Deluxe reverb - grounding reverb RCA jacks

[Petedub]

Hello

I am working away at my DR and slowly, carefully making progress.

Can anyone guide me - What is the best way to earth the reverb jacks. Direct through the chassis or should I isolate the earths and add them to my pre amp earth?

The diagrams all show the reverb jacks grounded to the chassis.

I have bought sockets with an isolated earth if required.

I have built my amp so that the pots are not earthed thru the chassis, I am using one earth for the preamp (near input) and a separate earth near the pt. I understand this is the best method. 

[mresistor]

I've built mine just like Fender did at the factory and haven't had any problems.

[tdvt]

It looks like you are all set to make them isolated with those jacks & washers, so why not..?

I did as you have, & isolated everything on an AB763 I recently finished. No noise.

I ran a single ground wire from the combined grounds of the RCA jacks to the same sub-bus that the reverb tube cathodes are connected to, which in turn connects to jack bus, then onto main ground point near the AC cord.

Internally, the trem footswitch utilizes the reverb footswitch ground (in a Fender footswitch) so no need to ground the trem footswitch jack on the chassis end, if you decide to go isolated.

[pdf64]

I can’t see any benefit in isolating the drive RCA.
The transformer secondary is completely isolated anyway, no possibility for hum loops.
And for safety, in case there’s a primary to secondary short, it needs a solid chassis earth reference.

[tubeswell]

Agree - little benefit in isolating the amp chassis' Reverb jack sleeves on a blackface amp. One of the RCA jack sleeves on the reverb pan chassis will be isolated anyway - preventing hum loops.


But on a stand alone reverb unit chassis, where you may be running a hum-loop block network for the signal ground - as a result of needing to avoid hum loops from having to provide a dedicated earth mains ground - it can be beneficial to isolate the RCA reverb return jack sleeve (i.e., if you have the reverb recovery grid leak resistor attached to the jack sleeve) and return the sleeve ground to the common signal ground point above the hum loop block network, because of the ground loops that would otherwise be created, seeing as how the reverb recovery stage is the most noise-sensitive gain stage in the amp. But that's not normally the case with a typical blackface reverb amp, cos you don't usually install a hum-loop blocker on the signal ground for those.

[Petedub]

Many thanks for the input here, I think I have the answer I need.

I'm going to ground the rev jacks thru the chassis and see how it goes.



There are so many wires already it looks like a bowl of spaghetti