It's not that complicated. A typical amplifier or other piece of equipment that has a bipolar power supply (+/- rails), and most audio gear does, is insensitive to changes or noise on those rails as long as is occur oppositely. This noise cancels out with respect to ground and the unbalanced signal path. Look at the nasty ripple on an amp rail sometime with a scope yet the amp is quiet. I'm applying the same thinking here to a 240V balanced supply. If a noise spike comes down the 240V lines whatever lies between the two hots suffers the increase or decrease of spike voltage but does not suffer noise caused by any relationship to ground. In typical piece of gear that increase or decrease in supply (from the spike) is of no consequence because it also affects the internal rails equally. With a 240V supply the ground and signal paths still sit quietly between all the opposing noise ruckus on both the 240V lines and the internal supply rails. Any other connected 240V gear also sits in the same sweet spot including an isolated 240 to 120V transformer which will also maintain that balance.If this were on a 120V line then the neutral and to some degree the ground, would also carry that spike. The internal rails of the gear would still cancel the voltage changes but the unbalanced signal path, which depends upon the ground for the signal circuit, is at the mercy of what ever noise is on the ground and leaking from the neutral. Also in the 240V scenario most of the leakage from internal transformers and other stray capacitances also cancels and leaves very little energy to leak to ground. I think a studio wired in this way would be rather quiet with regards to line noise and if I ever put together another large PA system (in the US) the entire thing would be 240V.

ptay wrote:When you say oppositely, i think you mean together.In the case of internal bipolar supplies in particular, I mean normal mode (opposite), not common mode.

When you say oppositely, i think you mean together.Fact is any glitch on the power line would get into the audio if it weren't for filter caps and voltage regulators. If both lines go up together, there's no spike between the conductors, but there will be one in the ground wire!So there are no sure bets!

What's the preferred way to organize comp/limiter sidechains In/Outs in the patchbay?I'd planned to put outboard gear inputs on a top row of jacks, with the bottom row being the outputs of the jack above. Like:Comp1 IN: (top row, jack 1)Comp1 OUT: (bott. row, jack 1)But when I thought about putting the sidechains side by side with their appropriate signal chain, I realized the logic gets inverted to outputs on the top row and inputs on the bottom row.I've got mostly outs on the top rows and ins on the bottom rows otherwise ... So now I'm confused.I have 4 limiters that have a sidechain output (which is identical to the main channel output, but isolated) and an input for the sidechain ... they're feedback limiters.The output/input is really a primitive type of insert.Another question: For limiters/compressors that have multiple sidechain options (like the brooke siren system ...) do you bring all of these out to the patchbay or just hte obvious 'flat' one?

I'm a jerk. I double posted:viewtopic.php?f=2&t=58996

I don't quite understand your question, but i'd maybe just dump the sidechain inputs somewhere else on the jackfield if you're wanting to be efficient with space.