I have this 1959 that sound really great. I was looking inside to see how in good shape this amp is. Everything look stock except the OT output transformer. The OT it self is original but there is a component on the red wire of the OT that look to be a mod.
I can't see what is it because the white shrink on it. The other brown and yellow wire have no mod on it. Only Red one.
Is somebody have a clue of what is this thing?

This amp is from L.A. region where a lot of mod guys living I believe.

Thanks a lot metro amp community
Steph