Push/Pull pots for ALs - Asking the knowledged guys here

[sabasgr68]

Not sure if I will ever get this project done, but it wouldn´t hurt to educate myself a little.

I´ve read about Push/Pull pots for splitting coils on HBs.

Questions:

1) Agile ALs use short or long size shafts pots?

1.1) CTS, Bourns, or generic ones (Musiclily, for example). Does it really matter?


2) I´ve read about the A pots and B pots. In plain and simple english, why would I want to use A or B, and what for (volume or tone)? I´ve read technical articles, but I guess I still don´t see it clearly; again, simple english... (but I have this in my notes: "A" pot for Volume (natural ear response). Push/Pull volume pot A500K).



3) 250K or 500K pots? If I´m not wrong, 250K are generally used for single coils PUs, and 500K for HBs. If I have the option of full HB and single coil, which one should I use: 250K or 500K?


4) Hoping I´m not asking silly questions...


Thanks!

[Gear_Junky]

I'm not a tech guy, I am just confirming: no, they are not silly questions. But I am someone who managed to do this in an LP type guitar on my own, so it's within your ability. However: I am here to tell you that if you have serious appreciation for single coil pickups (strats, telecasters, P90's, etc.), you will not be satisfied with any split coiling, IMHO.

[sabasgr68]

I'm not a tech guy, I am just confirming: no, they are not silly questions. But I am someone who managed to do this in an LP type guitar on my own, so it's within your ability. However: I am here to tell you that if you have serious appreciation for single coil pickups (strats, telecasters, P90's, etc.), you will not be satisfied with any split coiling, IMHO.

Thanks!

To be honest, no, I actually prefer HBs, but sometimes I´d like to be able to get a thinner sound; doesn´t have to be exactly like a strat or tele single coil sound, just simply less fatter than HBs, that´s why I like this coil split option on HB equipped guitars, and that´s why I´d eventually like to do it on my AL3000.

Thanks again for your input, I appreciate it!

[nomadh]

Split coils are more a checkoff list cool concept that anything typically used much. But they have a tone. Typically its 250 for sc and 500 for hb but I think there was some experimenting being done with 330k pots that may have been a good compromise? Also if you want the trickiest of trick pots try the push/push pots. Its a push to go in and another push to pop back out. No need to think about it. Someone just posted a great video on audio vs linear taper pots here in agf. So that answer is it depends on your use.

[Gear_Junky]

Thinner sound is exactly what you'll get and if you wire them to put them out of phase (with another switch), you'll have an even thinner "funky" sound. That's what I did on my guitar (boggles my mind that I managed!) - it can be a nice funky rhythm that doesn't drown everything out.

[Gear_Junky]

I recall that I used Seymour Duncan's diagrams (which are easier than proper schematics and they work, it doesn't have to be a Duncan pickup). It's a fun project until you have plans for all your guitars and all of them are "waiting" and you can't just pick one up and enjoy playing it. All this stuff has the potential to get in the way of actually acquiring musicianship

[sabasgr68]

Split coils are more a checkoff list cool concept that anything typically used much. But they have a tone. Typically its 250 for sc and 500 for hb but I think there was some experimenting being done with 330k pots that may have been a good compromise? Also if you want the trickiest of trick pots try the push/push pots. Its a push to go in and another push to pop back out. No need to think about it. Someone just posted a great video on audio vs linear taper pots here in agf. So that answer is it depends on your use.

That push/push pot sounds like a better option. Will try to remember about it.

Someone just posted a great video on audio vs linear taper pots here in agf. So that answer is it depends on your use.

You mean here in AGF before doomsday, or after? Well, I´ll try to find if it was here in the new home

[sabasgr68]

Thinner sound is exactly what you'll get and if you wire them to put them out of phase (with another switch), you'll have an even thinner "funky" sound. That's what I did on my guitar (boggles my mind that I managed!) - it can be a nice funky rhythm that doesn't drown everything out.

Haha... Replacing pots would be enough of a challenge to me should time for it comes. Adding another switch would be dangerous territory!

But yeah, that´s what I´m after, just a thinner sound.

[sabasgr68]

I recall that I used Seymour Duncan's diagrams (which are easier than proper schematics and they work, it doesn't have to be a Duncan pickup). It's a fun project until you have plans for all your guitars and all of them are "waiting" and you can't just pick one up and enjoy playing it. All this stuff has the potential to get in the way of actually acquiring musicianship

LOL In my case, having just that one guitar, should not be a problem. It gets playtime indeed, and gives me joy - it´s the part of aquiring musicianship that seems to evade me!

Now seriously, you´re right. Sometimes we let all of our projects to keep us from actually have the joy of playing.

[golem]

I'm not really knowledgeable, I'm lucky that I can go to [mention]andrewsrea[/mention] for help. Having tried Bourns and CTS you wouldn't notice the difference in tone but the feel of the pot as it turns. One turns more quickly and one is faster. I don't think anyone says the other brands are worse per se, but the famous brands are supposed to have tighter tolerances so that you're not getting a pot that actually measures hugely out of spec.

I'd suggest 500K pots. Perhaps Rob might be kind enough to explain how one can wire a resistor for the split so that it's like PRS DGT style wiring. I still don't fully get it, but I understand that it's less noisy and a bit fuller sounding. Anyhow, hopefully Rob will chime in giving a proper explanation to what I've poorly explained.

edit: meant to say 500K pots not 250K.

[nomadh]

Heres a real rabbit hole. Gibson came up with the fat tap . Something sort of a coil split but with a cap to ground so you sort of keep the hum bucking. Some people thought it was a great compromise and loved the no hum sc tone. Others thought it sucked or did nothing. Work was the cap tolerance was very specific and gibson cheaped out so the effect of the circuit was anything from great to meh to bad to nothing. I wonder if anyone here has played with it?
https://www.mylespaul.com/threads/les-p ... on.299899/

[nomadh]

Another review of the fat tap

I have seen a bunch of videos etc and all of the reviews/demos mention the split coil or what Gibby is calling "Fat Tap" sound as not having a big volume drop off as compared to the regular humbucker sound.

Anyone who has played a Trad Pro can understand how the volume on the split sound really drops off a ton and is thin and small sounding.

So, Gibson came up with a new idea. It's actually a great idea IMO.

Here's what they did if you're interested:

They did not split the coils at all, in the sense that one is not "turned off" like a traditional coil split.

What they did instead was take the hot and cold to one coil and instead of shunting it to ground, they send it though a .01 uf cap.

This does 2 things. First, it almost kills the one coil....it really takes the tone way down and it doesn't cut through much at all....leaving you with a really low volume bassy coil and the other coil in it's full presence. Second, since it doesn't kill the coil, you still retain almost all of the hum cancelling you would have had normally.

So, while it's not fully a split coil sound....you predominantly hear one of the coils so it's similar. Also, not having the volume drop off is a huge thing. It's sort of like a P90ish sound because it has some balls to it....although it's a good bit darker.

I feel like it was a great move by Gibson and it really adds a lot of flexibility to the 2012 line of Les Pauls that have it.

I'm sure a lot of you already know what they did, but I didn't see any threads on it so I thought I'd mention it.

You can see the "Fat Tap" cap for the bridge pickup in this pic. It's white and it's sort of standing on end by the top lug if the bridge volume pot.




I was able to confirm that no actual splitting is happening by just hooking up a multimeter to a cable plugged into the guitar and pulling out the volume push pull. No drop in DC resistance at all.

All told......well done Gibson!

[andrewsrea]

Hey, [mention]sabasgr68[/mention] !

I've done a few AL's with push pull. I've used short shafts. Others can jump in, but unless your model is one of the rare 3/4" maple top (AL-4000s?), your maple top is around 4mm to which a short-shaft can do. That said and you are risk adverse, a long shaft will always fit an AL. You'll just have to use two nuts (using one as a back-stop) to create the right distance on top, so your knobs don't look like they are sitting too high.

I suggest using A500K and I've used Bourns, because they have a nice taper, are affordable (Amazon) and you won't have to change the knobs. CTS are fine-knurl knobs (a.k.a. USA) and most Asian pots / knobs are coarse-knurl. If you go CTS, you'll have to buy new knobs.

Many humbuckers sound thin when split. The PRS DGT that [mention]golem[/mention] mentioned, IMHO really helps create a musical compromise. Here is a good image of how to wire it: https://www.google.com/imgres?imgurl=ht ... egUIARCAAg.

I'll have to try the Gibson Fat-tap that [mention]nomadh[/mention] suggested. It looks like instead of cutting one coil entirely to ground, they created a high-pass filter to ground. Which doesn't make sense to me. Theoretically, it is a high-pass filter sending all frequencies > 15mHz to ground, which means only those frequencies well passed the audible range, become 'single coils.' Everything below remains a humbucker.

[nomadh]

Hey, @sabasgr68 !

I've done a few AL's with push pull. I've used short shafts. Others can jump in, but unless your model is one of the rare 3/4" maple top (AL-4000s?), your maple top is around 4mm to which a short-shaft can do. That said and you are risk adverse, a long shaft will always fit an AL. You'll just have to use two nuts (using one as a back-stop) to create the right distance on top, so your knobs don't look like they are sitting too high.

I suggest using A500K and I've used Bourns, because they have a nice taper, are affordable (Amazon) and you won't have to change the knobs. CTS are fine-knurl knobs (a.k.a. USA) and most Asian pots / knobs are coarse-knurl. If you go CTS, you'll have to buy new knobs.

Many humbuckers sound thin when split. The PRS DGT that @golem mentioned, IMHO really helps create a musical compromise. Here is a good image of how to wire it: https://www.google.com/imgres?imgurl=ht ... egUIARCAAg.

I'll have to try the Gibson Fat-tap that @nomadh suggested. It looks like instead of cutting one coil entirely to ground, they created a high-pass filter to ground. Which doesn't make sense to me. Theoretically, it is a high-pass filter sending all frequencies > 15mHz to ground, which means only those frequencies well passed the audible range, become 'single coils.' Everything below remains a humbucker.

It does sound interesting. Supposed to be very touchy with the cap. I would think the circuit should be designed as an lc circuit so it passed everything except 60hz so it can still cancel hum? Then again just make a "tank circuit"? that cancels 60 hz? My ac theory is getting almost as old as me

[aullucci]

I installed 4 push-pulls on my AL-2K to install the Jimmy Page wiring thing. I was installing a new set of Buddha Pickups, and it would have been fundamentally impossible for an electrical noob like me to wire that thing without serious, sustained assistance from Tim. But honestly, after all the hand holding, even for me it wasn't really that bad, and that guitar now has like 150 different tone settings before you get to the amp. Each pickup splits on the volume control, one tone knob does series/parallel and the other does in/out of phase. I absolutely love that bridge HB just the way it is, so that's the way I usually play that guitar, but it is kinda cool to be able to play with a bridge HB, neck SC, in parallel but out of phase. There's lots of exploration there.

I honestly don't remember what brand pots I used. I did not have to alter any of my route holes for width. I believe they were all A500K, but I could be mistaken - could be 2 A500K and 2 B500K (I remember trying to figure out which to use and getting kinda confused as well; whatever Tim said I needed is what I got). They were long shaft, and [mention]andrewsrea[/mention] is right - the knobs are now about 3/8" too high off the top (I didn't think of the extra washer underneath trick - I might try that out). But it is only visible if you are holding the guitar and looking down while playing it - from the front it looks normal. Plus, with the knobs pre-raised, I find it actually easier to pull the pot than if it was flush with the top.

I tend to agree with others that the sound of a split humbucker and the sound of a true single coil are not the same. Not bad by any means, but different - you would probably not mistake my split bridge HB for a real Strat bridge pup. I like the option of splitting the humbuckers mostly for distortion purposed - if you leave the settings on your Rat or fuzz pedal the same, but switch from a neck single coil (maybe with the volume rolled off a little) to a full on bridge humbucker, you can go from singing to shrieking pretty easily...

[sabasgr68]

Hey, @sabasgr68 !

I've done a few AL's with push pull. I've used short shafts. Others can jump in, but unless your model is one of the rare 3/4" maple top (AL-4000s?), your maple top is around 4mm to which a short-shaft can do. That said and you are risk adverse, a long shaft will always fit an AL. You'll just have to use two nuts (using one as a back-stop) to create the right distance on top, so your knobs don't look like they are sitting too high.

I suggest using A500K and I've used Bourns, because they have a nice taper, are affordable (Amazon) and you won't have to change the knobs. CTS are fine-knurl knobs (a.k.a. USA) and most Asian pots / knobs are coarse-knurl. If you go CTS, you'll have to buy new knobs.

Many humbuckers sound thin when split. The PRS DGT that @golem mentioned, IMHO really helps create a musical compromise. Here is a good image of how to wire it: https://www.google.com/imgres?imgurl=ht ... egUIARCAAg.

I'll have to try the Gibson Fat-tap that @nomadh suggested. It looks like instead of cutting one coil entirely to ground, they created a high-pass filter to ground. Which doesn't make sense to me. Theoretically, it is a high-pass filter sending all frequencies > 15mHz to ground, which means only those frequencies well passed the audible range, become 'single coils.' Everything below remains a humbucker.

Thanks so much, Rob!

It´s an AL3000, no maple cap.

Gold info here. Whenever I can get to do this, the goal is to spend the less possible, so Bourns might cost a little more than generic ones, but if I don´t have to change knobs, I guess i´s better in the end. Good to know also that long or short shafts are not definitve issues.

Regarding your commentary on the Gibson Fat-tap, it´s like chinese or russian to me haha.

Thanks again!

[sabasgr68]

I installed 4 push-pulls on my AL-2K to install the Jimmy Page wiring thing. I was installing a new set of Buddha Pickups, and it would have been fundamentally impossible for an electrical noob like me to wire that thing without serious, sustained assistance from Tim. But honestly, after all the hand holding, even for me it wasn't really that bad, and that guitar now has like 150 different tone settings before you get to the amp. Each pickup splits on the volume control, one tone knob does series/parallel and the other does in/out of phase. I absolutely love that bridge HB just the way it is, so that's the way I usually play that guitar, but it is kinda cool to be able to play with a bridge HB, neck SC, in parallel but out of phase. There's lots of exploration there.

I honestly don't remember what brand pots I used. I did not have to alter any of my route holes for width. I believe they were all A500K, but I could be mistaken - could be 2 A500K and 2 B500K (I remember trying to figure out which to use and getting kinda confused as well; whatever Tim said I needed is what I got). They were long shaft, and @andrewsrea is right - the knobs are now about 3/8" too high off the top (I didn't think of the extra washer underneath trick - I might try that out). But it is only visible if you are holding the guitar and looking down while playing it - from the front it looks normal. Plus, with the knobs pre-raised, I find it actually easier to pull the pot than if it was flush with the top.

I tend to agree with others that the sound of a split humbucker and the sound of a true single coil are not the same. Not bad by any means, but different - you would probably not mistake my split bridge HB for a real Strat bridge pup. I like the option of splitting the humbuckers mostly for distortion purposed - if you leave the settings on your Rat or fuzz pedal the same, but switch from a neck single coil (maybe with the volume rolled off a little) to a full on bridge humbucker, you can go from singing to shrieking pretty easily...

Thanks! You went the full way. Almost a one-guitar-do-it-all kind of type. I´ll be happy if I can just get mine to do the spliting thing

[aullucci]

I installed 4 push-pulls on my AL-2K to install the Jimmy Page wiring thing. I was installing a new set of Buddha Pickups, and it would have been fundamentally impossible for an electrical noob like me to wire that thing without serious, sustained assistance from Tim. But honestly, after all the hand holding, even for me it wasn't really that bad, and that guitar now has like 150 different tone settings before you get to the amp. Each pickup splits on the volume control, one tone knob does series/parallel and the other does in/out of phase. I absolutely love that bridge HB just the way it is, so that's the way I usually play that guitar, but it is kinda cool to be able to play with a bridge HB, neck SC, in parallel but out of phase. There's lots of exploration there.

I honestly don't remember what brand pots I used. I did not have to alter any of my route holes for width. I believe they were all A500K, but I could be mistaken - could be 2 A500K and 2 B500K (I remember trying to figure out which to use and getting kinda confused as well; whatever Tim said I needed is what I got). They were long shaft, and @andrewsrea is right - the knobs are now about 3/8" too high off the top (I didn't think of the extra washer underneath trick - I might try that out). But it is only visible if you are holding the guitar and looking down while playing it - from the front it looks normal. Plus, with the knobs pre-raised, I find it actually easier to pull the pot than if it was flush with the top.

I tend to agree with others that the sound of a split humbucker and the sound of a true single coil are not the same. Not bad by any means, but different - you would probably not mistake my split bridge HB for a real Strat bridge pup. I like the option of splitting the humbuckers mostly for distortion purposed - if you leave the settings on your Rat or fuzz pedal the same, but switch from a neck single coil (maybe with the volume rolled off a little) to a full on bridge humbucker, you can go from singing to shrieking pretty easily...

Thanks! You went the full way. Almost a one-guitar-do-it-all kind of type. I´ll be happy if I can just get mine to do the spliting thing

That's funny, because I did intend it to be a one guitar does it all thing. And now 90% of the time I play it, it's through the bridge bucker. It just sounds so good. The phase thing is fun, too. Good luck!

[sabasgr68]

Not sure if I will ever get this project done, but it wouldn´t hurt to educate myself a little.

I´ve read about Push/Pull pots for splitting coils on HBs.

Questions:

1) Agile ALs use short or long size shafts pots?

1.1) CTS, Bourns, or generic ones (Musiclily, for example). Does it really matter?


2) I´ve read about the A pots and B pots. In plain and simple english, why would I want to use A or B, and what for (volume or tone)? I´ve read technical articles, but I guess I still don´t see it clearly; again, simple english... (but I have this in my notes: "A" pot for Volume (natural ear response). Push/Pull volume pot A500K).



3) 250K or 500K pots? If I´m not wrong, 250K are generally used for single coils PUs, and 500K for HBs. If I have the option of full HB and single coil, which one should I use: 250K or 500K?


4) Hoping I´m not asking silly questions...


Thanks!

Ok. According to your comments and some other things I´ve read, this is what I´ve came to:


1) Agile ALs use short or long size shafts pots?

Short size, but long shafts can be adjusted to fit well.


1.1) CTS, Bourns, or generic ones (Musiclily, for example). Does it really matter?

If you don´t want to change knobs, yes. Bourns are the recommended ones.



2) I´ve read about the A pots and B pots. In plain and simple english, why would I want to use A or B, and what for (volume or tone)?

Regarding this, it seems it will depend on how I like how each one works. Most people recommend "A" for volume and "B" for tone. Some others say "A" for both. Others say that most imports come with "B" for volume and "A" for tone. My AL has them that way: "B" for volume, "A" for tone.
There seems to be no right or wong way here, just what works best for you. Below are some of the comments I´ve found:

* you should use A's for both. B's are essentially on/off pots. For some reason though, most imports use b's for volume and a's for tone.


* I personally like audios for both volume and tone, although my Edwards came with audio A500K for the volumes and linear B500k for the tones.

* My Agile and my Epiphones have Linear (b) pots for volume, and Audio (A) pots for tone...

* Most manufacturers use either (2) audio taper pots for volume + tone or would use audio taper for volume, and linear taper for tone.

* the B (linear) will work smoothly as a volume, and the A (audio) will work smoothly as a tone. swap them and they'll both still work, and will sound the same on "10" or on "0", but they will abruptly change volume when you turn them, making it harder to dial in exactly what you want.


From a guitar site:

For our ears to perceive a halving of volume with the control at the midway point, the pot actually needs to be logarithmic. So, log pots are generally preferred for volume because signal level ramps up, and down more smoothly that it does with linear pots.

...The same can be said for tone pots, but things are less clear cut. Some prefer a smoother response, while others want a more dramatic wah-type effect. If you want the former, go linear and if you want the latter, go log.

From another guitar site:

Traditionally, audio taper pots have been used in volume control positions and linear taper pots have been used in tone control settings. We don’t pretend to understand the physiological reasoning for this but, apparently, the way we humans hear makes the use of audio taper in volume positions better.


An AUDIO taper pot increases the signal from your guitar to your amp in a logarithmic (exponential) fashion. Simply explained, “1”, “2”, or “3” on the volume knob will produce little, if any, signal but once you get past “3” or so, the volume will ramp up a LOT. Past “8” or so there will be very little volume increase.

A LINEAR taper pot increases the signal in a linear fashion. (“1” on your control is equal to 10%, “4” is equal to 40% and so forth) This works very different from an audio taper volume pot. For those looking for a smooth, predictable transition to volume, a linear taper pot will probably work best for you.

We would encourage you to experiment with linear taper and audio taper pots. There is no right or wrong. Only what you, the player, like. Some players would like audio taper pots on volume positions and some players will like linear taper pots on volume positions.



3) 250K or 500K pots?

Generally speaking, 250 for SC, 500 for HB.



I think I got it more clear now, whenever it is I may do this.

[Buddha Pickups]

My experience is the exact opposite of this ^
Linear has always sounded to me like its an on/off pot.
Audio is a gradual increase/decrease.
Unless my ears have changed cause I haven't used a linear pot since I first started tinkering 20 years ago.

[Gear_Junky]

My experience is the exact opposite of this ^
Linear has always sounded to me like its an on/off pot.
Audio is a gradual increase/decrease.
Unless my ears have changed cause I haven't used a linear pot since I first started tinkering 20 years ago.

I agree with this. From what I understand, our hearing (perception) is logarithmic in relation to power. Which is why decibels are logarithmic and so volume pots need to be "audio taper" (logarithmic).

[Gear_Junky]

One more thought... back in the 90's was the one and only time when I (as a "yute") purchased an auto stereo (it was a cassette player, had a remote) and paid to install it in my old beat up Taurus (which only had a radio). And that stereo had a button... I don't recall what it was called, but it was meant for when you're listening at a low volume - the manual explained how we don't perceive the trebles at lower volume and the button adjusted for that. It was noticeable. This was always in the back of my mind and I have a feeling that this somehow relates to those "treble bleed" mods

(yes, CD's existed but most of my music at the time was still on tapes and CD's back then were very easy to copy onto a tape, most home music systems were capable of that. I still feel that those tapes sounded better than CD's and especially mp3. I miss the hiss.).

[sabasgr68]

My experience is the exact opposite of this ^
Linear has always sounded to me like its an on/off pot.
Audio is a gradual increase/decrease.
Unless my ears have changed cause I haven't used a linear pot since I first started tinkering 20 years ago.

Well, the more I search for information to clear my mind, the more confused I get. To be honest, I would not know if I am pleased with the pots arrangement in my AL. Would need to try other guitars with different pots to "see" the difference and decide what I like best. But that´s nearly impossible.

Thanks all the same, this is what I wanna hear from you.

[sabasgr68]

My experience is the exact opposite of this ^
Linear has always sounded to me like its an on/off pot.
Audio is a gradual increase/decrease.
Unless my ears have changed cause I haven't used a linear pot since I first started tinkering 20 years ago.

I agree with this. From what I understand, our hearing (perception) is logarithmic in relation to power. Which is why decibels are logarithmic and so volume pots need to be "audio taper" (logarithmic).

Yes, that´s what a guitar site mentioned: "Traditionally, audio taper pots have been used in volume control positions...".

Why my AL has "B" volume pots and "A" for tone, I don´t know. O maybe the former owner changed them? I don´t know.

[tobijohn]

The only thing I can add to what's already been stated (and I might have missed it) is that if you're going with SAE pots such as CTS and Bourn, the shafts are thicker and you'll have to bore out the holes in the body a bit. Not much, there's a specific tool for it but a pencil wrapped with sandpaper works just as well albeit a bit more slowly.

Also, when a humbucker is split, you're going to get a noticeable volume drop-off. If you want to avoid this and you're not intent on using a budget set of humbuckers then have Tim [mention]Buddha Pickups[/mention] make you a set with an uneven wind and booster magnet on the split coil. He's done that for both [mention]Mossman[/mention] and myself...