floating the ground onthe input of a reverb tank

[pula58]

Could you do this:

Disconnect the shield of the input of the reverb tank from ground and drive the input of the tank without referencing ground?

The reverb driver tranny would drive the input of the tank differentially. That is, the secondary of the reverb driver tranny would have no direct connection to ground. You could put a 100k 1% resistor from each of the tranny outputs to ground (to keep the tranny outputs close to ground). Any ground noise (or signal) would then become common-mode and be rejected. At least, that is the thought.

Seems like this could eliminate any probelms with a ground loop from inserting unwanted signals into the reverb tank.

But maybe the actual problem is at the output of the tank.......

What do youthink about this?

[diagrammatiks]

Could you do this:

Disconnect the shield of the input of the reverb tank from ground and drive the input of the tank without referencing ground?

The reverb driver tranny would drive the input of the tank differentially. That is, the secondary of the reverb driver tranny would have no direct connection to ground. You could put a 100k 1% resistor from each of the tranny outputs to ground (to keep the tranny outputs close to ground). Any ground noise (or signal) would then become common-mode and be rejected. At least, that is the thought.

Seems like this could eliminate any probelms with a ground loop from inserting unwanted signals into the reverb tank.

But maybe the actual problem is at the output of the tank.......

What do youthink about this?

depends on what kind of tank you get.

accutronics has different codes for input grounded, output grounded, both grounded, or none grounded.

[billyz]

I believe Mesa Boogie already does this.
By the way, The new belton tanks have a little pcb on the inside of the rca jacks. You can unbridge the ground connection with solder wick. I had to do this recently on a Mesa when I encounter some squeal with a new tank. Some of their designs need it others don't.

[pula58]

I thought I'd draw it, make it more clear....

[Firestorm]

At least in Fender tanks, only one side is grounded (output) so you don't really have that much potential for a ground loop. If you do lift the ground, though, the tank chassis ceases to be a shield for the transducers which could then pick up all sorts of noise. The output side is the one to worry about since it's on the grid of the recovery tube.

[pula58]

At least in Fender tanks, only one side is grounded (output) so you don't really have that much potential for a ground loop. If you do lift the ground, though, the tank chassis ceases to be a shield for the transducers which could then pick up all sorts of noise. The output side is the one to worry about since it's on the grid of the recovery tube.

Wouldn't the output side then have its low connection to the tanks chassis if it is a Fender style (ex: 4AB3C1B) tank?

[Firestorm]

The reverb chassis is electrically continuous with the main amp chassis, because of the output jack ground. The input jack has its ground connection insulated from the reverb chassis (and thus from the amp chassis).

Source of noise in these things is two-fold: first, the output cable is a very big wire directly connected to a 12AX7 grid (good cable is essential, obviously); second, the driver side is single-ended so there's no phase cancellation of stray signals and the reverb tranny itself "sprays" noise, so placement and orientation are critical.