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Footswitch for Fender Princeton Reverb/Vibrato?

Posted: Fri Aug 14, 2020 10:01 am
by tlarson58
I've now tossed two Fender-brand "classic" two-button switches (one's wiring was repaired by a band mate but broke again). I purchased what I think is a slightly more durable alternative but the vibrato "heartbeat" can be heard through the reverb tank when it is supposed to be "off."

Could the leaking vibrato sound be a shielding issue with the cable? I have it packed for return but thought that I'd wait for a response from someone here before I do.
TRS shield info.jpg
switch and cable.jpg
My amp has a TRS jack, not the RCA plugs.

Re: Footswitch for Fender Princeton Reverb/Vibrato?

Posted: Fri Aug 14, 2020 10:35 am
by mozz
I'm gonna say the wires inside aren't separately shielded so the reverb is picking up the vibrato signal.

Re: Footswitch for Fender Princeton Reverb/Vibrato?

Posted: Fri Aug 14, 2020 10:53 am
by andrewsrea
^ my thoughts. I am also thinking the manufacturer may have a big (1M - 3M ohm) bypass resistor across the switch, to combat 'pop.' That might be enough leak to ground for the Vibrato to sub-oscillate when it is switched 'off.'

To Mozz' point, the vintage footswitch pedals have a lead inside a grounded-braided shield for the reverb and next to the shield, a lead for the vibrato. All that is enclosed in a plastic casing. So, the vibrato signal doesn't induct the reverb lead.

Re: Footswitch for Fender Princeton Reverb/Vibrato?

Posted: Fri Aug 14, 2020 1:56 pm
by mozz
Yeah, i just built 2 of these and just looked at the schematic, the reverb switch wire goes right to the grid of the recovery tube, so it is bound to pick up any signals placed near it. I'm wondering if anybody makes a shielded cable with the outside traveler wire. Or you would need a dual coax wire in 1 jacket, yet still be flexible.

2 separate footswitches would work but that's a pain. If i were you, i would just unplug the reverb to leave it on all the time and adjust to suit. If that wouldn't work this is factory switch for $36
https://www.sweetwater.com/store/detail ... footswitch

Re: Footswitch for Fender Princeton Reverb/Vibrato?

Posted: Fri Aug 14, 2020 11:02 pm
by tlarson58
mozz wrote: Fri Aug 14, 2020 1:56 pm Yeah, i just built 2 of these and just looked at the schematic, the reverb switch wire goes right to the grid of the recovery tube, so it is bound to pick up any signals placed near it. I'm wondering if anybody makes a shielded cable with the outside traveler wire. Or you would need a dual coax wire in 1 jacket, yet still be flexible.

2 separate footswitches would work but that's a pain. If i were you, i would just unplug the reverb to leave it on all the time and adjust to suit. If that wouldn't work this is factory switch for $36
https://www.sweetwater.com/store/detail ... footswitch
Thanks, guys. I have been playing sans switch for a month now. Reverb is always on and I leave the tremelo knobs at 0 unless I want to dial some up.