I've been attempting to do the 4 cable method to connect my BOSS GT-10 with my Marshall JVM410h suggested by my friend.

All night I have been watching youtube videos, doing everything as they said, destroying my precious settings, all to end up with the same result of no sound.

Can someone describe how to do this method in detail and also possibly answer why I have no sound coming out of the amp.
Is the effects loop in the gt 10 on?
Peavey 5150
Mesa Mark IV
Mesa Single Rectifier (Series 1)
Fender Custom Shop Tonemaster
Roland Microcube

-Whitebox OS 1x12
-Port City OS 1x12

Digidesign Eleven RackAxe Fx Ultra
well, yes you do need to enable the effect loop on the gt10 to get the 4cm to work properly, as far as im aware you have to set it on in each patch individually and then save them

BUT if you have the cables set up properly and the fx loop is turned off you should expect sound so i would start troubleshooting this way if i were you:

  • test all the cables you are using directly from guitar to the amp input with nothing in the amp effect loop to make sure you don't have a dead cable
  • test a stomp box that you know works in the fx loop of the amp to make sure that the fx loop isn't broken, chain should be:
    guitar -> amp in-> amp fx send -> stomp box in -> stomp box out -> amp fx return
  • if that works, set up the gt 10 in sequence with 4cm, you should get sound out of the amp even if fx loop is disabled on the patch, then enable the fx loop in patch settings on the gt10 if you haven't already (and save the patch or it'll be lost once you switch patches)

and just to check you have the order right for the 4cm (it being backward in the fx loop for example would cause no sound)
  • Guitar -> GT10 input
  • GT10 fx send -> amp input
  • amp fx send -> GT10 fx return
  • GT10 out (L) -> amp fx return

oh and once you have it working make sure you disable the preamp on the gt10 patches where you have the gt10 fx loop enabled so you don't send a preamped signal into the amp preamp, but if you have the gt10 fx loop disabled you should use the gt10 preamps (i wouldn't bother with the od/ds from the gt10 though they sound pretty thin and digital)

so yeah as to your question my best guesses are that the cables are in the wrong order causing there to be no sound or one of the cables is broken or the amp fx loop itself is dead so go do what i said above in order and you'll at least be able to find out if any of those are the source of the problem! woo

err and not to be patronising but check that the volume knob on the gt10 is turned up to at least 12 o clock and the volume pedal is fully forward ;p
Last edited by funeralllllllll at Oct 27, 2011,