Noise issue using new M13 at band rehearsal

[Lev]

Well my first band rehearsal with my new Line6 M13 didn't go too great last night. I had some serious noise problems that wouldn't go away. It started off fine, my bass player was late so we started with out him. I plugged my guitar into my Digitech EX7, then into the mono input of the M13, then the mono output of the M13 into channel 1 on my Fender Hot Rod Deluxe, Both the M13 and EX7 were powered using their own power supply. So everything was fine and I was diggin the tones I was getting from the M13.

About an hour in the bass player arrived and setup his Line6 Low Down amp, we started playing and all was well. About 2 songs later a really loud crackling noise came through my amp, similar to the kind of noise you get with a bad lead or input jack. I set about eliminating the issue, I went from guitar direct to amp - no noise. So went with guitar and M13 into amp, again no noise, next guitar EX7 and amp - no noise.

Went back to original config Guitar - EX7 - M13 - Amp and got crackling noise again so at this stage I suspected the patch lead between the EX7 and M13 so replaced this with a known good lead but still had crackling. I eventually gave up and used my old stomp box board instead of the M13 and all was fine.

I can only assume that this was some sort of electrically induced interference, the bass player thinks he heard a slight crackling interference on his bass amp too but it was plugged into a completely seperate power socket. We were practicing in the same room that we've always practiced in and when I stopped using the M13 the rest of the rehearsal went fine. I really don't want to have to send back the M13 but if it's that sensitive to interference then I don't think I could possibly use it live.

anyone else experienced similar issues or have any tips on how I might isolate the issue. One thing that I could try is on the M13 you can switch between true bypass and DSP bypass, I'm not quite sure what the difference is between the two but I've seen some posts on the line6 forum that switching this setting can help eliminate noise.

Oh by the way I know very little about electronics and grounding etc. as you can probably tell.

[Spudman]

I know that the M13 is pretty sensitive to cable directional layout. If they cross AC power cords they can pick up noise. Also, sometimes noise from other power sources come through the front end of the M13. It could be your EX7 was introducing some of that. Make sure the output of the EX7 isn't too hot for the M13. I've yet to run my EX7 into my M13 but that is my ultimate gig solution.

I'll post your info at the M13 forum and see what responses we get.

EDIT: The HRDLX is prone to input jack problems. I've had to fix a few and they sound like what you describe. It's possible that unplugging and replugging into that jack temporarily negated the issue. I've also had that experience with tubes that were about to go out.

[Lev]

I'll post your info at the M13 forum and see what responses we get.

EDIT: The HRDLX is prone to input jack problems. I've had to fix a few and they sound like what you describe. It's possible that unplugging and replugging into that jack temporarily negated the issue. I've also had that experience with tubes that were about to go out.

Thanks for this Spud, I'm pretty confident it's not an input jack issue, I did quite a bit of reconfiguring last night and the common denominator in the flow was always the M13 (while in parallel with the EX7). The power supply was close to the patch lead connecting the two but I moved the power supply suspecting that may be the problem and the problem persisted. I also powered the M13 off and still had the noise (obviously M13 was set in true bypass).

[Spudman]

First response from the Line 6 forum:

"I use the EX7 on my pedalboard with my M13, and I have no problems whatsoever. It sounds like you may have some sort of short at the M13's input. Did you try plugging your guitar straight into the M13?"

Lev, are your running it parallel or in line with the M13? ie guitar>Ex7>m13 >amph?

[Lev]

Sorry, in line gtr-ex7-m13-amp. I tried to recreate the problem at home this evening but couldn't, it was perfectly silent. I'm convinced there was something external my guitar rig that was causing the noise. We were rehearsing in the drummers home, using our 1200w pa, a 300w bass amp and any number of domestic appliance that may have been turned on in his house at the time.

I just don't understand why isolating the ex7 and m13 caused the noise to stop. The worry is if I gig with this thing will I get noise coming through from lights, aircon, poker machines etc. There was no way we could continue with the noise, it was really loud.

[Lev]

I think I've solved the mystery with my noise issues. My drummer informed me that he has an exterior sensor light on his house that's been giving him trouble for the last week (ie flashing on and off). The issues I had at practice only started when the sunlight started to fade and his two dogs were setting off the sensor for this faulty light in the back yard.

The noise coming through my amp was consistent with an electrical unit constantly tripping on/off. As I said the bass amp appeared to pick something up also but I think because of the frequency it was less obvious on the bass amp. I can only assume having both the EX7 and M13 drawing from the houses power grid at the same time exasserbated the noise issue, hence when I used them one at a time there was no problem.

Also, when I switched to my stomp box pedal board it has a power conditioner built into the power brick so I had no issue there. So I think the moral of the story is if I'm using the M13 in furture I'll be sure to plug it into something like this: http://www.lindy.ie/mains-conditioner-power-strip-6-way/30087.html

Thanks Spud for your help with this!!