Upgrading output transformer - wiring question

[Bob M.]

I'm upgrading my Fender Champ's output transformer with an aftermarket, higher quality replacement. But on the primary side of this new replacement transformer, the wires are differently colored than the stock Fender unit. One wire goes to B+ (rectifier output and 1st filter cap) and the other wire goes to the plate of the power tube. How can I determine which wire on my new transformer should go where or is this not critical? Will this affect the secondary if I get it backwards?

Thanks,

Bob M.

[The Dude]

If you get it backwards, it will simply be out of phase and you'll have positive feedback instead of negative. You'll most likely hear a squeal/oscillation when you power up the amp. If that happens, just reverse either the primary or secondary. I've found that even if the wire colors are the same they can be wired differently. It's best not to trim any transformer wires to length until you figure out which one goes where.

[Bob M.]

The Dude,

Thanks for the quick reply. Yes, it's about the phase of the feedback. I got thrown off cuz of the single-ended-ness of this transformer. Got is solved now. Good tip on not lead dressing the wires until all is well.

Bob M.