Keith G wrote:
"Serge Auckland" wrote

One of the many benefits of overall negative feedback in a valve amp
is that it ensures you get the output transformer phased right. With
no overall NF on these amps, they will work equally well either way
round. There's no excuse for sloppy manufacture, but at least with NF,
it would never have left the factory like that. (assuming of course
that they were tested at all)


OK Serge, where is this going to have happened then?

I'm certain I haven't buggered up the coax signal wires but I'm equally
certain they amps are out of phase, is it likely to be the transformers?
Doesn't help the amps are handed but the speaker connectors are colour
coded red/black/red, so it's not a question of how they are hooked up!





This isn't something that has changed, they must have been like that
from new. There's no mechanism that will change the phase. Nick's
suggestion is correct, compare the connections in and out of the output
transformer, and see if they are different. It could be that the
transformer connections are identically colour-coded but that the
transformer itself has been wired differently. If so, just reverse the
b+ and 300b anode connections on one amplifier. I suppose you should
find out which amp is out of phase, and reverse the other one, but
unless the new owner is one of these "absolute phase" nuts, it doesn't
matter provided they are both equally phased.

S.

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