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FDP Forum / Amp Mods, Repairs, and Projects / 1 Tube Amp + 1 SS Amp in a 4X12 Cab?



Feb 10th, 2017 11:54 AM   Edit   Profile   Print Topic   Search Topic

I have a Carvin MTS 3200 all tube amp w/ 4x12 cab (http://carvinimages.com/manuals/MTS3200.pdf). I just bought a used SS Marshall MG100HDFX (https://www.scribd.com/document/336022471/Marshall-MG100HDFX-Owners-Manual-pdf).

I want to be able to switch between heads "easily" (not in a live situation here). I can just unplug guitar from 1 amp to the other one if needed (amp switch too expensive). I was wondering if I can plug the Carvin (tube) amp in the left jack of the cab and the Marshall (SS) in the right jack... I think this should split the speakers in 2x2 right, or not? Setting the Carvin at 4ohms and the marshall is already 4ohms...

My worry is to have my tube amp running with no load when using the SS amp... does that make sense?

Thanks for your help guys!


Contributing Member

So. Cal. USA

Feb 10th, 2017 12:33 PM   Edit   Profile   Print Topic   Search Topic

Two heads and one cabinet is problematic because an open tube output will damage the amp and if the two amps are connected together at the outputs damage will occur most likely to both.

If the cabinet is wired so individual pairs of speaker are connected to only one amp it might work out for you. This would need to be checked and confirmed before you make any connections. Load values enter into the equation as well.

My best guess would be that the 4-12 cab has its jacks wired in parallel which is NOT what you want.



Feb 10th, 2017 01:08 PM   Edit   Profile   Print Topic   Search Topic

Thanks. I think I just gonna unplug and plug everything manually when I want to switch head. Just need to be careful to not turn on the tube amp when not connected to the cab...



Feb 11th, 2017 02:35 AM   Edit   Profile   Print Topic   Search Topic

If the 4x12 can be used as a stereo pair of 2x12 (something must have made you think it was the case?) then your idea should work.
If you've got a test meter, you could check that there was no connection between the 2 stereo sides, eg plug cables into each socket and check for continuity between their free ends.



He's dead, Jim!
Feb 12th, 2017 01:17 PM   Edit   Profile   Print Topic   Search Topic

If the cab is not stereo it would be easy to mod it to be. Basically a switch, one more jack, and some wiring. My Peavey 412MS came that way.



Feb 15th, 2017 03:54 PM   Edit   Profile   Print Topic   Search Topic

Looks like I have a switch on the back to make it Mono or Stereo... See pic below. Marshall is 4 ohms and Carvin, I can select 4, 8 or 16 ohms. So I'm good on that side.

So bottom line, if the L and R don't have continuity when on Stereo mode, I'm good. I could even have both amp going at the same time?


(This message was last edited by Slyyyy at 05:55 PM, Feb 15th, 2017)

Contributing Member

So. Cal. USA

Feb 15th, 2017 05:06 PM   Edit   Profile   Print Topic   Search Topic

Yes the switch would work once you confirm it works correctly. Personally I would rewire the cabinet to have two separate pairs into two separate jacks. There is always that chance the switch could somehow get into the wrong position and kablamo, you let the smoke out of something.

FDP Forum / Amp Mods, Repairs, and Projects / 1 Tube Amp + 1 SS Amp in a 4X12 Cab?

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