Trouble with my RM4 please help!!!!

[stm113]

Last night at practice my RM4 got funky with me and I am worried, we have gigs opening for nationals coming up and I am afraid it may continue being weird.

Here's a quick rundown of my gear:
Guitar->Wah->Boss GT Pro->RM4->GT Pro->MXR 10 band eq->5150 head (for power only)

I connect the GT Pro and The RM4 via the 4 cable method which allows me to run f/x from the Boss both before pre and post on the pre amp. This also allows me to bypass the RM4 if I wish which I do for my cleans and just use a preamp from the Boss.

At practice in the beginning of a song my volume dropped down so low that I could only hear it with my ear right next to the grill. The 1st thing I thought was maybe I lost a tube in one of the modules so I switched to a different module, same thing. I then switched to my clean preset, which bypassed the RM4 and SOUND. I then powered down the RM4 and ran direct into the head for a couple of songs then switched back to the RM4 and powered up and it was fine.

Looking back (and I cant be completely sure on this) it seemed that my volume was going up and down in slight variations all practice before that.

Does anyone have any ideas on what I may be experiencing? and how to fix this?

 

[JKD]

One of the preamp tubes in the RM4 itself is going out or you have a loose/dirty connection into one of the RM4 in/outs.

 

[stm113]

I was thinking that it could be a tube in the pre amp any suggestions on what tubes to throw in it?

 

[m0jo]

I was thinking that it could be a tube in the pre amp any suggestions on what tubes to throw in it?

Tung Sol works great in there

Otherwise EHX is cool too (but if you use super high gain it can get fuzz-ish).

Be sure to check your cables as well, clean out the jacks.
Many people have had this exact problem where a dirty jack turned out to be the culprit!

 

[stm113]

so why would lose cables or dirty jacks cause that like in the middle of a song? i should have mentioned that the rack was not sitting on the cab it was about 4 or so feet from it and we were running through a PA so the stage volume was low

 

[feefop]

I have a similar problem in which the volume cuts out to very low levels. This happens after about 30 minutes of playing. I then work the module master volume and it comes back. I believe my issue is the the master volume on the RM4. It might be a bad pot.