Fender Twin Reverb/"custom" Vibrolux Reverb foot switch noise

[g1]

The reason I mentioned trying to fix it is because cable problems are almost always where they flex. So that would be either the plug end or the footswitch end.
The shielding on the reverb switch line is because it is carrying the audio signal and can pick up noise. The vibrato line carries no audio so it doen't need shielding.

[jasonguitar]

If you have two otherwise identical footswitches, and one has a noisy cable and the other does not, then accept that the one has a bad cable and rewire it.


Cables can be microphonic or otherwise mechanically sensitive. The looser their construction, the more likely that will happen. Also, cables that have been walked on enough will start to have breaks in the shielding weave or wrap. The wire as a whole will still have plenty of continuity, but broken ends of strands touch and untouch and that makes crackles and pops.

I just had this problem with my super reverb foot switch where the cable had become extremely microphonic. I bought some nice Mogami dual conductor, shielded cable and wired it up exactly like the original and now the cable is dead silent when you move it or step on it and the foot switch operates correctly but there is a substantial hum when the reverb is turned on, only with the footswitch plugged in and the vibrato switch pops loudly when the reverb switch is on. Any suggestions?

[52 Bill]

I bought some nice Mogami dual conductor, shielded cable and wired it up exactly like the original and now the cable is dead silent when you move it or step on it and the foot switch operates correctly but there is a substantial hum when the reverb is turned on, only with the footswitch plugged in and the vibrato switch pops loudly when the reverb switch is on. Any suggestions?

Is this balanced mike cable where both conductors are twisted and enclosed in one shield?

The reverb switch line is directly connected to the audio path of the reverb return circuit. That's why the reverb cable is shielded. If both conductors are in the same shield then there is nothing separating the audio wire from the vibrato oscillator circuit switch and this type of noise and hum can happen.

[jasonguitar]

Is this balanced mike cable where both conductors are twisted and enclosed in one shield?

The reverb switch line is directly connected to the audio path of the reverb return circuit. That's why the reverb cable is shielded. If both conductors are in the same shield then there is nothing separating the audio wire from the vibrato oscillator circuit switch and this type of noise and hum can happen.

AH!!! Thank you very much for showing me my error! I knew I had overlooked something, that being that ONLY the reverb cable is supposed to be inside of the shield. I wasted $12 on 12 feet of Mogami but that'll never happen again and I'll find some use for it. Now I just have to get the RIGHT cable. I was hoping for something that might be better quality since it seems that these OEM cables tend to develop cracks and splits in the lead wire insulation.

[52 Bill]

I once built a custom length cable for a guy. I used the really thin George L shielded cable and a separate stranded wire. I got a roll of heatshrink and fed the two wires through the heatshrink and then shrunk the sleeve down around the two.

Feeding the wires through the heatshrink was the hardest part of the job.

[soundguruman]

I just had this problem with my super reverb foot switch where the cable had become extremely microphonic. I bought some nice Mogami dual conductor, shielded cable and wired it up exactly like the original and now the cable is dead silent when you move it or step on it and the foot switch operates correctly but there is a substantial hum when the reverb is turned on, only with the footswitch plugged in and the vibrato switch pops loudly when the reverb switch is on. Any suggestions?

One wire for the vibrato must be completely unshielded.
Separated from
One wire for the reverb that IS shielded.
That's why there is special wire made for Fender Amps exclusively.
Hum when the reverb is on? There could be a broken wire in the reverb tank. Very common problem.
Also, the cables to and from the reverb tank could be bad.
If there is problem, it may not be just the foot switch.