"Phil Allison" wrote in message
...

Gareth Magennis wrote:



** Found this pic of the insides of one:

http://gitaradiy.pl/uploads/2_974_JCM600_6.jpg

The OT is on the far left ( right behind the input jacks ) and primary
wires
run next to all the pre-amp valve wiring on their way to the valve sockets
on the right.

That is a *really* poor layout for a valve guitar amp and sitting duck for
oscillation.

Be worthwhile twisting the three primary wires and moving them further
back.





The multitude of grey interconnects are not actually screened cable, just
a
signal wire lying beside an earth wire.
I don't know what level of protection that actually offers.


** Close to none.

The layout relies on the two plate wires being in close proximity so the out
of phase electric fields cancel at a distance.



.... Phil




Thanks.




By the way, and off topic now, I had a young lad come to me today to ask
about how he might learn how to digitally model valve amps for his
University project.
He was sent by a customer of mine who I've repaired valve amps for, and is a
teacher at his college.

I recommended this book, as this is the one I first read to learn the
basics, and I think it is quite good for that. Certainly taught me a lot.
http://www.amazon.co.uk/Valve-Amplif.../dp/0750656948

Do you or anyone else have any knowledge/opinion of this publication, or
anything else I could recommend him?


Gareth.