Mike & Mike’s Pot[entiometer] Dispensary

IMG_6151-impby Michael James Adams

I… I really struggled to make a good joke there. I’m sorry for how lame that was.

So, we have this wonderful little Tumblr site where I keep a log of just about everything that I work on. Tumblr is easily one of the most fun blogging sites out there, and the community we’ve found there is so much fun. I’m constantly surprised to not only see our number of followers consistently rising, but also the amount of interaction we’re receiving. Day-in, day-out, we’re getting messages from all over the world asking for advice about pickups, setup techniques, which colors we like and why we’re so damn fond of Jazzmasters.

At times it’s daunting to answer all of the messages, but I LOVE it anyway; it is simply amazing to me that we can connect with other musicians across the globe, all of us united by our mutual enjoyment of gear. And to you reading on this website (mmguitarbar.com), it’s good to have you as well! I can’t believe anyone reads this drivel. You’re like secret Santas, every last one of you.

Among the topics raised, one of the most frequently asked questions goes something like this: “Why does my guitar not sound good? I replaced the pickups with [insert quality brand] and it still sounds like [insert expletive].”

Now that sounds familiar, doesn’t it? I’ve been there before myself, swapping pickups for new units that cost a decent percentage of my take-home pay, only to find my tone slightly improved; that’s a frustrating, seemingly hopeless place to be in.

IMG_3949-impSo what gives? You buy the pickups of your dreams, unsolder as few connections and you’re suddenly underwhelmed with your purchase. I mean, sometimes that’s because what you bought wasn’t that great to begin with, but in today’s age of Youtube demos and Rig Rundowns, guitar players are far more educated–tonally speaking–than ever. More and more, it seems highly unlikely that most of us would spend money without knowing what to expect. We’re extremely blessed to have the Lollars, Novaks, Creameries, Bareknuckles, Rio Grandes, Fralins and Duncans of the world toiling away so that we can all sound better!

What seems far more likely to me is that while we’ve all been focusing on pickup problems, we have perhaps carelessly overlooked something perhaps even more detrimental to our sound: the wiring harness.

Yes, it’s true: you could have the world’s greatest pickups ever made–some would argue a set of ’59 Gibson PAFs–and your guitar could still sound muffled and altogether dull if the electronics suck. Allow me to explain, and if you don’t mind I’m going to pick on Gibson a little bit just because I hear about this issue most commonly with regard to humbucker-equipped guitars. I find that, with the exception of P90s, most players don’t complain as often about dark single coils. Sry.

Conventional tonal wisdom states that most single coils sound best with 250K pots because these pickups have a wider tonal spectrum than ‘buckers, meaning they generally put out a wider range of treble and bass frequencies than most humbuckers, which cancel hum but also some of the common frequencies picked up by each coil. That pot value effectively sets a cap or dam, if you will, as to the amount and frequency range of the treble available, so you end up with a clear and balanced pickup that won’t hurt your ears, dig?

If you use 250K pots with a humbucker, what you end up with is a pickup that lacks clarity and detail, and is devoid of snappy highs and tight lows. This muddier signal is EXACTLY the reason so many of us prefer 500K pots with humbuckers*, which allow more treble through and produces a drastically clearer and fuller sounding, erm, sound. So that’s why Gibson guitars generally come stock with 500K pots.

Except they generally don’t; Gibson, like any other company, has to save money any way they can so they can offer a product with enough profit margin to blah blah blah business stuff. Everyone does this, and if Gibson’s buying bulk potentiometers, they can save a bit of money on each part by loosening the tolerance. Most standard pots have a +- 20% tolerance, but for a little more money you can easily find pots ~ 5-10%.IMG_3339-imp

So Gibson-branded pots that claim to be 500Ks? Yeah, it’s highly likely that they aren’t. Whenever a customer of mine tells me their guitar sounds muddy or isn’t sounding the way they imagined, one of my first fixes is to replace the pots, and so I measure their actual, real-life rating with a multimeter and the results are surprising.

You remember our buddy, Nick? He’s the one that brought me his newish Explorer back in 2012, a lovely guitar in that alluring naturalburst finish. He’d swapped pickups 3 times with similarly disappointing results, so I measured his Gibson-branded, stock 500K pots and guess what? They measured at almost exactly 300K ohms. That’s (I am so bad at math but I think this is right) a 40% deviation from the rating on the side of the damn pot! Sadly, this is not the first time this has happened; sometimes I’ll find a pot hovering between 450 and 420 [insert drug humor] and sometimes as low as 370, but 300K? Damn, son!

As mentioned in this older article, I measured out a set of pots that were within reasonable tolerance from their rating (most were within 5-7%) and built a new harness. Upon installation, the difference was dramatic, to say the least; the previously muddy, ill-defined signal was replaced by an articulate tone, replete with note separation and clarity. Trebles were snappy, the midrange was airy and open, and the bass was just as thumpy as our hopes and experience led us to believe. To this day, Nick frequently tells me that his guitar is now what he always wanted it to be.

So, if your guitar sounds as if its wearing the roughest of Irish sweaters and could use some tonal refinement, before you swap pickups please consider having your electronics replaced as well. Because really, if you’re spending the money on killer pickups but leaving stock, out-of-spec electronics inside your guitar, you won’t be hearing those expensive pickups properly.

wiring50sAnd while you’re on the hunt for a good set of pots (we like CTS, Bourns and sometimes Alpha) please follow this wiring diagram**, which is the proper 1950’s style wiring that Gibson used on their holy grail instruments. I attribute the coveted ‘59 Burst sound not only to the wood and pickups, but also this scheme, which differs from modern wiring in the way the tone caps hook up and the way in which the tone pot is grounded. This makes a HUGE difference, and unless a customer specifies otherwise, this is the diagram I recommend using for most jobs. Seymour Duncan has a great blog explaining the differences in layman’s terms, and I’d also recommend using a treble bleed/volume mod network across the 1 and 2 lugs of the volume pot. Link goes to my favorite, but you can easily build them with your own parts.

In conclusion, the way in which your guitar is wired can have a huge effect on the way your guitar sounds. The things discussed in this article are somewhat simplified, but I can say with complete honesty that this trick as worked literally every time I’ve tried it, on both my personal guitars and those of my customers. Give it a shot! Don’t trust me? Look how cool Nick felt after I swapped out his wiring harness. He felt so good he didn’t give a crap about traffic.

IMG_3368-imp

Nick is a traffic-hating badass. He’s crazy. He’ll point his guitar at you and everything. He doesn’t give a crap.

* Your mileage may vary, but most of us do prefer 500ks.
** The diagram omits ground connections for the bridge/tailpiece stud and to each pot.
*** Things come better in threes.
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4 thoughts on “Mike & Mike’s Pot[entiometer] Dispensary

  1. Ronnie says:

    I looked all through this article 3 times before I figured out that there wasn’t a *** footnote…

  2. Charlie says:

    You are aware that Gibson branded Pots are CTS pots? And I’m assuming you also know Gibson for YEARS has used a combination of pots? A 500k CTS Pot for volume and a 300k CTS Pot for Tone? I’ve got Gibson’s dating to ’62 and its got CTS 500k & 300k’s. I’ve been a Luthier for 35 years and worked for Gibson for 15 years, never saw any pots but CTS unless they had a request for Mauser/ Bourns or an occasional Duncan Pot and certainly nothing with a +/- 40% tolerance on them!

    • Yes, I’m fully aware of the fact that Gibson-branded pots are CTS in actuality, but in the case of THIS article, every guitar I’ve referred to has had 500k-stamped pots. And the article is mainly focusing on NEW Gibson instruments, as we’re all big fans of originals from the ’50s-70s, which had much sturdier components.

      CTS or not, Gibson’s using “500k” pots that just do not measure up at all. I’m telling you, loose tolerances is the norm, not the exception here, and these averages come from years of comparative measurements. Of course, not all pots are going to be that far out of spec, but I’m used to seeing 20-40% differences from having measured nearly ever newer Gibson I’ve had in my hands. ‘Newer’ refers to anything ’80s and later.

      I’m sure our personal experience is different, and I salute and respect your combined 50 years of experience; the proof, as they say, is in the pudding. Gibson’s figgy puddy, to be exact.

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