SF Princeton Reverb help - loud pop then....

[BootRoots]

While playing my drip edge PR yesterday, there was a fairly loud popping sound (almost like when you when you plug your guitar in to a live amp.) and then the vibratio basically pooped out. I first thought there was a short in the cord. The intensity knob seemed to almost turn into a gain knob with more grit and crackling as I turned it up. not good

The trem channel has been giving out a modest hum for a short while and I have been meaning to get some new tubes, but I'm curious if there is anything else I should be concerned with regarding this problem.

Thoughts?

 

[BobbyZ]

Yes it could be tubes. But has it had a cap job yet ?

 

[fezz parka]

How's the bias? Fresh electrolytic cap in the bias circuit?

 

[BobbyZ]

Fezz whens the next vidio coming out ?

 

[fezz parka]

I'm gonna try to do one tonight. With spring here, I've been cleaning up all the crap that was under the snow.

 

[BobbyZ]

I'm looking forword to it.

 

[trev333]

mmm!?.. sounds similar to a tube amp of mine...

working fine one day on for 6 hours quiet as a mouse,,,except for the tele going into it,
then next day.. turned it on... then after 30 secs or so a loud pop and a bit of a crackle stayed..
I reseated all the tubes to make sure it wasn't pins.. I didn't put a meter over it... tried it a few more times... mhea... one day...

just put it aside and plugged my super 210 in as usual...

man this thing's a truck.. on all day ,every day, morning until late night.. just sitting there ready for me to twang on,
it's got no hiss with 2 guitars and a 2x12 plugged into it mostly... hardly notice it's on except for the pilot...

Caps on the bias circuit eh?.. I'll have to check them... it's got old type valves with the cathode leads coming off the tops... 60's vintage Goldentone Reverbmaster,
Surf city!...

 

[kosmonautmayhem]

+1 on checking all tubes one by one. And a cap job if it's never been. Especially the electrolytics!

I have one power tube in my SFPR that's starting to go. It crackles and pops on startup and then after about 15 min. its okay. I only its this power tube, since I've subbed known good tubes in each one til I found the culprit.

BTW, Trem is being modulated by the power tubes and half of V4 12AX7.

Cheers,
kM

 

[fezz parka]

The popping sound could have been the bias cap going south. Remember, the PR has the bias wiggle vibrato.

 

[kosmonautmayhem]

The popping sound could have been the bias cap going south. Remember, the PR has the bias wiggle vibrato.

What he said.

 

[BootRoots]

The popping sound could have been the bias cap going south. Remember, the PR has the bias wiggle vibrato.

pretty ignorant as to what exactly that is, and I'm not sure if this will do any good, but is there anything in the following pics that looks suspect. It doesn't look like anything has been done to it.

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[max_twang]

Your amp has had a bunch of caps (I count 6) changed. Don't worry, that's a good thing. The exception appears to be the cap can, which should probably be replaced, even if it's not the cause of your current problem.

From your comment above, I'd recommend taking it to a tech, unless you want to invest a lot of time reading and a little $ in equipment, and then start replacing various components.

 

[BootRoots]

Your amp has had a bunch of caps (I count 6) changed. Don't worry, that's a good thing. The exception appears to be the cap can, which should probably be replaced, even if it's not the cause of your current problem.

From your comment above, I'd recommend taking it to a tech, unless you want to invest a lot of time reading and a little $ in equipment, and then start replacing various components.

thanks for the info. yeah, I wouldn't trust myself to work on this thing, so a tech would be the way for me.

 

[max_twang]

You're welcome

If you're inclined, there's a lot of info around here about how to work on and troubleshoot tube amps. I've learned a ton from reading the comments of other posters. Read first, learn the basic safety rules and start small. It's really a lot of fun once you start to know what you're doing!

 

[fezz parka]

Bias electrolytic is in the upper left hand corner:

 

[JoeBubbit]

thanks for the info. yeah, I wouldn't trust myself to work on this thing, so a tech would be the way for me.

9 years later, but did you ever figure that out? I'm having the same problem.

 

[BobbyZ]

Damn I miss Fezz! Bought two sets of his pickups, Oildales. (think that's what he called um) Best thing I ever did to my Teles!