Thanks for letting me join! Marshall origin 20 schematic?

[seth pittham]

Hi all.
Been restring all kinds of gear for too many years! I have the above marshall in. It has low gain, but around the first 12ax7, there seems to be lots of lively buzz if you inject a signal. All valve tested ok. Anyone have a schematic?
Cheers guys.

[EL34]

Welcome to the Hoffman Amps forum

There are many different boards on this forum for different topics.

The Tube Amp Building - Tweaks - Repairs board is where you can post amp questions.

That board is listed here.
https://el34world.com/Forum/index.php?board=13.0

Thanks,
Doug Hoffman