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In the Forum: Melquiades Amplifier
In the Thread: To drive the 6C33C...
Post Subject: Re: bad, bad, bad tubes ...Posted by guy sergeant on: 3/20/2006
Hi Romy,
Am I misunderstanding something about the 6C33C?
I had a look at the operating point you recommend for this valve in your 'full range' Melquiades amplifier. The way you are using it seems to give almost 20% THD.
Does this sound good or is it just more bathroom euphonics? This doesn't seem to be a very linear valve at all, certainly not one you would choose for high quality audio use. The load lines are horrible. I can't imagine it gives a very accurate representation of what is fed into it. Maybe that's not what you are after.
I tried a higher current/lower plate voltage condition which would give more acceptable levels of distortion but I'm afraid you only get about 5 watts out of it.
You'll have fun getting a nice sounding transformer with that much standing current passing through it though.
I've seen some negative comments on here about the 845 but that does seem to be a far more linear valve than the 6C33. Unfortunately no commercially made amplifiers I've heard load it, drive it or supply HT to it in a sensible way. They've all sounded poor. I have heard good 'home made' 845 amplifiers though so in my view it can be done.
best rgds,
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