Good Tube Selection for Atma Sphere S30?

Atmasphere, does this apply to the 6AS7s as well? You'd said above that power tubes from Russia were fine...

That's correct. The 6SN7 is the tube where we've seen problems. The Russian power tubes work just fine :)

I used Brimars and they were an improvement.
I also had the MP3, it was a great combination,I was using stacked Quad 57's at the time.

No problems with the stock output tubes.

I recently tried a newer version of the S30(I used to own the original version)and it had great bass impact on my Ref 3A Grand Veena speakers.

The S30 is the one amp I wouldn't hesitate revisiting.

12-14-11: Atmasphere
In practice, tubes with leakage can buzz ...

Ralph, assuming you are referring to heater-to-cathode leakage, how many megohms of leakage resistance would you consider to be the threshold of acceptability for a 6SN7, as measured say on a vintage Hickok tester?

Also, based on your experience is it expectable that a tube showing marginal leakage (perhaps 2 to 5 megohms, for example) during its early hours of use will improve over time?

Thanks! Best regards,
-- Al

Hello Al, We reject the tube if we see less than about 10M. On some speakers its not such a big deal, but if the amp is used on horns tubes with such leakage are trouble makers.

Its not really that hard to find tubes without leakage (+50 Mohms) if you stay away from the Russians (BTW we *have* seen vintage Russian tubes that work great). So far IME if the tube tests with leakage, that is not going to change over time.