Bad Reverb Transformer?

[Dandrix]

I have it grounded twice, once for the b+ side of caps then, grounded at pin 8 of power tube (6v6) to cap supply. yes, I think in the same spot (I closed it up already).

[Dandrix]

removed the second grounding point from pin 8 of power tube to cap supply. no dice. still got hum. changed reverb tank, and wires, no luck there. reverb sounds good with tremolo, just got a lot of hum with it.
any ideas??? thanks

[Chuck H]

If you have only one ground lead from each grounded point in the circuits then your only other option is to try swapping ground points for individual grounds. Assuming you have more than one ground point. If you don't then there is still some related circuit that is grounded twice between DC blocking caps.

Did you change the ORIENTATION of the reverb tank?

The RCA jacks mounted to the chassis are probably of little consequence. It's eddie currents between grounds and the differential between them that causes ground loop hum. Since the RCA jacks are very close together there shouldn't be much trouble. BUT... What I know and what I've heard sometimes contradict. I'm still learning a lot of this myself.

Isolating the sleeve on a jack simply means making sure the jack sleeve is isolated from the chassis and has a groundable sleeve lug so that you can choose to ground it where you want to or not at all. This may require some creative engineering and retrofitting.

Your Accutronics/Belton tank has the input isolated. That means that you must provide a ground for the shield at the input side. If your RCA jacks are chassis mounted then that is accounted for. The output jack and pan chassis are connected to the 0V output jack lug. So, with your particular tank, if you have chassis mounted jacks that should be fine. Just be certain that the input shield sleeve is grounded with the input signal circuit and the pan and it's output circuitry are grounded with the recovery stage. And distinctly NOT daisy chained together in any way.

[PfeifferElectronics]

The first filter cap from the rectifier tube should be grounded at the power transformer and NOT grounded to the other filter cap grounds, they should be on their own path to ground. I believe this is the best way to avoid hum. I had all the filter cap grounds connected together but grounded at each end, very bad as this created two paths to ground. Does this make sense?

[Dandrix]

I was just trying to follow the 5g9 schematic. showed all supply caps going to ground. how do you to break the chain? how do you know to break the supply path to ground?

The first filter cap from the rectifier tube should be grounded at the power transformer and NOT grounded to the other filter cap grounds, they should be on their own path to ground. I believe this is the best way to avoid hum. I had all the filter cap grounds connected together but grounded at each end, very bad as this created two paths to ground. Does this make sense?

[ATTACH=CONFIG]22750[/ATTACH]

[PfeifferElectronics]

you are still grounding everything according to the schematic. Just don't ground twice. There should only be one path to ground from any capacitor. (ie. don't chain ground points together unless it is the chassis doing the chaining. Best practice is to ground them close to where they are used, so caps in preamp should be grounded on the preamp end of your layout/chassis, and power caps should be grounded near the transformer/power section of your layout.