Puzzling Problem at Last Night's Gig, Tech Help Needed Please.

Bellycaster

Soundchecked at last night's gig and all was well. During the first track I thought I heard the amp getting quieter and then the signal came back at full strength. Then all of a sudden there was a massive buzz sound coming from the Suhr Badger amp.

I can only describe it as like when you hold the end of the jack plug while the amp is on, like a Short Circuit I imagine. I can't remember exactly what I did next in sequence as it was so frantic and I'd never had to trouble shoot in "Live" gig time.

I know I checked all the connections on the board, Guitar and amp before the gig started and they looked OK. I'm sure I briefly tried all pedals while setting up to see if they were working and to get unity gain etc, so couldn't fathom that out.

I ended up swapping amps to use the Maz and that seemed better, but I still had one instance of the buzz noise, which led to yet another frantic troubleshoot. Finally I got it to point of no noise, but I made sure I used only the pedals I knew weren't making a noise.

Today, I tried both amps and the pedalboard set up exactly as they were last night(except a different 4 gang socket and a different amp cab), same cables, different cables, even using both my speaker cables and they were both fine. All the set up was good.

I don't think the cab is the problem as after these 2 instances last night, I got through the gig with no noise. I can't describe what happened any better than this as it was panic stations and I was frantically swapping stuff around.

Anyone have any ideas? The last month has chucked up some problems gear wise and it's making me nervous. That experience aged me last night. I don't know how I held my nerve and got through the gig without dropping clangers all over the place.

I have a Fluke 10 Multimeter that my Boss gave me, but have no idea of it's application and how I could check things on my rig with it. So it would be a help if someone could explain some troubleshooting I could do with that in future.

This is the one in the foreground.




I'm pretty sure I have gaffer tape wrapped around the battery terminals inside the pedals too, so can't see how a short circuit could occur there.

Any help greatly appreciated.

Thanks.

ICBM

It's not the cab, no fault in one can do that.

It won't be the extension cable either for the same reason.

If it did it with two amps it's not the amps.

So it's either the guitar, the cables or the pedalboard. It's process of elimination to find which unless you can duplicate the fault. It's going to be a broken ground connection somewhere.

fastonebaz

Same thing happened to me once.  It was the Jack on my guitar.  It had come loose and one wire was hanging by a thread and then that snapped leaving only one wire connected and it was buzzmagedon.  Unscrew the guitar jack plate and check both wires are soundly soldered.  

Bellycaster

Thanks @ICBM and @fastonebaz ;

Is it possible to eliminate the Guitar as I carried on with the same Guitar through the rest of the gig? I will unscrew the jack pate and check though.

Another thing I ought to mention is last week at rehearsal two of my pedals didn't work, but I found that the port on the PSU they are both powered by (with plenty of juice to spare) had worked loose and wasn't plugged in properly. It didn't create any buzz though, it just cut off the signal when I engaged either of those 2 pedals.

I worried how I will eliminate what it is if I've recreated the set up today and nothing was amiss, I mean with the patch cables, it's quite a busy board.

Do you think the Power Supply and it's cables is unlikely to be the problem? I've had it 5 years and everything like current draw and voltage is correct for the pedals I have.

ICBM

It won’t be the power supply. The fault is a broken ground connection in the signal path, from the description. It could certainly be the guitar, if you didn’t get the same problem with different ones.

HAL9000

Had something similar many years ago now. IIRC it was a dodgy connection in an instrument cable.

Neill

fastonebaz said:

Same thing happened to me once.  It was the Jack on my guitar.  It had come loose and one wire was hanging by a thread and then that snapped leaving only one wire connected and it was buzzmagedon.  Unscrew the guitar jack plate and check both wires are soundly soldered.  

That's almost certainly the cause, it's happened to me and I've seen it happen many times with other live shows so why do these things never happen at home? It's always when you are either on stage or just about to go on..

Bellycaster

Thanks again, lads. I've taken some photos of the wiring/soldering/connections, which I'll upload in a bit. Another thing is it was the coldest room we have ever played in, could this be a contributing factor to problems. I've also had the multimeter on the Jack plug of the Guitar and I can get a constant tone by touching the other terminal on all the other metal parts. I put it on the OHMS setting with the "sound" symbol, I expect this is right from some vids I've watched.

Bellycaster

https://i.imgur.com/h3ocKDn.jpg

https://i.imgur.com/lSOqw8Q.jpg

https://i.imgur.com/5dQ15DR.jpg

Some of the solder on one of those connection looks a bit charred, but like I say, the multimeter sounded OK.

Bellycaster

https://i.imgur.com/QXsvkMb.jpg

https://i.imgur.com/7HhD75A.jpg

https://i.imgur.com/oPPXYHG.jpg

Bellycaster

https://i.imgur.com/7s9d2oT.jpg

https://i.imgur.com/RIUoREA.jpg

Sorry if they aren't crystal clear but it wasn't easy getting focus on some of them.

randella

The Ohms setting with the sound is testing for continuity, i.e. an electrical connection.  There should be a sound between the tag on your jack with the stranded wire, and other metal parts (earth).  There should be no sound between the two tags on the jack, or between the tag on the jack with the white sleeved wire and other metal parts.

Plug in a guitar cable and check at the other end that a) there's no sound between the tip and sleeve, and b) there's a sound between the sleeve and the metal components in the guitar.

Your jack looks OK from the pics, but the meter can dig out things that you can't see.

randella

While you're about it, check all your cables.  Get both ends of the cable, put a probe on both tips (sound), both sleeves (sound) and the tip and sleeve (no sound).

Keep your hands away from the probe tips as the body can conduct which will make your readings wonky.

Bellycaster

Thanks @randella ;;

I'll try that in a bit. This video was helpful



Rather than take out my patch cables one by one on my board and test them separate, could I just test for sound between each pedal on the jacks inputs while the cables are still plugged in. I know that means I cant touch the tip and sleeve on the same end of a given cable, but if I get sound between connections, should that mean it's OK.

Or could I plug a loose cable into the beginning of my chain and one at the end and test for sound that way?

randella

No problem.

Testing it that way is fine and makes sense but what you might have is a patch cable that's on the way out, and removing each one would help diagnose this as you'll be bending and moving them in the process.  It could be the case that one has failing insulation and intermittently causes your problem when you hit a pedal with your foot and things shift around on the board slightly.

I know it's an ache, but I'd test them one by one.  If you can just get the meter to each end of the cable to test then hopefully you wont have to snip any cable ties (which, if you're anything like me, you'll have all over the place).

hywelg

You don't use George L's patch leads do you!. If you do rip your board apart and redo all of the ends. And be prepared to do it again in two years time. There are more reliable solderless patch leads about. 

Unfortunately you might struggle to find the fault if it's only intermittent. You need a plan to deal with it next time, hopefully at rehearsal or setup rather than during the gig. 

First, to get you through to the end of the song, plug straight into the amp. If that doesn't cure it swap guitar AND cable. Alert the band that if you are due to play a solo you might have to skip it. 

If all was well going direct in, split your board in half and during the break between songs plug in half way along the pedal chain. Keep doing that until.you find the bad cable/lead.

Bellycaster

Just managed to get every cable loose from the board to test @randella I tested them all as in the video above.

My knees are shagged now and I've run out of swear words

Also did the Cable into Guitar method you mentioned above. I can't report a single fault on that either. I tested every cable I use and some I rarely use. This is probably worse than finding something wrong as now I've no idea what happened.

That photo of my Volume and Tone Pots, you reckon that slight blackening/charring is an issue?

What about Smoke Machines? There was one at my side of the stage, blowing directly toward the board, could this be an issue. I'm clutching here but I have a gig on 29th and I'm gonna go into it wondering if I'll get issues when I've done everything possible to find the cause. I'll use a different Guitar for that Gig, but I like to use my Wolfgang, it is my Workhorse Guitar.

Bellycaster

Thanks @hywelg ;

I might be being a bit naive here, but when you say "To get through the song, plug straight into the amp" Do I need to turn the amp off first, I imagine it would be detrimental to unplug the lead from the amp while it's on?

randella

Ah, you have my apologies for your knees!

The charring should be OK - I suspect it's the flux which is added to solder to ensure a clean joint.  It can burn a little with the heat of applying the iron, and that's what you can see in the picture.  It looks like caramalised sugar.  It shouldn't affect the joint, as long as the wire is physically secure and there's an electrical connection (which you've tested OK).

I'm going to defer to a higher authority now (probably @ICBM hahaha) as without looking I'm out of ideas.

It looks like you've ruled out a lot though.  I don't know about the smoke machine - I'd have thought not but someone else might well have a view on that one.

hywelg

No, just pull the cable out of the tuner or wherever your guitar cable goes first, hoik the lead out of the amp input and plug your guitar cable in its place. This will probably get you back and running and able to carry on the song. Once your band mates get used to the fact you've got an intermittent problem they'll just carry on whilst you get sorted and you'll join back in as soon as you can.

 It's the sort of thing a band should practise at rehearsal anyway since once you've started you really shouldn't stop until you finish the song unless it's impossible. 

Just like broken strings, you grab the spare guitar and carry on,  or you play with a broken one. Unprofessional to stop the song. 

Bellycaster

Right, I'll take that on board @hywelg ;

I wouldn't have dared to yank a cable out of a switched on amp unless someone with experience said it was OK. We managed to keep going at the gig, even if it means just with the 2nd guitarist, the song goes on.

Thanks @randella for your efforts.