Using 250K pots on Humbuckers

[Scott Peterson]

I have owned my main guitar - a Melancon Custom Artist - since the summer of 2004. The thing is a monster. Nothing I have ever owned comes close, IMHO, to the tone of this thing.

I have Wagner SR/SR/Goodwood pickups. (S/S/H). The electronics are stock from Gerard. The SR's are fantastic single coils, but what gets me about this particular guitar has always been the richness of the Goodwood humbucker.

I was inside the electronics looking at it, honestly trying to find out why it sounds so damn rich. Nothing fancy in there - even a ceramic cap.

But then I noticed the volume pot is a 250K pot.

Now I have fiddled with guitar electronics since I was a teenager, but it never struck me to use a 250K pot with a humbucker. I always just assumed 500K was it when using a humbucker and you use 250K with single coils.

My question then to those who know - what effect is this pot having on my humbucker?

And, since I dig this sound so much, should I just get 250K pots for all my humbucker loaded guitars to see if it sounds better? Does it make them brighter, darker, louder or what?

[scottl]

I use 250k pots on my hums.... Gene Baker was doing this for most of the hum guitars he made. The 250k pot loads the circuit more. The tone is usually less gainy and it may move the pickups frequency peak lower or down a bit. The pickup also stays clearer when rolling off. That is a big one. Gainiacs may prefer 500k or even 1M as you do get a brighter and gainier tone with the larger value pots.

All you need to do is add a 500k resistor across your pots outer lugs to simulate the effect. You want to try 750k or even 1M to get in between pot values per taste.

Scott

[sundaypunch]

IIRC, the larger value will give you more high end. Using a 250k with a humbucker rolls off some of the high end. Single coils generally have a 250k pot since they are a bit brighter to start with.

I actually like most of my humbucker guitars with a 250k or 300k pot.

[Scott Peterson]

Fascinating. I am hoping this thread really schools me on this - I feel a round of mod'ing coming on. Warm up the soldering iron!

[Jim Collins]

As the value of the volume pot increases, you will see more highs when the volume control is on full, but you will also see more highs rolled off when the volume is backed off. In other words, if you were to use a 500K pot in a Strat, where you would normally see a 250K volume pot, the guitar would be brighter with the volume pot full on, but would lose quite a bit of the highs as you backed off on the volume. With a 1Meg pot, both of those effects would be more pronounced. (That is why you frequently see a treble bypass cap, or a bypass cap/resistor in a single coil guitar with a 500K or 1Meg volume pot.)

The same holds true for humbuckers, but humbuckers are better able to withstand it. Using a 250K volume pot with a humbucker is not all that unusual. As scottl pointed out, Gene Baker did it with many guitars. Gibson has been using 300K volume pots in their production guitars (not the Historics) for quite a few years. Vintage guitars used 500K for both volume and tone. I believe modern Gibsons still use a 500K pot for tone. The net effect of using a 250K or 300K volume pot with a humbucker is a meatier sounding tone, with less treble rolloff as you back off on the volume.

[ScottB]

I found this link in another thread earlier today.

A very technical way of approaching it, and it would seem to provide some insight into this question, and even quantification of the effects.

http://terrydownsmusic.com/technotes/guitarcables/guitarcables.htm

Here's the original thread:

http://www.thegearpage.net/board/showthread.php?t=118318&highlight=cables

[AaeCee]

I've been contemplating these complexities for years, but never really experimented enough with altering my combinations. But this begs the question...how many of us have made the simple-minded (and yes, I include myself in 'us') decision to swap pickups, a potentially easy and apparent fix, when we should have taken the time and effort to consider the relations of all electronics first. My guess is that many of us would still be using our original pups had we tried different pot values first. I've done this a few times and eventually dialed in a great tone w/o pickup changes, but have changed pickups more often when looking to alter the tone, maybe mistakenly. IMO, if your pickups are already close to that ideal you're searching for, altering pot values is the most likely route to getting you all the way there. AC

[Clorenzo]

Frequency response of a typical PAF with 500k volume and tone pots:

http://img.photobucket.com/albums/v677/Clorenzog/PAF500k.jpg

250k volume and tone pots:

http://img.photobucket.com/albums/v677/Clorenzog/PAF250k.jpg

As you can see, the value of the pots determines the amplitude of the resonant peak.

I produced those plots with my guitar volume and tone circuit simulation spreadsheet which you can download here:

www.harryj.net/voltone.xls (http://www.harryj.net/voltone.xls)

Note that it only works if you activate a couple of Excel Add-Ins. Go to Tools -> Add-Ins... and check "Analysis ToolPak" and "AnalysisToolPak - VBA".

This article:

http://www.buildyourguitar.com/resources/lemme/

explains the behaviour of a pickup from the point of view of its equivalent electrical circuit. Very interesting reading.

[Scott Peterson]

Wow - ask and ye shall receive.

Thanks guys!

[RL in Fla]

Good (or bad) example : I got 8 "stock" CTS jobs in the mail today .


Four 500's - 465, 512, 525, 530
Four 250's - 207, 235, 240, 255


Had on hand CTS -

2 250's - 269, 270
1 500 - 482




With P90's try the 525/530 for the tones and 269/270 for the volumes ??

[Scott Peterson]

Just as a follow through, I dropped a 300K volume pot in my Thorn and lordy, you guys are so right.

Smoother, much more usable through the entire range of the pot. That big treble falloff you can get with out a bright cap on the volume pot.... MUCH smoother. Nice!

I think I have found the path to my happy place now. Thanks so much!

[Old Tele man]

...a VERY general "rule-of-thumb":

SINGLECOILS................
1Meg = ear-piercing, shrill
500K = bright, punchy
300K = clean, articulate
250K = normal FENDER

HUMBUCKERS................
1Meg = bright
500K = punchy
300K = normal GIBSON
250K = dull, constrained

[aleclee]

Joe Driskill shipped (ships?) his guitars with 250K pots. I've been happier since replacing them with 500K units.

Different strokes . . .

[TheArchitect]

I have used 250k on virtually everything with the exception of my Les Pauls and PRS. The 2000 Paul has 300k which work nicely. I have been trying to work with the 500k in the PRS and for clean sounds they are fine but when I hit the gain channel it gets painful. I just picked up some 250k CTS pots today to make the switch on those guitars. I've never found 250k to be dull or contrained personally. I can see how a tele player might see it that way given all of the natural highs in that style of instruments but I don't find it to be the case.

[TheArchitect]

Just as a follow through, I dropped a 300K volume pot in my Thorn and lordy, you guys are so right.

Smoother, much more usable through the entire range of the pot. That big treble falloff you can get with out a bright cap on the volume pot.... MUCH smoother. Nice!

I think I have found the path to my happy place now. Thanks so much!

So you removed the bright cap? I have been pondering whether to keep it on the PRSi when I make the switch on them.

[whoofnagle]

Scott,

I too dig 300 K pots. I have them in a tele with 2 P90's and in a tele with a P90 in the neck and an HD S90 (or whatever they call it) in the bridge.

They both are smooth!!

Bill

[axpro]

I use 250k pots on my hums.... Gene Baker was doing this for most of the hum guitars he made. The 250k pot loads the circuit more. The tone is usually less gainy and it may move the pickups frequency peak lower or down a bit. The pickup also stays clearer when rolling off. That is a big one. Gainiacs may prefer 500k or even 1M as you do get a brighter and gainier tone with the larger value pots.

All you need to do is add a 500k resistor across your pots outer lugs to simulate the effect. You want to try 750k or even 1M to get in between pot values per taste.

Scott

+111 on using 250's with HB's, makes em a little chunkier on the low down.

[1959burst]

my ears love 500k for humbuckers of the paf variety.

[ChrisB]

I changed to a 250k on a guitar with a Duncan JB and Bardens and much prefer the sound. The guitar is quite bright naturally though.....

[cswolfe]

Killer thread. Thanks, guys.

[cswolfe]

A line I don't understand from the article Carlos refers to: For some reason, I cannot seem to cut and paste it.

It says some single coils are equipped with a coil tap switch. Alright, me confused. If you have a single coil, with a coil tap switch, isn't that called an "off" switch? ;)

What am I missing here?

[Clorenzo]

A line I don't understand from the article Carlos refers to: For some reason, I cannot seem to cut and paste it.

It says some single coils are equipped with a coil tap switch. Alright, me confused. If you have a single coil, with a coil tap switch, isn't that called an "off" switch? ;)

What am I missing here?I see what you mean, but notice it's not a "coil split", it's a "coil tap". Basically, you wind the pickup up to a certain point, then make an extra connection at that point (simply solder a wire to the coil wire without breaking it), then wind the rest of the coil. Say that you make the connection when you have wound 6 kohm worth of wire and then continue to wind until the total resistance is 10 kohm. Now, if you use the full coil from start to end, you have a hot single coil pu. If you use just from start to the 6 kohm point, you have a vintage pu. That's the idea.

[macula56]

Just as a follow through, I dropped a 300K volume pot in my Thorn and lordy, you guys are so right.

Smoother, much more usable through the entire range of the pot. That big treble falloff you can get with out a bright cap on the volume pot.... MUCH smoother. Nice!

I think I have found the path to my happy place now. Thanks so much!


hey Scott, where are you getting those 300K pots from?
i'vee been using a 500K pot with a 220K/1000pf combo across the lugs and it sounds cool but i'd like to try the 300K. jmac

[hipfan]

I've found that 250-350K volume pots allow plenty of high end to come through with my humbucker and P90 guitars. I use those in conjunction with a high value tone pot (550K +) and the 50's style wiring. Smooth, full tone, with much better taper when rolling off the volume.

macula - http://www.blackrosecustom.emerchantpro.com/index.html?token=251722919-1862219697-1753716345&A=41&B=Electronics Black Rose Customs is a great place to get 300K's. He'll even pick out specific requested pot values if you want.

[macula56]

many thanks hipfan. lots of good stuff.

[hipfan]

Joe Driskill shipped (ships?) his guitars with 250K pots. I've been happier since replacing them with 500K units.

Different strokes . . .

For both volume *and* tone pots? A 250K tone pot on a humbucker (especially in conjunction with a 250K volume pot) would be really low and could lead to a pretty dramatically dulled tone, even when on "10". Might be good for jazz clean tones though, I suppose.

Just curious, but if both tone and volume were 250K stock, did you try swapping in the 500K's one at a time, or both at once?

[JohnnyGtar]

Gary Brawer once told me that he set up Satriani's FRED equipped guitars with 250K vol pots "to warm things up".

[Lex Luthier]

Holdsworth uses 250k pots with buckers. I've tried it, but I prefer 500k myself.

[Jon Silberman]

A line I don't understand from the article Carlos refers to: For some reason, I cannot seem to cut and paste it.

It says some single coils are equipped with a coil tap switch. Alright, me confused. If you have a single coil, with a coil tap switch, isn't that called an "off" switch? ;)

What am I missing here?

Like the other guy said but here's an example from one of my own (in-progress) guitars. The middle single coil will be a customized Fraline Split Pole 43. This is an 8.3K, P90-sounding Strat-sized single coil PU which Lindy is tapping for me at around 6.0K with a lead that will be connected to a minitoggle. This will allow me to toggle between P90 and a hot Strat tones on the middle PUP.

[kendog]

I just had this discussion with an amazing guitar tech that I recently met in NYC. A lot depends on the what you want your guitar to sound like, what type of wire and config. that you are using. Also, push /pull pots and switches can alter the equation. If you have a cap/resistor mod to your pots so you don't lose high end as you decrease your volume, then that must be considered as well. If your guitar and or pickups are dark or bright then you can do some tweaks with the electronics to make it more the way you want it. My advice is find a good tech and spend some time and money tweaking to your liking and then you will know what YOU like. BTW, my one off Baker RF custom shop clone has 2 x 500 K and 2 X 1 Meg and is not a bright guitar.

[suhr_rodney]

But then I noticed the volume pot is a 250K pot.

Scott, excellent thread you kicked off. Just wondering... what value is the tone pot? Does your guitar have the "treble bleed" circuit across the lugs on the volume pot and if so what value resistor is used? It would be helpful to understand the total external load on the pickups.

[Scott Peterson]

I'd have to open the guitar for the value of the cap, but the tone is 250K.

[suhr_rodney]

I'd have to open the guitar for the value of the cap, but the tone is 250K. Thanks for the info. No need to open the guitar up! I just ordered a couple of 250k pots from Acme and am going to try this mod on one of my Suhrs. :AOK

[ccoker]

I haven't done it in years, but I experimented with 250 and 500k pots on HB guitars, I prefer the 250 with a cap across it

I changed the guts of my PRS CE22 when I first got it like 10 years ago
the vol pot is starting to wear out, have to check it out, can't remember if I have the stock vol pot or I changed it out..

[macula56]

i use seymour duncan vintage stacks which are humbuckers. i used to use 250's with a treble bleed circuit and it sounded great. i recently switched to 500's because i read that they were better for humbuckers and the tone is definitely different. way too much high end. i think i'll switch back.