Conrad Johnson Premier 140 6922 tube swapping

If you can find matched Tungsrams they won't disappoint. What are the stock tubes?

Well I thought the 6922 I had in the 140 was a stock tube but it is a Electro Harmonix 6922

I had one of these--great sounding amp but mine was problematic--and rolled a few tubes in it. I even bought some vintage Tung-Sol 6550's which made an enormous difference, more than the 6922's. I thought the Siemens CCa was the best sounding 6922 variant but the Tungsram mentioned above is also good, as well as some Ediswans I bought at Upscale Audio.

That probably is their stock tube of choice. Very commonly spec'd tube. They don't totally suck - in fact, when mixed with NOS tubes in my SF Line 1 they do a fine job of adding bass slam.

Only thing is there are 8 6550's!!