Atma-Sphere MA-1 amps

I was wondering if Ralph ever visits this forum....if he does, does he usually comment about his products?

Hi Tom, good to see your post! One thing folks should be aware of about the A-S amps is that the choice of 6SN7 driver tubes will make a big difference in the sound. In the MA-2s you heard at my house on the standard Eidolon, Tom, we were listening to Sylvania 6SN7-GTA tubes manufactured in the '60s. These have a very clean, detailed and somewhat airy top end. Put in something like RCA grey glass and the top will get much softer and sweeter. Do you know what 6SN7 tubes were being used in the MA-2s you listened to on the Diamonds?

Warm regards my friend,

Hello Rush,

I'm afraid I don't know the brand of the 6sn7 tubes that were in the other 2 pairs of MA-2 amps that I heard. I imagine it was the stock 6sn7 that were supplied with the amps from the factory.

Rush, I heard far less of this treble abbreviation in your system then the other two systems I heard with the Atma/Diamond combo. This is before you had your amps brought up to to the latest version. If I'm correct, the latest upgrade included the new caps. I have a sneaking suspicion that the new caps are responsible for the sound I'm trying to describe. To me it's ironic that I think the caps are also what gives the sound this tremendous sense of openness. It would be interesting to hear from others if they feel the flaw I can't seem to get past is innate to the new caps.

Rush, I also remember you and Ann having issues when you first made the upgrade. Do you feel these issues have completely dissipated over time with break-in? Or is there still some remnants of those reservations remaining? Thanks so much for your candor. Maybe a learning experience can come from this discussion.

As always - your friend,
Tom

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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