PTB Wiring

[joelorigo]

I have a 87 MIJ Squier that I want to try the PTB wiring. I have been researching and have come across the attached diagram which doesn't look to hard fro a beginner like me.

How does it look? Any opinions / tips to do this?

Forgive me for what are noob questions but here they are. The diagram doesn't specify but I have seen the pots needed are exactly A250 for volume, A500 for treble and C1M for bass. Why does the bass pot need to be reverse taper?

The guitar is left handed so it came with reverse pots. If I wanted to have the knobs operate in the same direction I am used to, the pots I would need C250K, C500K and A1M, correct? If not the operation will be opposite to what is currently on the guitar? (which isn't really a big deal for me since my left handed Gibson guitars operate opposite of my fenders - it's frustrating, even after all these years, mid-song to reach down and forget which way to turn the volume pot)

On the diagram, what is the ground symbol on the 1M pot? is it just pointing out that it is grounded?

 

[ragamuffin]

I have three guitars with PTB wiring now and I've really come to like it. Your diagram looks correct.

The potentiometer resistance values for the volume and treble pots depend on the type of pickups that you're using and your personal preference. 500k=a little brighter, 250k=a little less bright. Normally you would use 500k for both with humbuckers, 250k for both or a mix for singles. Reverse audio taper is used on the bass pot because that is what is needed for a nice gradual taper on the bass cut circuit; regular audio taper would be very abrupt like what you get when you wire a volume or tone pot backwards.

I don't know much about wiring in left handed guitars so I'll let someone else chime in on that

The ground symbol is indeed just saying that the pot gets grounded.

 

[joelorigo]

Thank you.
I have found out some info on being a lefty and wiring and pots. I am getting the recommended pots and not the reverse as I asked above.

Anyway, I'm sourcing the parts for this project.

For anyone interested in this in the future the C1M is hard to find but G&L sells one in their online store.

I am looking at Orange drop caps for the .0022 and .022 needed. Is this correct or the type not important? I saw a photo of a G&L Doheny and they were not orange drops.

 

[ragamuffin]

Thank you.
I have found out some info on being a lefty and wiring and pots. I am getting the recommended pots and not the reverse as I asked above.

Anyway, I'm sourcing the parts for this project.

For anyone interested in this in the future the C1M is hard to find but G&L sells one in their online store.

I am looking at Orange drop caps for the .0022 and .022 needed. Is this correct or the type not important? I saw a photo of a G&L Doheny and they were not orange drops.

Nice! Capacitor type doesn't really matter in guitars as long as it's not a polarized cap. I used some funky vintage caps that I got on Ebay, mainly because they look cool.  ccasion14:

 

[joelorigo]

I have ordered the A250, A500 and C1M pots, a new switch, caps, and some wire.
I found this description of the wring on another board:

- Your pots go V/T/B = 250K A, 500K A, 1M C (A = audio taper; C = reverse audio taper).
- Your caps are .022uF treble and .0022uF bass
- The pickups hook up to the switch like a Strat
- The output from the switch goes to lug 1 on the treble pot, then from there to lug 2 of the bass pot
- The treble pot's cap goes between lug 2 and the back of the pot
- The bass pot's cap goes between lugs 2 and 3
- A wire runs between lug 3 on the bass pot and lug 3 on the volume pot
- Your output wire runs between lug 2 on the volume pot and the jack's hot lug

Now for the grounds:

- The p/u grounds, the claw ground wire, and lug 1 of the volume pot all connect to the back of the pot
- A ground wire runs from the back of the volume pot, from there to the back of the treble pot, from there to the back of the bass pot, and from there to the ground lug of the jack


That seems to match the above diagram except for the grounding. The diagram doesn't show of a ground wire from the volume pot, to the treble pot. And it is missing the claw wire. Do I need to run a grounding wire connecting all the pots together? The current wiring does have have this

 

[ragamuffin]

Yes you want to connect all the grounds on all the pots as well as the bridge/claw

 

[joelorigo]

Ok, so I drew some more things on the above diagram to make it more complete for me. Look ok?

 

[ragamuffin]

Looks good to me!

 

[joelorigo]

Thank you. And I follow this even though this is a lefty guitar, correct? The switch will just be on the other side?

 

[ragamuffin]

Thank you. And I follow this even though this is a lefty guitar, correct? The switch will just be on the other side?

Ok so I did some googling and it looks like I may be wrong: lefty wiring is different. It looks like you want to use reverse audio taper or "left handed" pots for the volume and tone, and that means you would want a regular audio/log taper pot for the bass control.

Any lefties want to chime in?

 

[joelorigo]

I had read that using a regular audio taper for the bass pot would mean a less desirable taper. That's why I decided to buy the "regular" pots and not work about it being customized for lefty. I am used to pots working both ways because my Gibsons go one way and the Fenders the other (The Gibsons use the same pots and wiring for left and right handed apparently). So to make it easy I just want to wire it as the diagram shows. I also found a photo of the G&L Legacy wiring that seems to match the diagram.

 

[joelorigo]

I have all the parts and I'm going to start the re-wire this week.

I bought some non-shielded and some shielded wire (because that's what the Stew Mac Premium upgrade kit contained). Links below.

I have found some different opinions about the shielded wire. One source said to use it on longer runs, like to the output jack. Another said it is not necessary at all. What should I do?


https://guitarelectronics.com/gavitt-cloth-covered-vintage-style-stranded-guitar-wire/
https://guitarelectronics.com/gavitt-vintage-style-guitar-wire-w-braided-shielding/

 

[ragamuffin]

I'd say (and I probably most here would agree) that the braided wire is not necessary, it just makes things more complicated without much benefit. I'd just use the regular pushback wire if you have enough.

 

[joelorigo]

I just finished wiring this. With the switch in the number one position, I am getting signal only from the neck pickup - should be the bridge.  In the 2 position, I am getting the neck and the bridge. Position 3, 4 & 5 nothing. (Note: the bridge pick up is a Seymour Duncan Little 59 that I had to reverse the black and green wire to get the correct polarity in position 2 previous to this) I'm attaching a photo of my switch. Also, the treble knob does seem to cutting treble and the bass know does seem to be cutting bass. I am just testing with a screwdriver on the pickups.

 

[joelorigo]

With some guidance from another board and some research on how a 5 way switch works, it's all fixed now. the wires were in the wrong place. I didn't have the output on the switch leaving from the common.

 

[joelorigo]

I have a random question. Does the value of the caps one the treble and bass pots effect the signal when the pot is turned up all the way? No, right? The value of the cap only makes a difference once you start turning down the knob, right? I am only asking because I'm trying to prove to myself that this rewiring did not change the tone of the Seymour Duncan Little 59 that I have in the bridge, when the knobs are all the way up.   

Other than that, I just spent some time messing with the knobs and I like this system.

 

[ragamuffin]

Should not have an effect (or extremely minimal) when the knobs are all the way up.

 

[joelorigo]

Thanks!

 

[joelorigo]

I think I had just lowered the Little 59 too much when I was trying to even it out with the single coils volume-wise. I raised it and it's like I remembered it.

I’ve spent some time getting used to this circuit. I purposely left out the treble bleed part as to keep it simple in case there were problems. I’m going to add the treble bleed npw. The Kinman. Looks like we are using lugs 2 and 3 on the volume pot. A couple of questions.

Does or matter which lugs of the volume pot the the 2 sides of the cap are attached to? In other words, does the side that has the resistor attached need to be on a specific lug?

in general, does adding a treble bleed smooth out the taper more than it was before. This pot is an audio taper but does roll off volume more on the beginning of the rotation than the later part. My 1993 American Standard, which I have learned has a treble bleed, is more of a gradual volume reduction through the rotation.

 

[stratamania]

With regard to your treble bleed...

https://kinman.com/perfect-guitar.php#volumePots

[youtube]https://www.youtube.com/watch?v=uxrFn1bekNQ[/youtube]