Popping Sound through Amplifier ?

[Guitar Cowboy]

 I am very new to playing plugged-in ... not much experience at all and I am playing my first hour-long gig other than the local "open mic" night next week. I have a 2013 816 with ES I  and a Bose Compact L1 . I have noticed while practicing with the guitar  and microphone plugged in , after about 1/2 hour I get a single "pop"  through the speaker. I have not had a chance to try to isolate where the problem is coming from ( guitar, mic, Bose system, one of the cables?), so that is obviously what I have to try to do next. Just wondered if anyone had any suggestions on what it might be and or how to proceed. I guess I'll  be practicing with only one of them plugged in for a while. Thanks for any suggestions you might have.

[Guitar Cowboy]

So I think I was able to isolate the problem to the ES system in my 816. First, I practice with only the mic plugged in to Channel 1 of the Bose L1 Compact. No popping after 1.5 hrs of practice. The next night, I practiced with only the guitar plugged in to Channel 2. And got two pops in about 1.5 hours . Finally, I listened two my MP3 player through Channel 2 for about an hour with no pops. So it appears to be something with the ES. Any ideas on what it might be ?

[Edward]

Does your pop sound like it does when you unplug the cable from your guitar when still in the amp?...or at least resemble that sound?  It may be an intermittant poor fit of end plug to the ES jack, or intermittant bad cable (typically near the plug's end), and when you move it opens or shorts the circuit ...either way will give you that momentary pop. 

Try wiggling the snot out of it at both plugs' ends, throughout the length of the cable, and also grasping right at the plug and wiggling at the strap endpin to see if it's the ES' jack.  If you can reproduce the noice, it's either a bad cable, bad ES jack, or maybe a poor fit (some plug ends are shaped and sized oh-so-slightly differently, just enough to mis-match "that" particular plug that doesn't seem to like it).  Hopefully you can reproduce the pop, then try antoher cable to see if that solves it. 

Edward

[MikeB]

Are you  using a balanced TRS-XLR cable? (Not that it should make a difference)  If not, try one plugged into the Mic input.

Does the popping keep happening?  If so, how regularly?  The fact that it is happening after that much time indicates something is building up heat and eventually making the sound (bad solder joint for example).  I can't imagine what in the guitar is doing this, I would tend to blame something on the input of the L1.

[Guitar Cowboy]

Thanks Mike B  And Edward. Haven't had a chance to do more testing but I will try the suggestions. I am not sure if it's a balanced cable or not,( I'm new to plugging in ), but I'll check in hopes that its indicated on the length of the cable.

The popping has occurred almost ever time I have plugged in during the last couple of weeks . In one session it happened twice, first  about 1/2 hour  in  then again in about another half hour.