Don't F**k with coupling caps...

[bren-hur]

So I got the urge to do some tweakin on my amp... rebuilt a few bits and pieces, cleaned it up... in the process I though I'd be cute and throw in this old .022 Goodall paper/oil cap I had as the coupling cap for my tweed bassman channel... I powered the amp up..and it had this wierd thing like you'd hit a note and it would hold...then die out in volume real quick..

STRESSED TIME! after rebuilding the PI section a few times to no avail.. I remembered the coupling cap and a little bit of info I had read on here a few days before bout what a bad coupling cap sounds like.... I changed it out for a Jupiter...the amp was back! thick and strong.

Lesson: don't be cute. don't f**k with coupling caps.

on the positive...I now have heard for myself what a bad coupling cap sounds like!!!

[pineapple49]

im happy for you

[stokes]

Was it a bad cap or just a bad place to put a paper/oil cap?The thing to remember when modding is to do one mod at a time,listen and make the change back right away.Will save time hunting down a problem as you experienced.

[drewl]

As nice looking as some of the old vintage .022uf caps I have lying around are, they had to be replaced because they were breaking down after many years of use.....so....they get used in guitars!
They usually work fine in low voltage conditions even though they can't handle plate voltage anymore.
YMMV.

[bren-hur]

It was a bad leaky cap... and yeh I shoulda been checking as I go!

live and learn...