The minimum and nominal impedance of the speakers is a major factor in determining the suitability of OTL amp. Without this info it's impossible to offer an opinion, IMO.
With 91dB speakers, the room size and the volume at which you typically listen are also important factors considering the 60wpc output of the M-60 amps.
Not sure the autoformers make sense if you want to get the output tansformer less sonics.
Atmasphere Amps are well known to the forum and professional publication set. I am sure a search will yield a couple of formal reviews which would be more informative than a line or two in reply to your post.
That said in a few words - yes they are all that - within their limits. But you have to read about what those might be.
I own M-60 amps for years. When they match to your speakers, they are very reliable and excellent from sonics.
One of the great Designs in Amplifier Design.
Can you audition any of the Amps in question?
Agree with Mechans on autoformers, to some extent it defeats of the purpose of OTL, though they we still be excellent amps, but not the same with as without.
Thank you for your responses I can audition the amps at the sales location, but not in my listening room, where typically components sound better. Autoformers are not "transformers" in the denotative sense; you can read up on them at the "anti-cables" website. Anyway, the OTL design seems to make better sense in theory. As silly as it sounds, it's going to be hard to beat the sound of those Carys. Of course I once thought of that with my first tube amps; Golden Tube Audio SE-40 monoblocks back in the 80's!
Erfranke I remember those amps as well;they made a big hit when they arrived on the audio scene;its to bad you can't bring the amps to your house for a real audition.It might be worth talking with Ralph from Atmasphere directly to get his point of view;he is a straight shooter and won't jam his gear down your throat to make a sale.I had cary slam 100's once and they were a fantastic amp but I think with ralph's amp and if your speaker will match the result will be unbeatable in my opinion.
Eric- Did you ever get to make the comparison? I own AtmaSphere MA1s and remember hearing Cary 805s at CES in 2006 and thinking they sounded fantastic (in the Cary room, with all Cary stuff, including speakers (single driver horns, maybe, not sure)). There was a definite magic there, but not sure if it was due to SET amps or single driver speakers, or what. If I were rich, I'd buy a pair of 805s and have both just for fun.
I had M60's MKIII for a couple of weeks. Partnered with Cabasse Iroise 500 speakers (4Ohm, 91 db) often referred as tube friendly. First the clarity of these amps where impressive but over longer time I missed body / substance and the "it's just right" feeling of my VAC PA60 KT88 amps back then. The Autoformers made it better, but overall I was not satisfied with the sound of the M60. The sounded somehow steril, too polished, slightly thin, mechanical and more hifi-ish than my VAC. I gave them back in the end.
I would strictly recommend to audition these amps on your specific speakers and system.
Btw I would rather think that the Vienna Acoustic speakers are not really an ideal match for any SET as well as M60's if you are in need for the autoformers even with the Cary.
I feel Xronx sums up what some will love about the OTL presentation and others will not. To my ears OTLs matched with the proper load get closer to the sound of live music. Less additive richness and flavor. Some will like this others will not but when all in the system is properly addressed, I feel this sound is difficult to beat in reproducing music accurately. When you think about it what can a transformer do but add artifacts to the sound, it ultimately comes down to a matter of taste and what you are trying to achieve.
For my taste, no amp has sounded better with my Merlin VSMs than the M60s, I even preferred to my CAT JL2s which I thought I would never replace and if I had a more difficult speaker to drive I might well have kept them. I don't focus to much on "warmth", what I hear with the OTLs is a sense of presence to the musicians that sounds more real than other amps I have tried - it is uncanny, and particular to OTLs (I think).
Dennis Had ( Cary) 805's are fantastic amplifiers, highly recommended .
Pubul57, IMO the 805's does deliver such an presentation.
That is a good thing:) Might be part of what is special about SETs as well.
I agree with Xronx opinion regarding some OTL amps, They certainly do have their good points, but ultimately come off on the thin and lean side of reality. I listen to live un amplified jazz quite often, and in my experience a very good SET amp gets closer to the true natural sound of instruments and the human voice. There`s an undeniable fullness and organic bloom/warmth the live music presents that seems watered down, at least with some OTLs(the diet coke version).SETs preserve more of the fundamental tone as well as the beautiful overtones present with acoustic instruments, at least to me.
I have`nt heard the Tenor OTL, just the Atmasphere models. I understand in theory, removing the output transformer should be an advantage, however SETs with good transformers just sound more real.
Very happy with my 805 AE. Pretty versatile with it's power rating. Had it on my Maggie 3.6's last night.
Charles1dad, I know we share our love of 300b amps. I use them on my hi-eff system. The 805 was an experiment to see if I could get that SET magic with the Mags. Works for me. I thought Cary used the 300b tube as just a driver tube for the 845/211 output tube but found out the 805 is really a 300b "amp" driving the 845/211 tube thru an interstage transformer. That's probably why I like it so much. Kinda like a Cherry Coke? :-)
That`s very interesting, of all the maggie threads I`ve read over the years 90% of the owners say these speakers require much power(usally SS amps) to really make them come alive. Your system must sound special with this unique combo.
Goes to show the difference between theory and practice, on paper you would never think the 805s could drive the Maggies optimally, in terms of both power and current to drive the low impedances in the bass region - yet you never know till you try. The 805s must be very special, would love to try them with my tube friendly speakers.
It's a bit dangerous to overgeneralize about OTL sound. The AtmaSpheres sound much different than the Juole-Electras; the J-Es sound very rich, to the point that I htought they were colored. Very unlike the AtmaSpheres, adn very unlike the demo I heard with Cary 805s.
I think of the Joule warmth can be attributed to their very fine, but warm sounding preamp, did the same (added warmth and color) thing when I paired it with the M60s - a signature sound many love, but hey, I like passive preamps, so not the way for me. Hard to say if one will prefer the 805s or the Atma-sphere, different approaches that will appeal to different types of listeners.
You`re correct, that why I limited my impressions to the Atmasphere(M-60 and MA-1) as I`m not familiar with the Joule or the Tenor OTL sound.
Pubul57 neatly sums it up, it will just come down to individual preferences.
Pubul57 I listened to the Joule with a Cat SL1 pre-amp. My impressions were the same as Honest1, very rich to the point of euphonic but not at all in a negative way. I really loved the upper frequency extension and air presented by the Joule. There seem to be variations in the presentation of the different OTL's. Maybe the output tube along with circuit design is contributing to the differences in sound as the Tenor and Joule use the same output tube. My guess is, although I wouldn't put money on it as I only heard the Tenor once in an unfamiliar system, the Joule and Tenor are probably quite similar and the Atma-sphere might be a bit leaner by comparison, just a hunch.
I think most would agree, the Atma-sphere is generally leaner by comparison to the Joule, or the Joule is plumper, depending on your perspective - I guess that Ying/Yang thing - my ears lean towards a preference of the Atma-sphere soundscape, I also expect that impressions and preferences between the two will vary based on the speakers being used with the respective amps.
Thanks. I'm positive your system is very special. Curious as to how loud you like your listening level?
I think specs have to be interpretted correctly to get theory to hand off to practice. I see my Maggie specs as, 1: a very flat 4 ohms (flatter the better for tubes and especially SET's). 2: bass is around 5 ohms, mid 4 ohms and treble mid to high 3 ohms. 3: crossover freq has a bump instead of a dip (tubes like that, don't have to dump a lot of current as in a dip situation). 4: They are a line source so they will sound louder than a point source of the same sensitivity.
The catch of course is you can only go to x loudness with x amount of power. It has to fit ones desires. SET's have such vanishing low distortion at low power levels that I really enjoy them on the Maggies at my desired level.
FWIW, I had VSM's back in the 90's. From what I remember of them and what I heard recently when I demoed an S-30, I think that would be a great combo.
I picked up an S30 listed here on Audiogon. I chickened out and kept my 805AE instead of selling to fund an expensive pair of Atmasphere monos. I have a small listening room, and my listening is mostly direct energy from my speakers. My listening triangle is a bit less than seven feet in all directions. I have to say that little S30 is phenomenal! Sound stage is very large, airy, detailed, with precision and three dimensional life size presentation; plus the amp is only a model 2 version, that was well taken care of. Russian power tubes, however a mix of vintage 6SN7 drivers....nothing fancy. I am a believer in the OTL amplifier. In comparison to my humble system, I can't imagine what the rest of you folks enjoy with you wonderfully elaborate systems. By the way, you all may cringe at this, but I am completely Anti-cable equipped including XLR interconnects, speaker cables and autoformers. I am impressed. These new cables have satisfactorily replaced my Nordost Red Dawns and Audio Zen interconnects. Comments?
Thanks Onemug. I recently read the reviews of the 3.7 which sounded very interesting indeed. The I went to the Mag website and reading the stuff on type of amplifier needed and they almost defined a "good" amplifier as one that doubles down output between 8 ohm and 4 ohm and started thinking this leaves me out, at least with the M60s, and most other tubes amps, sounded like a recipe for SS which I will not do. So perhaps this hope, I know they use to show with ARC for many years so you would think it must works with certain tube amps. You are right of course, for tube amps, smooth impedance is the key, and just enough watts.
I`d say on average 70-85db (depends on the CD) listening levels, I find that I can also listen at 55-60db range and maintain a good sense dynamics and lively energy with very good resolution and engagement.
I have owned and compared an Atma-sphere S-30 and a pair of Shuguang S845 MK monoblocks and the 845 sets were far better than the Atma driving my 16 ohm 101 db Zu Soul Superflys.
The Atmas left me numb when I'd listen--not very musical at all.
I disliked the MA-1s driving my buddy's Daedulus Ulysses speakers--actually flat out hated the sound (which is an extreme I don't normally feel in hifi) but I think synergy was way off in that rig.
Gopher - I can't comment on the Shuguangs, having never heard them, but I can see not liking the Atma/Daedalus combination. I did get to hear a recent pair of Daedalus in someone's home (they did not have the upgraded caps in the crossover). I found them to be very bright and aggressive in the highs and upper midrange. This was a surprise, as I had read very good things about them on line, and had heard one of their pro stage combo amps with an electric violin, and it sounded phenomenal (but that was in comparison to other stage gear, not high-end home gear). I would say they definitely need something that will warm up the sound, and the AtmaSpheres won't do that.
Eric - What did you do with your Carys? Do you ever go back to them for variety? Is there anything they do better than the S30 (other than put on a really cool green light show)? If you ever get the upgrade itch, seriously consider the update to 3.1 on the Atmasphere. I got it on my MA1s, and have been very happy. There was a touch of upper mid agressiveness before that is gone with the update. I think it's quite affordable, too. The only drawback is handing your precious amplifier over to Fedex for a round trip to Minnesota.
The Cary's are a high-calorie sweet dessert with a focused sound stage. They do lose air around the instruments with more complex pieces of music. They are great for listening to jazz, vocals, acoustics, and the like. The Atma Sphere has a very broad spectrum sound stage, with a velvety black background, contrasted with timbre and detail with strings, chimes, and other types of percussion. Bass also has color, texture and warmth along with visceral punch I have never experienced before. Music is absolutely "real sounding" The instruments and vocals become life-size even with the small listening dimensions I am limited too. I am tempted to sell the Cary's however both have attributes I enjoy. In the end however, the Atma Sphere is the amplifier I prefer; clean, realistic with the soul of tubes.
Glad you had a chance to try the Atma-sphere OTL and come to your own conclusion, we all hear differently and seek different things from the sound of our equipment, in both cases it seems we might be on the same page. Which is not to say I would not also love the Cary, simply have not tried it.
In my case, I prefer the Atma-Sphere's speed and intimacy. I can hardly imagine anything that could touch the M-60's at their price point. I compared the exceptional BEL 1001 MkV's, 220 Watt solid state monoblocks which I would also pick over the Cary by a slim margin.
There's a nice pair of Atma-Sphere M-60 3.1's with every available upgrade (the Caddock resistors are very expensive and worthwhile) available on AudiogoN now.