Grounding Fender reverb unit

[drewl]

So if you have an amp that's already grounded with a 3 prong power cord, does the Fender reverb unit need to be grounded also?
I know the new reissues are grounded with a 3 prong.
Trying to settle an argument between a couple friends.
One is worried about ground loop noise from the reverb unit having it's own 3 prong grounded cord and doesn't believe grounding the reverb unit is needed.

What do you guys think?

[pdf64]

To comply with modern day good practice, any exposed metalwork of the reverb unit needs a proper ground connection, made via the line cord.
If there was an insulation failure in the power transformer then the chassis may get shorted to the line. In that situation, a solid ground connection is required which can pass significant fault current and quickly blow the line fuse. A ground connection made via an instrument cable / jack connectors would be unable to pass that kind of current. If that was being relied on for the ground connection, it may go high resistance or fuse, resulting in the reverb unit chassis getting pulled up to line level.
If being used by a singer/guitarist using a mic, then a fatal electric shock could result.
To avoid ground loops, the reverb circuit ground should be kept seperate to the chassis line ground; that will probably require insulated jack sockets etc.
The reverb circuit ground can then be referenced to its chassis ground via 2 back to back diodes.
Pete

[52 Bill]

And if the ground loop is a problem, you can create a patch cord with the ground lifted at one end to connect the reverb unit and the amp.

[Enzo]

Ground loops are a POTENTIAL problem. It is like discussing politics at dinner. It MIGHT start a fight, or it might not. Easy enough to find out by touching the chassis together. I'd ground it and deal with any loops IF they occur.