Rickresource Rickenbacker Forum

My 1971 Fender Super Reverb suddenly developed a problem where a simple turning of the volume knob in the Normal Channel or tapping it on it lightly leads to seizure activity in which it sounds as if it is shorting out. Cutting in and out rapidly to the point where the immediate response is "turn it off quick." I replaced the preamp tube V1 but there was no change. The Vibrato channel works fine. I am wondering, Greg, if you have any thoughts or suggestions.

I will chime in and say it could be a dirty pot or a loose wire around the pot. I am assuming (yeah, I know!) you mean tapping the pot, not just tapping the amp itself.

Could be a bad solder joint on one of the components for that channel.

Thanks guys. The plot thickens.

Could be the pot, a resistor or a cap. My '61 Pro 15 did the same. Replaced some resistors and several caps, and it went away.

Thanks Paul. It looks like this is pot luck.

admin wrote:Thanks Paul. It looks like this is pot luck.

RIM SHOT!!!

That was funny Peter. Based on the suggestions so far, I think the solution to your problem is close at hand.



I don't want to hijack your thread Peter, but perhaps you can help me. I have a 1971 Twin Reverb that has been modded to black face. I found over the years that it is hard to get Fender's silver face amps to break up and provide a little distortion without increasing volume so high that it is barely tolerable. My amp has loads of crunch but little sustain. Maybe I need new tubes or some other kind of tweak to the circuitry?

I don't like to rely on the use use of outboard effects as you know but it would be nice to be able to use it on the odd lead solo with one of my Gibsons.
Right now all I use the amp for is recording my 360/12 WB.

A healthy Twin (BF or SF) should be hurting your ears long before it breaks up. That's the point!

There are lots of ways to mod them to break up sooner, but what you end up with is a heavy mid-powered amp. Perhaps a Deluxe Reverb would suit you better?

- Scott

Oh thanks Scott.............now I feel better. Look out neighbors I am gonna crank it.

Brian: I would say it is possible to have your cake at eat it too. Have you tried a powerbrake or THD Hotplate. These powersoakers can allow you to have the gain you want under lower volume conditions. I have one with my AC-30 and it allows for the breakup you want without having the fluid from you inner ear fall out.

The added bonus (or perhaps not depending on your point of view) is that the family and neighbours can get your attention even while you are playing.

That's a great idea. Thanks Peter, I will look into getting one of those. I figured you might have the answer since you have a similar amp.

Peter, a simple solution....don't use the normal channel! The vibrato channel is where its at on the blackface amps because they often have an extra stage of gain. Especially if you put in a switch to disconnect the trem because the trem roach in the amp loads down the channel it is working on. That said, it could be a bad pot, a bad solder joint on the circuitry related and/or directly connected to the pot, a bad cap or resistor connected or related to that circuit, or a bad tube. If you haven't replaced the electrolytic caps in that amp since original, then you should do that, and your problem may just go away. I have a friend who has a 1967 Super Reverb that would cut out after playing for at least 30 minutes, then if you put it on standby and then back in play about a minute later, it would work fine for awhile again. It was also down on power. It ended up being worn out power tubes and a bad rectifier tube.

Greg

Greg: I appreciate the sage advice. I took out the chassis and the pot was in very bad shape. I had a friend replace the pot and the Super Reverb is back to normal. He also discovered that it was running hot and so he fixed that as well. If you shake the old pot it sounds like a baby's rattle or perhaps more appropriately in this case a rattlesnake. Thanks for your advice everyone and for being there.

Glad it was an easy fix Peter!

Greg