“Vintage” Les Paul Wiring: BS or BFD?

Which sounds better: modern or vintage wiring? The experts disagree!

There’s a wealth of information online about the relative merits of “vintage” vs. “modern” wiring in Les Pauls. And after reading page after page on the topic, I was more confused than when I started. So here’s an attempt to pinpoint the sonic differences in a meaningful and relatively “scientific” fashion.

For those new to the debate, here are the basics: Nowadays tone pots in electric guitars usually connect to lug 3 of the volume pot, the same junction as the input from the pickup or pickup selector. Wired this way, the tone control siphons off highs before the volume control siphons off level. But in ’50s Les Pauls, the tone control often connects to lug 2, so treble is nixed after the volume pot does its thing. (I say “often,” because, as in so many other regards, vintage Gibson aren’t 100% consistent.) Here are some comparative schematics.

Most online sources manage to pinpoint the most basic difference: with vintage-style wiring, your tone retains more brightness as you lower the volume. But beyond that, there’s a buttload of b.s., including the frequent claim that vintage tone capacitors sound better or different from new ones. (They don’t.)

Anyway, I’ve made some comparative recording and measurements. After digesting all this geeky goodness, you’ll probably know whether ’50s wiring is an attractive option for you.

I made test recordings using the same ’80s Les Paul I victimized during the Pagey Project. The pickups are Seymour Duncan Seth Lovers, extremely accurate reproductions of vintage PAFs. I started with modern-style wiring, and made three sets of recording of the neck pickup:

  1. Playing the same phrase with the tone knob at 10, but with the volume decreasing from 10 to 6.6 to 3.3.
  2. Keeping the volume at 10, but lowering the tone from 10 to 6.6 to 3.3 to 0.
  3. Lowering the volume to 5, and then lowering the tone from 10 to 6.6 to 3.3 to 0.
Next, I rewired the guitar and repeated the same performances at the same settings.

Here’s what I found:

  1. As expected, with vintage-style wiring, you retain far more highs as you lower the volume knob, but there’s more to it than that: Modern also generated a pronounced low-mid bump. The brighter sound of vintage wiring has at least much to do with clearer low-mids as with stronger highs.
  2. With the volume control stationary, the “curve” of the tone control varies radically between the two wiring methods. With modern wiring, the tone rolls off much more quickly. To generalize, you need to lower a vintage-wired tone control about two-thirds of the way down to get a tone similar to a modern-wired tone control about one-third of the way down.
  3. You get about the same amount of treble loss with the tone control at 0 with both vintage and modern wiring — but modern wiring produces a stronger low-midrange bump, which probably makes the results seem darker.
  4. The tone-control properties described in #2 and #3 are similar whether the volume knob is all the way up or partially lowered.

Hear for yourself. For the test recordings, I recorded the Les Paul direct to disc via a Universal Audio Apollo interface. There’s no amp simulation or other EQ — you hear the harsh, unfiltered sound. (Plus some sketchy intonation, because I used garden-fresh strings for both recordings.) Without amps, tubes, and speakers (or virtual amps, tubes, and speakers) to filter highs, this is brightest sound you can get from a Paul, so take that into account when considering the results. Your amped tone will probably never be as bright as what you hear in this demo! Your results will also vary, depending to your pickups, amp, touch, and so forth. Contrasts will probably seem less extreme that they are here with the raw, direct sound. But you will almost certainly notice meaningful differences between the two wiring schemes.

Pretty dramatic, ain’t it?

Here are some readings I made using the Match EQ function in Apple’s Logic Pro. First I measured the sound of modern wiring with the volume at 10 and the tone at 6.6, and then measured vintage wiring at the same settings. Match EQ compares the two, and creates an EQ curve describing their differences. In other words, this is the EQ you’d have to apply to the modern sound to bring it in line with the vintage sound:

With the tone control lowered to 6.6, vintage wiring yields stronger highs and weaker low-mids.

Now let’s flip the equation: Here’s the EQ you need to apply to the vintage wiring with the tone at 6.6 to make it as dark as modern wiring:

With tone at 6.6, modern wiring displays strong treble roll off and thick, wooly low mids.

So which approach is better? It depends on your taste and gear, but allow me to offer a few recommendations:

  1. If you like your Les Pauls on the bright side, go vintage. (I love bright Pauls, so I’m sold already!)
  2. If you avoid using your volume control because of treble loss, go vintage. If you like exploiting the darker sound of a lowered volume knob, stick with modern.
  3. If you tend not to use your tone control much because you don’t like its dark, wooly-sounding effect, a switch to vintage might inspire you to use it more.
  4. If you’ve ever been tempted to replace a standard .047uF tone capacitor with something smaller for  a more subtle treble roll-off (a .033uF or a .022uF, say), definitely try vintage! If you’ve ever contemplated a larger tone cap, go with modern.

This experiment also reinforces something I’ve learned over the course of our various experiments with Vari-Tones and other multi-capacitor tone controls, both homemade and commercial: Until recently, I failed to appreciate the extent to which standard passive tone controls not only filter out highs, but introduce resonant peaks surrounding the cutoff frequency. They don’t just cut highs — they emphasize mids. Even if you’re happy with standard controls (they’re standard for a reason, after all!), a little experimentation might uncover things uniquely suited to your style.

Has anyone else explored this territory? I’m especially eager to hear from anyone who’s applied this approach to any pickups other than a vintage-style PAF. Do tell!

Oh, one more thing: This is a super-easy soldering job. If you’re looking for a nice, n00b-friendly guitar mod, this one is a great choice!

59 comments to “Vintage” Les Paul Wiring: BS or BFD?

  • I had an ’81 Les Paul Standard. I rewired it for independent controls, and one tone control wired vintage style. The other tone control hole was for a 6-position Varitone with choke, for midrange notching. Then I had series parallel switches for each pickup. I could get ton of tones from that guitar; everything from a thick jazzy tone to tele twang.

    I also love bright Les Pauls, and if you look at how many great LP players back in the day used RangeMasters, I guess they did too!  I also like bright humbuckers. I guess that makes up for not having a RangeMaster. 

    Makes me wish I still had my Paul! 

  • Bill Burgess

    I own a real ’59 Les Paul and a real ’61 SG Les Paul as well as 3 Historic RI’s ( I just sold my real ’57 Les Paul Custom) and I’ve tried both ways many different times. I prefer the “modern” method because I use the volume control to roll off a little high end backing it off from 10 to 9. It’s definitely different than using a tone control. I also always use a drop out pot for the neck tone control.

  • Bill Burgess

    By the way, the dis-information that Eric Clapton used a pedal on the John Mayall album is not true – he DID NOT use any pedal. This b. s. was probably started by somebody building Range Masters.

    • joe

      That is indeed what E.C. claims. I’m just not sure I believe it. A couple of Beano tracks really, really, really sound like Rangemaster, and I’ve never heard quite that tone from an early Marshall combo alone. I’m just sayin’… 


  • Matt N.

    Not to open a can of worms, but I would love to see those Match EQ functions run against the “modern” wiring with treble bleed circuits consisting of 0.001uf caps and 150k resistors in parallel across the volume pots.  Supposedly very similar to “vintage” in sound and behavior, but I’ve never seen it analyzed.  –Matt  

    • joe

      That’s a great idea, Matt. I should do that! 🙂

    • At the risk of being a boring know all I simulated modern wiring with a 0.001uF and 150K in parallel wired between the top of the volume pot and its wiper.

      It doesn’t behave anything like the vintage wiring. Basically with the volume at 7 it behaves like the modern wiring with a +9dB peak ranging between 730Hz (tone fully anticlockwise) and +4.8dB at 3.4KHz. If you remove the treble bleed network the only change is that at the high end the response rolls off smoothly (no resonant peak) and is 3dB down at 3.9KHz. At the low end the resonant peak shifts down slightly to 680Hz. So what that 0.001uF / 150K combo basically does is preserve the resonant peak you get with the volume and tone rolled up, for when you turn the volume down.

      Of course to see exactly what all these different versions of the circuit do at all possible settings of the volume and tone you would have to plot multiple curves and present them as pseudo 3D surface graph. Drat! I’ll never get all those worms back in the can now.

      • Lido Bender

        I love that stuff. I don’t find it the least bit boring. But, did you simulate cloth wire for the vintage, and how about tropical fish caps? These things are important! :smirk:

        • Lido, I suspect you are well aware that all the hoo-hah over cloth wiring and tropical caps is bullpucky.

          People who do tone shoot outs on different capacitor types never seem to realise that they may be hearing tone changes due to up to a 40% difference in capacitor value given the 20% plus or minus manufacturing tolerances. With old caps it’s even worse because they drift even further with age. I wish these guys would at least measure their cap values first (or afterwards). Then they could check their listening results against the differences in value.

          • Lido Bender

            Yeah, sigh, I know. I think we all want to understand why the things we like sound the way they do so that we can adapt those things to new and different ends. Unfortunately, getting a real good understanding of even something as simple as the interaction between an inductor and a cap requires you to come to grips with concepts like the square root of negative one. Since that makes a lot of people’s brains hurt, they go back to just describing what they see. Hence cloth wire and tropical fish caps.

  • David Fung

    I’m liking the sound of clips – it’s definitely “direct” sounding, but not anywhere near as harsh as your write-up prepared me for.  Are you not liking the Apollo?

    • joe

      Oh, those comments were to prep listeners who might not be used to hearing direct-recorded guitar, and were maybe expecting a Duane Allman tone or something. 🙂

      I love the Apollo. Really delighted so far!

  • Oinkus

    Makes me wonder what Jim does in his wiring scheme now that made my Les Paul so bright ? Is it more then just how he made and wrapped the pup ? He also runs a solid  wire to all 4 pots for a more “secure?” grounding. I have always set my tone knob at 9 on both pups and of course do the “woman” tone thing just for texture or a specific song. Back to why I changed where I set tone knob, I was told when I was a kid that  until you turned down the tone a touch your pickups weren’t actually “humbucking” weird things can improve your sound even when they have no reasoning or make any sense. Then again the same guy used to call me “Porkus Non-Gratus” and thats the last partial slice of bacon that no one will eat go figure? Once again great work Joe you have made me think !

    • Turning down your tone pot has no effect on whether or not your humbuckers are humbucking, UNLESS you have the trick wiring where the tone pot wiper is grounded and the clockwise end is connected to the mid connection between the two coils on the pickup ( the tone cap is then wired between the volume pot and the anticlockwise end of the tone pot. With that wiring, turning the tone pot up full clockwise shorts one of the humbucker coils to ground and you are left with a single active coil.

      And – all commercial guitar pots have neutral ‘landing zones’ at either end of their rotation where the resistance does not change. Which means that when you turn your pots from 0 to 1 or from 9 to 10 usually absolutely nothing changes. The extent of the landing zone at either end of the track can vary, but it is normally 5 to 10% of the rotation. If you take a pot apart you can see the landing or parking zones at either end of the track as lighter grey or silvery areas.

  • el bjorch

    Works great with strat and .033uF caps.

  • Lew "Guitar" Collins

    Thanks for this Joe.  I’ve been pushing the benefits of 50’s wiring for many years as well as claiming there was no difference that I can hear between tone caps of the same value but made from different compositions in a guitar tone circuit.  I’m very glad that your research bears this out.  I have a ’54 Telecaster with Joe Barden pickups that I wired 50’s style as well as a Stratocaster with Seymour Duncan Antiquitys that I wired 50’s style.  I also have a ’63 Stratocaster is wired bone stock, right down to the original 3 way switch.  What I hear is the same thing you hear: when I lower the volume of the guitar with the 50’s style wiring the sound stays bright enough to sound clearer than with standard wiring.  There is a certain overall warmth that my ’63 Strat has with the standard wiring that I like – but it also gets dark and a little muddy when I turn the volume way down.  I think the reason some guys don’t like the 50’s wiring is that they feel it makes the overall tone of the guitar to bright for their tastes.  I suspect these guys also rarely play clean or play music with more advanced harmony in the chords.  Since most of the time we guitarists are playing rhythm with the guitar volume turned down, and since the 50’s mod makes our guitars clearer and brighter than “normal” when the volume is turned down, the sense is that the 50’s mod made the guitar to bright.  Personally, I prefer the 50’s mod.  Only reason my ’63 Strat isn’t wired that way is because it’s worth more $$$ stock.

  • JH

       Its all a matter of taste!  I like the treble bleed mod! But it can make the guitar too bright at lower volumes depending on what values you use. It can also in some cases change the taper of the pot!
    Glad to see your enjoying the new interface Joe!

  • zyon

    Joe, let me ask you a question about caps. I use Drop Orange caps and change the caps in every humbucker guitar I purchase. It instantly changes the tonal characteristics of the guitar even though I use the same cap value. The Drop orange gives you a cry baby type tone set approximately half way. It gives a more nasal tone. I’m interested in why you say vintage caps don’t sound any different than modern, when different brands of modern caps sound so different. 

    • joe

      Despite the fact that any electronics expert will tell you there’s no difference, I used to insist that there was — until I made actual before-and-after recordings and measurements, and had to admit it was all in my imagination. By all means, prove me wrong — next time, make recordings before and after you sap the caps. 🙂 

  • zyon

    I currently have zero way to record. These are the ones i use in a Les Paul conversion with PAF style humbucjers. http://www.ebay.com/itm/Sprague-715-Orange-Drop-Capacitor-0047-F-600V-2-pack-/310405933045?pt=LH_DefaultDomain_0&hash=item4845a2a7f5#ht_500wt_922

  • This was very interesting, thanks for the run through… I may use this as a starting point when I work up the courage to mod my Paul..

    The difference is so distinct it makes me wonder why they switched from vintage to modern in the first place? Was it to accommodate a change in consumer taste towards the darker tone or some unrelated change in the process at the factory.?

  • joe

    Oh, just go for it! What could go wrong, aside from injuring yourself, voiding your warranty, and burning down you house? 

    Seriously, though — it’s a pretty easy mod.

    I don’t know why they changed it — maybe because players wanted more predictability from the tone control? I know there were a LOT more players back then dialing in darker tones in the ’50s, as opposed to the balls-out, wide-open tones that have prevailed since the ’60s 

  • greg

    Wow, never thought about the order in the signal path of the volume pot and tone pot before, very cool. I guess why my vintage wired guitar and bass don’t suffer much treble loss with the volume knob turned down. Anyway, I do have some experience with something mentioned near the end of the article so here’s what I’ve learned:

     All pickups have a resonant peak. Capacitance (tone cap, cables) change the frequency of the peak. Resistance (volume pot, input jack of amp or pedal) reduces the amplitude of the peak. I think the main difference between the way a humbucker and single coil pickup sounds is due to the the fact that humbuckers generally have more of a mid-frequency emphasis due to the extra windings, as well as a less severe (and lower pitch) resonant peak. I find I can get a strat to have a very similar tonal balance to a humbucker-equipped guitar by placing a 100k resistor across the outer lugs of the volume pot (same as using a lower value pot) and using a higher value tone cap. This along with a wide-q mid boost before a clipping stage can give a very crunchy distortion tone to a strat bridge pickup which is a sound that most people would generally not associate with a strat. 

    Hope that’s not to off-topic but it took me along time to realize that and I hope it helps someone.  

    • joe

      Hey Greg — thanks for the GRET comments! That’s a terrific explanation of an often confusing principle.

      Hmmm — now I want to cook up a Strat mod that switches between standard bridge sound and the pseudo-humbucker tone you describe. 🙂

      • greg

        Cool! Make it a “global” mod and get more of a jazz tone from the neck pup. Thanks for all the great articles. I just discovered this site. Keep up the great work!

  • greg

    Well, I like about 12db gain centered at 1k with about a 3 octave wide Q prior to distortion. I found this out by using eq and distortion plugins in my recording program. Out in the real world I don’t yet have a good way to implement this. Since I have duckbucker pickups I suppose I could add a switch to run *individual* pickups in series mode for a boost in mids and gain, but I don’t think it would be enough (maybe it would, I should try). I would prefer as few pieces of gear as possible (and a guitar with as few switches as possible) so an overdrive pedal with the ability to do this sort of midrange pre-emphasis would probably be ideal for me.  

  • This is the best mod I have tried yet. I don’t why I didn’t try this sooner, over all of the other more esoteric mods, of questionable use.

    • joe

      I hear you, man! I think I expected it to be a fairly modest difference, but sheesh — it’s huge! I too am muttering, “Vintage wiring, where have you been all my life?” 😉

  • Will

    Must check all my guitars now…my hollowbody has P-rails, Les Paul copy with Lace Sensor Duallys and Samick Flying V with Dimarzio PAF Pro (Peter Green mod) and Super Distorition.

  • Diogo

    Greetings from Portugal!

    I was wondering. What are the differences between the vintage wiring and the modern wiring with treble bleed mod? From what I have read, they achieve the same result, however vintage wiring seems more simple and requires less work.

    Could the vintage wiring be applied to Teles, Strats,guitars with p90, etc?

    Last question. Is it possible to combine a treble bleed mod with the vintage wiring? If so, what would it sound like?

    Thank you for your time!

  • Colm

    Hey Joe, thread from the dead. What (if any) significance do you think the difference in response between the two wiring schemes above the 10k mark has? Is there a difference between the two schemes when volume and tone are wide open? Thanks.

  • Since electric guitars put out nearly no signal at, or above 10KHz I’d say the answer to your question is – none. And with all controls at maximum the two wiring schemes are electrically identical.

    I think perhaps it is also worth considering that on more recent Gibson’s the company has used 300K linear volume pots. I’m guessing the changes in wiring over time have been attempts to cater to changes in taste. The early guitars where sold to customers who played jazz, popular and dance music with no distortion and with restrained volume. When the Les Paul in particular was re-discovered it was used for blues and rock where the top end was rolled off and some distortion was always used, as well as high volumes. Loading the pickups a little more with 300K pots kills some of the treble. Using linear pots makes the control rather on-until-rolled-all-the-way-down-then-suddenly-off. Perhaps the idea is to give finer control of volume towards the top end of the rotation and maybe this works particularly well with distortion.

    So if you are re-wiring your Paul check your volume pots, I think I’m right in saying that the early LPs used 500K log volume pots, so if you have 300K lins in there you should perhaps change those out too.

    Pots commonly have a plus or minus tolerance of 20% so what is supposed to be a 300K could even be as low as 240K! Fortunately today a number of vendors are starting to sell 10% tolerance guitar pots.

  • Just did some quick SPICE simulations. With the tone circuit connected to the volume wiper and the volume set around 7 (with an A curve log pot that’s with equal resistance from the wiper to either end) the tone control has a much wider range than with the “modern” wiring. Modern goes from around 3.7kHz to 470Hz. Vintage from 6.5KHz down to 23Hz. Both with a 0.047uF tone cap, frequencies measured at -3dB points.

    It seems if you are a player that habitually plays with the volume knobs rolled down then the ‘vintage’ wiring gives you a much wider range on the tone knob with a much brighter sound with the tone all the way up. On the other hand if you normally just wind the volume all the way up then tone wise there isn’t much difference between the two wiring schemes. At least that’s as far as I can see from a quick analysis.

    • joe

      Terry! Thanks so much for these posts. You explained the behaviors way better than I could have done. Bravo.

      My empirical observations are similar to yours — just not as well informed! But are you sure about those measurements? The cutoff frequency at end of the pot’s range is really a sub-audible 23Hz?

      FWIW, my current take on all tone control stuff is … configure to suit your needs, and don’t feel locked into how Fender and Gibson did it a half-century ago. If you only use the tone control for maximum bright and maximum dark, consider a switch instead. If you never use it, remove the damn thing. If you like the subtle gradations with only a bit of treble rolled back, try a Tonestyler or homemade equivalent. It would even be pretty easy to add a vintage/modern switch that toggled the tone-cap connection between volume control lugs.

      • Hi Joe – I just double checked and yes that is what the simulation shows. It’s pretty close to a 250K resistor connected to a low impedance signal source with its other end shunted to ground by a 0.047uF cap. The output being taken across the cap.

        Mind you I assumed a full anticlockwise wiper to end of only 1 ohm. Real pots are likely higher. Hmm … just bumped it up to 100 ohms and it doesn’t make much difference. I should point out it won’t stone wall kill the signal – its a gentle 6dB per octave. So you should still hear something – just rather muffled.

        Actually I’ve now played around with the test settings a bit more and having the tone network shunting the volume wiper does something I did not expect when the volume is at half (7 on a log pot). With the tone pot at max the electrical response is flat up to around 6.5K (3dB down) then it rolls off at 12dB per octave. As you turn down the tone pot the entire response from around 400Hz upwards doesn’t change shape (much – it does gain a bit of a high peak), it just moves down in relation to the low end. Only when the tone pot resistance is very small does it become a gentle slope down from low to high. Amazing how a relatively simple network of a few inductors, capacitors and resistors can exhibit such complex behaviours.

  • I know the 23Hz figure does seem hard to credit so just to nail this one to the wall – rather than rely on the SPICE simulation I calculated the frequency at which the capacitive reactance of the 0.047uF is equal to half the Volume pot resistance (250K). That frequency is 13.54Hz. So if you take a 250K resistor and a 0.047uF cap in series, connect the outer ends of that network to a signal generator and measure the signal across the cap, the signal will be half the input at 13.45Hz.

    In the case of the ‘modern’ wiring the signal source is from the relatively low impedance of the pickup so the tone cap isn’t bleeding off the signal at anything like such a low frequency. In the vintage wiring with the Volume on an A law log pot at 7 you are feeding the cap from a much higher impedance which explains why the tone cap has such a large effect. Turn the volume up or down and that impedance gets smaller and the effect of the tome cap is less dramatic.

    In the sim the roll off is modified slightly by the other components in the circuit and I didn’t bother to extend the frequency scale below 10Hz so finding a flat portion of the response curve for a reference gets a bit tricky.

  • Colm

    Thanks for the replies, gentlemen.

  • Paul

    What a well done informative paper here, bravo, a toss of the pick indeed.
    Been building a desire to swap out my board mount Gibson 2015 wiring for a vintage prewired orange caps, Bourne’s pots, with thick cloth wire and solid ground. Price is right, I am just wondering if the difference is going to be night and day? I am thinking it is really going to sound different.
    The ’61 pickups I like which are Alnio V and sound fine to me but I am itching to redo the wiring loving that vintage tone difference.

    • joe

      Hi Paul — thanks! Swapping out the board sounds like a cool idea, but mainly for quality/durability reasons. In other words, don’t expect a big difference in sound. The Bournes pots are great — they’ll last for many years. The cap VALUE matters a lot, but the brand does not. Orange caps sound great — but so does just about any cap of the same value. (More info here: http://tonefiend.com/uncategorized/capacitor-smackdown/) The cloth-shielded wire sounds no different from modern wire in this context, but it looks cooler when you open up the control cavity. (NOTE: Some of these opinions are controversial, and you’ll find many contrary views online. But my conclusions are based on systematic and reasonable scientific A/B/ tests.)

  • I have been doing quite a bit of guitar repair recently and every Les Paul I open up, ranging from the budget Studio models, or even the Epiphone versions, all the way up to Custom Shop models, has had cheap, crappy, small disc, ceramic tone caps.

    This is despite Gibson having a page on their web site explaining why they fit high quality Orange Drop capacitors.
    Now maybe they have changed to Orange Drop just recently (probably due to pressure from customers moaning about the cheap caps) and I have yet to see a brand new Les Paul in for fixing.

    The cheap ceramics have a wide variation in value, they can be microphonic, they have a high sensitivity to temperature (this actually makes them hard to measure, you can hook them up to an LC meter and watch the digits spin, particularly if you warm the cap with your finger) and they have a high ESR. I have yet to run some simulations to see if the difference in ESR between a ceramic and an Orange Drop is perhaps audible.

    And I totally agree with your opinions Joe, about cloth wire etc. These companies selling paper in oil caps or ‘vintage’ bumble bee caps for $150 a pair, on the basis that they have a magical sound, are just exploiting peoples gullibility. The good things about cloth wire are that it is not very floppy, it tends to stay were you put it, and the insulation does not melt when you hit it with a soldering iron.

    • Shizmab Abaye

      It’s interesting thinking about the temperature coefficient of ceramic caps. Seems like you could exploit that for “armpit wah” – uiellann pipers would go crazy!

      I did see the Converse sneaker wah – seems a little weird as you have to flex your foot backwards. At the same time, this might help stave off plantar fasciitis as it’s the same stretch as recommended by my doctor. If you don’t know what that is, consider yourself lucky.

      • Well it’s not a good idea to use ceramics as time constant components in an oscillator if you want the oscillator to be stable. I’m not sure if you could get a wide variation in an audio oscillator though. You could probably use some sort of capacitor multiplier, such as that used in the standard Wah Wah circuit, to enhance the effect. Maybe a box of three or four oscillators with ceramic caps would make a fun electronic wind harp.

        Anyway I have been trying to research the infamous Sprague Vitamin Q capacitors. These seem to have been military spec. capacitors with a paper and oil dielectric, a metal tube case and glass end seals.

        In the days before cheap reliable plastic film, the most convenient dielectric material for capacitors was paper, so that’s why they used it in capacitors. The performance of the paper could be improved by impregnating it with a high dielectric mineral oil. Apparently, if a voltage spike did happen to punch through the paper, the oil would act as a self sealant and mend the hole.

        Various proprietary mineral oils were used by capacitor manufacturers, many of them toxic. Vitamin Q was Sprague’s name for the oil they used. Probably because it reduced the dissipation factor for the capacitors and as result they could achieve a higher Q in tuned circuits.

        The problem with oil impregnated capacitors is, the oil can evaporate, hence the metal case and glass end seals.

        The Vitamin Q range was high spec. back in 1950’s, perhaps not so wonderful now compared to modern capacitors that use high performance plastic film and no oil to dry up or give you cancer.

        So, is there any reason at all to use NOS Sprague Vitamin Q (or any other old weird and wonderful caps) for tone control caps? Based on the above info alone, no absolutely not. Even the Gibson repro Bumblebee’s at $150 a pair use plastic film.

        • Shizmab Abaye

          It’s frustrating to regular folks, because you’d like to be able to use actual principals of science to help guide people making decisions.

          On the other hand, it would be great to be able to get the e-mail addresses of guys who actually HAD purchased $150 capacitors, because, y’know they might be interested in an unobtainium tune-o-matic bridge.

  • wjmwpg

    Hi Joe,
    I’m much happier with my overall tone since going to the vintage wiring scheme on my Tokai and Electra LP’s. Thanks for the tips and clear explanations.
    The one thing I’d like your opinion about is that now I find my tone knobs do nothing until down to about 3. From 3 to 0 there’s action (touchy action), but nothing audible happens from 10 down to 3. This is the same in both guitars and both have high quality 500K Log pots for tone, so I’m wondering if this means I should be looking at larger cap values? The Tokai’s got 33’s and the Electra 47’s, but would going “bigger” get me more (smoother?) use out of my tone knobs?
    . . . oh wait, there’s a second thing! Since you don’t believe in all the cap-type hype, what kind of caps do you use in your guitars?
    James (eagerly awaiting the Cult pedal that’s in the mail!)

    • Joe Gore

      Cool — I’m glad it (mostly) worked out for you. Hmm — if you’re handy with solder and have a few parts around, I’d try experimenting with a linear B500K pot. It’s not the the usual choice, but it should make it so that darker tones aren’t all clustered at the end of the pot’s range. Your larger cap idea might help too, though I’m not sure its onset would occur much earlier in the pot’s range.

      I’d go with this game plan: Choose a cap value based on the darkest possible tone you’re ever likely to use. (Some payers go small with a .022µF, or even less. But I usually use the orthodox .047µF because I like the super-dark sound for EBow and fake bass lines.) Then play with log, linear, and anti-log pots (A500K, B500K, and C500K, respectively) till you find a feel you like. And remember, it’s always possible to make the overall tone a bit brighter by using a 1M pot, or darkening it a touch with a 250K. Hope that helps!

      • wjmwpg

        I tried out my Linear 500K pot in place of the Audio 500K, but it actually just made matters worse. With the Linear 500K the tone control became almost like an on/off switch between 1 and 1.5. Tomorrow I’m going to order myself a couple of Audio 250K pots and see how those perform. I’m hoping the darker pot with a lower cap value might get me more usable play out of the tone controls. Thanks again for all the suggestions.


        • wjmwpg

          Quick update that I finally got my 250K Log pots in the mail and they are an improvement. Now I get audible results from my tone pot between 0 and 5, which may not seem like a great improvement (over the previous range of 0 to 3), but it actually makes the tone pot feel far less touchy and jumpy. Thanks for the advice and ideas. Am really loving my tone with the 50’s style wiring and the improved tone pots are just a bonus.

  • wjmwpg

    Thanks Joe! I actually dropped by my last local “radio repair shop” (run by a guy in his late-80’s) and grabbed some caps of different values and played around all morning. Your hunch about the onset in the pots range was 100% correct – it did not change. It seemed to my ears rather that the slope of the LPF simply got steeper, (like the difference between 12dB, 24dB and 48dB filters on a synth) with each successive, larger cap value. I went all the way to a 0.2µF just to make the difference extreme, and indeed 3 on the pot still sounded pretty much wide open, but once I started dialling it down from there the cutoff was stupidly extreme.

    I think I’ve got a 500K linear pot hanging about somewhere so I’ll give that a shot. From your advice I suspect the B250K might be my answer . . .

    Thanks for the pot advice Joe!

  • The interaction of tone capacitors and the rest of the guitars electronics is way more complicated than you might think.

    When the tone pot is near maximum resistance then the pickup inductance forms a resonant circuit with its own self capacitance in parallel with the capacitance of your instrument cable. The response of the guitar electronics (not considering the interaction of the strings with the pickups) is flat all the way from very low frequencies up to the resonance point in the low kilohertz range (actual frequency depends on the pickups and the capacitance of the cable) where it can peak to over +12db above the low frequency level. Past the peak the response rolls off at -12db per octave. Just changing cables can have quite an audible effect.

    As the tone control is rolled off the response looses the resonant peak and becomes more gentle treble roll off at -6 dB per octave. Then as the resistance of the tone control gets near zero the tone capacitor forms a low frequency resonant circuit in parallel with the inductance of the pickup and the response starts to peak again (a broader peak this time) and to roll off at -12dB.
    With the tone control at the low resistance end of its travel the centre frequency of the resonant peak doesn’t change much, its more the height of the peak that changes as the control is adjusted.

    Since the shape of the response curve changes so much and how it changes is affected, not just by the guitars controls and the tone cap, but also by pickup inductance and instrument cable capacitance it becomes very difficult to decide on capacitor value and on tone control taper. It also becomes very difficult to decide on what the ideal control taper (or law) would be for a tone control that would offer a smooth and consistently musical change from one end to the other. Both linear and log law (10 or even 20% law) seem to bunch up the operating range at one end of the pot or the other.

    The above assumes that the volume control is at maximum. Once the volume is turned down the resonance effects start to disappear and the tone response is a smooth -6dB per octave roll off. When and how this happens depends on whether the tone components are connected to the top of the volume pot or to its wiper. So if you are a player that always has the guitar volume backed off, your choices of tone cap and tone control might be different

    Joe is spot on with the idea of choosing the tone cap value to give the darkest tone you would want to use. As to cap type any modern plastic film type will do and voltage isn’t critical since we are only dealing with signal voltages inside the guitar. I would recommend using 5% value tolerance capacitors just for the sake of consistency, although if you are only concerned with one guitar and you audition your caps you can use 20% if you want. If you happened to have two tone caps in a 4 control guitar and one cap was at the +20% limit of tolerance and the other was at the -20% limit you would certainly notice a difference compared to two caps of the same nominal manufactured value that were both right in the middle of the tolerance range. This is the problem with a lot of the cap comparisons on YouTube – the person doing the comparison doesn’t measure the caps for actual value, or even to see if the ‘vintage’ caps they have are performing as capacitors.

    I wouldn’t spend over a dollar for a tone cap and even that is expensive.

    • wjmwpg

      Wow Terry, thanks for sharing that. I had no idea that the relationship of all the components involved could have such a varying effect on the freq curve of the tone control. That was a very informative read.

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