Super Reverb with "issues"...:-(

[FenderSuperReverbUser]

Hello!

I'm glad I found this forum...I have tried searching for info on this but didn't have much luck.

I have a Fender Super Reverb (I think it's a '68 or '69 model) and it has developed some problems over the years. I would like to get it fixed up and use it again.

The main problem is when it warms up, it generates a horrendous noise. It has low output until it makes the loud noises and those are REALLY loud. This may sound silly, but the sound is as if someone were dropping marbles in there somewhere. Just a loud *POW!* occasionally. The warmer it gets, the more frequent those sounds. I haven't tried to use it in a few years, so that is from memory. I can fire it up again if that would help. I also remember that it has pretty much constant static/white noise sound after it warms up also.

I have a PA100 head that I would like to use too, but need to see if I can get some speakers for it. (Used to have the matching ones but I don't anymore...long story.) Not sure how it's working at the moment...it may be in the same condition as the SR since they're about the same age and approximately the same amount of use.

I apologize if my information is incomplete...I can get whatever information anyone would need to help me troubleshoot this. I know a little about solid state electronics but next to nothing about hollowstate.

I would really appreciate any help with getting this working again. I do recall that it sounded great in its earlier days. I'd really love to use it again.

Peter

[Paleo Pete]

I'm no amp tech, the guys who are can give you much better info, but I can say I'd be willing to bet you need to replace every capacitor in it, they're over 35 years old and most likely dried out, especially after not being played for a few years. My Super Reverb (73 model) had a different problem, it would cut to about half volume after 10-15 minutes as if you pulled a power tube or three, and that turned out to be capacitors. after I changed every electrolytic and "orange drop" in it that problem went away.

The "white noise" you mention. Like the sound of frying bacon? Mine did that too, it was cured by replacing all the 1/2 watt resistors. I also have a dirty preamp tube socket causing frying bacon noise right now, narrowed it down by wiggling tubes one at a time and listening for which one changed it.

I would also be willing to suspect bad tubes, which is the first thing I always think with tube amps. The popping noise, I'm not sure, I'll say I'm thinking resistors getting hot just to see if I'm wrong. I'm sure these guys will let me know if I made a bad guess...I'm still learning, so stay tuned until some of the much more experienced [actual] techs chime in, I may be completely off base.

And since you don't say if or how much experience you have with tube amps, please be careful, the voltage inside is dangerous.

[FenderSuperReverbUser]

Thanks for the good leads to start with...I will keep those in mind. I've heard that capacitors age out after this length of time.

And fortunately, I do know enough about tubes to know there are high voltages in there. But that's about it. Thanks for the warning though.

Peter

[Bruce / Mission Amps]

Thanks for the good leads to start with...I will keep those in mind. I've heard that capacitors age out after this length of time.

And fortunately, I do know enough about tubes to know there are high voltages in there. But that's about it. Thanks for the warning though.

Peter

Peter does that mean you do not want to work on it by yourself?
Where are you located?
Maybe somebody close by who frequents the board can help out locally.

[FenderSuperReverbUser]

Hi, Bruce! Thanks for the note...

I am mechanically inclined, so replacing parts wouldn't be a problem for me. But no, I would prefer not to stick my hands inside the amp with it powered on. I'm just not used to dealing with tubes. (I know...I am a chicken...hehe)

So that would be cool if someone nearby might be able to help me out. I live about an hour from Houston (in College Station).

Thanks again!

Peter

[Enzo]

Before you go changing caps, how old are the tubes that are in it? Especially the power tubes? SOunds like bad power tubes to me.

[FenderSuperReverbUser]

Thanks for the reply...

As far as I know, the tubes are all original to the amp and head. It is possible it could have been retubed at some point in the mid 1970's, but if so, that's the last time it has seen any maintenance.

Peter

[FenderSuperReverbUser]

Ok, I've got some good (old) 100w Technics speakers I'm going to try hooking up to the PA100 tonight and see how it sounds. Maybe I can use that until I get the amp working again. I've read the PA100 is looking for an 8 Ohm impedance...I'll double-check the speakers before I hook 'em up to make sure they're 8 also.

Thanks for the help, so far!

Peter

[FenderSuperReverbUser]

Well, I just checked and they're actually 200w...and they are 8 ohm. Very cool...now I just need to find a couple of cables. I thought I had one here I could use but I can't find it. I think I have one at work though.

Peter

[FenderSuperReverbUser]

Ok! So I got one of my speakers hooked up to the PA100...and it sounded nice -- at first! Really warm, rich sound (I'm using a Kurzweil K2500S)...until it warmed up a bit. Then, I got a VERY loud, startling "POP!!!!" and sudden power output loss. It seemed to come back a little after playing some more. It was only turned up to "4" on the dial. Kurzweil volume was halfway. It did it again so I turned it off.

Maybe power tubes? If so, I need to order some...I'd like to get some that will last a long time, even if they cost a little more. Open to suggestions on those...

Also, the reverb popped a little bit and then squealed after turning the reverb knob up. We promptly turned it back down and that went away. More tubes, maybe?

I have some 12AX7's and 12AT7's that a friend gave me that are pretty old...might be worth swapping them out (can't remember which it uses, offhand but I have the tube list written down...I did read that I should only replace one at a time...) I also read there may be lethal voltages, even if it's been sitting unplugged for a long time. Sure wish I could find someone local so I don't end up killing myself!

Anyway, thanks for the suggestions so far! It sure sounded nice when it was working.

[FenderSuperReverbUser]

Sorry to bump this...I was going to just edit my previous post, but it looks like the ability to edit goes away after a length of time.

I tried the PA 100 again tonight...I did some research and found it has four 6L6GC's and figured I'd try the other channels. I did and had similar results...(the startling, VERY LOUD "POP" noise with immediately reduced audio level...)

So I turned it off again.

Can anyone recommend a good source of tubes and also brand? I read another webpage that had a list of reputable dealers, but would like to hear recommendations from folks here, please.

This will be used primarily with the K2500S...I'd like a good, clean, warm sound.

Peter