Found my SSE 12AT7 Keeper
 

It's a GE 5 Star 6201 that was hiding, lost and unloved, in my stash.

Just sounds "better" than the new production JJ and EH Gold AT7s I'd tried previously.

My SSE wore-out a JJ and the JAN tube that is in there is forming a clear spot in the top of the getter. I haven't checked how strong the tube is, but the SSE has a lot of hours on it since it was built. It still sounds fine.

Glad this subject came up. I've been looking for the optimum 12AT7 for one of my Simple PP's. Seems like I should have some 5 Star 6201's in my box of 12AT7's and related types. I'll give them a try.

The SPP is a different story. I had some interesting experiences with it using modern tubes. I ended up having to change some resistors to get the fixed bias of the phase splitter to work out right. NOS tubes worked fine as designed.

I actually gave George those problematic tubes. I wonder if he ever looked at them....

Great! I am have tried several 12AT7 (Telefunken, RCA, Sylvania, GE, Siemens, and EEI). I settled with the Siemens and EEI.

I believe I have a 6201, I will try to find it and see how it sounds. Thanks for the tip!

Abe

+1 on the 5-star 6201.

The Telefunken 12AT7 is THE weirdest sounding tube I've ever experienced.

Love it! I just received one in the mail today. I had Tele AT7 drivers in Bottlehead Paramours years ago and liked the extra detail and sparkle they gave. Maybe not so good in the Simple?

What weirdness did you hear?

It's been a while - and it wasn't in the SSE but rather Alex Kitic's RH84 (IIRC) - but it seemed to "warp" the sound with some sort of psychedelic twist. :hypno2: Imaging was overly large and just, well, "off".

It could have been a bum tube even though it tested ok, but as it was the only one I had I couldn't compare against another one.