Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: firemedic on July 09, 2013, 02:33:28 pm
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Howdy all, I've got the bug again & I was thinking of throwing together a little 6AQ5 SE amp using what I have laying around. I have a 54-195 Heathkit PT, from a cannibalized o-scope.
A google search tells me it's 980v 0.04A w/ 2 separate adequate 6.3v windings; nothing about whether it's CT or not.
My question: how am I gonna drop that voltage to something I can use? I also have a 120v isolation tranny somewhere, am I better off using a voltage doubler on that for my B+?
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Do you have two Yellow leads? And a Red-Yellow?
Tape-off the two Yellows.
Ground the Red-Yellow.
Probe each Red to ground. Is it 360VAC? That's the 360-0-360 (720CT) to drive the little tubes. (The 900V is *only* for the CRT.)
If so, you can "maybe" pull 500VDC at 50mA. Which is a very awkward SE design. Probably end up dropping 200V in a 6K 20W resistor to get down to 300V 33mA to feed the 6AQ5.
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That is awkward. I'll just get a little PT from somewhere.