Two-Band “PTB” Tone Control:
Useful, Easy, Cheap & AWESOME!

The PTB Circuit was one of many G&L innovations.

After the frantic soldering fest that was The Pagey Project, I figured it might be time for a nice, simple DIY wiring project. At the suggestion of tonefiend reader JH, I played with variations on the 2-band tone control that appeared in some G&L guitars. And I am over the moon with the results!

This circuit, sometimes called “PTB” (for “passive treble and bass”) combines a standard treble-bleed tone knob with a bass-cut control. The latter has a huge effect on the way distortion pedals and amps respond to the pickups, especially with humbuckers. Cutting some bass makes the pickups sound cleaner, airier, and more dynamic (i.e., less compressed). To my ear, the bass pot is not so much a tone control as a clarity knob.

Check out this brief demo video:

Savvy stompboox builders emphasize the importance of filtering the guitar signal as it enters the effect. And if you’ve built or modded your own fuzz/overdrive effects, you’ve probably discovered how the importance of the input cap’s value. This cap filters out lows. Too large a value, and the tone gets flabby/sloppy. Too small, and it gets thin/shrill.

This tone circuit lets you make similar adjustments from the guitar. And as you can hear in the demo, there’s more to it than just nixing lows. With fewer lows bombarding downstream amps and effects, the signal becomes brighter, cleaner, and livelier. At times you’d swear you were adding highs rather than just removing lows.

This arrangement works great it three-knob guitars, provided you can live with global volume and tone controls for both pickups. Alternately, you could modify it for a four-knob Les Paul so that there are two volume pots and global bass and treble controls.

Here’s the original schematic provided by JH:

I actually prefer how it sounds with three 500K pots — the pots you probably already have in your humbucker guitar. In other words, you can probably mod this circuit without buying anything extra, except maybe some wire and solder.

Here’s a (literally) sketchy wiring diagram I drew up:

Please do like i didn’t the first time I tried this, and note that the bass control capacitor is a .0022uF, not a .022uF like the treble cap. If you’d like a little more treble cut in the fully counterclockwise tone-knob position, try substituting a .033uF or a .047uF for the .022uF.

This circuit also works great paired with single-coil pickups, the way Leo intended. But it seems even more relevant for humbuckers, since low-frequency control is so much more an issue than with brighter single-coils, like classic Fenders or G&L’s signature MFD ceramic-magnet pickups.

This one stays in the guitar! :thumbup:

87 comments to Two-Band “PTB” Tone Control:
Useful, Easy, Cheap & AWESOME!

  • Derick

    I’m totally gonna try this. I have a Hamer Sunburst with a Kent Armstrong High Output in the bridge and a Seymour Duncan SH-5 in the neck. I’ve been able to tame it quite a bit with pole adjustments and pickup height but am still not satisfied. I bet this wiring will help me balance it out! I’ve already re-wired it for 1 volume and 2 tones so this modification should be a snap. 

  • joe

    I think you’ll love it. It’s so simple, but so effective for humbuckers. I can’t believe more people haven’t done this. I can’t believe I’d never even heard of it till JH mentioned it, even though I’m a G&L fan (though I’ve never owned one with the PTB circuit).

    • HI..

      LATE AS HELL AS USUAL..I ATTACHED A PAGE OF ACTUAL G&L SCHEMATICS..ANY ?? EMAIL ME.
      I SEARCHED FOR THE G&L ‘SECRET ‘ DIAGRAMS. GENIUS..BUT WHAT ELSE WOULD I EXPECT FROM A MAN THAT SCREWED 2 PIECES TOGETHER AND CHANGED THE WORLD!!!
      I ALSO DID A DOUBLR TAKE AT THE CAP VALUES…

      I THOUGHT’ MAN, A STRAT(OR) WITH THE TONE CONTROLS OF A STEREO SYSTEM (AM I SHOWING MY AGE )….PUT IT TOGETHER..WONDERFUL..ALL THE BS. I EAD ALL OVER THE NET..
      I AM JUST ABOUT TO WIRE UP MY ‘JAZZ TELE’ BUILD. I HAD 3 HOLES IN THE TOP (HAMER LOOK ) 2 VOL..1 T. OR 2 T..AND 1 VOL.?

      DID NOT REALLY LIKE EITHER…
      I STUMBLED INTO YOUR PLACE….
      S WILL WORK FINE ON A 2 HB GUITAR…….THANKS, ARNIE

  • Bass roll-offs are great for guitar. I’m mainly a bassist, and I see where a lot of guitarist use too much low end. It muddies up the overall tone, and sometimes a thinner guitar sound is better.

     Incidentally, whereas I think G&L was the first company to use this on production guitars, it’s not unique to them. Carvin included pretty much the same circuit in their instruction sheets back in the early 70s. 

    • joe

      Yeah, you’re totally right about guitarists and excessive bass. Sure, it’s gratifying to feel those lows when you’re standing next to the cabinet, but nixing some of them often makes the guitar sound a lot better. Not to mention the bass!

  • Chiller

    So for us n00bs, how would we adapt this for the Les Paul 4-knob setup?  I have an Epi Sheraton that I hardly ever use the tone knobs on, and this mod sounds like a great fit for this guitar.

    • joe

      Hey Chiller! I don’t have time to draw up the wiring diagram this week, though I will soon if no else steps up to the plate first. (Hint, hint.) The tone control part would be exactly the same — the main difference is you’d run the pickups through the volume controls before the pickup selector, and then route the single wire from the selector through the tone controls as seen here.

  • Sam Geese

    Doesn’t the ‘bass’ pot need to be grounded as well?

  • Morti

    Reverend Guitars do a Bass Contour Control in most of their guitars, I wonder how close it is to this.
    If you’re up for another adventure, there’s always the Fender TBX tone control, which uses a dual pot:
    http://terrydownsmusic.com/Archive/baritone/baritone_wiring_diagram.pdf
    http://www.premierguitar.com/Magazine/Issue/2010/Nov/The_Fender_TBX_Tone_Control_Mod_Part_2.aspx

  • Laertes

    I may be asking something stupid and showing my ignorance, but cutting bass can not be done with the EQ? What is the difference between the EQ and this circuit besides one being on the guitar and the other in the amp and thus affecting the stompboxes or not?

  • JH

      No it does not get connected to ground Sam. All this really does blend the signal dry and wet
    I tried it yesterday with a LP special copy with p-90s. However I wired it outside of the guitar. I set up 2 jack,s wired the pot in between and used a .0033 cap. I was just wondering what it would sound like. It was ok, definitely usable. I just want to experiment with different values of caps. Im also using a 1meg pot. When I get the time Im going to try out .0022, .0047, and .0068. I have this setup in my strat and love it (1 meg, and .0033). I never thought of trying it in a different guitar.
     
    Here is a pic so you could understand how I wired it outside the guitar. 
     

  • That sounds incredible. The bass roll off sounds so musical. I’d type more glowing phrases but I have to run to the electronics store t…see ya. 

    • joe

      Let us know how it goes! :)

      • Whew, you wouldn’t believe the line up.
        Ok, I got the bits, got soldering and it don’t work.
        Here’s the diagram. It’s a Burns Marquee that has a push pull to switch on the neck pup to get neck and bridge sounds. With that switch on, it works; otherwise, absolutely nothing. Dead. Do you have any idea what I’ve done?
        In the drawing, the pink lines are what I changed from the stock wiring, shown in other colours.

        https://www.dropbox.com/s/3g2374kwzo52j3m/Guitar%20%28page%2015%29.png

        • I figured it out….I had too many wires going from the output side of the switch. They were the ones doing the typical one tone per pickup thing.

          And the result?

          I loved how my strat (ok, Burns Marquee) sounded, which means it had to be fixed (not being broken….naturally). This circuit sounds simply amazing. I was planning on putting a humbucker in the bridge because I wanted a bit more guts at times, but not now.
          If I dial in a beefy gain sound on my amp, and turn up the bass cut, I get a lovely chimey strat tones. Lovely. Just what I usually play with. But wait – I then turn down the bass cut and WOW, it’s like I’m getting more gain, more…MORE! Great for gain swells. It’s like having a gain control on my guitar without changing the volume. So rather than using a preamp to get more gain, I set the amp to that tone, and turn it down with the guitar, giving me loads of headroom.
          I’m so excited. I just can’t hide it!

          • joe

            Oh, I’m so glad it worked out. :)

            You know, I did TONS of alternate wiring experiments last year when I was working with Seymour Duncan. And out of all of them, this is the one that is so amazingly great, I can’t believe more people don’t use it. It’s unbelievably expressive with humbuckers — there’s so much you can do to shape distortion just by dialing out some lows from the guitar. So I’m gratified to hear that it works well on a single-coil guitar! I haven’t tried that yet, but now, I definitely will — maybe on that parts strat I use in the MIDI guitar videos. (And thanks for an idea for a future post!)

  • Jeff

    Just had a thought, I typically run two humbuckers with the tone full on.  Could I substitute the exiting tone pot and for that bass circuit above which should allow me to roll off some low end?

    • joe

      Yeah, that would totally work if you don’t need a treble cut. Though I’d try nudging the capacitor value up and down a bit till you find your perfect sweet spot.

  • Eric

    Another very awesome post, sir.

    A friend of mine that builds guitars posted a while back about a similar knob for metal players and guys who use extended range instruments(7 and 8 strings and more). It’s a really useful mod and I’m with you I’m not sure why more builders don’t use it. 

    • joe

      Yeah, I can see how it would extremely relevant for metal. Cutting bass doesn’t necessarily mean no low-end impact — it can help focus the lows. It’s my understanding that some metal pickups designed for low-tuned chunking (like the Seymour Duncan Mick Thomson) actually actually do something similar — namely, filter out some of the lowest lows so the low end has more definition overall.

  • Groat post, I have to give this a try.  My neck pickup sounds good clean. But when I turn on the fuzz distortion the neck pick up is no fun any more, too muddy. Seems the bass treble control provides a wider range of options than a treble  roll off for  each pick up.  

  • Peter

    hmmm, so I’m guessing that on a two knob guitar I could use a stacked concentric pot (two knobs in the space of one) and have vol, treb cut, and bass cut.

  • Bear

    Dangit, Joe.  Even with concentrics, I’m gonna need more knobs.

  • Matthew Seniff

    I have a buddy who had a 60′s noname japanese guitar that has the bass and treble controls. I did a bit of circuit sleuthing to figure it out as it didn’t work correctly when he got it. The guitar also had seperate volumes for each of the 3 pickups plus a master volume. I’ve never seen another guitar like it very ugly with a big fat neck and chrome pickguard. It would have won the ugly guitar contest hands down. It even had spiral sound holes in the hollow body. Unfortunately it was burned up in a house fire 20 years ago. 

  • Matthew Seniff

    BTW the reason  it reduces the distortion and compression when you roll off the bass is because most of the energy of sound is in the bass frequencies. This is why we use sub woofers in hifis and PAs once you remove the lows to the subs  you need less power to produce clean mids and highs. 
    For the record tho’ I like to hit my fuzz with all the lows then roll the lows off a bit afterwards with a tight EQ or even a parametric EQ. It gives me a more garbled fuzziness that I dig on single notes and 2note chords with slide (but as an excuse I grew up with psychedelic music of the 60′s and blacklight posters on my walls) :-)

  • Jon

    Funny thing i stumbled across this while looking for how to wire a PTB a day after its posted. i put it in my 2 Pu “jagcaster.” it sounds amazing, i used a 1m volume pot and two 500k for the tones a .01uf on the tone and a .001 on the bass cut, it worked great with my seymorduncan tweakfuzz.
    I think one of the secrets to good single coil tone from fuzz is bass reduction, the ptb bass cut reminds me alot of the highpass filter on a jaguar, which has roughly the same effect on fuzz and distortion. which was what drew me to that for my attempt at a jaguar strat fusion.
    i drew a schematic up in visio if anyone wants it.

  • jeremy

    I’m late to the party, but keen to try this but the guitar in question only has a single volume and tone control. I know there’s the dual-concentric option, but was wondering if maybe a push-pull pot could switch the tone control between bass and treble.
    I know that would miss out on the possibilities of using both at same time, but on the other hand I’ve already got some push-pull pots to hand and I’m cheap. :)
    if indeed it’s possible, could someone maybe draw out an easy-to-follow schematic?
    thanks – I only just found these pages a couple of days ago, but I’ve hardly been anywhere else online since!

    • joe

      I don’t think that would work, or at least, it would only work part way. Yes, you could use the switch portion to select between two destination for the pot, but once you switched it, it would be removed from its former role in the circuit, so you couldn’t have, say, a bit of treble cut and a bit of bass cut — and that’s one of the most fun options in this circuit. But if you’re cool with that limitation, it should work. It may help to check out my “How to Install Onboard Effects” tutorial, which includes a rundown of push/pull wiring.

  • jeremy

    thanks for your reply, Joe. my thinking is that even a limited version is still better than just leaving it as-is. I’ll read up on push-pull wiring and hopefully give it a go soon.

  • Deyo

    Hi, can anybody help me please??!!
    I have an Ibanez hollow body and my neck humbucker is way too bassy, could you please tell me where to insert a capacitor and what are my choices as far as the capacitance value vs. bass reduction. Here’s the schematics I dug out online. Also, what are some good quality capacitors I can buy?
    http://www.guitarnucleus.com/gitschems/ibanezAF120.jpg
    Any help is greatly appreciated,
    Deyo

  • Sebastian Enriquez

    This is awesome! I’m a noobs in these things. So, if I want to do that in a Strat with 3 single coils, should I use the same pot rate? or use it with 250k, 500k, 500k?

    • joe

      Hi Sebastian! I’m glad you find the info useful. :)

      Well, with a three-knob Strat, you’ll have to reconfigure the wiring so that all three pickups are routed through the same volume and tone controls.

      I haven’t yet tried this circuit in a Strat, though your email makes me want to do so! My suggestion would be to use the same pot values as in the diagram above and see how it sounds!

      • Sebastian Enriquez

        Well Joe, I have a Diagram and I can share it with you (:

        But it is a little bit “tangled” haha, I’m trying it Today, so if I finish. I tell you if it works

        The diagram includes:

        DPDT swith for Expand mode, As the comanche guitar from G&L
        SPDT swith for diode clipping (Idea taken from one of your posts)
        Pots: 250k 500k 500k (I’ll see how it works)
        A different kind of 5-way toggle switch that I took from another guitar that uses another kind of wiring.
        And possibly I’ll add a Volume kit, to prevent the tone loose when you decrease de volume.

        Hope you get interested (:

      • I just did it in my Squier Double Fat Strat, and I love it. It’s a simple HH guitar, but I’m a metal guy and the ability to clean up the lows is awesome! It brought “fatty” some new life after 14 years of ownership!

        I am trying to do the same to an epiphone G-310, and I’m reading through the comments to see if a diagram has been given for what to put where after the volume pots run into the selector switch (I’m still pretty much a noob at this, and am relying on diagrams hardcore). I’ll keep looking, but if one has been posted I’d love to see it.

  • joe

    That sounds so cool — let us know how it goes!

    ¡Buena suerte! :)

  • Sebastian Enriquez

    Mr.Joe, I need help D:

    I did this scheme:

    http://imageshack.us/a/img59/1196/ptbwiringscheme.jpg

    But something went wrong and the guitar didn’t sounded :cuss: so I keep searching, viewing pictures and googling collecting information and I made another:

    http://imageshack.us/a/img337/4406/legacywiringscheme.jpg

    I haven’t tried it, because I need a new 5-way toggle switch because I think that the other switch is not working :what: and before starting, Can you give me an advice? :)

    Thanks in advance

  • Shaggy

    So I tried this out with a dual concentric pot. 500k/500k but couldn’t get it to work. I guess my confusion is on the bass control with the cap on the two outside lugs. The wire on your pictures’ right is it jumped to the center lug or is that line just dark. Anyway I tried both ways and couldn’t get it. I want to see if this has a different effect than the “Modified TBX Tone Control” I tried. Withe the 1meg and 250k in the TBX my guitar got wayyy too bright (ice picks).

  • Geoff

    Hey,

    Cool idea!

    I tried it in my les paul, and I think am having an issue…

    The bass knob will roll off bass and maaaybe some other frequencies… not sure… but it does it when the capacitor isn’t even installed… and then when I install a capacitor with what I believe to be the recommended rating, I hardly hear a difference in sound to when there was no capacitor…

    I’ve wired it just as is in the diagram I believe.

    Any insight into this would be greatly appreciated!!

    Best,
    Geoff

  • Angelos

    Hey man, allright?

    Did you used wish kind of 500k pot? Log or lin?

    Sorry about my english (it’s not my natural language).

    And thank you just since now.

  • Keith

    It should be noted in the article that the sketch provided will give you an opposite rotation for the bass cut. That means 0 = no effect and 10 = full effect. That’s not desirable at all IMHO, because it is opposite from a standard tone pot’s operation. The way a tone pot on a guitar works is engrained in all of our minds. We are used to 10 being no effect and 0 being the full effect of the control. Having it the opposite way is tricky on the mind, especially if the treble cut pot on the same guitar is wired the standard way.

    Additionally, the jumper between lugs 1 and 2 is unnecessary. All it does is to create an extra solder joint for the technician, without doing the circuit any good. For sake of efficiency, the input to the bass cut pot (and the input side of the cap) should be connected at lug 2, and lug 3 should be left unconnected. (Assuming you DO want the reversed control as illustrated in the diagram.) I can see why the author might have put that jumper in there. Connecting jumpers is sometimes used to create a backup in case of failure of the wiper, so it might have been done out of habit. However, in this particular use for a pot, wiper failure will result in exactly the same result whether or not that jumper is there. With or without the jumper, the entire signal will be routed through the cap, because the pot will effectively be “stuck” at full resistance. In short, the jumper is a backup that doesn’t back anything up, so why bother using it? It’s like carrying a four-lug spare tire when your car takes five-lug wheels.

    In short, sure, this works…but the way G&L wire the bass cut control makes more sense than what is shown here, both from the users P.O.V. and from the designer’s P.O.V.

    Nonetheless, thanks for spreading the word about passive bass cut controls. If people only used this type of tone circuit more often, they’d possibly save thousands on aftermarket crap they don’t need.

    Keith

    • joe

      Hey Keith — thanks for the info!

      Yup, you’re right about pretty much everything. Though I kind of like the way the “reversed” bass pot behaves, or maybe I’ve just gotten used to it. (I still have this wiring in that red Hamer I used in the demo, and it still sounds great to me.) I guess it depends whether you prefer to think of all pots fully clockwise as “maximum signal” or “maximum brightness.”

      Got any favorite cool wiring tips or techniques? You obviously know your stuff!

    • David

      Excuse me Keith but i think you’re wrong about the jumper!
      I mean you invert the lugs numbers, don’t you?

      Regards

  • Preston

    So how exactly do I make this work with two volumes, a master bass cut and master tone control?

    • joe

      Just make sure that the output from both pickups gets routed to the single tone circuit (as opposed to having a separate cap/tone pot for each pickup).

  • Dan

    Hi,I’m building a bar Bass from a Fender delux import J bass and would like to upgrade to hi quality controls with this type of tone control and a push pull volume control that allows me to go series or parallel.Do you have any wiring diagrams,info and opinion on this setup and any detailed recommendations on a bridge pick up or parts would be appreciated? My guitar has a soft maple body,hard maple neck,Hi mass bridge(added)and Seymour Duncan designed pickups. I love the sound of both the Fender J bass and the early Ricks so I’m trying to get sort of a Rick sound in addition to the classic J bass if I can. Hey if this works reasonably well I wouldn’t have to carry 2 expensive guitars around and into places they could be stolen or damaged Thanks Dan

  • I first found out about this circuit back in 1977 when I bought a Carvin APH-4N humbucker to stick in my ’73 Rick 4001 bass. The pickup came with a sheet of paper with wiring diagrams, and the passive bass control was one of them.

    It really is handy to roll off the low end in guitars. You can get all kinds of nice overdrive sounds that way. Too many guitarist use too much low end.. sounds good in the bedroom, but leaves little room for bass and drums. ;)

  • Homesick

    Sounds so great – especially for a Les Paul, with 2 volumes & master bass/treble like Joe suggested. I hope somebody will post a diagram I want to try this with my epiphone Les Paul. THanks!!!!!

  • Homesick

    Hi Joe!! 2 volumes 2 tones converted to 2 volumes & masters bass/treble. is that it? Many thanks.

  • CroftyTTL

    I’m reckoning that this, in a stomp box, would be outstanding, not only as a tone tweaking tool, but for so many other applications (maintaining tone between two different pickup types, say 2 LPs with passives and actives perhaps, or different tunings)

    I think I’m going to have a go knocking this up!

  • Oinkus

    I want to build a varitone stompbox !

  • Rick

    Hi Joe! I modified your drawing for use on a Es 335 (2 volumes, master bass/treble), but I’m not entirely sure if it will work.

    Could you take a look at it?

    Thanks!

    Uploaded with ImageShack.us

    • HELLO..
      AND THANK YOU !!!
      I AM STRUGGLING WITH ADAPTING A SEMI-HOLLOW GUITAR ( 2 VOL/ 2 TONES)… TO THE ‘PTB’ SYSTEM…ANOTHER GENIUS ADDITION TO THE WORLD BY MR. FENDER…

      I AM STUCK WITH THE 2 VOLUMES, AND HOW TO WIRE THE ‘BLENDED’ SYSTEMS TOGETHER.
      I DID SEE YOUR ORIGINAL SCHEMATIC..BUT ONLY 1 VOLUME…
      ALSO-LOOKED AT THE ES-335 SCHEMATIC…RICK WAS ASKING IF THIS WOULD WORK. WILL THIS DESIGN WORK?
      …I HAVE TROLLING THE ‘NET FOR A DIAGRAM..AND ONLY YOUFOLKS HAD THE ANSWER–OF COURSE .
      WHAT CAN YOU TELL ME?
      THANK YOU—THIS IS A GREAT SITE…AND SOME ‘ENLIGHTENED’ MUSICIANS WHO HEAR THE BEAUTY& GENIUS OF THE ‘PTB’ SYSTEM…
      ARNIE

  • Brandon S. Hire

    Being a rewiring, maintenance, and modding noob, I'm recognizing what is what above. But I'm a huge fan of the 0.1uf capacitor on the tone pot (I put one in my Jackson PS-4 with OUTSTANDING results), to help get a hell of a lot of rolloff if needed (I'm thinking of calling it the overkill knob). All I understand at this point is that the higher the cap value, the more treble you roll off. Does it work the other way around (the lower the cap, the more bass you roll off)? I'm unclear on how this mod works, but am EXTREMELY interested in trying it.

  • Joe,
    I LOVE this mod too! I often wonder why it hasn’t become more popular also. I think it can be counter-intuitive and alarming to new users who aren’t use to a bit of apparent volume loss. The mod particularly excels in a band situation where you’ve really got to find a small sonic space to inhabit.

    The one particular struggle I’ve had is finding a taper that felt right for the bass cut pot. As Leo suggests and I’ll confirm, it really needs to be a reverse audio taper IMO. I started with a 1 Meg linear which was incredibly notched feeling, then tried a 1 meg reverse audio which didn’t really fit the guitar and was quite cheap, but the taper felt right. I’ve finally landed at a reverse audio taper, 3 Meg pot, from the amp parts section at Mojotone. It works very well, much like the PTB G&Ls I’ve played.

    If I had it to do over, I would likely just try a “lefty” 500K pot, which are all over the place! I was always worried there wouldn’t be enough blockage of the dry signal that way, but it would appear from your video, there is plenty!

    Thanks for sharing.

    • joe

      Hi Glenn — well, it won’t surprise you to hear that I couldn’t agree more! :)

      There are a LOT of circuits that benefit from reverse taper pots. Especially (hint, hint) distortion pedal gain controls. They’re easy to source these days, but that wasn’t always true. Which explains why we encounter so much gear with lousy feeling tapers.

      Interesting — I don’t think I’ve ever SEEN a pot over 1M. I’m going to have to poke around Mojotone myself…

  • Ok, I’d be extremely greatful if you would please show a diagram of some kind showing how to wire this for an SG or Les Paul. I’ve got two guitars that I want to do this to, and am ready to start screaming. :rant: :cuss: :cuckoo: :shake: :what: :noshake:

    This site has opened my eyes to a lot, by the way, so thank you very much for all your helpful info!

  • Rod

    Hi Joe,

    On the original schematic provided by JH, all 3 pots have a “dot” on one of the terminals, can you explain what this is for as I am not familiar with that notation for a pot?

    Rod

  • I was able to find someone to help me put together a diagram for Les Paul wiring. It’s crude, but from what I understand this should work.

    Any feedback on the accuracy of this would be awesome.

    • SCRATCH THAT DIAGRAM!

      Here is how to wire this on a Les Paul style guitar. After scouring the web for a week, I found someone willing to help me find the answer and he drew this diagram for me. I just installed it in an Epiphone G-310 and it works! (I used a 0.1uf capacitor and a 0.001uf capacitor, but I like extremes).

      The signal flow goes into the pickups first, then to the selector, and out from there into the two tone pots.

      Looking forward to more awesome mods like this. Am contemplating using a cheap bass to add the PTB circuit to (with my extra high and low cap values) on mini toggles, as well as a switchable overdrive and a kill switch. Planning to use it to get synthy tones. Thanks for inspiring me to dig into my guitar and for opening new doors for me! :thumbup:

      • joe

        Oh man — thanks so much for posting this, Brandon. I’m definitely going to try this out! :)

        • No prob! Sold the SG earlier today based on that mod, it was a quick sell. Guy wanted flat wound strings put on the SG too, which made me think of the part of your blog where you mentioned flatwounds. Tried those out before delivering the guitar, and I have to say that they’d take some getting used to. But flat wounds might be the solution for the synth tones I’m looking for out of heavily distorted guitars.

          More than stoked that I was able to get it to work, as I’m planning to install the exact same config in my Ibanez GAX 70, which is a cheapo I use for C-Standard tuning.

  • Pete

    Having trouble getting this to work. Setup: 12 string acoustic, UST piezo with endpin preamp that booms bass, so I need a bass roll off. I also wanted to move the vol/tone out of the soundhole. Baggs gave me a schematic for 2 (vol/treble) external pots, using 25K pots and .033uF treble cut. Only difference is the volume works as a rheostat bleeding to GND instead of a divider. So I used this diagram to add in the bass roll off (25K, .0033uF) The treble does nothing unless I short out the bass cap and turn the volume way up. Seems to be some impedance magic that I don’t really understand. I tried the volume as shown here (divider), still didn’t help.

    I am assuming the controls are on the output of the preamp, but I can’t confirm that.

    I expect i’ll want to play with cap values, but I have to get it working first. Right now it’s way too bright.

    • Pete

      OK, duh! Figured it out! The existing volume/tone control circuit is actually wires taken off the preamp circuit, which would explain why the volume is also bleed off. So my bass control actually just works as a bleed of through the volume pot, making it just another treble bleed. I’ll have to put this in line between the pick up and pre amp to make it work, I think the 25K pots will still be OK, but not sure what it will do to the rest of the sound. If I learn anything helpful, I’ll post.

  • David

    Hi Joe,
    I’m on a guitar project and i m very interested in your PTB rough schématics.
    But i notice that the bass pot is not grounded, i wonder if it’s not better for my project to ground it with a floating mass because my bass pot is far from the volume and treble pots, So the wires are very long. I’m affraid this cause hum!
    (In facst the bass pot is located in the pickups selector location on a LP)
    Have you any advices about that?

    I also notice that the treble pot is grounded on the volume pot, and it makes me wonder if it’s not a issue (hum issue) if the whole cavity is grounded with adhesive copper?

    Best regards

    • joe

      Hi David! I don’t experience any hum due to the ungrounded bass pot — but there’s certainly no harm in grounding it. The other ground wires, however, must be connected, no matter how good your internal shielding is. You can even ground all your pots directly to the shielding.

      • David

        Ok Joe thx for answering So quick!
        I will try your wiring as soon as the painting is finished.

        But just a last question: the guitar you put this wiring in (the one on the vidéo) is it shielded in the pots cavity or not?

        I’m wondering if it’s necessary to shield the pots cavity with humbuckers?!?

        Best regards.

  • Salman Ansari

    like yout page

  • David

    Hi Joe
    I post again because this ground wire between the vol pot & the treble pot cause me matter
    I explain. I’m adapting your scketchy diagram using a telecaster control plate which already connects
    These two pots together !! I’m talking about ground loop but i’m not an expert.
    The fact is that at this point i’m wondering if the pickups selector which is screwed on the same
    Control plate should be grounded on the volume pot? Or not?
    I will try the 2 possibilities but any advice is welcome ,please help me!

  • hey joe,
    i’ve done this on several guitars now bro,
    i love you man!!! thanks!! quite awesome, particularly with anything thru a fuzzface. you can dial in/out the perfect amount of woof..

    but i got a problem, and i think someone else may too… especially at stage volumes, i notice when i cut the bass, the hum level goes up substantially in the guitar. it’s doing it in all of ‘em, which is leading me to suspect that this pot’s case/shielding may need a jumper to ground.

    anyone else have this issue at all? i have the afternoon off, gonna take a peek down in my workshop at my firebird and see if i can suss this out. i’m thinking the ground is floating as i turn up the pot/cut the bass cuz of the cap, hoping a ground strap may help.

    also wondering if having the wiper tied to the unused input lug may be doing it.. if i have any luck i’ll report back, but man, i could really dig advice and/or if anyone else has had this issue.
    thanks man
    peace out
    pjp

  • ok, i figured out what i did wrong…

    it was multiples. ;)

    used a 22n on the bass pot instead of a 2.2n;

    exTREME bass roll off.

    so i rewired the whole mess with fresh caps/wire etc, and got it working using Brandon S. Hire’s second layout.

    still had a hum problem as i cut the bass tho… nowhere near as badly tho.
    so i shielded the control cavity and made sure there was a good ground connection to the shielding and it worked out great.

    i guess when ya roll the bass back, it lets a bit more hum be noticeable that would normally be masked by the guitar’s frequencies…. or something.

    anyways… onwards and upwards…
    thanks guys
    peace
    jimi

    • You get more hum because when you roll off the bass you increase the guitar circuits impedance (by the value of the bass pot – 500K if its a 500K pot). That’s compared to maybe 6 to 10K with volume at max and bass at max. The higher impedance means that the control circuit itself (not just the pickups) is much more prone to pick up hum fields. The solution is to shield the control cavity and connect the shield to the output jack ground. I think it is good practice to always shield all the cables and controls in a guitar. It’s not just the pickups that are prone to hum. A lot of guitar companies don’t bother, particularly on the cheaper guitars. They seem to think electric guitarists expect hum.

  • Ciarán Mulligan

    Hi Joe,
    I was wondering is it possible to do this on a 72 Thinline Reissue? What pot would be suitable for tone control without having to drill an extra hole and add an another pot? Purely for aesthetics.
    Thanks in advance.
    Ciarán
    Ps love your v informative videos and my kids love your expressive facial expressions.

  • How would this work with 4 wire humbuckers and a coil splitter?

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