Change Your Caps, Change the World!
(or at least your tone pot response)

The capacitor value matters. But for guitar tone controls, the type of capacitor does not.

Many players know you can change the voicing of your tone pot by substituting capacitors of different values. I’ve seen many explanations online, though I’ve never come across side-by-side audio comparisons. This post is designed to fill the gap.

I’ll skip the “what’s a capacitor?” spiel. If you’re curious, check out this easy-to-understand article from Beavis Audio Research, one of the best (and funniest!) DIY sites.

For our immediate purposes, here’s all you really need to know:

The tone pot and capacitor comprise a low-pass filter, so, when you lower the pot, you lose treble and your tone gets darker. So far, duh. More intersting: as you substitute caps of higher value, you lose more and more highs as you lower the pot.

Today I was working on my fave guitar, a James Trussart Steelcaster. Instead of reconnecting my tone pot and capacitor as usual, I ran two wires from the tone pot’s wiper and ground terminals, the spots where the cap normally connects, and soldered them to a little piece of stripboard with sockets for connecting the caps. Then I recorded quick demos for six possible cap values. I started with the two most common values, and then added two lower values and two higher ones.

A few things to remember as you listen:

  • The capacitor only contributes to guitar’s tone when you lower the tone pot. If you always play with your tone pot wide open, none of this matters.
  • The guitar I used to demo the caps has passive single-coil pickups, but the principle is the same with humbuckers and even active pickups.
  • The value of the capacitor—denoted by a number—is what matters. However, the type of capacitor makes no audible difference whatsoever, though it can make a sizable difference on your wallet. (If that statement makes your hackles rise, read the postscript below.)
  • For whatever reason, there are three common systems for expressing capacitor value. I’ll skip the “logic” behind that and just cite all three names the first time I mention each cap value.

In this first section, you’ll hear three things in each demo: Some chords with the pot all the way open (maximum treble); all the way closed (minimum treble), and then a “manual wah-wah” effect as I strum chords and roll the pot throughout its range.

The test rig: I'm'a put a cap in yo' ass!

Let’s stat with the most common tone pot cap value, .047μ (also expressed as 47n and 473). This, BTW, is the recommended value in most of the wiring diagrams on the Seymour Duncan website.

.047μ Demo

But if you never play with a tone as dark as the fully-rolled off sound, you might consider a lower-value cap. The next example is an .033μ (also know as 33n and 333), another popular choice, followed by the smaller .022μ (also know as 22n and 223), and the even smaller .01μ (also know as 10n and 103). As the cap gets smaller, the minimum tone knob settings gets less dark. As the overall range of the tone pot decreases, it may be easier to locate any desired “nooks and crannies” between the highest and lowest settings.

.033μ Demo

.022μ Demo

.01μ Demo

Get the idea? Now let’s go in the opposite direction, using higher value caps for a darker sound when the tone knob is lowered all the way. You’ll hear a .068μ cap (also called 68n and 683) and a .01μ (AKA 100n and 104).

.068μ Demo

0.1μ Demo

A good question to consider at this point: What the absolute darkest tone you’d ever want from your guitar? I know the two times I’m likeliest to lower the tone pot are when I want a dark, jazzy neck pickup sound, and when I’m trying to get a clarinet-like sound using an EBow. These next examples show how the various caps behave in those situations. We’ll go from lowest value (minimum treble cut) to highest (maximum treble cut).

.01μ Dark Jazzy

.022μ Dark Jazzy

.033μ Dark Jazzy

.047μ Dark Jazzy

.068μ Dark Jazzy

.1μ Dark Jazzy

Now let’s hear some EBow:

.01μ EBow

.022μ EBow

.033μ EBow

.047μ EBow

.068μ EBow

.1μ EBow

Put ’er there: The tone cap connects to the middle lug of the tone pot and to ground. The orientation doesn't matter for non-electrolytic caps (i.e., the kind you use here).

In the end I decided to go with the .033μ. Everything larger sounded too wooly to me on the neck pickup. If I didn’t play much EBow, I might even consider the .022μ. But you might make a different choice, especially if you were using brighter pickups. You won’t know for sure till you try it out with your instrument, amp, and hands, but I hope this gives you some idea of what to expect.

Postscript: About that “capacitor type doesn’t matter” statement: Them’s fighting words in many online forums, especially in the stompbox realm. You’ll often see the inclusion of some rare “mojo” capacitor cited as a selling point for a particular product. I used to think I sometimes could hear a difference—until I built a couple of effects with quick-change sockets for comparing cap types. The audible differences were negligible, no more meaningful than the variations between two caps of the same value and same type. My advice is, if someone tries to sell you anything based on cap type, proceed with much caution. I now strongly believe that cap type is of no importance, at least in guitar and analog stompbox applications.

Disagree? Don’t argue—supply me with repeatable audio evidence of how the same circuit sounds before and after swapping cap types, and I’ll happily admit I’m wrong. :)

“Mojo” is a fascinating word. It originally meant a magical talisman or amulet. Nowadays it’s used to refer to an abstract special something—talent, charisma, whatever—a remarkable quality that’s hard to define but impossible to miss. And in the world of DIY electronics, it has an additional meaning: total b.s.

Anyone have any cool to add to the capacitor conversation?

16 comments to Change Your Caps, Change the World!
(or at least your tone pot response)

  • imenator

    Wow! That was such a revelation for me. I understand that for two caps they would behave the same as long as the value is the same but, What about the material the capacitor is made of? Some guitar parts builders will try to sell me an expensive capacitor but I can get an affordable one in the electronics store anyway.

    Can you add an example when you don’t wire a pot at all? I also heard once from I friend that the pot should be there even if you won’t use it.

  • joe.gore

    Well, you’re REALLY close to the sound of no pot when you have your tone control wide open. So if you always play that way, maybe consider doing something else with the real estate? One-knob fuzz? A holder for a fresh flower?

  • Tom

    I’m a complete convert on getting the caps right in your guitar…pots too! I spend a lot of time dialling new guitars in this way. I’m pretty much satisfied with 10nF at the neck and 15nF on the bridge of my guitars – both humbuckered Gibsons, pickups on the PAF end of the scale.

    Don’t forget to bring 50s wiring into the debate!

    • joe.gore

      What value pots did you go with, Tom? I totally see the reasoning behind going with a smaller-than-normal cap value, as you’ve done. How often do you roll back the tone while playing?

  • sean twomey

    hi-can you put two caps on your two tone pots or will just the one do as is mormal-aslo on a push pull pot do you need two tone caps one for the bottom half as regular-if putting on the square part  of the push pull pot -can you put on any of the six lugs ie the ones not used -i have instaleed a push pull swich but when down the tone on the neck pickup does not seem to have any effect -when i pull it when usingn the pull pull it does have a effect is this normal-i have now neck-bridge-and all three in a row-when not pulled which would be normal five wat switch sound i seem to get a telecasster sound ,i thought this was the case when i pull it up=i have now a nice selection of sounds—thankls sean

  • sean twomey

    hi-can you put two caps on your two tone pots or will just the one do as is  normal-aslo on a push pull pot do you need two tone caps one for the bottom half as regular-if putting on the square part of the push pull pot -can you put on any of the six lugs ie the ones not used -i have  installed a push pull swich but when down the tone on the neck pickup does not seem to have any effect -when i pull it up when usingn the pull pull it does have a effect is this normal-i have now neck-bridge-and all three in a row-when not pulled which would be normal five  way switch sound i seem to get a telecasster sound ,i thought this was the case when i pull it up=i have now a nice selection of sounds— ignore speeling in previos messege–thankss ean

    • joe

      I have the answer: IT DEPENDS! ;)

      You didn’t mention which wiring scheme you’re using, or what the function of the push/pull is. In most cases, you use a cap for each tone control pot.

      If you haven’t yet, check out the massive library of wiring schemes here: http://www.seymourduncan.com/wiring.

      If you can’t find you’re arrangement on this page, give me the details, and I’ll ask around for you. :)

  • sean twomey

    hi-its the standard wiring for a strat-i have the push pull in the middle position-i have two wires going from two lugs on the push pull pot- one   giong to neck position on 5 way selector swich and the other to voloume on selector switch-when i have select     brige position when  i pull  middle pot i get neck and bridge -next position all three – middle position neck /middle .next neck middle and first position -neck=also if you put two tone  caps on one pot will it effect the pickup sound when it maxed to ten  and willit sound too bassy–thanks sean

    • joe

      Yes, putting two caps on a pot increases the capacitance, resulting in a bassier sound when you roll off the highs. If the two caps are wired in parallel, you get the sum of their total capacitance. 

      Were you able to find the relevant wiring diagram at the link above?

  • Joe,
    Thank you for the clearest, cleanest explanation of capacitor effect I’ve read. And, even better, quick and easy to access, clear to the ear, short and no shrudding (sic), audio clips. Best ever. Really good job.
    On my bench today, a partscaster with a Hamer Slammer neck, Carvin Rail in the bridge, Ry Cooder Dearmond middle, and PRS P90 in the neck. Wasn’t quite right (throbby) with the usual 3 250K pots and an 022 orange drop (i know, i know, but they aren’t that expensive). So, i went with 500K master vol, 500K master tone (found an old ceramic PRS 022 cap too), and an acme blender pot (neck and bridge) in the last position. Now it’s fun. Lots of variety in positions 1, 2, 4, & 5. 3 knobs and a whammy and she’s done.
    cheers,
    David 

  • sean twomey

    hi-thanks joe -i have  installed a push pull pot to get middle and neck and all three pickups totegher-it works prefect but when not pulled it has seemed to change the sound on my normal five  selector sound and made all my normal five sounds very twangy-is this normal as when i pull the push pull pot up the extra sounds get clearer-is it becuase i have two tone caps on the push pull one on top half and one on the bottom but i thought that should not matter when the tone is at 10-thanks sean

  • Thank Gawd for the article Joe…. I get so tired of trying to explain the above. I feel like a lone voice crying out in a crowd….these high priced caps are nothing more than a device to facilitate separating you from your money.

    In the real world of the electrical physics involved, the $$ have nothing to do with the quality of the sound…. Caps do not have a “sound” they have a “value”. That is what shapes the tone you hear.

    Now… for those that will note that I do use rather pricy caps… it’s simply because, I’m like you guys…. I don’t wanna open the “hood” on an expensive guitar and see a 3 cent cap in there… I would expect that y’all feel the same way.  No shortcuts…

    Ron Kirn 

  • imenator

    Hey Joe, sorry for coming back to an old topic but it was such a great article.

    Do you have information on how the volume pot does affect the overall brigth/dark and how the selection of the vol pot may interect (if it actually does I don’t know) with the selected tone pots? It is obvious to me that when playing with vol a 10 it is zero resistance no matter if it is 250k or 500k pot, it is clear to me that I can put a 500k vol pot at 5 and it would put a 250k resistance in the cirtcuit but it will not complety mute the guitar if you are using all 500k pots as oposed to a strat with all 250k pots then putting vol on 1 that puts the same 250k in the circuit and it actually mutes the guitar.

    I ask this because I wanted to put a tone control with 500k in my HSS strat (keeping the 250k vol pot) just for the HB to try to make it a little brigther. I know you have already posted a high pass example that could help me on this but I would kike to know your comments on the traditional low pass approach.

  • […] an example of how much a simple capacitor can change the tone check out this post from Joe Gore: Change Your Caps, Change the World!(or at least your tone pot response) – tonefiend.com […]

  • Changing the caps on a guitar was the first mod I ever did, and it was after reading this article I found on a google search. This article uncovered your site for me, and I was soon absorbing it all and modding…

    I chose the 0.1uf capacitor as my favorite based on the samples you gave in this post. I loved the results so much, I started calling it the “Overkill” mod. Fans of ours have asked me about the Overkill mod, as I’ve shown it and talked about it on our bands instagram page. I decided to make a little video showing off what I’ve done with it.

    I like the simplicity of your video approach, so I borrowed the format. Otherwise, I’d have been talking endlessly about it before playing it, and you’re right…it’s better to just start playing the damned thing. So here’s the video I made using the 0.1uf capacitor on a Squier Double Fat Strat (I put the ptb circuit in it, as referenced in comments on the ptb page), as well as a bass. I put the 0.1uf capacitor on a SPDT switch, and it’s the same bass I referenced in the Black Ice post. You may get a better idea of what I’m attempting with the mods I discussed there by listening to how I’m using the mods in this video.

    Thanks for a killer website. I’ve been referring our fans to you left and right.

    http://youtu.be/mIjijjuKfpM

Leave a Reply

  

  

  

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

:1up: :alert: :ban: :beer: :borg: :coffee: :cuckoo: :cuss: :finger: :goombah: :stupid: :megaman: :mad: :pity: :noshake: :oogle: :pacman: :pill: :poison: :poop: :rant: :satansmoking: :shake: :shiftyeyes: :shroom: :sick: :smirk: :spammer: :stfu: :thumbdown: :thumbup: :turtle: :what: :whatever:

Click to upload a JPG