Grateful Dead Music Forum

A place to talk about the music of the Grateful Dead 

Chat about Equipment Info
 #57326  by Laytonco
 Mon Mar 02, 2009 12:18 pm
Hey folks,
I have a blackfaced 1974 Fender Super Reverb and the Vibrato is not working. It was working perfectly and then stopped all of a sudden. I replaced the preamp tube twice just to make sure that wasn't the problem. I also checked the footswitch connection in the back. In fact, when I unplugged the footswtich, the reverb stayed on and I am guessing the vibrato should too. Anyhow, before I take the amp in, I am curious to hear any suggestions on what else to check. I really miss the vibrato in this amp!!!


 #57341  by jonarobb
 Mon Mar 02, 2009 5:34 pm
SarnoMusicSolutions wrote:Needs a new bug. (the lamp/photoresistor device that makes the tremolo happen) ... id=4113400

The bug is usually the last thing to go. They generally outlive the amps in my experience. A Tremolo that suddenly dies on a Fender amp without any other signs of fading, etc, is 99% of the time a bad foot switch, cable to the footswitch or dirty RCA jack.

If you did have some other symptoms leading up the Trem dying, such as weaker than usual intensity, or volume dropping when you turned the intensity up, then it's the string of blocking caps that are leaking. They would be the .02uf, and the pair of.01uf's.

The Trem bug does have to be replaced in some instances but they are few and far between.

FYI, Unless the amp has been modified, with no footswitch attached the Reverb should operate BUT NOT the Tremolo.
 #57345  by Laytonco
 Mon Mar 02, 2009 6:40 pm
Thanks all. I'll check the connection and the footswtich. I will say that the reverb side of the footswitch "clicks" properly and the trem side is not so clean feeling although it does click. Could I reverse the plugs and plug the reverb path of the footswitch into the trem jack without harm?
 #57354  by SarnoMusicSolutions
 Mon Mar 02, 2009 8:24 pm
You can just take an RCA plug and connect the tip to ground with a wire inside the plug, and then just plug that in. It's the same as what a working switch would do. People will do this to keep the vibrato (actually tremolo) on all the time without a footswitch.

Let us know what the fix turns out to be.

 #57418  by strumminsix
 Wed Mar 04, 2009 6:37 am
Jon, it must be an east coast thing. I think your "roaches" are more resilient! HA!
Seriously, anytime I hear of vibrato going on an old fender it's the roach.