The Counterpoint SA4 was designed by Roger Modjeski of Music Reference. It was an OTL amp, and he sold the design to Counterpoint, who manufactured and marketed it. Modjeski has some OTL's in his current Music Reference line. To find them do a Google search for Music Reference, and Music Reference / RAM Tubeworks will be the first site shown. Click on "Complete Price List" for a little info on all his amps, including the OTL's.
Not trendy, high-profile, or flashy (Roger's not a flashy kinda guy) but REAL good amps. His RM-200 Mk.2 is currently in the Stereophile Class A / Tube category, along with some way more expensive amps from trendier, higher-profile, flashier companies. Undeservedly under-owned. High owner satisfaction, very rarely for sale used.
My brothers upgraded Tenor amplifier amp $25 k range,which uses I believe small input tubes as well as big Solid state power. Is probably the most musically involving amplifier I have heard .that being said preamp, digital or turntable, as well as cables and of course a Loudspeakers all contribute to the success of that amplifiers greatness .
my system sounds very respectable at just under $50k,but compared to my brothers $100k + system I can pick out things maybe lacking in my own system
when directly comparing to. My point is, your system is only as strong as its weakest link .
There are some really good companies listed. Here are a few more suggestions that you may want to check out.
Rogue Audio - Tube - great solid build, best value for the money $$
Ypsilon Electronics - Tube - fantastic design, it will cost you $$$
Tidal - Solid State - "The Rolls Royce of High End Audio" $$$$$
I drove many speakers over many years with an SA4. I loved it. A few years ago, I moved into a smaller home and listening room, which forced me to consolidate my amp, pre, phono pre and dac into a single integrated. I was devastated by the prospect, certain my audiofool life was over. But, it wasn’t! The Devialet 220 integrated is both more transparent and dynamic in my home than the SA4 amp, SA5000 pre (both with premium gold Alta Vista upgrades), and PS Audio Perfect Wave dac it replaces. I’m driving currently a pair of Reference 3A MM de Capo BEs with a REL sub. I never expected such fine performance from a digital amp.
IF you want Transparency the Atma-Sphere OTL has to be the first choice Coupled with the Classic Audio Loudspeakers T3.4 Project or the T1.5 Reference. This setup will challenge ANY World Class Systems REGARLESS of COST!!!
This is coming from a Guy who had them all, The OTL Amps are Superior in nearly all facets of sound except one! you are not going to able to mate them with hard to drive Speakers unless you buy the larger OTL Amps such as the MA-1 or MA-2 from Atma-Sphere.
Most transparent power amp
You’ll just get personal favourites asking this.
But if you want to do some of your own homework, you may get what you asked.
Pick an amp with low output impedance, with the lowest distortion without having to resort to high negative feedback, and one that is able to drive your speakers without becoming a tone control.
This should give you your best chance to your question. Pity there's no such thing as a passive poweramp, otherwise it would be your answer.
awence_carpioI take it from this speaker thread you started, you have the Sasha’s, then my last statement in the 3rd paragraph,
" and one that is able to drive your speakers without becoming a tone control." should be well considered.
BTW OTL’s and most tubes, even mosfets have no chance driving the Sasha’s without becoming a tone control, you need current at low impedance for these speakers for the amp to stay flat (transparent) across the frequency range.
Stereophile: " Sasha's plot of impedance magnitude and electrical phase (fig.1) reveals the speaker to be a demanding load for the partnering amplifier to drive. Not only does the impedance drop below 4 ohms for most of the lower midrange and upper bass, with a minimum value of 2 ohms at 86Hz, but there is also an amplifier-unfriendly combination of 3 ohms and –43° phase angle at 61Hz."
^^ FWIW we've had good luck with Sashas running our MA-1s. I think it might be helped by a set of ZEROs (www.zeroimpedance.com) but the amp didn't sound like there were any problems making bass despite the Sasha's rather low impedance in the bass region.
I can't speak for other OTLs out there. But since we don't run any feedback, it seems that our amp should have been a problem on that speaker. This leads me to believe that Wilson may have used a tube amp during the design phase of this speaker.
What is the compromise in implementing the ZEROs
Easy, you can hear/do this for yourself. On any amp that has no problem driving whatever speaker without the Zero’s. Then put the Zero’s in and you will then hear the compromises they make.
But they do allow amps that are not driving the speaker well, to be able to do so, but I’d rather change the amp for the right one for those speakers, as these Zero’s are not cheap, for what to me is a band-aid fix.
Hey Ralph. Here's my chance to zero in now that you've chimed in. My experience has been that there's no free lunch. What is the compromise in implementing the ZEROs? It seems you would lose extension one way or another, no?Because the ZERO does not have to block DC, and also because you need an amplifier that already has a low output impedance, the result is a very low turns ratio with low distributed capacitance. Translated that means it has a very wide bandwidth- wider than our amps (which is quite a bit different from the usual output transformer which is often the limiting factor in tube amplifier frequency response); about 2Hz to 2MHz!!
So, 'no', you don't loose any bandwidth at all. What you loose is a bit of voltage gain as the transformer steps down the voltage.
How it seems to work is if the ZERO creates sonic compromise, you probably don't need it.
I have never seen it as a band-aid as George puts it; prior to the ZERO we actually made a similar product called the Z-Music autoformer, which did pretty much the same thing (ours also allowed for one ohm operation, allowing Steven Stone in a TAS review 25 years ago to have a set of our MA-1s drive a set of Apogee Full Range loudspeakers with very convincing results to my ears).
The simple fact is that four ohms is not good for **any** amplifier made regardless of the technology, and this is easy to see in the amplifier's specifications. Distortion is always higher, and the distortion is of a type that is easily heard as brightness and hardness. This is why Steve McCormick sent a letter to Paul Speltz (who makes the ZERO) stating that his amps sound better driving 4 ohms through the ZERO rather than directly. The amp has lower distortion and you can hear it right away.
That's not a band-aid so much as its a fix for a problem; the problem being speakers that cause amps to make increased audible distortion.
This being high end audio and all, distortion **bad**, music **good**!
The simple fact is that four ohms is not good for **any** amplifier made regardless of the technology, and this is easy to see in the amplifier's specifications. Distortion is always higher, and the distortion is of a type that is easily heard as brightness and hardness. This is why Steve McCormick sent a letter to Paul Speltz (who makes the ZERO) stating that his amps sound better driving 4 ohms through the ZERO rather than directly. The amp has lower distortion and you can hear it right away.George; I have nothing but respect for your technological expertise. All I have is my empirical experience. My ARC Ref150se sounds lifeless and dull with one set of speaker cables mated to my DeVore O/93's unless I use the 12 ohm taps and yet with another set of speaker cables (lower gauge, completely different design) my DeVores sound hard and bright unless I use the 4 ohm taps and with the 4 ohm taps the sound is magical. Can you unequivocally state that using the 4 ohm taps on any tube amp, including my ARC Ref150se, ipso facto results in brightness and hardness? ARC in it's owners manual states that the consumer should try 4, 8. and 12 and judge for oneself. I have to wonder, why would such a reputable amp manufacturer even offer the option if it were such a compromise? And what might account for my experience described above other than accusing me of having bad ears?
@fsonicsmith, I think you are addressing me, not George since the quote is mine.
The DeVore is not a four ohm speaker; as far as their website is concerned, they don't make any. But it works best on your four-ohm taps. That is quite a bit different from the speaker actually being four ohms. It simply means that combination works best for you- and as you noticed, the speaker cable is a bit critical in the overall scheme of things.
Can you unequivocally state that using the 4 ohm taps on any tube amp, including my ARC Ref150se, ipso facto results in brightness and hardness?Not- at all, and if you got the impression I said that, I didn't. What I did say is that the use of four ohm speakers results in higher distortion from any amp- and that the distortion is such that is perceived as brightness and hardness. There is a distinction here- you are not using a 4 ohm speaker.
Using the four ohm tap gives you the lowest output impedance available from the amp and for some reason that works. FWIW, usually you loose some bandwidth using the 4 ohm tap; IME its usually in the bottom octave.
Yes, Ralph, sorry.
Thx-I misread your post. I think I was tired from a long day at the office when I read it. When you said;
The simple fact is that four ohms is not good for **any** amplifier made regardless of the technology, and this is easy to see in the amplifier's specifications.I thought that "four ohms" referred to the amp side of things and not the speaker. Your post is clear, it was my failure to carefully read it.
Kosst, not to belabor a minor point, but a "passive" electronic device would usually be considered to be one having no "active" components (e.g., transistors or tubes), at least in its signal path. A device which provides zero voltage gain but amplifies current and power is not a passive amplifier, in the sense that George was using the term and per what seems to be generally accepted terminology.
I've been using a pair of Valvet solid state single ended mono blocks for a few months now & am finding them very transparent & musical. My history has been tubes of various designs for the last 25 years so this was a bit of a departure. I'm hearing more on top and bottom now while still having a very satisfying midrange.