[LAU] Shielded electrical wiring for studio (or not)

[Ralf Mardorf]

On Sat, 06 Jun 2015 06:15:04 +0200, Robert Edge wrote:
> One side of the power line coming in to the amp is tied to the chassis
> through a capacitor, the ground switch changes which one.  This is what  
> is known as the 'death cap' in amp-dude circles.
>
> When it dries out and fails (not if, when), the chassis will be hot
> when the switch is in one position.

I didn't know that, but indeed, in a book [1] I see an old Fender:

        ac switch
~ o──┬─o/ o──────────────)│(
      │                   )│(
      o ground switch     )│
       \o────┐            )│(
      o      ┴ C 50n      )│(
      │      ┬   600V     )│(
      │      ┴            )│(
      │      ground       )│
      │                   )│(
~ o──┴────────[fuse]─────)│(  The audio IOs are connected to ground, so
                               guitar strings would be hot too, if the
                               capacitor has got a short.

[1] "Röhren-Verstärker  reparieren, restaurieren, modifizieren", Rainer  
zur Lind, ISBN 3-89576-028-5