GT-Pro & External preamp = 3 amps at once. It's possible

[paul525715]

Hi everyone.

Maybe I'm being thick but until now I've thought it impossible to mix an external preamp with the GT-Pro preamp an get successful results. If what I've worked out on paper is correct, this could provide us with three amps, and I think I've figured how to do it.

1) Solder up a lead consisting of 5 1/4 inch jacks connected together. This shouldn't tax anyone too much, right?

2) Connect 2 of the jacks to the pre loop send and pre loop return (yes, effectively shorting them out)

3) Connect another two of the jacks to loop #1 send and loop #2 send

4) Connect the fifth jack to the input on your external preamp

5) Take the stereo output from your external preamp and connect it to loop #1 return and loop #2 return

Now, these options are possible...

STEREO EXTERNAL PREAMP (WAH BEFORE PREAMP)
------------------------------------------------------------

Preloop = off
Wah = on/off
Preamp = off
loop = stereo 1 / normal
send = 100%
return = 100%
effects as necessary

STEREO GT-Pro PREAMP (WAH BEFORE PREAMP)
--------------------------------------------------------

Preloop = off
Wah = on/off
Preamp = on
Loop = off

STEREO EXTERNAL PREAMP & GT-Pro PREAMP MIX (WAH BEFORE ONBOARD PREAMP)
----------------------------------------------------------

Preloop = on
Wah = on/off
Loop = on direct mix
Loop send = 0%
Loop return = as required

The GT-Pro and External preamp can be mixed using GT-Pro preamp levels and the return levels

Of course, you could assign the CTL pedal to fade between the 2 preamps, or use the EXP pedal AND the CTL pedal, one for the GT-Pro preamp mix and one for fading between them.

Maybe I'm covering old ground and maybe there's a much easier way, but if 2 amps sounds huge, three could be massive!

Cheers,

Paul

[paul525715]

Just soldered up my cable and... it works.

All I've tried so far is a JC120 on channel A (left speaker), Vox Clean on Channel B (right speaker) and JMP-1 on overdriven tone (stereo mix).

WOW!

3 amps in one. Now all I've got to do is spend hours thickening my tone more than it already is.

Just remember if you're gonna do this to set your loop send to zero or you'll get lovely feedback from a loop "short circuit".

I love my GT-Pro! :D :D :D

Cheers,

Paul

[Velle]

Clips Please.

[Myedvyed]

Couldn't you also send your Guitar out (or Tuner out, don't remember what it's called) to the external amp, and then connect the external amp to FX1 (and FX2 if you want stereo)?

You could then turn on/off each preamp separately and determine each volume in the mix, and there's no need for soldering.. for those a-technical guys out there, like me :P

[paul525715]

Yes, you can use the guitar/tuner direct out, but if you decided to use just the external preamp for one of your patches then you couldn't put any fx before the preamp, only after it. With the bastardised cable you can disable the onboard preamp and have fx before your external one.

I would love to put up a decent sound clip but my gear is about 300 miles away at the moment. The only clip I have is a very quickly made intro to Baba O'Reilly by the Who. It was a first take affair just to show the basist and drummer in my band how it would sound. It's a bit out of time and needed tweaking but here's the basics of it...

Guitar --> GT-Pro
GT-Pro output via Pre-amp loop modified cable, feeding into the Marshall JMP-1 and also shorting straight back to GT-Pro pre loop return
Preloop return --> Dual stereo onboard Preamp (Vox Clean & Vox Drive with delay (approx 50ms if I remember right) --> Auto Riff --> Chorus --> Stereo delay (approx 100ms, again this is only from memory!) --> Main effects loops input (set to mix with loop send at 0 and JMP-1 returning via loop returns) --> Reverb --> Output

I use an FC-200 as my foot pedal.
The CTL pedal is set to hold the arpegiated sound created by the AR function.
The Exp pedal is set to raise the level of the JMP-1 return and lower the level of the onboard preamps when it is rocked, thus providing enough headroom for a guitar solo over the "synthy" sound.

Once again, it IS only a rough edit, and yes, it's one take... i.e. all of what you can hear is one guitar in one recording. The timings awful and for that I apologise, but you get the idea. Please tell me honestly what you think (I was impressed but that's me and I expect everyone else to slate it).

http://www.1-4theroad.co.uk/baba.mp3