Lefty G&L PTB wiring

Sun Apr 15, 2012 7:13 pm

hey guys! I was directed here from reranch for my question on the PTB wiring for a lefty custom guitar, here goes!


So i'm putting the G&L PTB tone system in to a left handed guitar of mine. But I'm a bit confused about the pots to put into it.

(if I'm correct) Normally it calls for:
Volume: 250k linear
Treble: 500k linear
Bass: 1 Meg REVERSE audio log


So for the left conversion i'm fine for the 250k and 500k because they're linear, but for the 1 Meg, does it need to be just a normal 1 Meg audio log as opposed to being reverse?

Being a lefty is a bit confusing at times!

Re: Lefty G&L PTB wiring

Mon Apr 16, 2012 3:17 am

you need reverse if you want it to work in the right direction with the right taper.

Re: Lefty G&L PTB wiring

Mon Apr 16, 2012 6:04 am

louis cyfer wrote:you need reverse if you want it to work in the right direction with the right taper.


so even if i'm turning in the opposite direction of the normal PTB, i should still use the reverse audio? My very simple understanding of things made me think that this would negatively effect the useful range of the dial

Re: Lefty G&L PTB wiring

Mon Apr 16, 2012 10:08 am

dksouthpaw wrote:
louis cyfer wrote:you need reverse if you want it to work in the right direction with the right taper.


so even if i'm turning in the opposite direction of the normal PTB, i should still use the reverse audio? My very simple understanding of things made me think that this would negatively effect the useful range of the dial


if you turn the opposite direction then the normal one works. you need the reverse if you want to use it in the proper direction. it does not effect the useful range, just the direction of the taper.

Re: Lefty G&L PTB wiring

Sun Jul 08, 2012 4:34 am

I have a lefty asat special deluxe and my volume pot has always acted weird. it goes from no sound to really loud (and slightly scratchy) really fast. Now, it turned the proper way, but I didnt like it.

I ordered a new LEFTY cts pot for it and also a new capacitor. I took it to my luthier to install and he said that while the old pot turned lefty, it had a righty taper so was never going to work properly.

Guitar is great now, no issues.

I ordered the cts lefty pots from allparts.com they only have them with the normal sized shafts and in my case only had split shaft in stock. they come in either 250 or 500. No biggy, the split shafts work just as well, just needed new knobs after.

Re: Lefty G&L PTB wiring

Thu Aug 09, 2012 5:48 am

Hi,

I was looking for a place to buy a 1 Meg reverse pot and for more information to confirm that you really need the pot to be reverse and I found a page that explains that you only need to wire differently the lugs of a regular pot to make it cut the bass (or hence anything else) in either way.
Here's the page: http://www.metalguitarist.org/forum/guitar-tech-electronics-diy/773-tight-control-simple-passive-bass-cut.html

Here is the diagram with the explanation:
So, how's it wired? I'll assume the guitar in question has a master volume control that runs straight to the output socket. The cap goes between lugs 1 and 3 on the pot. The wire that normally runs from the volume control to the socket now runs from the volume pot to lug 2 ('in') of the 'tight' pot. Another wire runs from the 'out' lug, as specified in the drawing, to the socket tip. You can wire it to cut bass when turned clockwise or anticlockwise, depending on your preference. Remember to bridge lug 2 to the outside lug that is not the output. And ensure the body of the pot is earthed. Here's a wiring diagram...

Image

Thoughts?
Last edited by Xochitl on Thu Aug 09, 2012 3:45 pm, edited 1 time in total.

Re: Lefty G&L PTB wiring

Thu Aug 09, 2012 11:24 am

if you use regular audio taper, you either have the taper in the wrong direction or have to put up with the control working backwards.

Re: Lefty G&L PTB wiring

Thu Aug 09, 2012 3:54 pm

That's what I understood before seeing this diagram. So as this is always cutting bass (obviously a passive systme can't add a frequence.), what is the diffrence between anticlockwise and clockwise?

Re: Lefty G&L PTB wiring

Thu Aug 09, 2012 3:57 pm

Xochitl wrote:That's what I understood before seeing this diagram. So as this is always cutting bass (obviously a passive systme can't add a frequence.), what is the diffrence between anticlockwise and clockwise?


you have to turn it the other way. rolling it up will make the bass go down and rolling it down will make it go up. just works backwards.

Re: Lefty G&L PTB wiring

Thu Aug 09, 2012 4:35 pm

OK. If I follow you, you mean that "rolling up for the bass to go down" is clockwise. like on the lower diagram. Hence I'll have to wire the pot like in the upper diagram (anticlockwise) for it to work like on a right handed G&L PTB.

Re: Lefty G&L PTB wiring

Thu Aug 09, 2012 11:22 pm

Xochitl wrote:OK. If I follow you, you mean that "rolling up for the bass to go down" is clockwise. like on the lower diagram. Hence I'll have to wire the pot like in the upper diagram (anticlockwise) for it to work like on a right handed G&L PTB.

but the taper will be backwards, so the control will work very differently. that is why you need a reverse taper to make it work on a lefty and still turn in the right direction.

Re: Lefty G&L PTB wiring

Sun Aug 12, 2012 7:05 am

Hey louis! I was failing to see your point. But I get it now. I didn't keep in mind we were talking about a audio taper (and not linear). It's obvious to me now!

BTW, do you (or someone else) have an idea where to get a 1 Meg audio reverse (righty) pot (besides the G&L online shop as their shipping charges are too steep for Canada)? I've been looking around the internet with little succes.