If you have a single hi Z signal (guitar) that goes into a Y box, how will it have the same voltage on both sides? Afaict, it would need to be active as you say.
Voltage will be the same because it's a parallel circuit. Current will be lower...but the whole point of having a high z signal is to keep current to a minimum.
Will a passive Y box have an identical signal on both outs compared to the input?
No, for ABY you want a good active box, or at least have a buffer before a passive one.
So if, for instance, I had a noise gate pedal first, then a passive Y, it would work well? (Only getting the coloration of the noise gate?)
Yeah that'll work.
It all depends on what you are plugging into after the aby pedal - if it’s splitting to two amps your guitar is not running into a 1 Mohm input as usual, but into two 1 Mohm loads in parallel. That’s not the aby pedal adding coloration, it’s the different load.
This looks like what I need, for cheap.
No you can’t because of ground loops.
Isolation is, of course, better. Hence the "get away with". However, I have a simple buffered Y setup at home that works fine, so... Yes you can! :-)
Isolation isn’t better it’s essential.
Agreed.
