Shielding/Wiring Les Paul 1vol, 1 tone, 2 HB's

[esp400]

So I'm wiring up my buddy's Les Paul. I'm putting in Seymour Duncan Jazz PU's. How does the star/central ground work with Les Paul's? I don't have the protective capacitor but I'd like to get the shielding correct. I've installed copper foil tape in the electronics cavity, the pickup cavity, and the jack cavity(I'm going to insulate there too!). Do I just bring all of the bare wire from the pickups, bridge, jack hot wire shield, other cavities shield connection to the volume pot and solder on the pot?

If anyone has any diagrams for this I'd greatly appreciate it. I read the Quieting the beast article but as I indicated, I don't have the protective cap, the ring terminal for under the volume pot. Just attempting to learn basic shielding for the LP so that when I do my own I've got a handle on it.

I'll try and post some pictures tomorrow.

Thanks in advance!

[newey]

esp400-

Hello and Welcome to G-Nutz2!

Do I just bring all of the bare wire from the pickups, bridge, jack hot wire shield, other cavities shield connection to the volume pot and solder on the pot?

Essentially, yes, although I'm not sure what you mean by "jack hot wire shield". The jack's barrel (or "sleeve") connection goes to your grounding point, not the "hot" connection, which on an LP would ordinarily be wired to the center lug of the three-way switch.

Note that any means of collecting all the grounds in a single place is "star grounding". It doesn't depend on the use of the ring connector or of the "safety" capacitor. The ring connector is just a convenient way to ensure that the pickguard shielding is grounded- it's useful on a Strat-type guitar with a plastic pickguard, but you don't have that with an LP. The "safety" cap is useful only if you play through vintage tube amps.

The alternative to star-grounding is a "daisy-chain" of grounds, from one to another, which is the way most guitars come wired from the factory. Star grounding is tidier, and is considered a "best practice", but both methods will work just fine.

I don't use either the ring connector or the cap in my builds. However, I also don't use the back of a pot for the grounding point, since it means a lot of soldering to the back of the pot. Modern pots are mostly plastic on the inside, and it's easy to melt the innards if you aren't careful with your iron. Instead, I use a washer, to which all the grounds are soldered, then the washer is held by a screw to the side of the cavity, contacting the shielding.

EDIT: I should add that, on a Strat with a shielded pickguard, the pots will be in contact with the shield and the bodies of the pots are grounded by contact. On an LP, you may want to ground the bodies of each pot, one to another, and then to the star point. While grounding the pot shells may not really matter much, there is a chance that some noise could be introduced thereby.

[esp400]

although I'm not sure what you mean by "jack hot wire shield"

When I soldered the wire that goes to the tip of the 1/4" jack it has a drain/ground wire in the wire jacket. It's not a foil shield type. Should I get something else there? I saw that in the 'Quieting the beast' article that audio wire is recommended which I'm guessing by the description has both a drain/ground wire and a foil shield.

The jack's barrel (or "sleeve") connection goes to your grounding point, not the "hot" connection, which on an LP would ordinarily be wired to the center lug of the three-way switch.

First time I've wired a LP. I have a short frame 3 pos switch typical of LP's. It has 4 terminals on one side (two in the middle to be combined for the 'both on' position) and one terminal on the other side of the switch. So I'm under the impression that the single terminal is where I land the hot from the tip.

The spider web shield ground that you were describing (going from pot to pot and to the case) was where I got confused looking at the 'QTB' diagram and trying to figure if I should still star ground in the center of the foil with a ring terminal to solder to. Yeah, I forgot we aren't dealing with the pickguard here. I will try your method. I did have to open the pot holes to accommodate CTS shafts. The lock washer for the pots is definitely in contact with the foil (speaking to your point of pots in contact with the shield on a strat).

My apologies if anything was confusing when I posted. It was late (for me). And now it is early so there's probably more gibberish above. Let me know if anything is unclear and I'll get a pic or two posted this evening.

Thanks for your help!

[newey]

I missed the part where you said "1 Vol, 1 Tone". I was thinking of an LP with individual V and Ts for each pickup- on those, the pots get wired before the switch, and the switch goes to the jack. Yours will be different. Pickup "hot" wires go to the switch, switch center terminal(s)go to the V pot clockwise lug, otne pot gets wired off the volume pot. Jack "hot" connects to the V pot center lug.

Gibson has made some single V and T LPs, so you can probably find a diagram to work from for the wiring of the pickups only your grounding scheme will differ. Epiphone probably has made more of them, so maybe look for an Epiphone wiring diagram to fill your bill.

It has 4 terminals on one side (two in the middle to be combined for the 'both on' position) and one terminal on the other side of the switch. So I'm under the impression that the single terminal is where I land the hot from the tip.

Probably not, although a picture of the switch would help to be certain. But it sounds like you're describing a grounding lug on the back side of the switch, which just grounds the frame of the switch. It is not a signal connection. With 2 center terminals, these will be wired together and then wired to the output jack "hot".

When I soldered the wire that goes to the tip of the 1/4" jack it has a drain/ground wire in the wire jacket. It's not a foil shield type. Should I get something else there? I saw that in the 'Quieting the beast' article that audio wire is recommended which I'm guessing by the description has both a drain/ground wire and a foil shield.

You can use the cable, just leave the ground wire disconnected at both ends. John Atchley suggested using audio cable with a shield for a Strat-type guitar because there are a few inches of wire run out to the "canoe-style" jack plate, and this wire run is not contained within the cavity, and thus doesn't benefit from the cavity shielding. So he recommended separately shielding this wire run, lest some noise be generated in the wire to the jack. This is perhaps overly cautious on Atchley's part, but hey, if one is going to go to the trouble of shielding the thing in the first place, might as well do a thorough job. But I'm doubtful that any real noise would result from not using shielded wire.

You don't have this problem in an LP, where the jack is right next to your shielded cavity and the length of unshielded wire run to the jack is negligible. I wouldn't worry about it.

[esp400]

I have a diagram to work with (see below).  However, it is standard wiring and I'm trying to get '50's' wiring configuration in this LP. As I understand it, I need to reposition the cap (.022uf) that is connected between the Vol pot and the Tone pot in order to get the tone pot input landed on the volume output.

So I have some audio cable that I borrowed from work . I will add that and probably twist up the foil and drain and add it to the ring terminal and leave it disconnected out by the jack. Also, I'm assuming the switch lug that is all by itself will get added to the ring terminal for shielding. It functions as you described.  Yellow wire in the pic goes to the bridge.  Two black harnesses are the pickups.  Grey is two conductor (black/red) to the output jack and the bare wire goes out to both pickup cavities soldered to the foil.

Pickup "hot" wires go to the switch, switch center terminal(s)go to the V pot clockwise lug, tone pot gets wired off the volume pot. Jack "hot" connects to the V pot center lug.

Clockwise lug?? Do tell...what's the difference there?

Here is a pic of the electrical cavity and the diagram. Thanks again for your help!






upload

[newey]

Clockwise lug?? Do tell...what's the difference there?

guitarnuts2.proboards.com/thread/6612/potentiometer-orientation
As shown in your diagram (which, by the way, is fine), we are looking at the pots from the rear, just as you will be wiring them in the LP

Also, I'm assuming the switch lug that is all by itself will get added to the ring terminal for shielding.

Yes.

As for the '50s wiring, I'm sure there are diagrams out on the web. Essentially, the '50's wiring puts the tone before the vol. pot.
JohnH's "modern and '50s wiring" is required reading on the subject.

[esp400]

The article you wrote is informative. Good work there.

As for the '50s wiring, I'm sure there are diagrams out on the web. Essentially, the '50's wiring puts the tone before the vol. pot.
JohnH's "modern and '50s wiring" is required reading on the subject.

You would be amazed at how little there is for Les Paul Junior(1V, 1T) 50's style wiring. I've searched some forums where people have said as much. I will figure it out though.

Thank you for the references to work from.

[newey]

We'll be happy to help. As I said, maybe search for an Epi LP Jr diagram.

But the '50's wiring is easy enough to explain. In a normal "modern" LP w/ a single V and T (i.e., 2-pickup LP Junior or LP special), the output from the switch would be wired to the CW lug of the volume pot, with the "hot" output wired to the center "wiper" lug of the volume pot. The 3rd (CCW) V pot lug is then grounded. The tone pot is wired off the volume pot, from the volume pot CW lug to the center "wiper" lug of the tone pot. The tone cap is then wired to the CCW lug at one end and grounded at the other.

In '50's wiring, the volume pot wiring does not change. Rather than wiring the tone pot off the V pot clockwise lug, wire it from the center "wiper lug of the V pot instead, with the cap in between the two pots. From the wiper of the V pot, wire first to the cap, then from the cap to the CW lug of the tone pot, and then the middle "wiper" of the V pot is grounded.

If that's not clear, ask questions!

[sumgai]

Jun 5, 2019 22:01:40 GMT -5 newey said:

As for the '50s wiring, I'm sure there are diagrams out on the web. Essentially, the '50's wiring puts the tone before the vol. pot.

Errr, that's a bit different than what the linked thread says.   In modern wiring, the Tone comes before the Vol pot, in so-called 50s wiring, it's after the Vol pot. Fortunately, you describe it correctly, and in greater detail, in Reply #7.

---

esp400,

Hi, and to The NutzHouse!

In essence, you can (and probably should) think of anything that looks like a guitar circuit as a collection of modules.  The simplest module would be nothing more than a pickup, some wire, and an output jack.  From there, you can add a Volume control, and doing so would be modifying the simple circuit by adding a Vol pot module.  Then you can add a Tone pot module, if you so desire.  I trust you're starting to get the picture, eh?   So we've got one pickup, with some controls.  It goes without saying that we can duplicate that whole schmear, and have two pickups, each with their own controls, and they can share an output jack.  (But do ask newey about doing this with two output jacks, for a stereo guitar.)  By adding a Switching module, we can now select which pickups are used.  And so it goes, building up a complex circuit out of simple modules until we get the desired results.

Your original question was about modern versus 50s wiring.  I'm fairly certain that after reading the linked thread, you'll consider very carefully your options, before implementing the final circuit.  But if you wish to experiment, that'd be a good thing.  After all, nothing is permanent inside of your axe -  you can always take it apart and do something else, then try it out for tonal appeal.  It's a bit difficult to do accurate Before/After experiments, unless you can record your trials (relying on your own memory can result in errors - trust me!), but for the most part you should be able to settle on which way to go, and lock it in as your final setup.

My final word on the topic - there's a reason why so-called 50s wiring didn't stick around... why it morphed into modern wiring, and that schema being pretty much the standard since then.  John's thread deals with this to some degree as well.

HTH

sumgai

[esp400]

and then the middle "wiper" of the V pot is grounded.

I assume this was supposed to be the tone pot?

Is there a tonal difference in the placement of the cap in the circuit? I would think one is either putting the cap on the input of the tone circuit (in between the two pots) or on the output of the tone circuit where it's grounded on the case of the pot. If not tonal, what's the difference there? Why not always one or the other?

Thanks again for the clarification.

Sumgai,

I read the reference article but in all honesty it is over my head a bit. I understand that the 50's wiring retains the high end a bit and that you'll play with the tone control a bit more. I think I have the jist of it. I do appreciate the effort.

[sumgai]

espy,


Stick around, you'll get the hang of it soon enough. And never forget, none of us here were born knowing all this BS, we had to learn it too - we just got curious earlier than you did.


As to where the cap goes, that's easy. If you know what "series" means, then skip the rest of this paragraph. In essence, when we put two components "end to end", we say they are in series. From that, it's only a short jump to understanding that the order of those connections makes no difference to the final results. Just be aware that if the connection between those two components is also hooked up to something else, then the order/arrangement is important.

For most simple tone controls, the Tone pot is often wired "closest" (electrically speaking) to the Vol pot, and the capacitor is hooked to ground.  There is no hard and fast rule anywhere that says a Tone control must be hooked up this way - the positions can be reversed with no effect on the control's ability to change the tone.  In a few cases, you might see this reversal, but as often as not, that was probably done as a way to simplify something in the design.  That might be the choice of values, or potentially the physical connecting points (where the leads are soldered... one way might be easier than the so-called "standard" way), but like we've been saying, the end effect will still be the same.

HTH

sumgai

[newey]

I assume this was supposed to be the tone pot?

Yes. And, sg, remember he's wiring his buddy's guitar and experimentation is probably not the order of the day

[sumgai]

Jun 9, 2019 8:18:44 GMT -5 newey said:

I assume this was supposed to be the tone pot?

Yes. And, sg, remember he's wiring his buddy's guitar and experimentation is probably not the order of the day

So let his buddy do the final tone testing. Done is.

[esp400]

Yes. And, sg, remember he's wiring his buddy's guitar and experimentation is probably not the order of the day

Well, truth be told, I am hoping to do my Les Paul next and so this is a refresher/practice for me. I have an Epi Standard which I bought P-90's for (SD Phat Cats). I have wired my Strat in the past (2 years ago) but I very strictly adhered to diagrams. I'm finding that the LP is another animal. That is why I inquired. I do have an electronics background but everything has some nuance to it's function.

[sumgai]

Jun 9, 2019 18:44:19 GMT -5 esp400 said:

... I do have an electronics background but everything has some nuance to it's function.

For a Rookie Solder Flinger, you exhibit a nice grasp of that which bites most guitar modders on the butt, so to speak.  Even we well-experienced axe-hackers occasionally get myopic, often with embarrassing results.   Which also speaks to many eyeballs usually prevent disasters in the making, or at least they can find errors and offer corrective solutions.

My only sticking point in our discussion is that regardless of the manufacturer, all guitars are basically cut from the same mold.  Meaning, don't let anything that appears different at first glance prevent you from applying a logical examination and analysis.  If some circuit component/feature functions in a certain way inside of a Strat, it will function the exact same way inside of a Les Paul.  Of course, that's provided it's hooked up in the same manner.  Which of course gives rise to the 50s vs. modern wiring practices - a good example of why and how to interpret a circuit designer's intentions.

Stick around, I've a feeling that you're gonna be contributing more to The NutzHouse than you might now think possible.

HTH

sumgai

[esp400]

Here is what I have so far. It's not horrible but it's not great either. In retrospect, I would've put the ring terminal back where I have the pickup wiring wrapped in electrical tape on the opposite wall. That way I could've had the shield wiring on one side of the switch and the signal wiring on the other. This is only my second wire up but I've already discovered that I need more supplies as well. Electrical tape is just not going to cut it when I wire up my own. I had shrink tubing but recently moved and apparently it moved somewhere else.

Anyway, I'll test it out tonight with the screwdriver tap test and probably string it up.

If you have suggestions, let me know.

[sumgai]

Jun 10, 2019 14:40:34 GMT -5 esp400 said:

I had shrink tubing but recently moved and apparently it moved somewhere else.

Yeah, you just hadda go and play ChrisK's "it's in another city" card, din't ya... Which is to say, by the time you finally catch up with that tubing, the ambient heat (from global warming, of course) will have done the job for you. Usefulness will be rduced to -1, at the least. Sorry 'bout that.

Oh, and your photo is pretty clean, certainly better than some we've seen.  It lets me say that I see no reason not to button it up... provided it passes that tap-test, of course.

sumgai

[esp400]

Yeah, you just hadda go and play ChrisK's "it's in another city" card, din't ya... Which is to say, by the time you finally catch up with that tubing, the ambient heat (from global warming, of course) will have done the job for you. Usefulness will be rduced to -1, at the least. Sorry 'bout that.

In addition to that, the shrink tube I did put on was waaaay too big. So I thought I'd borrow the right size from work , but we're in the middle of adding a bunch of automation and had to relocate/reorganize our maintenance area and all of the cabinets which contained the electrical supplies were buried among everything that is to be moved. Cleaner next time for sure.

[esp400]

After closing up the electronics and setting up the guitar (my buddy wanted .012's put on), the guitar was very clean but distinctly bright. I'm okay with that. I own a Vox AC-15C1. Chimey is good. I had it running through the normal channel. It occurred to me to try the top boost channel and then things got really...well top boosty. There was really no usefulness in the tone knob until the very end. So I changed out the .022uf cap for a .047ufcap and things warmed up a bit but not as much as I thought. Also, the tone knob cuts treble going full clockwise and dumps the bass going full CCW. I think this is opposite of normal. How did I go wrong there? I'm guessing I want that cap wired to the CCW lug with respect to the wiper (which is on the ground). Am I correct? Image of the wiring is earlier in this topic.

[esp400]

The tone cap is then wired to the CCW lug at one end and grounded at the other.

I see I have it wired incorrectly according to Newey's instructions.