"n cook" wrote in message
...
Peter Wieck wrote in message
ups.com...
My thoughts are that a guitar amp which spends most of its time driven
to distortion will have transformers able to take considerable abuse
without failure. So, I expect it to be much lower than an audio amp
(which I will check anyway).

Peter Wieck
Wyncote, PA


I found this in the archives, putting
matching transformer henries ohms
as keywords in google usenet, on a guitar group

"Primary winding, by direct meter measurement with a Fluke 8600-A:
DCR Blue side to center tap = 44.91 ohms
DCR Brown side to center tap = 51.03 ohms "

I assume DCR is DC resistance of that matching transformer.
Mine was measuring 14 and 15.5 ohms which seemed a
bit unbalanced but no worse than this example


This may sound like a silly suggestion but .....

Why not just ring Jim Marshall, and ask ? They're only up in Milton Keynes,
and are a pretty friendly company.

FWIW, for a paralleled pair of EL34s in this application, I'd say that the
readings you have obtained are fair. If it has been standing for a long
time, I would strongly advise bringing the power up slowly on a variac. The
main resevoir and smoothing caps, may not be in a state to accept HT right
away, and might need reforming.

If you are a reader of " Television " magazine, look out for the new one
that will be coming out at the end of March. It's going to be called "
Technology @ Home ", and when I get round to it, you can read my ramblings
on repairs to valved group and PA amps.

Arfa