H's LPA-1. How much more black?

[Simon Barden]

A twin humbucker guitar shouldn't be particularly noisy to start with, even without cavity shielding. In addition to WeirdBits suggestions, check the potentiometers for smooth travel. It's possible that you may have overheated one or more of them when soldering the ground connections to the casing. They normally end up feeling a bit rough and scratchy if you have. I've done it before, despite trying to be careful.

But it still could simply be that you are testing it in an electrically noisy environment. Any other guitars/basses that you can use for a noise comparison test? Any nearby electrical equipment that you can turn off (including lights - especially fluorescent lights or those on dimmers)?

[UpperCaseH]

Thanks for the replies and advice!

It's noisy in all switch positions, but the noise is different.

Adjusting the tone and volume controls changes the noise. It's loudest when the tone controls are between 60% and 90%.

I don't think I've got any bad/cold solder joins. I'll check everything out with a multimeter and also redo anything that looks visibly dodgy.

It's noisier than my other guitars and basses. Not much in a low-gain situation, but very much more noisy than even my tele once the gain's up and/or there's a distortion pedal on.

It's entirely possible I cooked a pot, it wouldn't be the first time I've managed it, although it'd be the first time I've done it in a guitar. A couple of the pots are a tiny bit scratchy and one of the tone pots doesn't travel smoothly. If all else fails I'll just replace them all.

One question that's maybe silly when referring to guitars - Are all the "ground" connections supposed to be the same? As in, does the ground on the output jack connect to the ground on the bridge connect to the ground on the pickup wires connect to the shielding? Or is the shielding supposed to be kept separate from the bridge/pickup/pot/output grounds? Or are the bridge/string/shielding grounds supposed to be kept separate from the pickup/pot/output grounds?

Because I've got them all connected ont he guitar, and I know on some effects units the circuit ground wire connects to the output ring and you get problems if it touches the case or the input ground.


With all that said, I'll pull it back apart tomorrow and check and re-check everything, re-solder anything that's not right, and test it again. If I need to replace the pots, eh, at least they're fairly easy ones to find.

[Simon Barden]

Every ground should connect back to the same main ground point, the ring connection on the output jack. It becomes slightly more complex with shielded cavities as they can also act as the ground connection between pots and it really is best not to duplicate ground paths. For reduced noise, it's best not to connect the ground in a ring. I know that this is often the case in house wiring - but then it's a safety ground, not a signal one. That's why when you look at pictures of vintage Gibson control cavities, the bare wire often soldered as the ground connection between the backs of the pots is in a U shape, not a circle. If you've got copper shielding, that should act as a ground connection between the pots and you don't actually need separate earth connections. Likewise, with a standard metal Tele control plate, there shouldn't be any need to run a ground wire between the pots (but it's certainly worth using a multimeter to check that this is the case before omitting it, as not all pots are created equal).

I'd try and sketch out how you've run your ground wires. If you've followed a standard schematic there shouldn't be any real issues. I've been taught that star-wiring the grounds is the best way to do it (so that every ground connection has its own wire back to the jack ring connection). But that means lots of wires and is very messy. So the next best way is to do it in a tree-branch type network, so that everything connects back, but there aren't any cross connections between the different branches - there's only one path back from any connection to the main ground point.

It's also worth checking that things like the jack socket is firmly screwed down onto its metal fixing plate (if it's not a plastic one). If it's loose, there can be a high resistance connection to the metal, which can allow RF noise into the ground signal. Sounds silly, but I've often found a loose jack fixing nut to be the cause of excessive noise.

[UpperCaseH]

Thanks Simon, wasn't too sure about how to ground everything properly and I didn't know that about the socket at all.

Took the covers off and spent half an hour with the multimeter trying to see if anything was disconnected or connected where it shouldn't be, and I found the problems.

Slightly dodgy solder on the ground wire from the 3 way switch. Fixed that up and the problem lessened so I kept searching and found the main culprit. A single strand of wire from the connection between the neck volume and tone pots was loose from the solder and was bridging pins 2 and 3 of the tone pot. Clipped that off, and the problem went away entirely. Pots are still a tiny bit scratchy, but definitely not something I'm going to worry about.

Now I'm gonna go play the hell out of it for an hour or two

[UpperCaseH]

Aaaaaand pictures. Looks kind of flat in low light, black in dim light, and apparently in sunshine it transforms completely.

[WeirdBits]

Nice. No more noise problems (except the kind you want it to make)?

[UpperCaseH]

Yep, no longer noticeably noisy in normal use.

Being mostly a bassist I have no "real" guitar amp, just my home made one. So I've been plugging into my interface and playing through Guitar Rig 5 and Positive Grid Bias. Sounds fine through anything "normal" on those, but gets a bit noisy once I start getting into the super high gain stuff that I'll never afford in real life anyway (like, crazy bi-amp stuff with heaps of fuzz and distortion). But as I understand it, pretty much anything's gonna be noisy in that scenario.

[wazkelly]

Finished axe looks good H.

[Simon Barden]

Really glad you got the noise issues sorted.

I can see the finish issues that you mentioned on the upper rear body now. A real shame about that little bit, as the rest looks really professional and well done. So you'd better start playing it a lot and adding your own wear marks to it!

[UpperCaseH]

Haha, yeah when I first saw the flaw I was thinking about antiquing/relicing/weathering/whatever the guitar, but then I thought "nah, this'll be the one that I leave sitting next to my desk, take out places, play while drinking heavily etc and it'll look worn soon enough".

Speaking of worn guitars, I've got my first real electric guitar still sitting around. It's a yellow yamaha super strat from the '90s and the finish is in fairly poor repair. I've got some ideas about re-doing it in somthing other than bright yellow. Is this an appropriate forum to post a diary/log of refinishing a store-bought guitar, or is there a better one?