Showing 50 responses by tmsrdg
@unsound,Yikes -- I pasted the specs for the DMA-300 into the DMA-400 slot. To amend:
Power Output DMA-400 (continuous)
@ 8 ohms - 350 Watts RMS
@ 4 ohms - 560 Watts RMS
@ 2 ohms - 705 Watts RMS
90 Amps peak
ą0.1 dB, DC-150 KHz
ą1 dB, DC-1 MHz
ą3 dB, DC-1.8 MHz
Thiel actually checked out worse on Stereophile specs, going down to only 26 kHZ, not 22 as stated in my manual (weird), DMA-300 is same as quoted. Alright! Sorry about the confusion.
Is there a technical reason that the "double down" ratio keeps popping up?For instance, the DMA_400 listed above does not do this in sequence from 8 ohms to 4 to 2, but as I run the numbers it seems more than adequate. Is that right, or does "doubling down" refer to an important harmonic ratio needed here? Also, the minimum impedence of the 3.7 is 2.8 ohms, so perhaps we need to consider that the DMA-400 does indeed double from the 8 ohm rating to the 2 ohm. Thanks again for any thoughts on this.
I just bought a pair of barely broken-in 3.7s a few weeks ago from a private party. Considering the news, I was concerned about the longevity of the repair service that Rob Gillum at Thiel runs, so I called him. Things are indeed in a state of flux, but he was able to put my fears to rest. Perhaps some due diligence is still required in monitoring the goings-on, but I'm not terribly concerned now.
Currently listening to the Koopman Bach Cantatas. Such wonderful music.
Your remark "I'll venture to guess that a tricked-out CS2.4 would retail for $10-15K but compete sonically with other designs up to $40K. A tricked-out CS3.7 might retail in low $20Ks but be considered as among the best speakers available" got me to thinking. I'd certainly be interested in something like that for my 3.7s, not that I'm unhappy with them in their current incarnation! It certainly would be an opportunity for an enterprising individual to offer that kind of mod service. FWIW, eBay lists a "crossover upgrade service" for Thiels -- I have not explored this though.
Any savvy technicians out there with knowledge of the Thiel crossovers?
I spoke with Rob, an excellent individual and one of the nicest people on the planet, yesterday. He is in the process of buying the repair service. There is no need to worry. I also asked about the idea of recapping my 3.7s. He told me that would definitely be a plus. He even took the time to mark out what would need to be done on the circuit schematic, and sent that to me. Doesn't get any better than that!
I engaged in an email exchange with Rob last week re upgrading the caps on my 3.7s. He told me "To upgrade the CS3.7, a 76uf, 151uf, and a 16uf cap would need to be installed in each cabinet." I was unable to find these values. He then suggested "The values I listed are the values for upgrading the CS3.7. It is possible that the capacitors may have to be purchased with the values described (NB: in the catalogs). For example: The 76uf CSA cap may have to be summed from a 75uf CSA and a 1uf CSA cap. The 151uf cap may have to be summed from two 75uf and a 1uf. The 16uf CSA cap may also have to be summed from a 15uf CSA and a 1uf CSA."
There you have it. I'd like to do this, but do not have the technical acumen. If Thiel Service offered this, I'd jump. Also, there a lots of varieties of caps out there, and it's a little scary for me that I might alter the speakers in a way I did not like!
You wrote "Regarding outboard crossovers, tread lightly. The crossover network works in an environment of the woofer magnetic field and the close proximity between various crossover inductors as well as vibration."
In my conversations with Rob on this, he said that size was indeed an issue for internal placement (this was re the 3.7), and that if one really wanted the best caps this would have be be an outboard mounting. Are you saying to forget about an outboard mod?
I looked at this link http://www.humblehomemadehifi.com/Cap.html too. Right -- how does this guy have the time, etc to review all these!? But it was interesting to read the various descriptions. I was a little wary of the "warm" sound described for the Clarity ESA and others. I don't want or like added warmth. I'm a classical musician, around live acoustic all the time in vastly differing venues. What I love about the Thiels is the clarity and ability to accurately reproduce timbre and transients. I don't want any of that rolled off. I realize that some (many) people actually like a warmer sound. Not me.
>A good amp for current hungry Thiels doubles power from 8 to 4 ohms >and again doubles or nearly so into 2 ohms.
I've been wondering about this. I run a Classe ca-300 amp with my 3.7s. The soundstage does get a bit congested at large orchestral climaxes, for instance. The Classe is rated 300wpc into 8 ohms and 600 into 4ohms, but there is no specification regarding doubling into 2 ohms in the literature. The 3.7 has a minimum impedance of 2.8 ohms with sensitivity 90dB/2.83V/m. Do I need a more powerful amp?
Well, I don't think I listen THAT loud -- we were listening to the 2nd Beethoven piano concerto this weekend, it's got very quiet passages with just a few instruments, and then full orchestra passages. Our room's 20 x 21, speakers are 5 feet away from the wall. My Alpha DAC digital volume was 38, fed directly into the amp. So, not earsplitting! But the small ensemble music is very nice, great imaging, timbres, etc., and as I wrote, the climaxes seem a little "scrunched." I've had the 3.7s for three months. before that the 2.2s. Nice speakers, also.
That's great to hear. I would be happy with the option that provides the best sound fidelity. I have 3.7s (my old 2.2s are in the closet) so I would be interested in upgrading the newer speaker. Personally, the rear placement of the outboard crossover would work much better. But that might be a problem with the 3.7 since the posts are on the back, as opposed to underneath with the 2.2 model. Thiels rule!
TomThiel,Would you be able to supply a short list of amps that actually do double and double again into 2 ohms. I've been pretty happy with a Classe CA-300 pairing with my 3.7s, but now have started to worry!The Classe is rated 300 8 ohm, 600 4 ohms, but no rating into 2 ohms.Thanks in advance for any input.
Thanks, Tom and brayeagle. I've been on the lookout for a "tradeup" for the Classe ca-300 that I use with my 3.7s, and it would be nice to know what the pros where using for voicing. I remember a conversation with Rob a year or so ago who said that Jim Thiel used the Krell FBP 600 for voicing (apparently among some others). The Classe 300 is very nice, but I want to squeeze every last bit out of these fabulous speakers potential.
thosb --I used a Classe ca-100 for years with my old 2.2s. Then I bought a Classe ca-300. BIG difference: dynamics, stage, you name it. Couldn't believe I had lived with such low power for all those years! I still have the 2.2s (which I plan to sell), but now run my 3.7s with the Classe ca-300. It sounds terrific, but a teeny congested on orchestral climaxes, stuff like that. So I'm on the lookout for an amp upgrade at some point.
Sure. Of course I want my old speakers to find a knowing and happy home. I am thinking currently that I will hang on to them and get the upgrades done, and then sell (unless they turn out to be better than the 3.7, hard to imagine, though...). I’m very curious as to what changes will transpire!
unsounds post from 09-18-2018 re the doubling down into 2 ohm requirement has me wondering -- can we once and for all clear this up: is it absolutely necessary to have that capacity in order to drive Thiels (I'm thinking of my 3.7s) to perfection? I mean, very few amps advertise this ability. What about the Classe CA-M600 (600 8 ohms/1200 4 ohms)? Not rated into 2 ohms, but certainly enough current, no?
Tom - Thanks for the response. Just to clarify: by "other amps in the family," are you referring to the Classe family?
Finally, can we get a list going of amps that satisfy the continuous 2 ohm criterion? Certainly the big Krells, the Classe Omega ... but, what else? And, what does one look for besides a 2 ohm provision in the published specs? Are there other ways of discovering that an amp without the 2 ohm spec will work?
I think we tend to forget about the vagaries of an actual acoustical presentation and the coloration endowed by the hall. For instance, my wife and I attended a solo piano recital a couple of nights ago. We knew the hall, we knew the performer, and it was one of two Steinways used in the hall, both of which we also knew. But there are contingencies--audience size, hall size, curtain across back of hall open or closed, the way the pianist voiced (not to mention the way the piano tuner voiced the piano), seat location, all kinds of variables. These all affect how we hear, in real live music, qualities such as attack, decay, envelope, stage, etc. that we as audiophiles use in evaluating components.
But what was very nice was when, a day later, I put on a cd of Peter Serkin playing some Wolpe , Lieberson, et al. It was just like being back in the hall. That's what the 3.7s do for me.
Nice observation re spruce soundboards. Although I've pretty much retired from "the scene," I spent many years as a professional classical guitarist. My instrument has a Sitka top. If left unplayed for any longish interval, it sounds terrible at first, and takes days to open up. But open up it does. It is an enormous difference. That's why I choose spruce and not cedar. Cedar tops have a more colored sound, loose vitality as they age, etc. But this is just like my system with the 3.7s. Sounds small and uninviting if not played in a while, but after some hours back in play -- whoa!
Just an aside in response to the amp mini-thread that preceded Tom's last post:I've had Thiels in my system since the mod-90s. First the 2 2, now for the last three years, the 3.7. Recently, the sound from the speakers has been breaking up. It sounded like an amp problem (Classe ca-300) but just to make sure I called a friend who works in pro audio to see if he could lend me an amp to swap for troubleshooting. He supplied a 400 watt amp that he uses for PA systems. I thought, oh boy, what will that sound like. But it was a revelation. First, it is my Classe that is going. But ... the sound. At first it sounded a little "thin" but after a few minutes, it was obvious that this was a much better presentation of the material. We listened to Boulez' cummings ist der dichter from the excellent Erato recording and some tracks from the equally excellent new Innova recording of pieces by Jeremy Beck. Everything was in its place and just as it should be, no added warmth or profiling. Timbre, stage, dynamics, transients, balance and placement of instruments in the orchestral sound field all spot-on faithful. That from a nuts and bolts pro audio machine. Quite a few implications here.
Tom and 'tweak,
Yes, as a matter of fact it was QSC model USA 850. My only critical observation was that it could have had a bit more "filling out" or saturationof the colors. But even so...
Tom, I remember you posting here a while back re the Benchmark AHB2. Do you think this could drive the 3.7s, either bridged mono or single unit?I've been looking into amp upgrades and the shortlist includes Hegel, Ayre, maybe Spectral. But the Benchmark looks very intriguing, especially since that unit would do two things that make me very happy: save a bundle and get better sound. I've spent my life in and around acoustical music in orchestral halls, chamber halls and studios. All I need and desire is (as Jack Webb famously put it) "just the facts, ma'am."
Since we're talking about amps again: some time ago I posted a plea for a list, however small, of amps that by spec would be completely capable of matching the low impedance needs of the Thiels. Has anything materialized? I mean, besides the Krell FPB 600. Seems like we are stuck in "I like the sound of it, but..." land.
Thanks for any input.
Tom --The story behind Morado and Amberwood that you relate is amazing and rich! I'm looking at the Amberwood finish on my 2.2s right now. Absolutely beautiful and amazing.
I have a question. The 3.7s are the models currently "in my system," and you mentioned in a previous post that the electronics had gone through several upgrades during the lifetime of the run. I have serial numbers 1041 and 1042. Are you able to speak to where these belong on that continuity? Or would Rob know about this?Todd
Something fishy with these numbers. My Thiel 3.7s are serial 1041, 1042. This is indicated on the shipping carton. However, I talked with Rob yesterday about the issue of different crossovers being used with this model. He told me that the 3.7 run had an earlier crossover version, and a later one, for a total of two. He thought that given my serial numbers my speakers would have the earlier version (which he prefers!). He also emailed schematics of both crossover types to me.