using two amps and spliting the preamps and power sections

Q & A for building and interfacing your rack gear with Ground Control Pro and GCX-based systems.
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toolshed
Posts: 44
Joined: Tue Nov 16, 2010 3:15 pm

using two amps and spliting the preamps and power sections

Post by toolshed » Sat Oct 22, 2011 2:04 pm

has anyone used two amps and seperated the preamps and the power sections so they could run either preamp on either power amp section of two amps? I was thinking about maybe doing this and also putting a stereo fx processor between them. hmmmmmm... as i ponder.....!

gerax
Posts: 35
Joined: Thu Jan 27, 2011 10:45 am

Re: using two amps and spliting the preamps and power sectio

Post by gerax » Mon Oct 24, 2011 6:01 am

I'm putting together a similar setup.

I have a Mesa DC3 and I'm looking for a Mesa Maverick. Both are 35W EL84 amps (so the power sections are very similar as they both are Dynawatt Technology based), while the preamps are voiced quite differently.

My plan is to tap the signal at the FX loops (running them 100% wet to make them serial) and use the GCX to choose which pre and which channel should be used for any given patch. Oh, I also threw a Triaxis in for some extra sounds...
Then after the amps I have a few pedals hooked up to the GCX and the last loop goes to the mono in on a DMC System Mix Plus for 2 parallel FX units (Eventide Eclipse and Lexicon MPX-1). The stereo L/R output of the mixer goes back to the two FX returns so I have a stereo power section. From there to speakers.

I'm still missing the Maverick (they are quite hard to come by at a reasonable price and the size I need) but the rest is about to be completed.
If you are interested I'll post back my results as soon as I have the rig up and running.

L.G.

toolshed
Posts: 44
Joined: Tue Nov 16, 2010 3:15 pm

Re: using two amps and spliting the preamps and power sectio

Post by toolshed » Mon Oct 24, 2011 10:46 am

That would be great.

domct203
Posts: 157
Joined: Fri May 20, 2011 11:07 am

Re: using two amps and spliting the preamps and power sectio

Post by domct203 » Mon Oct 24, 2011 11:15 am

gerax wrote:I'm putting together a similar setup......

My plan is to tap the signal at the FX loops (running them 100% wet to make them serial) and use the GCX to choose which pre and which channel should be used for any given patch......
FYI- Most Mesa parallel FX Loops will never be truly series (serial) with the mix knob turned fully clockwise. I know that the mix knob on my old Triple Rectifier was labeled 90% at full wet.

There is a simple test you can do to determine if this is indeed the case. Simply plug one end of an instrument cable into ONLY the FX Loop SEND. Turn the mix knob all the up to wet, you will still hear some dry tone passed through. If the amp goes completely silent when turning up the mix knob then it is indeed true series.

The reason I mention this is that strange phase artifacts may be present when using some digital effects. The may be even more noticable at lower volumes. It will be a comb filter effect, sounding like a phase or chorus pedal with the speed on zero.

Dom
Ground Control Pro | GCX | Control Switcher | PP2+ | Mesa Dual Rectifier Roadster | Mesa Mark V | Mesa Stiletto Deuce | (2) Mesa Rectifier 4X12's | '73 Gibson Les Paul Custom | '12 Gibson Les Paul Trad | '10 Carvin CT6M | TC G-Major

gerax
Posts: 35
Joined: Thu Jan 27, 2011 10:45 am

Re: using two amps and spliting the preamps and power sectio

Post by gerax » Mon Oct 24, 2011 3:04 pm

The FX loop on my DC3 actually works like this: you have to plug a cable into the send even if you aren't using the preamp section: the manual states that the power section can be used as a straight power amp if the loop level is 100% wet. I tried that and I got some strange behaviour, so I got the schematics and noted that the send output must be isolated from the circuit by simply plugging a cable into it (it doesn't have to necessarily lead anywhere as it does in my setup, it just has to break the connection) and the loop becomes serial, the two sections are isolated. I tried it by plugging my Triaxis in to the FX return with the send isolated that way and it works great.
In my case I have the preamp send go to a loop return on the GCX for preamp selection, so it should work as planned; I'll have my GCX delivered in a few days so I'll be testing and reporting.

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