Do I need a ground wire to bridge?

Kalimna

Thanks I think I have some 400VDC film caps somewhere - I assume they will do. Couldn't tell you if they are Class Y or not though....

Cheers,

Adam

ICBM

Kalimna said:

Thanks I think I have some 400VDC film caps somewhere - I assume they will do. Couldn't tell you if they are Class Y or not though...

They won't be unless they're specifically marked as such, and if you bought them for some signal-path type application they won't be anyway.

It doesn't really matter all that much because in order for there to be a shock hazard, there would have to be a mains fault and the cap would have to fail at the same time - which is vanishingly unlikely.

bbill335

ICBM said:

You called?



The value isn't very important - anything in the .01uF to .1uF range seems to work fine. The important thing is the voltage rating, which should be at least 250VAC or 400VDC (higher than the peak-to-peak voltage at 240VAC) and preferably a 'Class Y' safety capacitor, although that's really belt-and-braces.

You need to fit it in the connection to the string ground, which is the wire that goes to the tailpiece or tremolo claw - undo it at the control cavity end, connect the cap to it with some heatshrink over the joint, and the other end of the cap back to where the wire was.

Is there a reason not to connect the safety cap in series to the shield connection at the output, then connect the strings/bridge to the usual back-of-pot ground point? 

ICBM

bbill335 said:

Is there a reason not to connect the safety cap in series to the shield connection at the output, then connect the strings/bridge to the usual back-of-pot ground point? 

Yes, it will lift the ground from the guitar electronics and it won't work properly.