Posted by Lew on May 24, 2004 at 10:39:42:
In Reply to: From reading responses at AA posted by Matt Rogers on May 22, 2004 at 17:40:08:
If 6C33Cs sound "more like solid state than like tubes", I wager it's due to other elements of the
circuit design and construction, not intrinsically to the 6C33C. I am very allergic to that kind of
sound. I bias mine at 300mA current with about 120-140V at the plate, so to dissipate 36 to
42W. The max plate dissipation is 60W. So far, I have used my first set of tubes for about 5
years with no failures and no problems whatsoever. I re-bias the amps about every 3-4 months,
and often I find that no adjustment is necessary. (My amps use six 6C33Cs per chassis, and I
built them so that each tube can be individually biased. That requires three dual-section driver
tubes per chassis, with each driver dedicated to a pair of 6C33Cs, one in each phase of the
balanced circlotron.) I bought my tubes from Victor Khomenko of BAT, as a set of balanced
pairs. He seems to have done a good job selecting good matched tubes for me. I've also got
some 7241s intended to replace the 6C33Cs, but so far the latter tubes have been so satisfying
that I am loathe to change. Maybe some day I will build a second pair of amps using the 7241s.
They too would be great in an SET.