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Two preamps at once??!

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Two preamps at once??!

Postby plantingclaymore » Sun Oct 23, 2011 8:40 am

Hello, I'm just sorting out my rig and its getting more complex and I need a bit of help. Currently I'm using a JMP-1 preamp. I run it through the return of my fx loop of my Marshall TSL60 Head - so effectively bypassing the TSL60 preamp and solely using the head's poweramp. So...that's all fine, but for my clean tones I really want to use the clean channel on the TSL60 head. Is there any way i could set something up where I can carry on using the tsl60 as a poweramp but switch between the jmp1 preamp and tsl60 preamp instantly??? And...not only that but I'd like my g major to work with both???!!!!

thanks :headbang:
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Re: Two preamps at once??!

Postby Jack Ruston » Sun Oct 23, 2011 9:26 am

Not easily. You'd need a buffered AB box, one to go after the guitar, switching between the JMP1 input and the TSL input. AND you'd need a way to bypass the fx loop. As for the processor you'd have to put it between the guitar and the AB and use it in series. Honestly, if I were you I'd either...

1. Sell the JMP and the TSL and buy something that has channel switching that you can live with.
2. Buy a power amp and speaker for the JMP1.

In option 2 you can either run the FX in series but what you might consider is running them through the FX loop of the TSL, and then using an ABY box to add the JMP for gainy sounds, but leaving the clean running underneath with the fx on the clean sound. It might not be what you want, but it can be a very cool sound.

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Re: Two preamps at once??!

Postby plantingclaymore » Sun Oct 23, 2011 9:53 am

Nice one thanks, might try and percivier with the original idea with the ab box you speak of. I might be after the impossible as i'd probably want the g major to have different effects on both. I could switch preamps but then i'd have to switch effects, tricky dancing. Its that quest for the perfect sound without compromising which is tricky at times. I need the precision and cutoff of the jmp1 distortion but the warmth and lushness of the tsl60 clean. Hopefully i'll get there in the end....cheers
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Re: Two preamps at once??!

Postby ef37a » Sun Oct 23, 2011 11:34 am

Hmm, I can't see why, in principle you cannot treat the amp send as one feed and the preamp as the other and feed both to a simple, passive A/B box. That feeds the FX return to the amp and you can put the g-major in that link.

A passive splitter (3 jacks soldered pin for pin) will get guitar into the two inputs, seeing 500k instead of 1meg will have little effect.

In PRACTICE the levels could be all over the shop! Talk to The Men at they will know of such things. But in any event you can do no harm if you try.

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Re: Two preamps at once??!

Postby Music Wolf » Sun Oct 23, 2011 5:46 pm

Boss LS2 Line switcher?

Guitar to LS2 input.

LS2 Loop A send to TSL input
TSL effect send to LS2 Loop A return
LS2 Loop B send to JMP1 input
JMP1 output to LS2 Loop B return
Output of LS2 to TSL effects return.

Loop A and B have their own level so no problem matching volumes.

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