Guitar Jack Grounding Problem

[lpa53]

I had a gig yesterday and all was fine, but when I set my gear up at home this morning, my B-Band pickup-equipped Guild suddenly has a grounding issue. I get a loud whine unless I touch the cable end. This happens with any cable so I'm thinking something came loose inside. I've never installed a pickup myself so wouldn't know what to look for. Any suggestions would be appreciated.

[jonfields45]

Originally Posted by lpa53

I had a gig yesterday and all was fine, but when I set my gear up at home this morning, any guitar cable I use produces a loud whine unless I touch the jack end. Could something have come loose inside the amp, and if so, what would it be?

Have you tried more than one guitar?

[lpa53]

Originally Posted by jonfields45

Have you tried more than one guitar?

I've only been retired from my tech-nerd days for a few years and already my troubleshooting skills are going! You're right and just now I changed the thread title. It only happens on my Guild so it appears it's a problem in the signal chain of the pickup somewhere. I've never installed a pickup so wouldn't know what to look for.

[Gordon Currie]

Originally Posted by lpa53

I had a gig yesterday and all was fine, but when I set my gear up at home this morning, my B-Band pickup-equipped Guild suddenly has a grounding issue. I get a loud whine unless I touch the cable end. This happens with any cable so I'm thinking something came loose inside. I've never installed a pickup myself so wouldn't know what to look for. Any suggestions would be appreciated.

What you describe might be explained by a ground wire coming loose/opening up. But that kind of thing doesn't happen often by itself. If you can locate the hot and ground wires inside, try and gently wiggle the ground wire and see if there is any change.

More likely, I would suspect the UST element itself. I had a 20+ year old Fishman develop a super intermittent ground buzz. One day I plugged in and it was dead. Unless a wire got knocked around somehow, you may be looking at a just-starting-to-fail pickup.

[jonfields45]

Do you know which B-Band model you've got (so I can look it up)?

The easiest thing to do is to see if it is installed using pluggable connectors. If so I would remove and reseat all of them.

Next I would suspect the UST, if it's got one. Non-coaxial USTs are known for developing ripped shields and starting to hum. The Fishman Matrix is famous for this, though probably more so for how many have been manufactured than something weak in their design.

Coax based USTs are built from (usually flattened) coax piezo material that is put into asphalt for letting traffic lights know if a car has passed by. Prior to flattening that material is pretty bullet proof. After flattening it is still more robust than the non-coax USTs, but sometimes prone to failure where it bends entering the saddle slot.

[lpa53]

Originally Posted by jonfields45

Do you know which B-Band model you've got (so I can look it up)?

The easiest thing to do is to see if it is installed using pluggable connectors. If so I would remove and reseat all of them.

Next I would suspect the UST, if it's got one. Non-coaxial USTs are known for developing ripped shields and starting to hum. The Fishman Matrix is famous for this, though probably more so for how many have been manufactured than something weak in their design.

Coax based USTs are built from (usually flattened) coax piezo material that is put into asphalt for letting traffic lights know if a car has passed by. Prior to flattening that material is pretty bullet proof. After flattening it is still more robust than the non-coax USTs, but sometimes prone to failure where it bends entering the saddle slot.

The B-Band in my Guild is the A2.2 system that has both an AST and a UST. One thing I just remembered about the gig is that when if pulled the Neutrik cable out of the Guild to switch guitar, I must have moved part of the connector in a way I don't do normally and I did get a loud pop and some static sounds.

I've searched the web for a B-Band site but have come up empty.

[Gordon Currie]

OK, now that we know this is a dual source, is there any difference in hum between UST only and AST/SBT only?

If not, and following on the possibility that you dislodged a wire, can you view inside the guitar and see if there is a loose wire at the endpin jack?

[jonfields45]

Originally Posted by lpa53

The B-Band in my Guild is the A2.2 system that has both an AST and a UST. One thing I just remembered about the gig is that when if pulled the Neutrik cable out of the Guild to switch guitar, I must have moved part of the connector in a way I don't do normally and I did get a loud pop and some static sounds.

I've searched the web for a B-Band site but have come up empty.

That seems like a good hint that the problem might be in the end pin jack. I took a quick look on eBay and there are gray market "used" versions of that system for very low prices (probably left over inventory from when manufacturing stopped). I thought I heard B-Band has given up the US market or potentially the pickup biz all together. The picture on eBay shows a system that is entirely soldered together and swapping out the end pin jack is not going to be easy (and no guarantee that you've fixed the problem). A cheap first step would be to remove the strings, reach into the guitar and surround the end pin jack with a rag to absorb over spray, and then spray contact cleaner into the end pin jack. Maybe the switch that powers the system up has gotten dirty (I don't suspect the ring ground to your cable).

If that does not do the trick, I think it makes more sense to swap the entire system out for something still in production. If you check the current AGF threads you find many good options with strong proponents.

[varmonter]

you said it happened after you pulled out the cord.
Are you usingbthe same cord. Try another cord.
just to illiminate a cord problem.

[Mandobart]

First off, standard 1/4" mono jacks don't have a "hot" and "neutral." I was an electronics technician in the USN for 14 years. I've done a lot of pickup installation, amp repair and cable makeup/repair.

Your jack on your guitar should have an insulated signal lead(s) coming from your pickup(s). On your B-band the pickup goes to a preamp, and the preamp leads go to your output jack. Signal lead should be soldered to the tip terminal. The ground is usually a bare copper shield, twisted up, tinned and soldered to the ring terminal. Again, the leads coming from your B-band preamp may be different. A good installer will insulate both jack terminals with heat shrink to make sure they don't ever get any dirt, dust or moisture providing any connection between them. In a standard round soundhole guitar its not too hard to take off the strings and loosen the output jack so you can pull it back out and look.

The pickup end could also be where the problem is, though most piezo pickups we use come with the piezo connection(s) already made and sealed. Is your B-band the UST one? If so, there is a chance the constant pressure of the string force pushing the saddle down on your piezo element has finally worn through? One reason I prefer SBT's over UST's. If yours is the model where the band mounts under the bridge this shouldn't be a problem. You should also check the connection from the band element to the preamp. Could be something has gone wrong within the black-box (non-repairable) preamp. That's one reason why I like external preamps too.

[lpa53]

While poking around inside in the wake of the many good suggestions, I fell into a "solution" of sorts. As I mentioned before, the loud hum would disappear when I touched the metal at the jack or cable tip. I found it would also dissipate somewhat when I touched the small connections on the soundhole controls. Then I reached inside and very lightly touched the metal cover of the main electronics box and the hum disappeared. And when I removed my finger, the sound was entirely gone, and has stayed gone since. Was this just some buildup of static electricity? Who knows. Oh, well ... false alarm.

[mandowilli]

Welcome to the world of electronics troubleshooting and repair.

The dreaded intermittent problem!

[varmonter]

Originally Posted by lpa53

While poking around inside in the wake of the many good suggestions, I fell into a "solution" of sorts. As I mentioned before, the loud hum would disappear when I touched the metal at the jack or cable tip. I found it would also dissipate somewhat when I touched the small connections on the soundhole controls. Then I reached inside and very lightly touched the metal cover of the main electronics box and the hum disappeared. And when I removed my finger, the sound was entirely gone, and has stayed gone since. Was this just some buildup of static electricity? Who knows. Oh, well ... false alarm.

More than likely where your problem resides.
And more than likely to return at a most inopportune time.
murphy strikes again.

[jonfields45]

Originally Posted by lpa53

While poking around inside in the wake of the many good suggestions, I fell into a "solution" of sorts. As I mentioned before, the loud hum would disappear when I touched the metal at the jack or cable tip. I found it would also dissipate somewhat when I touched the small connections on the soundhole controls. Then I reached inside and very lightly touched the metal cover of the main electronics box and the hum disappeared. And when I removed my finger, the sound was entirely gone, and has stayed gone since. Was this just some buildup of static electricity? Who knows. Oh, well ... false alarm.

Something is loose or cold soldered. If you are adventurous you can try moving the electronics box closer to the sound hole for a few minutes and see if there is something obvious, like one of the transducer being plugged instead of soldered and needed to be reseated. Otherwise I think you are headed towards a new pickup system if it is important the guitar work on a gig.