Tone Pot/Capacitor Wiring (SD Drawings vs. Switch Drawings)

[Trueno07]

Hey y'all,

Background: Bought a Pegasus/Sentient set for my LTD 7 string. First pickup swap, first guitar wiring project, so I decided to have some fun with it and go all out and use a Free Way switch for more options. I set it up a 3x3-03 switch in the "HHum+S/CoilCombinations2V/2T" where 1,2 and 3 on the switch are Neck/Neck+Bridge/Bridge and 4,5 and 6 are Neck + SC Bridge, SC Bridge + SC Neck, Bridge + SC Neck. (https://www.stewmac.com/freeinfo/i-0055/free-waydiagrams.pdf page 8). Because my guitar only has two holes in the body, I decided to go with 500k Audio concentric pots so that I could have volume and tone control over both pickups independently. I ised .022uF tone capacitors

Ultimately, I managed to get it all completely working but the tone knob behavior is confusing me. The slightest turn of both knobs takes the tone from totally underwater and closed to completely open. Bringing the volume down gives me a bit more space on the knob, but not much more. I've got it wired just like the diagram I shared, but I'm wondering if there is anything I can change to give me a little more variety. The SD Drawings that came with my pickups show the caps running from the wiper to the back ground and with a capacitance of .047. I assumed the wiring was different due to the way the freeway switch works. The referenced Free Way drawings have it wired the "modern" way. I've also found drawings with 60s and 50s wiring techniques. Would any of these things help me get some of my tone adjustability back?

Thanks,
Trueno

 

[beaubrummels]

Re: Tone Pot/Capacitor Wiring (SD Drawings vs. Switch Drawings)

Make sure the tone cap leg on the wiper lug is not touching the pot body or any other ground point and acting like a second volume. Also, were the concentrics audio taper or linear taper? The taper, if not the right kind, can make a tone act like a quick switch instead of a smooth tonal transition from bright to warm.

 

[shadowfire90]

Re: Tone Pot/Capacitor Wiring (SD Drawings vs. Switch Drawings)

their way will work, there are a ton of ways to wire in a tone capacitor and some have advantages over the others. The only way I see a guitar going under water is going with an insanely high capacitor value like 0.47uf (470nf) which is not to be confused with a 0.047uf (470nf) tone capacitor. The only time you'll ever see anything over 100 nano farads is in a guitar with active pickups. The usual range of values I had to put into guitars was 0.01uf (10nf) to 0.1uf (100nf) but most of the time it's 22 - 47nf I'm putting in guitars.

beaubrummels brings up a good point too are the pots A500k or B500k.
When I had to go out and buy concentric pots for a few projects it was really difficult to get what I was after on ebay. Finally someone put a B500k/B500k concentric pot up and I grabbed like 4 or 6 of them to justify shipping. I knew if I had A500k/A500k stacked my wiring wouldn't work the way I wanted.

This is an interesting article about some pros and cons about different tone capacitor hook ups and the person goes into detail about it I read recently on premier guitar when I was looking for an obscure wiring diagram or something.
https://www.premierguitar.com/articles/29161-mod-garage-three-ways-to-wire-a-tone-pot

 

[Trueno07]

Re: Tone Pot/Capacitor Wiring (SD Drawings vs. Switch Drawings)

Make sure the tone cap leg on the wiper lug is not touching the pot body or any other ground point and acting like a second volume. Also, were the concentrics audio taper or linear taper? The taper, if not the right kind, can make a tone act like a quick switch instead of a smooth tonal transition from bright to warm.

I will check for grounding issues, good idea. With as many wires as it took to get the free way switch working I can see that being the case. Both pots do act the same way though.

They are audio taper pots, A500K, not linear. I was under the impression that you want A for tone and B for volume? The tone pot I removed was an A pot and the volume pot next to it was a B?

 

[shadowfire90]

Re: Tone Pot/Capacitor Wiring (SD Drawings vs. Switch Drawings)

For pot tapers

A for volume , B for tone traditionally
personally I go with all linear pots in my guitars but it's what works best for the players.

A when you turn it down you hear more of a swell when you do it quickly which can be heard in the openings and as a trick guitarists do in a lot of songs
B is more smooth and consistent so you'll have more control over the capacitor
10 is 10 for full volume , 0 is 0 for no volume.

while still on the subject
for volume controls if you want it smoother you can do a treble bleed mod to fix this, carbon resistors and polyester capacitors are more than enough.
for make the tone controls more useful is a good question to make the taper smoother.

this is what a treble bleed mod does. I suggest the Kinman treble bleed and don't get the stuff stewmac says. Their repair tools are great but "golden age" treble bleed circuit is extremely overpriced. Stuff from Thailand from ebay like tayda2009 will do the same job but much cheaper and you'll have enough components to do around 30 guitars instead of 1.

 

[Trueno07]

Re: Tone Pot/Capacitor Wiring (SD Drawings vs. Switch Drawings)

Shadowfire90, thank you for the advice. I've found some linear stacked pots in the US so I'm going to give those a go and see if it makes a difference. Anything is going to be better than the on/off effect i'm getting now.

Question though, reading around not just internet forums but also taking into consideration what guitar manufactures themselves do, it seems that you can kinda just do whatever you want concerning audio/linear taper for the tone pot and that there isn't really a standard. Do you really think it'll make that much of a difference? Do the pickups themselves have any affect on how that knob will behave?

The treble bleed stuff is really interesting and I will probably end up doing that as well while I'm in there.

FYI: https://www.thompsonguitarandthrift...concentric-stacked-pot?variant=29244875440192

 

[beaubrummels]

Re: Tone Pot/Capacitor Wiring (SD Drawings vs. Switch Drawings)

There’s a guy on here named David Collins who builds guitars and created a rig to test what the difference is and show it on a scope. Start with this thread.

https://forum.seymourduncan.com/sho...or-tone-pots&p=2519105&viewfull=1#post2519105

He posted links to his videos in thread I was going back and forth trying to find long shaft push pulls with specific taper. I can’t find the thread now but it’s very interesting if you can find it.

 

[shadowfire90]

Re: Tone Pot/Capacitor Wiring (SD Drawings vs. Switch Drawings)

There is roughly 25 plants around the world that make guitars so you'd be surprised who makes what.. or better yet; who owns who. Willseasyguitar or philipmcknight both go into great detail and it's fascinating for those who claim say a schecter is better than an LTD or a Dean is better than an Ibanez if you got very similar spec guitars.

for pickups affecting a pots taper i doubt it would change anything. I've heard that 1950s tone capacitors hookups affect the pots reactance similar to that treble bleed mod. However. If you go with B500k (lets say) pots in a build skip the treble bleed. Linear pots are already very consistent.

for how to do 1950s tone capacitor method of hooking the capacitor up and the pros and cons this is a great read. Short and simple
https://www.premierguitar.com/articles/29161-mod-garage-three-ways-to-wire-a-tone-pot


in my experience for your standard question of lettering.

cheapest chinese guitars you'll ever get I've seen single coils with 500k pots and 0.047uf capacitors (robson strat copies , bullet squiers , counterfeit guitars from this or that site copying fender jazz basses i remember seeing). Putting 500k pots with ceramic single coils is a bad idea. Nothing wrong with ceramic but 500k pots in a guitar with single coils is usually a mistake unless the guitar is really warm.

the cheapest pickguards on ebay from China I've seen guitars with nothing but audio taper (A) pots. However not every ebay seller is the same from China. Some do a fantastic job.

I've taken my share of guitars apart and it seems
Ibanez always has a B500k volume , D500k for the tone. I can count on one hand how many other times outside of Ibanez I've seen "D" pots
Epiphgnes , squiers seem consistent always "A" volume and "B" tones
schecter, LTD , Jackson and so forth all seem to follow the A volume , B tone as well , though it's been a while since I took apart a jackson

This is a great video on something called resonant peak to check out. It's made by a guitarist for gutarists. At the end of the day it's preference. If I know a player doesn't use the volume knob as more than an on/off switch I could put anything in their guitars. Then you get the picky people who played guitar their whole lives who like A500k for their humbuckers.

This video explains the correlation between resistance of pots and of course capacitors. It's super simple to visualize and once people know it, it's a great foundation. Inductance is a must learn aspect of pickups too as way too many people rely on just DC resistance.

 

[Trueno07]

Re: Tone Pot/Capacitor Wiring (SD Drawings vs. Switch Drawings)

Guys, thank you for the info.

shadowfire, I did find what David said interesting though: "For tone pots however linear taper simply does not work. Try it. Put a linear pot in your tone control, and what you end up with is a tone on/off switch between 2 and 1. There is no taper, there is no fade, it is all or nothing right there at the bottom."

This is exactly what I'm getting but I'm using an Audio taper pot like he suggests.

I mean, I'm going to try linear either way. They're in the mail and it's not like I spent a fortune on them.

 

[GuitarDoc]

Re: Tone Pot/Capacitor Wiring (SD Drawings vs. Switch Drawings)

I've heard that 1950s tone capacitors hookups affect the pots reactance similar to that treble bleed mod. However. If you go with B500k (lets say) pots in a build skip the treble bleed. Linear pots are already very consistent.

(First of all, 50s wiring is about how the tone POT is wired not the capacitor. There are many ways to wire a capacitor within the 50s tone system which are electrically identical and don't change the tonal output.)

If I understand what you are implying with this statement, then you are wrong. Using a B500k pot does NOT give you the same result as using a treble bleed circuit or a 50s wiring scheme. A B500k pot affects how your ears hear the speed of the volume or tonal changes as the pot is rolled down (compared to an A500k pot). 50s wiring (or treble bleed circuits) affects the frequencies and amounts of high frequency loss as the pot is rolled down.