Folks --
I bought a chassis that used to be a stereo, and I want to turn it
into a guitar amp. One big ol' PT using a 6X4 rectifier, driving two
channels that each used a 12AX7 and two 6V6s. I want to make a
semi-low-power amp, like a Champ, but the two OPTs are push-pull.

My question: Can I just use one of the trannys SE, by just capping off
the center tap? Or will it smoke the transformer? If I'm only running
one 6V6 and a 12AX7 or two, that shouldn't kill it, right?

If not, can somebody recommend a PP amp using four 6V6s and two
12AX7s? If I can't turn this thing into a low-watt growler, I'll at
least turn it into a beast.

And, while I'm at it, how can I make the calculations so I can figure
out all this stuff on my own?

Try http://www.duncanamps.com/, http://www.aikenamps.com/, and
http://www.dogstar.dantimax.dk/tubestuf/

These sites are full of excellent info on amp designs and the equations you
need to make reasonable decisions on modifying or building amp circuitry.
JamesG



"Chris Grier" wrote in message
om...
Folks --
I bought a chassis that used to be a stereo, and I want to turn it
into a guitar amp. One big ol' PT using a 6X4 rectifier, driving two
channels that each used a 12AX7 and two 6V6s. I want to make a
semi-low-power amp, like a Champ, but the two OPTs are push-pull.

My question: Can I just use one of the trannys SE, by just capping off
the center tap? Or will it smoke the transformer? If I'm only running
one 6V6 and a 12AX7 or two, that shouldn't kill it, right?

If not, can somebody recommend a PP amp using four 6V6s and two
12AX7s? If I can't turn this thing into a low-watt growler, I'll at
least turn it into a beast.

And, while I'm at it, how can I make the calculations so I can figure
out all this stuff on my own?

Hey Chris, you mention caculating, butt.. you need a starting point.
Don't start clipping wires untill you've measured plate volts on those
6V6's. That'll give you somewhere to go from. If the plates, at pin 3
counted clockwise from the pin, measure around 300-350 or less, you
can probably build a SE Champ, but I'd reccomend the Deluxe 5E3
circuit, using that PT. Two 6V6's and about 18 Watts, self-biased.
Either way, leave the center tap alone or you'll be putting double the
volts to that poor litle 6V6.
Get the schemos from schematicheaven.com.
You could possibly go to the Twin Reverb circuit with what you're
starting with.

Porky
never re-invented a wheel, butt..
never above
re-arranging the spokes a bit.