Another Blue Angel question: FX loop

[Mincer]

If I plug something like a reverb pedal in the FX loop of my BA, there is a *really* loud hum at any position of the fx loop knob, and no signal through the amp, except the hum. It cuts off the guitar signal, and replaces it with hum. The pedal works in front of the amp. I wanted to try a reverb pedal in the loop since I have been having problems with the internal reverb on the amp.
A level mismatch? What can I do to test it? Why would the pedal work fine before the amp, and with other amps, but hum loudly through the speaker in the fx loop?

 

[acidguitar]

Not too sure if this helps any but some of Mesa's gear can struggle in the loop department, especially if it's a parallel loop i've found. Reverb pedals should be run in the front anyway. Pretty much only time based effects like delays should be run in the loop. And EQ's also sound better I've found through the loop.

 

[domct203]

Reverb IS a time-based effect, and should be run through the loop. Why else would amp designers put spring reverb after the preamp?

Were you running the pedal with batteries or with a power supply? If you are using a power supply you could be experiencing a bad ground loop hum. Try batteries to see if the hum goes away (or at least gets better).

If you try a battery and nothing changes then I would suspect a dirty FX loop jack or failing FX loop driver tube, I do not think it is an FX pedal problem.

Try just a patch cord from the send to return jacks and see if that causes the hum. If so, swap your FX loop driver tube with a known good tube to see if anything changes.

Good luck, get back to us with the results.

Dom

 

[Mincer]

The patch cord trick worked. No hum. Using a reverb pedal caused loud hum (imagine the amp turned all the way up, but humming, no audio- this at any setting on the volume knob) when turned on, either with batteries or AC.
A chorus pedal had the same result. Maybe it isn't meant for pedals? Anyone using fx pedals in the fx loop of the BA? I can get by without it, but I'd like to figure out if this is an actual problem, or an inherent design of the amp.

 

[Murphy Slaw]

Can't help ya Mincer. I don't use any effects other than the reverb built in, and a tube screamer in front, giving my more room to ramble around the stage.

Best of luck though.

Murph.

 

[SixVeeSix]

Mincer, I am only asking this question to be sure what is going on, please don't take offense as none is intended. You have a cable running from the Send jack to the input of the reverb and a cable running from the output of the reverb to the Return jack?

Pedals hum but a straight cord does not. I am grasping at straws but all I can think of is the effect is plugged in backwards? You should still get signal though, the loop in an Angel is parallel (unless somebody has boogered it).

If I think of anything else I will bring it

 

[Mincer]

Mincer, I am only asking this question to be sure what is going on, please don't take offense as none is intended. You have a cable running from the Send jack to the input of the reverb and a cable running from the output of the reverb to the Return jack?

Pedals hum but a straight cord does not. I am grasping at straws but all I can think of is the effect is plugged in backwards? You should still get signal though, the loop in an Angel is parallel (unless somebody has boogered it).

If I think of anything else I will bring it

No, I understand why you are asking- it doesn't make sense. This is what I know:
- pedal works in front of the amp
- patch cable in fx loop works
- pedal plugged in correctly into fx loop howls on AC or battery, no matter where the fx mix knob is...it shouldn't, but does..its a parallel loop.
- tried a few pedals, same result. no amp signal, just howling, so loud I have to quickly turn the amp off.

this is really odd.