Using a Mark 3 head for a power amp?

[Rob227]

I've got GAS again and I was thinking that a compromise on weight, tubes and wattage might be to try and use a Mark 3 simulclass head as a power amp to run my quad into. This would require half the tubes and would be able to run in class A at 15 watts which would be perfect for home use.

Now for the technical part which I am sadly lacking in. How can it be done? How can I utilize the Mark 3 with it's three channels and have the four quad channels available as well all running through the power section of the Mark 3. Any idea's?

 

[daveg62]

You could take the loop out of the Mark and run it into A side of an A/B switch and then take the quad out into the the B side of the switch, Then run the A/B back into the loop return. Could be done with a midi amp switching system also, which could be programmed to switch channels on the amps also. RJM has some nice units.

 

[Whoopysnorp]

I used to do this exact thing, but with a Studio Preamp instead of a Quad. Before that I had used a Simul 395 power amp, but like you, I decided it didn't make sense to lug around the weight of the extra output transformer and run an extra set of tubes that I never actually used. I accomplished this using a simple passive A/B box (it was a Radial BigShot I/O to be specific). I took the effects send of the Mark III and the output of the Studio Preamp into the inputs of the A/B box and ran the output of that into the Mark III's effects return. It worked pretty well, but the long cable run all the way from each preamp to the A/B box and back again degraded the tone noticeably. A better (but more expensive) way to do it would be to use a MIDI amp switching system like the Voodoo Lab GCX, which allows you to keep the cable runs short.

In the end, I ditched this arrangement and now just use a Mark III head on its own. My Studio Preamp lives in my apartment now and runs into the effects return of an Egnater Tweaker for low-volume playing. The complexity just got to be too much of a hassle, and I decided that having five channels wasn't necessary considering they were all fairly similar. but Actually, it was really only four, because the Mark III I was using at the time didn't have the R2 mod, so that mode was sort of useless. No, the Mark III can't get the same tones the Studio Pre can, but so what?

 

[Rob227]

I'm liking this option the more I consider it. The A/B box seems like a decent short term solution.

Now I just wonder if the Mark 3 can be switched to a rack mount case to top it off.

Thanks for the info guys.

 

[D2dark]

get a midi looper switcher, I've seen some go for 150$ used.
it's will even allow you to add an fx processor in the chain.