A blog of my tube amp design and modification work. Primarily my own builds, but occasionally I feature work I've done on others' amps (with their permission.)

Saturday, May 30, 2015

Peavey Windsor mods

What a fun little toy.
Okay, picked this guy up cheap and I'm going to somewhat follow through on my "Matange" plans, except I'm dropping the Orange part in favor of a Matamp/JCM800 blend. Hey, its got a third preamp tube, why not?
So far all I've done cosmetically is move the back grille to the front. Not sure I'll do much more; maybe cut a new back grille out of expanded metal.
The preamp is currently fairly awful. Way too much gain, too little decoupling, lousy tone stack. I'm probably going to turn that cold clipper preamp stage into a cathode follower and the tone stack into a James with mid shift. I'll probably use the worthless "texture" control for the FAC. Then I'll use the "boost" relay to switch the second gain stage in and out.
For now I've started in on the power amp mods: 100k for the EL34 grid leaks, suppressors tied to cathodes, grid stoppers up to 47k, and 1k8 screen stoppers (didn't have any 1k5). Very noticeable improvement already!
Incidentally, Peavey seems to have paid the extra nickel for halfway-decent circuit board material. Id rather remove every component in this amp twice than remove one resistor on a Marshall made in the past decade.