very strange problem with 5150

[bryan_kilco]

Been tracking guitars for my bands EP (real mic'd amp, no DI/amp sim). Had 2 sessions that worked out fine. Yesterday I show up, hook up and flip standby.....amp is MUCH quieter than it was the previous sessions. No knobs turned, amp wasn't moved, etc. Checked cables, tubes....was getting very frustrated. Then it dawned on me that my FX loop has been funny in the past, and had a significant volume drop when engaged. But I thought "How could the FX loop get switched when it needs the pedal to be switched?!?", as there is no button on the amp to switch. So luckily our other guitarist had a switch, hooked it up, and BAM! Problem solved. But as soon as I unplug the pedal, the amp goes quiet again.

I have no clue and am very stumped as to what the hell is going on here. Very, very strange. How could it get switched automatically?!??!!

 

[LosingReality]

Very common issue. The FX jack is dirty. Take a Q tip and contact cleaner and clean the jacks VERY good.

After you clean it....if you arent using the FX loop. Take a small patch cable and keep it plugged into the loop jacks....to help prevent it from happening again.

I clean my FX loop ALL the time with a 5150

 

[cobhc]

Yeah, some contact cleaner on a patch cable, then work it in and out of the jack.

 

[bryan_kilco]

Yeah, but how the heck could it have worked the previous sessions and then somehow the FX Loop got switched to ON, when I never had a pedal hooked up at all?!?

I'll clean the jacks and see what happens.

 

[lolzgreg]

It's not about the FX being switched on; There is a physical discontinuity in the circuit from fx send to fx return that is closed iNSIDE of the amp when the FX loop isn't on. If the contacts are dirty it will break the circuit, and you will lose signal/the amp will fluctuate in volume. It sucks. It's happened to me before.

Greg

 

[guitarguru777]

Just keep a patch cable in the damn thing when you are not using it. Thats what I do and it works great. Never had this issue.

 

[bryan_kilco]

Just keep a patch cable in the damn thing when you are not using it. Thats what I do and it works great. Never had this issue.

Just to keep the jacks from getting dirty?

I heard that if you jump the FX Send - Return with a patch cable it clears the issue as well, but it didn't work for me. I had to physically hook up a footswitch and turn the Loop OFF.

Thanks for the help guys. It just boggled me as I knew the FX was kinda screwy to begin with but never quite had this issue.