Transformer swap Question

[baddog]

I gave a friend this amp and he blew the power transformer while he was recaping the amp. Im not sure how to install the new weber replacement


How do i hook up this weber transformer in place of the existing one. I noticed that the original transformer for the filiments has a variable resister to ground but the new one has a center tap. Do i remove the variable resitor and use the center tap to ground on the new transformer and which voltage taps do i use for the rectifiers ? If anyone could draw it out that would help.

This is a stereo amp
4 el84's
4 12ax7's
2 6cA4's

thanks
Baddog

[Enzo]

That variable resistor - a pot - is a hum balance control. You set it for least hum. Usually it is centered or all the way to one end for best results. Your new PT has a center tap. You have two options. Don't connect the center tap and leave the hum pot wired in. OR ground that center tap and remove the hum pot.

[baddog]

HI ENZO

thanks for the help. What voltage taps do i use for the rectifiers or how do i determain the voltage needed?


thanks
keith

[Marc]

Baddog,
Get him to biuld light bulb limiter to give this PT a chance at surviving.
I'd suggest starting with the lower (red/white) taps on the PT and see what kind of B+ you get and if the wiring problem has been corrected. If I remember the formula right (540*.707) it should be about 380V - the rectifier's voltage drop. Say 350~360 should be good for that amp....

Marc

[baddog]

Hi Marc

Im going to help him with the rest of his restoration on the amp. When he first recaped the amp he installed the filter caps reversed and shunted the secondary high voltage side of the transformer to ground . He blew both rectifier tubes but physicaly everthing else looks ok. Thanks for the advice i will have him try the R/W wire taps first and see what happens.

Keith

[kor]

Easy transformer replacement! Only 5 wires. 2 green wires@6.3 volts to all the tubes filaments. 2 red wires are the B+, one each to both plates on the 6CA4's. Center tap goes to chassis ground. Leave everything else as was originally wired.

[baddog]

Thanks for the advice . I thought it was pretty simple but i wanted to make sure. Will be fireing it up soon with my fingers crossed.

Thanks Again to everyone