Sirshredalo

Hello,

New guy here, My name is wes and I thought my screen name was Sirshredalot, but it shows up as Sirshredalo...hmm.

Either way I have a 1978 100w jmp master volume, with the dual vertical inputs.
The amplifier has been modified by Uncle Albert out of indianapolis IN.

IM still not too sure what was done, but the low input is crystal clean untill 11, and the high input is dirty until 1.
There was an effects loop added also.

My question is, Recently I have noticed (ever since I had a tube go microphonic) that the treble is just absolutely piercing. It has always been a bright amp, but now it just seems so much more shrill.

It turns my Wolfgang into a tele.

IM playing it through a peavey 412 cab with un known speakers, but theyre not the original peaveys.

Is there a cap that can be installed to bleed off some high end? Maybe some alternate power tubes or preamp tubes to cut some of it down.

Its forcing me to play with the mids and bass full tilt, with the treble and presence all the way down.
Ive had two sets of EL34's in there and they both sounded the same.
they where EH's and Groove tubes...number 5's.

Also, the back of the chassis has a sticker that says "EL34's" ONLY. Is there a mod that can be done to make an amp only useable with a certain tube?

IM not an amp tech so I couldnt tell you the plate voltages or anyting fancy, I just know it used to be a killer amp, now its still killer, just much less flexible.

God bless
-Shred