Atma-Sphere S-30 MK3 Update.....

Original Post

Hello again,

Just wish to post my further impressions after some more days of breaking-in this wonderful amplifier..

Tonality has greatly improved, the hardness and/or glare is almost gone, there's more body or more fullness to the sound and there's also more of the finer musical details across the board. It's definitely going in the right direction. The changes have been drastic albeit over an unusually long period of time.

Since day 1, the S-30 proved to be VERY stable in general and with regards to minor AC fluctuation in particular.

Only one 6AS7 went south in a nice display of fireworks with no damage to the amp or the speaker. Forunately that took just a few seconds as I rushed to kill the B+ switch!

FWIW, here's my set up with the S-30 :

-Dedicated PC Drive

-TrendsAudio UD-10.1 USB->SPDIF Converter

-Assemblage DAC 3.1 Platinum w/D2D-1 Jitter Buster-Upsampler


-Atmasphere S-30mk3

-Tannoy Edinburgh TW

-SlinkyLinks Balanced Interconnects, SlinkyLinks Bi-Wire Speaker Cables.

-Acoustic Zen El Nino power cords throughout..

Thanks again to all who responded to my first post and to Ralph for always going that extra mile!


Just out of curiosity, have you tried other Atma-sphere amps? How do they compare?


Actually this is my first Atmasphere amp AND first OTL experience. I believe Ralph's amps are very similar if not identical, in design, except for their power output capabilities and the available mods. The bigger Atmasphere models might have more edge in the usual sonic parameters due to bigger and beefier output stages. The main sonic strengths are undoubtedly shared within all the range.

Which 6AS7s are you using?
Pubul57, these days we've been using the Chinese 6AS7s. Its been a lot less politics than using the Russian tubes.
Ralph, I am under the impression that the output tubes are not matched to each other. How does that work? Why is it not necessary to match the tubes the way it is with other amps? Maybe I have been misinformed.
Pubul57, its true that we don't match the tubes. They have a mu of 2, which is to say that they have the lowest gain of any power tube made. So you have to drive them with some really high input voltages, compared to a pentode. The result is that for variations in the tubes, you're not going to see a lot of difference between the actual sections. We can only do this because the mu is so low, and because the transconductance is not outrageously high either. A different power tube would have required matching.
Ralph, are the chinese 6AS7 "fuse-protected" as the Russian 6C13's?
Microstrip, they are built in a very similar fashion, and so have similar internal links.