Amps Atma-Sphere M-60 Mono blocks OTL design

It sounds like ozzy has gotten the amps to work in his system.

I have some tips:

The most important tubes for the sonics are the ones at the input of the amp. The precise location varies depending on when the amps were built (the M-60 has been in production in various forms since 1991). NOS 6SN7s get rolled into the amps quite often; the input tubes can be GTs. This means you can use Ken-Rad (of the NOS tubes they get the best marks from our customers), the Sylvania metal-base 'chrome domes' or the RCA Red Base (and its variant, the CBS Zalytron). But our customers have indicated that the Sophia, Psvane and TJMusic tubes seem to have all the best properties of the NOS tubes but without the weaknesses!

Keep the speaker cables as short as possible and the speaker connections as tight as possible- but don't tighten them so hard that you strip the threads or you will really regret it! Tight connections do sound better.

Ozzy sounds like he's running the amps on platforms. To test the efficacy of the platform, place isolation devices (squishies) beneath the amp and audition. If better, the platform isn't doing its job. If worse, then apply some sort of point system (Tip-toes, Stillpoints, etc.) to get the most out of the platform.

Damping rings can be applied to the 6SN7s but not the power tubes.

Power cords make a difference and the difference is measurable and audible. We've had excellent luck with the Purist Audio power cables and there are many more.

Fuses can made a difference too, but the most important fuse is the one by the power cord, and that one is the speaker protection fuse. If a tube arcs and does its worst, that fuse is going to blow, so if you have a $30 fuse in there it can get old pretty fast.

Of course in that regard,  our experience is that the Russian 6H13s (the Russian version of the 6AS7G) hold up a lot better than the Chinese tubes. Set up on the right speaker we've seen them last many years.

Never apply contact enhancers to the input connections or the tube sockets other than a light spray contact cleaner. Radio Shack sold a spray contact cleaner that was quite acceptable and you can also use the red and black DeOxit in a spray can. Anything stronger than that is asking for trouble.

Thanks Al/Ozzy.
Since were still encased in snow here in the NE, GardenerBob hasn't been doing much gardening. So, after a sunny Friday afternoon, I have been aquainting myself with the DEQX. I still have to go through the Agon thread, but it really is interesting. (Perhaps next winters' project).
@ozzy , I probably will buy used, too. Has DEQX been okay with non original owners, in terms of support?

Bob

Geez Ozzy, I moved from the east side to the west side a few years ago and I just caught wind of this thread where you are making changes once again. I'm taking delivery of a pair of older Atma's that Ralph did years ago to try my hand at OTL's as well. I bought them last week and they are being shipped now from the west coast. Not thrilled with the expected heat in the room but excited about the potential for another step up in "magical sound".