all the noise on my amp is gone when I plug in a diy pedal

[zjokka]

I have to put this to you guys, because the following is beyond belief.

When I bought my blackfaced Super Reverb a year ago, it's was entering into tone Nirvana after playing to many solid state amps. It had a considerable amount of noise, which I thought to be normal for such and old circuit. It doesn't interfere when playing at all

Yesterday I tried out the Fat Boostered I built and

EVEN IN THE BYPASS ALL THE NOISE IS GONE

I had built a fuzz face as well, but because it was too loud I couldn't really use it, so hooked it up briefly and the same phenomenom occurred. I believe...

...in happy accidents? no, really, something else is going on.

I can only conclude there is something wrong in the wiring of the amp, or not...

this is strange,
ZJ


OT:
Let me briefly say also that I built the Fat Booster as an amp sitter, no stompbox, so you don't have to go on your knees to change the tone... and you will, because you will never ever turn it off -- it's simply incredible in richness, control and depth. Everyone in the band was amazed by the sound and wanted to play it (even the drummer can play guitar). Recommended, really!

[idlechatterbox]

and you're telling me this AFTER I tore apart an amp because I could never track down the source of its infernal hum? 

On a more serious note, I'd be interested in knowing more about what type of noise problem the FB cured. Hum? Oscillation? Clipping? 

[AL]

That amount of noise in an older circuit is normal IF your amp needs a tune-up. Parts get old and don't work as well as they used to (insert joke here ______ ).

What type of noise? Maybe someone here can help.

AL

[Ben N]

I'm no amp guru, but I do know that it is common for the Switchcraft shorting jacks on the inputs of SF/BF Fenders lose tension so they stop grounding the inputs.  That makes the affected amp channel noisier with nothing plugged in.  Of course, plugging anything in--including a guitar--ought to stop that noise.  If that is the problem, you can usually retension the jack so that it shorts with nothing plugged in, or replace it--those jacks are easy to get (Weber has them, for sure).
Ben

[zjokka]

I don't really know how to describe the noise, it's really 'normal amp noise' in the sense that you cannot hear it when you're playing, but it's louder than the other amps. Didn't heed to that as a reference, because the Peavy Classic 50W is the only tube amp to compare to.

The guy I bought it from was an aspiring amp builder and he had just gone through it, putting new mojotone speakers and revising the whole circuit. He had a real 50s Tweed amp sitting there in the corner and told me to call him if anything is the problem. Which I will be doing tonight.

thanks for the useful suggestions, but keep m coming, i'm all ear

ZJ

[AL]

There are a lot of noise sources in older amps. It's hard to tell (without opening it up) exactly what the builder did - I'm not saying he did anything bad.

A few things you can try without opening the amp up.

1) Retension and clean the tube sockets. When retensioning don't use anything metal unless you've drained the filter caps. Spray some deoxit on the tube pins and insert the tube/pull out the tube a few times.

2) Swap some known, good pre-amp tubes in one at time. It may be possible to pin-point a noisy tube.

Other sources of problems in older amps?

Caps - if it hasn't had a cap job it could probably use one.

Plate Load Resistors - Big source of hiss in older Fenders.

There are a couple of resistors on the power tubes - 470 ohms 1.5k. The 1.5K's (especially) take a lot of heat and sometimes burn up. I usually just replace them.

AL

[Paul Marossy]

and you're telling me this AFTER I tore apart an amp because I could never track down the source of its infernal hum?

Any old amp could benefit by getting star grounded. I did this to my 60's Gregory Mark X amp, and it made a huge difference! It would be much harder to star ground my '74 Twin Reverb, however.