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#1039705 - 01/26/06 10:58 AM PLEASE HELP - Need wiring help on a complex rig
Duolos Offline

Registered: 01/26/06
Posts: 10
Loc: Orlando, FL
I am trying to run a total of 4 heads and 8 cabinets with an ISP pro rack G decimator, TC Electronics g-major, Peterson 450 strobe tuner with a GCX guitar audio switcher and the GCX ground control unit. I will only be using 2 heads at a time or even just one but there are 4 heads I want to use total. I may not always use effects but will use light effects most times. All the amps have effects loops and will be used as heads, not pre-amps. Can somebody help me wire this thing up the proper way so it can work without ground loops and so forth?

Much Thanks

#1039706 - 01/27/06 07:38 AM Re: PLEASE HELP - Need wiring help on a complex rig
philbo_Tangent Offline
Platinum Member

Registered: 10/08/00
Posts: 1175
Loc: Iowa
Several issues arise:
Power, audio phasing (both amps and cabs), and switching amps & cabs.

If you need to switch amp outputs between different cabs, you need something that will handle large currents (calculate current like this:
current = square root[(power out of amp)/(cabinet impedance)]
Do this for all amp/cab combinations, and use the biggest number you get as a minimum current the switch needs to be able to handle.

Switching amp inputs, you need good shielding on all switches and cables to avoid hum and crosstalk.

You might consider having a couple of switch matrix boxes made.
One would allow feeding any amps to any cabs. Arrange switches in rows & columns, with amps listed on each row and cabs listed in each column. To connect any amp output to any cab, just turn on the switch where the row & column intersect.
Beware: You should never turn on any 2 switches in the same column, that would short the 2 amp outputs together. It MIGHT be OK to turn on 2 cabs for one amp, depending on whether the amp can handle it.
Also, no switch should ever be moved while the amp it is connected to is turned on. (Some amps will tolerate abuse like that, but many will fry if you do it.)

The other box would do the same function for feeding your signal(s) to different amp heads (it may be more economical and easy to just buy a patch bay for this, though).

You might want to hire an experienced studio tech or audio tech to put this together for you if you're not handy with electronics work.
Tangent Studios