Do I need an ABY pedal?

I am considering a dedicated two amp set up. Both are one channel amps with high and low input jacks. The plan is to run my signal path to the hi input jacks of both amps direct from the pedalboard, with the dry signals from two stereo delay pedals going to the low input jacks of one amp each (delay 1 dry to amp B delay 2 dry to amp A)

I also want to be able to toggle between amps or run both together at times... hence the ABY question.

Will this cause undesirable shifts in volume when I switch from a dual amp mode to a single amp mode, and if I am running amp A only, will its delay pedal stereo signal still bleed across to amp B?

Will my volumes from A and B be decreased when they are both on, coming up louder when using amps individually, and if the volume drops when using both through an ABY, will the dry delay signals be at the original volume, overpowering the overall signal???

probably, if you have no control over the power and grounding where you will be using them... daisy chaining 2 different amp brands will usually cause a ground loop and you will get loud hum... also, your 2 amps can be out of phase and daisy chaining will cancel the preamp signals and you get next to know audible sound even at 10.... even when everything works, when you daisy chain you are effectively blending the preamps of the 2 amps sonically like when you jumper channels on a plexi, so its not precisely the sound of 2 individual amps, its a new thing....

there are so many things that can go wrong

you need an ABY that's worth its salt, isolated outputs, a phase and ground lift on one channel.... maybe active circuitry so your signal isn't halved (because that's what happens in passive units as you surmised and the loss of volume is less of an audible issue than the reduction in gain which will change the way your 2 amps sound).... personally I think the best ABY going is the radial 'switchbone', but I have one so I'm biased, but mine has served me VERY well for about 15 years... they also make what I consider to be the best passive box, the big shot

most buffered stereo pedals also make good ABY boxes in bypass and work without hum or buzz 90% of the time... my flashback X4 does this trick really well and is capable of giving me some pretty cool ping pong delays between 2 amps but I've never tried using it in place of my dedicated ABY outside my house because my full rig is routed a little more intricately than just that

Pretty sure my last entry was confusing being generic.

If I run guitar to pedalboard to ABY with channel A going to Marshall high input and Channel B going to Roland high input, and have the stereo out from the H2O going to the Marshall low input and the stereo out from the DD2 to the Roland low input, is that still daisy chaining?

So will running (for example) DD2 dedicated output to marshall and stereo output to roland achieve well enough without me trying to bounce the H2O back the other way... ?

you probably souldn't use both iputs for the same basic signal unless the wet delay signal is long beyond the has effect withminimal feedback

heck, I am not even sure that the roland will allow you to use both at once, fenders will, early amrshalls will, jcm800s will not, the signal is out of phase and wired to be an 'either or' affair

on a tangent what do you think about the h2o I've been lusting over one lately and just need to try it already once i get a day i can go to shop and fiddle around with stuff

The h20 is beautiful. It says it is an analog delay but it holds up to the boss digital. The chorus is really nice. Very similar to my jazz chorus or a boss CE2. I don't use the "lush" setting that much... a bit too rich for chorus applications. I have the version 2, the v3 adds a vibrato. Seriously great pedal though. I only wish the signal chain went chorus then delay instead of delay chorus. But still brilliant.

I think with it being delay into chorus its trying to be like the deluxe memory man and aquapuss