doesn't jive with the honorable way they have always done business in the past. |
Unsound: Strike that sentence about the 2.4 redesign seeming to be merely an "intermediate holding action"! I just realized something I had missed before in the ad - the woofer is listed as only being 6.5" instead of 8" as in the 2.3 (and 2.2), so I can only assume based on its looks and size that this is in fact the exact same driver used in the 1.6. That would seem to be a step in the wrong direction for the 2-series, leading me to wonder even more how the new 3-series model - whenever it appears - will follow in the established progression. For the time being though, I'd have to guess that the new speaker will not possess the bass prowess of the model it replaces... |
Definitely VAC amps. Kevin Hayes the designer of VAc does a lot of work around thiel 3.6's. This would be a great match. e-mail VAC for recommendations.
SP |
Unsound, the precise ad copy reads "Uniform, resistive load works well with lower power amplifiers". I think Thiel's trying to tell us something - namely, that the 2.4 won't suck current like a Shop-Vac. So I will assume for the time being that they present a load not dipping much below 4 ohms and not having any high capacitive phase angle magnitudes. Like I said, we shall see. |
Zaikesman, "stable resistive load" is a bit vague. I would assume that it just means that the impedance doesn't vary much. Typical Thiel. I think they do this to maintain "amplitude coherence", IMHO a good idea. It still doesn't suggest current needs. I hope Thiel comes forward with the straightforward specs that they usually and responsibly do. |
Gs556 -- that's a nice performance of the Sonata (Serkin)! Sorry, off topic. |
If anyone's still interested, playing a Rudolph Serkin Beethoven piano sonata CD, the average SPL at the listening position (9 feet away, 13ft x 25ft x 9ft room) with the preamp pot at 12'oclock (50%) was 65 db with 71 db peak ("C" weighted scale, fast response). Not bad for a wimpy 2A3 with the Thiel 3.6. |
Unsound, as Drubin emailed me today, Thiel is listing the 2.4 on their website as being 87dB sensitive (the correct term for almost any measurement like this you'll encounter, though since almost all the measurements tend to be fudged a bit anyway, it doesn't really matter!), but they're also advertising it as being a stable resistive load, implying the impedance doesn't dip as low or the phase angle swing quite so much as on the 2.3, I suppose. My 2.2's are pretty decent in these regards, but I think we'll have to wait for some outside tests to know if anything's changed for sure, and I'm not sure Stereophile for instance will be reviewing a design that looks a lot more like an intermediate holding action than a completely new exercise. |
Zaikesman, with the the 1.6's it seems that Thiel is making their speakers more efficient/sensitive (I still don't know which term is technically correct). I can't help but feel that their efforts may be a bit misplaced. I think keeping the impedance load over 4 Ohms would have a greater appeal. |
Turnaround, maybe you've noticed that Thiel lately seems to be paying more attention to making their speakers a bit easier to drive than sometimes in the past. I do not think this is specifically in response to demand by tube amp users, but more for the home theater market, where one multi-channel amp may be called upon to drive several speakers and do it well. So it may be interesting to wait for the introduction of the long-anticipated replacement 3-series model, which could well improve on the 3.6's sonics while not being quite as much of a pig to drive. Mere speculation, but it does seem to be the trend around there. |
i have thiel 3.6. i used them with a krell 200c (now up for sale on audiogon) until about a year ago, when i moved to a bat 75se (75 watts per channel).
i chose the bat partly because it's one of the few tube amps that can easily go to low impedence levels, which the thiels need. (and it doesn't hurt that at lower impedences, an amp gives up a more power.) i chose the bat also because i wanted an amp that didn't get too tubey. i've never felt that i had too little power with the bat, but then, i don't listen to music very loud.
the differences i hear between the krell and the bat with my speakers are essentially those fundamental differences between solid state and tube amps. for example, joni mitchell's voice is more sensual and fleshy with the bat amp - yeah, sounds more real! - but the drum kit playing in the background has more punch with the krell amp - whoa, that defnitely sounds more real! (maybe the "kick" in the drums is an issue of power?) i also like the broader soundstage i sense with the bat, but on the other hand the krell enlivens the images within that soundtage (the bass, man!).
at least with these two amps, you're always trading off realism in one area to get realism in another. ultimately i've come to see it as a zero sum gain between these two amps. for me, however, i value listening to, say, miles davis in glorious hi-fi much more than, say, keith moon. that is, i'm okay listening to the who on a boom box, but less so miles. now the difference between these two amps is all in the nuances, not boom box versus hi-fi, but at this point it's those nuances that we chase after. so i've stayed with the bat because it's the more appropriate amp for what i most like listening to in hi-fi.
i think the choices available to you in tubes with the thiel 3.6s are very limited. if i had fallen in love with another tube amp at the time - one that wouldn't have worked as well with the thiels - i might not have gone tube because bulky speakers like the thiel 3.6 are hard to sell.
today, if i could very easily sell my speakers and get new ones, i would give it serious thought - not because i don't like the 3.6s, but because now that i've committed to a tube set-up, i suspect that another speaker might be a 100% match instead of 90% (am making up numbers here). but then again, maybe not - i really don't know, but i would appreciate hearing feedback from people on this point. |
Gs5556, I didn't really doubt you, I was just ribbing you. I don't dismiss low power - I've just never been set up to exploit it, as I like to listen to all kinds of material, and at higher levels than your amps would drive my Thiels. You are an explorer, and diverse too - hope your SET's and homemades work out well.
Bryhifi, despite Elevick's misgivings, you will not be in danger of damaging a tube amp by presenting it with a lower-than-optimal-impedance load, due to the self-limiting nature of the beast, but you won't get the power you paid for either. So I wouldn't worry about "failures", just sound that might not be up to what you've been used to in certain respects. But since you say you just want to get your feet wet before jumping in, who am I to say that you're risking not being persuaded by the results? When I ran my 2.2's from the MV-55, the combo did sound better than my previous SS amps, but those weren't even in the same county as what you normally use. Best of luck! |
Zaikesman: I am not having anyone on... I would never do that, especially here. I purchased the 2A3 amps to use with my DIY single-driver speakers I'm building. In the meantime, I hooked them up to my Thiels - yes, they do make more than enough SPL levels for classical/jazz for my ears in my room. But, the CAT preamp has a signal gain of 24 db which goes a long way in making them work the way they do for me. Granted, they cannot handle orchestras, rock, choral, pipe organs, etc., but string quartets and the such come through loud and clear. Heck, even symphonies are handled for the most part satisfactorily. I'll dust off my Radio Shack sound level meter and post back what I get at my normal listening levels.
My mainstay amps that I currently use with the Thiels are a pair of Mark Levinson 20.6 monoblocks (100W ea). I'm not saying that all SET's work for everybody's setup the same, but don't outright dismiss low power, high dynamic headroom SET's with 86 db/2.83V/4 ohm speakers - especially that most listening levels in a lot of living rooms are produced by far less power than one would think. But if you're tastes lean towards shaking the walls... and, to recall, this thread stated that "... volumes are kept very low..." |
Thank you all for the input so far.
I know all too well how the 3.6's are demanding speakers at higher volumes and extreme dynamics. In my insane search for absolute resolution and clarity in dymanics it took the mighty MDA-500's to totally blow me away. Unrestrained power and impact was amazing and resolution was beyond my expectations. My hearing is a precious thing to me being a musician and has lowered my listening levels in the past year. So now the MDA-500's are major room heaters and not needed (but truly loved) in my room. I kinda knew going into this that more power would be the obvious but wondered if anyone had tried an integrated tube amp without any major faults or failures. I'm encouraged to hear that Gs5556 has used a pair of 2A3 amps and surprised at the same time.
I know that I'm giving up the control and authority of the Krell's but really want to hear the sonics and warmth that tubes can offer. The Krell's will be with me always as a known combo with the 3.6's, But the levels of playback are kept much lower now and musical taste has shifted back over to acoustic, classical and sweet vocals.
Thanks all,
Bruce |
Be careful about resistance. The 3.6 tend to drop well below 4 ohms and are not too efficient. You should have a tube amp with 2 ohm taps and a fair amount of power. You could kill a 50 watt tube amp with 4 ohm taps if you listen long/hard/loud. |
TT's with big speakers of low efficiency, unless you listen at ambient levels in the 80db range, and noise ambient in a quiet house is at 70db's. Hmm, I don't think thats a good match. Remember headroom will consume at least 10 times the nominal power so with a SET you limited to listening at about 0.5 watts nominal and 5 watts for the peaks. Which means on a low efficiency speaker about 78-83 db nominal.
Current output for the bass simply cannot be there.
I recommend a lager toob amp. The VTL 100 compacts can be found for well under a G but plan on another 200$ to upgrade the toobs, and 300 if you want to upgrade the caps on the output stage, if you can do it yourself.
In anycase when you try it, don't give up the SS amp until your convinced that you've made the right move.
jeff |
Hey, anything will produce a sound, but I don't expect that sound would be for me. You're honestly the first person I've heard of running these speakers with a low-powered SET - what else have you used? (Unless you're having us on, that is... ;^) |
I use a pair of Wright-Sound WPA3.5 (2A3) amps with my 3.6's. No problem filling up my room, and no problem at all with the sound quality. I listen mainly to classical (string quartets, small scale orchestral, and jazz).
But - I have a CAT preamp (high gain) which does make a difference over conventional gain preamps. My room is about the same size as yours, has carpeted floors and drapes. So a 50 watt amp shouldn't be a problem. |
In my opinion, you are not going to get the most out of your speakers trying to use the amps you list. They just cannot supply the current and control these speakers need. If you want to go tubes, IMO you'll need to stay with more powerful models that use larger power supplies and output transformers, and with at least four or more higher-power variety output tubes per channel (probably twice that if using lower-power variety output tubes). To me, this pretty much rules out tubed integrateds, and I think these results will obtain even when listening at low-to-moderate volumes. I say this as a CS2.2 owner who has tried both moderate- and higher-powered tubed power amps (C-J MV-55, VTL MB-185 Sigs.) - and those Thiels aren't even as demanding (impedance-wise and in woofer size, though their sensitivity is similarly moderate) as yours, and my room where I used the smaller amp was also much smaller than yours. Even my newer, larger room, in which I was really forced to move to the higher-powered amps, is not as large as yours is. Also, keep in mind that your speakers are very revealing of amplifier quality, not just quantity, and the lower-priced models you mention will not be shown to their best advantage by speakers which really want top-notch amplification, not just plenty of it. |
I had Thiel 3.6 speakers that worked really well with an Audio Research VT-100. you may want to consider the ARC integrated although more than 50 watts really would be best. |
I had a CJ Premier 11a driving my Thiel 3.6's and loved it. I only sold it because a friend made me an offer I could not refuse. I ended up buying a CJ MF2500A and I must admit the bass is better with the power of this ss amp. But the 11a was pure magic in the mid and high end and I often times wish I had it back. I have been considering looking for a pair of CJ Premier 12 or 8 A's. I too do not listen at extremely high levels and the 11a seemed to have enough punch to drive the Thiels quite well.
Chuck |
