@lewm thanks. I do believe there is something already wired into the connection between the circuit ground and the chassis/main AC ground receptacle inside the amps, but I don’t feel comfortable messing with it. I will continue to investigate, perhaps talk to Vlad- since I’m sure this came up at one point over the years. I suspect it may have something to do with the woofer amp that is part of my Avantgarde Duos- I think there is something internal I could do with the speaker (have to check the manual on the speaker, but I think that is user-permitted), not sure.
@atmasphere Ralph- using my Fluke, I measured .2 at the ground pin on the amp cord, unplugged. Measuring at the RCA input to the amp, with everything, including speaker cable, disconnected, the shield or collar side of the RCA jumped around radically, nothing nearly as low at the ground pin, but high voltages, lower voltages- and no OL type reading on the meter suggesting it is "off scale." Why is that so? (FWIW, I use the XLR input on the amps, not the RCA (though these amps are not a balanced design, i just prefer the integrity of the connection).
@lowrider57 I can offer this much-- the Granite Audio as far as I know-- mine’s in a box somewhere- is very much like an external star ground that supplements but does not replace the AC ground. It does allow some switching of the impedance of the grounds depending on which channels on the back you plug the wires into, and how you position the switches relative to each other. I don’t think it does much else. I’m also not sure how star grounding overcomes some inter-component grounding problem within a system if everything is still hooked up to the normal AC grounds, but at one point, it did minimize noise when I was first setting up this system in NY some years ago. Beyond that, I cannot say.
The passive Synergistic looks very much like a standard copper bus(s) bar, mounted in a small box that may have some additional passive material in it. (The connection to the wall is only for ground, not to power it, I believe, much like the Granite Audio).
I cannot speak to the SR Active device, but there are, as you know, a host of things available now as @folkfreak mentioned in his OP.
@atmasphere Ralph- using my Fluke, I measured .2 at the ground pin on the amp cord, unplugged. Measuring at the RCA input to the amp, with everything, including speaker cable, disconnected, the shield or collar side of the RCA jumped around radically, nothing nearly as low at the ground pin, but high voltages, lower voltages- and no OL type reading on the meter suggesting it is "off scale." Why is that so? (FWIW, I use the XLR input on the amps, not the RCA (though these amps are not a balanced design, i just prefer the integrity of the connection).
@lowrider57 I can offer this much-- the Granite Audio as far as I know-- mine’s in a box somewhere- is very much like an external star ground that supplements but does not replace the AC ground. It does allow some switching of the impedance of the grounds depending on which channels on the back you plug the wires into, and how you position the switches relative to each other. I don’t think it does much else. I’m also not sure how star grounding overcomes some inter-component grounding problem within a system if everything is still hooked up to the normal AC grounds, but at one point, it did minimize noise when I was first setting up this system in NY some years ago. Beyond that, I cannot say.
The passive Synergistic looks very much like a standard copper bus(s) bar, mounted in a small box that may have some additional passive material in it. (The connection to the wall is only for ground, not to power it, I believe, much like the Granite Audio).
I cannot speak to the SR Active device, but there are, as you know, a host of things available now as @folkfreak mentioned in his OP.