Atma-Sphere MA-1 amps

Rushton's comments on the driver tubes are right on. I found a combination of RCA GT Grey glass with Sylvania GTBs to be just right, the RCA are a bit more "romantic" sounding than the Sylvania and just right in combination for my ears. Same thing in the preamp, where tube rolling changes the sound a bit from neutral to warmer - in general RCA (warm) Sylvania more neutral. I'm not sure that tube rolling would address what Tom hears, but it might.

Tom, it did turn out simply to be break in for the new capacitors installed as part of the update. It took 400 hours for those capacitors to break in, and I was concerned about it. Then one day the amps just clicked over and the magic was back. Ralph was surprised at the amount of break in time, too. (BTW, the update to my amps did not include the new V-Cap coupling capacitors that Ralph has since made standard for the MA-2. All capacitors sound different and I haven't yet heard an A-S amp with the V-Caps. From what I've heard, the V-Caps are exceptionally nuetral and take 400+ hours to break in, sounding pretty brittle until they do break in, but outstanding thereafter.)
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Rush, I could be wrong but I strongly suspect that for me the unnatural treble characteristics and slight thinness in tonal textures that I hear can be attributed to the V-cap, no matter how long they break in. I'm learning time after time there is always a trade-off, a decision to made, from both the design stand point and for us as consumers even at this extreme level.

I think there may be a price to be paid for the gains that this cap has made to the performance of the Atma-Sphere amps. Again this is only my opinion, and being that the virtues of the Atma-Sphere amps are so plainly obvious I strongly encourage others interested to audition so they may deduce their own conclusions.

Best to all,
Tom

Thank you Rushton, Tom, Pbul57, Tvad, and others for your comments and insights. I really appreciate listening to others describe the same equipment I've heard. Imo, the Atma-Sphere circuit - whether in the amps or preamps - is highly revealing of virtually any change made to it. I finally grasp what RK means when he talks about 'listening to the circuit'.

Having heard the amps and preamps with and without V-Caps, I find increased tonal depth across the frequency range with the V-Caps. 'Tonal depth' being characterized as the sheer amount of harmonic and overtone information accompanying the fundamental. What I have not heard from the V-Caps is an increase in warmth, or put differently, an increase in pleasing second-order harmonic distortion that lends a sense of 'fullness' to notes. Lack of fullness is not lean tonality.

Because I presently use the amps and preamp as my review references, I've been round and round debating with myself how best to characterize their sound in contrast with other gears. Crudely put, 'thin', imo, means lacking information - one is not hearing all the harmonics and overtones available to be heard within ones audible range because they have gone missing - all else being equal, lost in the circuit. At this juncture I don't believe the Atma-Spheres are lean or thin in tonality.

Hopefully I'll solve this with a better vocabulary some day, but for now the way I parse things is to say the Atmas have plenty of tonal depth, but do not display the same tonal weight as some other components I've heard. And I cash *that* out not as sweet/dry or rich/lean, but as warm/cool, where warm suggests pleasing distortions and cool suggests a more analytical sound verging on displeasing distortions (more odd order). The Atmas are not 'cool', but they're not warm and I presumptively think that may be what some folks intend when they say they're thin or lacking tonal texture. In effect, texture is distortion. The Atmas do not convey less tonal information, they distort less, but its less of what turns out for us humans to be a pleasing distortion, and its absence is noticeable if that's how you like your music. I struggle with this, and don't mean to say any other person's characterization is incorrect; I just need a way to put consistently into words the similarities and differences i hear between the Atmas and other gear that will make sense.

Tim
 

Hello Tim,

Thanks for the contribution and insightful comments to this thread. Is it possible for you to characterise your experience with the Atma amps before, during (break-in) and after when the sound finally settled?

IMO I do hear the Atma amps as sounding a little less dense in texture than what I would consider ideal or neutral.

Best,
Tom