Grayhill Rotary Switch Shorting Against Chassis?

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MrG

Well-known member
Joined
Jul 22, 2018
Messages
126
Location
Nashville, TN
Hey all,

This is potentially a very simple, noob question, but I got a nice Grayhill rotary switch to use in an HPF in a guitar pedal,  and connected hot to Pin 1, and the “out” paths to pins 2 and 3. This works great when I wire it up, but whenever I connect it to chassis it shorts hot to ground? Is this intended and obvious? Just use rubber washers? I find myself hoping not and wishing it wouldn’t be quite that fragile but this is my first time encountering this.

Thanks in advance!
Mark
 
It's impossible to tell what you mean without some kind of schematic or at least a pencil drawing of the wiring.

But the metal bushings of switches and potentiometers are not connected to any terminals. They are meant to be and should be grounded through a chassis.
 
squarewave said:
It's impossible to tell what you mean without some kind of schematic or at least a pencil drawing of the wiring.

But the metal bushings of switches and potentiometers are not connected to any terminals. They are meant to be and should be grounded through a chassis.

Is that the case even if you use non-metal knobs (i.e plastic)?
 
warpie said:
Is that the case even if you use non-metal knobs (i.e plastic)?
The knobs have nothing to do with it. If the switch / pot is vaguely high impedance and carrying an analog signal it should be shielded. This is why if you look at a new-ish gear where the pot bushings are plastic and the housing is plastic, high impedance pots like in a guitar amp usually have a metal bracket around them that is soldered to the ground plane to shield it. For best results, use something with a metal bushing and mount that to a metal panel connected to a metal enclosure connected to earth ground so that the shielding of the chassis is extended to the switch / pot bushings.
 
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