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RE: 6c33c warm up time

Posted by Lew on February 5, 2017 at 13:03:12:
I have used the 6C33C in my Atma-sphere OTL monoblocks. I rigged them so that I could turn on output tube filaments well in advance of applying plate voltage. I used to let the 6C33Cs get beyond "warm" to hot to the touch, before applying plate voltage. That seemed to take 5-10 minutes. After applying plate voltage, I would not say that the amplifiers sounded as good as they did get after maybe 30 minutes, and I attributed that to time required for the plate voltage to equilibrate. After 30 min or so, there was usually an apocalyptic moment when the amps really started to sing, but I never felt short-changed up to that time. (The Atma-sphere circuit is pretty near exactly like your BAT, except that BAT puts an output transformer between the output tubes and the speakers.)

About 1-2 years ago, I changed over from 6C33Cs to 7241s. I was thus able to cut back from six output tubes per channel to four, with no loss in power. It's a tough call, but I would say that the 7241s sound a bit better than the 6C33Cs, and the difference between "cold" and warmed up operation is not as pronounced, although I can still hear that happening.