That dreaded untraceable intermittant fault nightmare thing

Travisthedog

Really loving the Egnater Rebel 30 I bought a while back here. Its the gigging function/wedding/pub guitarists dream amp really as its so bloody versatile.

Anyhoo - played a bigger venue on Saturday that necessitated putting everything through the PA. The Rebel has a XLR emulated output for this very purpose (our sound man hates mic-ing amps) - So I used it.

All well and good until the end of the 1st set when I noticed the amp cutting in and out. I couldn't really hear if it was cutting right out or just dropping dramatically in volume. Then, all was well. I didn't change anything or do anything to make it come good, it just did.

Only thing that I have done differently that night was to use the XLR out to the PA, I had rewired my pedal board but that, I'm sure is ok.

I hate intermittent faults. I'd sooner the amp just exploded

Unlikely but, any ideas @ICBM @ECC83 et al

Ravenous

I'd start by looking at the XLR lead you used.

If that's known to be a good lead then I'd try to use the amp at home, in silent mode, running the record output into a stereo or some other amp.  See if any odd drops occur then.

cj73

Possibly telling  granny how to suck eggs but had you used the XLR out before?

Travisthedog

No never @cj73 ;

rico

Travisthedog said:

No never @cj73 ;

That's a schoolboy error. It's like a contestant on Masterchef just cobbling something together on the day rather than using a recipe they'd used before many times. 

Danny1969

Even if all 3 pins on the XLR cable were shorted together it wouldn't make the amp cut out .....either the amps got a fault or the pedal board rewire is to blame 

Travisthedog

Danny1969 said:

Even if all 3 pins on the XLR cable were shorted together it wouldn't make the amp cut out .....either the amps got a fault or the pedal board rewire is to blame 

See, that's what I thought Danny.

ecc83

Looks as thought the EM output is derived from the cathode circuit of the PI? If that is the case loss of heater volts would cause loss of XLR feed. Dry joints on heater supplies are not unknown?

dave

DJH83004

On the Rebel 30 the XLR emulated output is derived from the 8 ohm tap of the output transformer, which is also used as -ve feedback into the PI cathode leg. It is then processed through a series of op-amps to the XLR socket. So first question would be, was there a drop off in actual speaker volume at the cab or was it just through the PA? To be honest, a cable / plug issue would be my first port of call.  

Travisthedog

It was the amp dropping out

vasselmeyer

@Travisthedog Glad you're enjoying the amp, dude. I used it many times like that and it worked perfectly apart from one time when the sound guy had a dodgy cable. When I switched to silent mode, it worked fine. Turned out the vibration from the amp caused a problem on a semi-dry solder joint. 

In my experience, 99% of sound issues are cable-related. 

Travisthedog

Hi @vasselmeyer ;
Yeah I'm certain it's a cable. I've gigged it hard since I bought it and it's been fab. I really really love this amp and the rest of the band do to. It's so easy to balance it!! And get any sound you like out of it!!

crunchman

Travisthedog said:

It was the amp dropping out

If the amp was dropping out, not just the feed to the PA then it's not likely to be the XLR cable.

It's not something as simple as a valve going bad is it?