Tidying up complex wiring (with grounding issues)

[karmicluca]

Hi all! ^^

I've already posted for this project, a frankenstrat I've started modding years ago, and that has received a good new custom neck! ^^ 
So I brought it to rehearsals and found it buzzed the hell out, which was disappointing seen all the effort put in thorough shielding..

But it was no surprise either cause the wiring is really complex, so I'm seeking suggestions on how to wire a complex diagram in little space while keeping it decently tidy, avoiding ground loops.

The circuit comprises standard 5 way switch, two tones (separate caps), one volume with improved treble bleed (res and cap), on off switch for neck pickup, phase control for bridge, pots bypass and series/parallel switch.
It also includes the ground wiring suggested on GN1 with the (ginormous, hugeantic) cap for security.

Here it is disassembled, tho I can assure it was not pretty put together ^^'

I was thinking stuff like taping long wires to the pickguard and following a soldering order so cables don't overlap too much, but for the rest I'm a bit clueless..
Anybody willing to help? ^^ pleeeease

PS Suggestions on how to properly solder those tiny little mini-micro-nano switches are also much appreciated  

Luca

[newey]

So I brought it to rehearsals and found it buzzed the hell out,

This raises a number of questions:

Was there an unacceptable level of noise when playing the guitar elsewhere?

Did the noise change or vary as you moved around the room?

Did the noise change or vary if you touched the strings?

Were you playing through any pedals, or was the noise level also unacceptable when plugged straight into the amp?

Do other guitars also buzz in your rehearsal space?

Did you try swapping out the cable(s)?

Did the noise level change or vary when the 5-way switch was placed in positions 2 or 4?

Did any other combinations of the switches change or vary the noise level?

I'm making a number of assumptions here. First,I'm assuming everything works as intended with your new scheme. Second, I'm assuming that "buzzed the hell out" means a noise floor that is unacceptable. Third, I assume these are three standard SC Strat pickups (I didn't go back and re-read the original thread to see).

It seems odd to me that you had not tested the guitar or, if you did, that you did not notice the noise before taking it to practice. Shielding is not a cure-all, and there may be electrical elements in your practice space that are contributing to this. Grounds loops or sloppy wire runs are unlikely to be contributing significantly to the noise; most buzzing comes from the pickups (which is the reason for most of my questions above).

One other possibility is that some component is touching your shielding when it shouldn't be. Applying some non-conductive tape (like electrical tape) over the shielding in the areas of the controls and switches will sometimes fix those issues, although usually when that happens something is being shorted to ground, and whatever it is won't function properly in addition to being noisy.

Another possibility is that you have reversed the wiring to the output jack, which is an easy wiring error to make, and easy to double check. Also, if you tried to shield the jack cavity under the traditional Strat "canoe"-style jackplate, this often causes problems due to lack of space (and is why the original Guitarnuts shielding plan calls for using a shielded cable to the jack instead).

Finally (although this wouldn't contribute to the noise if done properly), I assume that you have read the information we have here on the use of the so-called "safety cap" prior to including it in your build.

[karmicluca]

Hi, 
sorry I rushed through the introduction  

The reason why I assumed most of that is that  the ROOM I had already played in with my other, humbucker loaded guitar (the thread one yes has single coil pups) and everything was fine with the humbucker axe, so I assumed everything was fine, same cables, same everything.
The strat seemed fine at home in the sense that it buzzed a little (almost as much as before shielding), which was already weird to me, expecting far improvement.
No improvement in pos. 2 and 4, tho it is to say that I have the middle pickup from Ibanez S570 in the middle and not sure it is RWRP...

Also I have good reason not to blame my room since, at the beginning, I had shielded the guitar without modding it and noise ratio was very low!

I will try to remove the shielding jackside cause it seems not a very good idea. And I had already swapped ground and signal, been there, done that   can't help it. Still makes lotta noise. 
And yes I meant unacceptable by all standards, almost 1:1 ratio with signal. To be noted that it reduced when holding the body at a certain angle, which made me think of a ground contact inside the cavity.

Since the wiring is quite complicated I'm not too confident about it, also because I took some mods and put them together. I have a semi-complete sketch of the scheme here that I'll upload if useful.

So far the most likely stuff seems to me a contact with shielding surface (the whole circuit is quite bulky) and jack shielding.

Hope I've been clearer ^^ so you say that it's not much of a problem if cables look like spaghetti, as long as they are insulated?

Also, I've read the safety cap post, what specifically do you mean? The part about checking the power supply et cetera?
Thanks!

Luca

[newey]

On the safety cap, I meant that with modern amps the risk is minimal. To be completely safe, go wireless. And outlets should be checked in new (to you) venues.

If the noise is the same regardless of which pickup is selected, this points towards something contacting the shielding. I'd try the jack area first, as I suggested, and go forward from there. Taping over the shielding in the cavity may also be helpful if the jack cavity isn't the problem.

[karmicluca]

I'll make sure to go safe and remove that shielding, though I've taken everything apart and it will take time  I also have already taped part of the cavity, will try again.
About the safety cap then maybe I'll leave it out, things are cramped up even without it

Thanks for the advice

Luca

EDIT Done drawing the diagram, switches are NECK on/off,  Bridge phase invert,  series/parallel for middle. Is anybody willing to check this spaghetti wiring?    Also had to remove tone bypass due to (apparent) incompatibility.




 
HQ    

[nikogo]

Hi Luca,
Just a couple of comments:
Could you answer exactly on each asked question please?
It would help to analyze your problems.
I did not notice a ground wire from the neck pickup on the diagram.
Also did you ground the strings?
For a tidy wiring the wires should not be of a coarse gauge. Gauge 26 - 28 is good enough.
The shielding should be on a pickguard and in all recessed channels of main body and interconnected when pickguard is in place.
Do not solder the pickup ground wires to shielding. Solder them to the housing of the volume pot. That pot will be connected to shielding when locked to pickguard with its fastening nut. All shielding has to be connected to the pickup grounds in one spot only and it will be the  volume pot housing. 
For some noisy pickups I used the double shielding: the pickup leads were placed into braided sleeves connected to pickup's ground spot and to the volume pot. Not only volume pot could be used as the ground hub (the output jack is good too) but the pot has more room for soldering and is mechanically connected to shielding anyway.

[karmicluca]

Hi, thanks for your attention!

I'll try to reply now, I'll be synthetic tho cause it's a bit late here, maybe come up with more details tomorrow

I did not notice a ground wire from the neck pickup on the diagram. Right, forgot that, it goes to the star grounding, the lug which you can see as a grey circle.
Also did you ground the strings? Yes the strings are grounded through the usual cable soldered to the trem, which is connected to a lug, screwed into the cavity.
For a tidy wiring the wires should not be of a coarse gauge. Gauge 26 - 28 is good enough. Um.. i actually recycle cables inside an old (but out of the box) SCART wire... they're thin, work fine... i guess... should i not? honestly i've never considered a fault in those cables, wiring everything together seems to be a bigger problem.
The shielding should be on a pickguard and in all recessed channels of main body and interconnected when pickguard is in place. The cavity is good! Checked continuity and it's fine. I have no means of checking that it makes good contact with pickguard shielding... I just know the pickguard is fully covered too.
Do not solder the pickup ground wires to shielding. Solder them to the housing of the volume pot. That pot will be connected to shielding when locked to pickguard with its fastening nut. All shielding has to be connected to the pickup grounds in one spot only and it will be the volume pot housing. I wouldn't solder ground to shielding, at the opposite, i would connect it to jack ground, and then isolate the lug. Would this be correct? I'm trying to follow the instructions on star grounding from this site.
For some noisy pickups I used the double shielding: the pickup leads were placed into braided sleeves connected to pickup's ground spot and to the volume pot. Not only volume pot could be used as the ground hub (the output jack is good too) but the pot has more room for soldering and is mechanically connected to shielding anyway. Will keep in mind the braided shield option, sounds interesting

Thank you!!

[nikogo]

In case of atypically high noise it does have sense to check the components too.
Sometimes the volume pot may have disconnected the grounding lug from the rest of conductive element. 

[newey]

If you are using a "star grounding" scheme, then you don't use the back of the pots for shielding. Most modern pots are plastic inside, and excess heat from the soldering can damage them. I usually use a screw and washer, screwed into the side of the cavity, as a place to collect all the grounds.

If you are using recycled wire, I would certainly check it for continuity before use. But a break or fault therein wouldn't be a likely culprit for your noise problem, more likely you'd just have no signal at all through a bad piece of wire.

Yes the strings are grounded through the usual cable soldered to the trem, which is connected to a lug, screwed into the cavity.

Check that connection. Using your meter, you should have continuity between that lug and the output jack sleeve (or "barrel", as it's sometimes called) connection.

Nikogo is right, checking components before installation is a good practice, and can save a lot of grief later on.

Have you done anything with the output jack area, as we discussed above? That would be the first place I'd check.

[karmicluca]

Uhm I'm kind of becoming confused now.
My knowledge was that the lug which is screwed to the cavity and linked to the strings, shouldn't carry all the other grounds, is that incorrect then? 
Should that one be my ground "star" which is then sent to output ground? 
I've never soldered anything to the back of the pots in my life i swear 

Last not least, the continuity between jack negative ("barrel") and the lug would be... directly through a cable? So checking the cable should be enough?
Anyway it makes good sense to check everything, including the tiny little SCART cables.

So: A wire goes from the trem (strings) to a lug in the cavity, which also receives all of the wiring's ground and goes into jack ground? (also barrel == jack ground?) 

Thanks a lot! ^^

[newey]

So: A wire goes from the trem (strings) to a lug in the cavity, which also receives all of the wiring's ground and goes into jack ground? (also barrel == jack ground?)

Yes, that's the "best practice", although having two separate grounding points won't really hurt anything, so long as everything gets to the jack barrel eventually. The jack barrel is the "negative" connection, although "positive" and "negative" aren't really accurate descriptors for an AC circuit. Hence, the quotation marks

As for the string/trem ground, for completeness' sake, check the entire length of the thing, from trem to jack, for continuity.

[karmicluca]

Ok I will for sure! thanks for the advice.