Dsl40c

[Silent bob]

I have a carbon fiber mg100hcfx and I was wondering if I could run a dsl40c through the fx loop on both amps and then run the two amps as a head without damaging either amp or the carbon fiber mg cabinet

 

[Jethro Rocker]

Through the FX on both amps? Doesn't make sense. One amp needs the preamp section, you need a guitar plugged into one of them, presumably the 40C, to be connected to the other through FX loop.
So Effects send on 40C could go to effects return on mg to run the preamp of the 40C into the MG. But not both at once in that fashion.
You can run two amps together with an ABY switcher.

 

[Conghaille]

I sometimes do something like this. What I do is use my DSL as my instrument input and preamp stages for both.

In the effects loop for the DSL, I have a couple of stereo effects pedal (reverb and chorus). I then take two outputs from the last stereo effect in the loop chain and send one back to the receive on the DSL and the other to the receive on my 2nd amp (your MG, for example.)

This way I bypass the preamp, etc. of amp 2 and keep it from changing the tone I have going to the first amp.

(Note: doing this on most amps will render all controls on amp 2 useless, since I'm only using the power section on that amp. This means that the volume balance between the amps could be off a little or a lot. Neat trick: I use an EQ pedal between the last fx chain pedal and the slave amp to control input signal and it works great, and since it's a stomp box, it's always line-level boost which is safe for your input signal and ultimately amp 2.)

I hope this helps.

 

[Jethro Rocker]

^^^ Yep, same basic thing. I think (?) OP wants to run both amps through the one cabinet. Unless it has stereo inputs...he hasn't weighed in yet.