ground...groundloop?...yes...problem...solved!

[pop.adams]

and after all...its a groundloopwall...
i solved the problem.
i had to disconnect the ground to the mixer. now everything is deadquiet.
maybe i shouldn't drink too much beer before i post unreflected stuff like this.
sorry folks!
have a nice and sunny day.
c.

hello.

something is driving me mad. and this @#$%ing something is called GROUND.
my setup:

orange (@#$%er 30)
presonus (acousti-q)
alesis (quadraverb)
wah (dunlop)
tuner (boss tu-2)
a diy rodent rat (sounds great...yes
and my diy "switching-matrix" called relovution (a 19" central-box with all the relays for the routing is housed in my rack for shortest way from git to amp and a remote-box with the wah and tuner in it)

the 1. thing my reloution can do is to mute the electric and the acoustic guitar each has its own switch (great, isn't it? haha).
if its muted the signal is routed to the tuner where another switch selects which guitar can be tuned. here is the first problem: i have to use both grounds (for the acoustic the ground from the presonus and for the e-git the ground from my orange. if i don't do this...guess what...hum. but this isn't a problem 'cause the signals are at this point seperated).

-> question1: is it a problem to use different grounds? at which points do i have to be careful? how is it done in bigger setups with much more grounds?

sorry i didn't want to explain my equipment, i wanted to ask some questions. well here is the main problem:

with a 3pdt i can select wether to use the quadraverb with the orange OR the presonus. but somehow ONE of my amps always hums. if i use the ground from the orange with the quad's ground the orange is quiet but the presonus hums and the other way round if i use the presonus's ground the presonus is quiet and the orange hums.

-> question2: what can i do? is this a groundloop-problem? which ground should be the "main-ground"? do i have to use a transformer?

someone told me NOT to use the supply ground (6V for the relays and LEDs and 9V for the tuner, wah and the rodent rat).

-> question3: is this true?

if i don't use it, all the effects hum...i have to use both grounds otherwise everything hums.
hum hum hum.
i can't hear that any longer.

is there anyone who can please hum me...äh help me?
thanks in advance.
carsten