Gibson 300k pots

[Danny G]

Just thought I'd put this over here too, not just in the lounge.

I heard somewhere online that the 498 equipped Gibbos have 300k pots instead of 500k, and that if you change out the pickups it'll sound weird. I changed out the PU's of my LP Studio and noticed that it did indeed sound a little weird... like the volume was only up 3/4's.

So I went by Guitar Center on the way home from work and asked the dude there. He'd never heard that. I go home and test them anyway with my DMM.

You know what? They WERE 300k pots!!!! I swapped them out with the 500k's I got at GC and will test it on my rig this afternoon. Just thought I'd spread along this handy piece of information to any Gibson owners.

[Fret Wire]

Gibson has been using 300k's for quite a while. Alot of the Epiphones use 300k's too. The higher the value, the brighter sounding the guitar will be. Strats, and most single coils use 250k, most humbuckers use 500k. Most LP owners switch all the pots out for 500k's. Certain pickups will sound better with 300k's. Depends on your setup and taste. Try em' on the volume's and tone's.

[Mark Hammer]

Since the pots simply divide down the signal coming from the pickups, they do not have any impact on how much total volume is derived from the pickups.  True, if you max a 500k pot and a 300k pot, its like having your guitar plugged into the amp with a 500k resistor going to ground vs a 300k resistor.  On the other hand, with respect to what signal is derivable, the value of the pot acts in conjunction with the input impedance of the amp or whatever the next device in your signal path is after the guitar.  To be fair, though, signal flow will be most affected by whatever poses the lowest-impedance path to ground, and input impedances for pedals and amps is usually higher than the 250k to 500k imposed by guitar pots, so guitar pots DO have an impact.

Typically, lower value volume pots will result in more treble loss, when the pot value and cable capacitance comes into play.  What this has translated to traditionally is the use of 250k pots to offset the much greater treble of single coil pickups, and 500k pots to offset the rather frail treble response of many humbuckers.  There are probably many other values that would yield the optimum loading/sound for any given pickup, but 250k and 500k are standard component values, with 100k and 1meg being the commercially available values in line.

Gibson produced (probably contracted, more likely) and introduced 300k pots for some of their brighter pickups, as a way of achieving the most desirable treble control for those pickups.  It is quite possible that switching to 500k pots changes the resonant bands of the pickups by interacting with the inductance of the pickup, and in so doing changes the tone of the pickup in a way that you obviously noticed.

Craig Anderton had a cute little no-brainer add-on circuit in Guitar Player last year in which he simply had a rotary switch to select between a couple of fixed resistors that would alter the load placed on the pickups.  That way, you could install 1meg pots for max treble, but be able to get the same loading as you would with 500k, 300k, 250k pots, etc., by simply placing a resistive load in parallel.

Bear in mind that the moment you diverge from max volume, all bets are off.  The maxed 500k pot that represents a 500k resistive load in parallel with the pickup, turns into a resistance in series with the pickup and a smaller resistance than the total pot value in parallel with the pickup/pot combo.  So, move a 500k pot over a bit and what you have is essentially a pickup in series with a (for example) 100k resistance (between the pot input lug and wiper), and a 400k resistance to ground from the wiper.  In effect the pot-to-pot differences in tone are most likely to be noticeable at max guitar volume.

[Fret Wire]

Here's a little article on guitar pots, and how to change them with resistors, it's much simpler than with effects.
http://www.projectguitar.com/tut/potm.htm

Your amp, string gauge, and wood resonance come into play also. A maple top axe will sound brighter than a mahagony one, etc. The old rule of 500k for Hb's and 250k for CS's works for most.

Or, you can play around with different values. Before you put your pots in, you can try different resistors to get 400k or 300k, etc. Then you can add them after the pots are in.

The 50's style wiring layout lets you use the volumes independently. It's posted all over the internet. There is a kit called RS that has 500k pots, mojo caps, and wiring for the 50's layout. You can do the same yourself for much cheaper.

[phillip]

There is a kit called RS that has 500k pots, mojo caps, and wiring for the 50's layout. You can do the same yourself for much cheaper.

That mojo tone capacitor thing that's all the rage in the guitar wiring bunch always make me laugh.  People actually pay an arm and a leg for those oil in paper (oil in film?) capacitors, which are supposed to sound better or something.

I just used a Panasonic metal film capacitor in my Tele and it sounds fine to me...only cost 5 or 6 cents, too  

Phillip

[Fret Wire]

That 300k pot is also being used in cheaper Strats and clones. It's cost effective for some companies to use the same pot for all models, whether they have HB's or SC's. Most of the large company's cheap models are made by the same Asian factory. Some guitars, even though they are made elswhere use these Asian components.

In the strat/clone cases, a CTS 250k pot does wonders to kill excessive brightness.

[bwanasonic]

So I went by Guitar Center on the way home from work and asked the dude there. He'd never heard that.

I don't know about your local GCs, but the help at the stores in my area are not exactly encyclopaedias of useful info, let alone accurate info. I can't imagine asking them much beyond what the store hours are. Anyhow, as mentioned, the pot value effects perceived brightness, not perceived volume. If your pickups sound too dark, change them to 500k. If you like the sound of your pickups, don't change them (500k pots will not make them *louder*).

Kerry M

[Mark Hammer]

Without wishing to offend anyone, expecting music store people to be fountains of technical knowledge is a bit like expecting pet store clerks to be veterinarians.  Some folks just seek out work because they like to be around certain activities or objects, whether animals or guitars, and I don't hold it against them.  If they DO have any technical expertise, that's usually over and above what the job typically calls for.  It'd be nice to have more technically astute sales staff, but I suppose if we were to expect that, they would justifiably expect to be paid like the electronic engineers and acoustic physicists we were hoping for, and the stuff we buy from them would cost just that much more.

[Mikado]

Hi guys. My first post to this site.
I understand this post is old but I thought I would post this as a warning to those considering changing from a 300K pot to 500K.  I have been using a Les paul Supreme on stage for the past 5 years. It is my fave guitar with 498T and 490R pickups. About a year ago I had the volume treble pot replaced because of all the crackling I was getting when using it. Ever since then I have been getting uncontrollable feedback with it to the point that I have put it away and I now use my black beauty live. I have had the supreme in to 2 different repair shops (I have moved from Sydney to QLD so different repairers) to try to rectify the problem. No luck at all.

A week ago I thought I would give it one more try and I took it to a guy on the Gold Coast of Australia. He found that the initial repairer had replaced the pot with a 500K instead of the standard 300K. This made a huge difference to the amount of treble to my guitar, hence the feedback. My guitar has now been fitted with the 300K and is now sounding as great as it used to.

cheers
Shane
Gold Coast
Australia 

[pinkjimiphoton]

sounds like it may have had bad soldering on the pot, or a miniscule bridge. i've seen guitars feedback like that with bad grounds on the pots.

[Johan]

sounds like it may have had bad soldering on the pot, or a miniscule bridge. i've seen guitars feedback like that with bad grounds on the pots.

500k pot's make some pickups too bright for modern taste ( think high gain distortion with many, many overtones) Gibson switched to 300k for the volume as early as July 1974 when they realized where things were going and peoples fondness for distortion would not go away..
if you play blues and use a fifties style amp, try 500k.  if you play pop/rock/metal with a modern amp, stick with 300k...IMO there is such a thing as too much treble...
J

[ashcat_lt]

I just remove the pots from most of my guitars so that the only load is whatever pedal or amp I'm using.  Talk about sizzle!

That thing Mark posted about the Anderton "load switch" deal is kind of funny.  Most guitars come with a continuously variable one of these built in.  It's called a Tone pot!

[zombiwoof]

Sometimes a change to 500k on the bridge pickup of a modern Gibson production guitar makes it too bright, however, many people complain about the neck pickup being too muddy or bassy, and a change to a good 500k pot will cure this.  The other factor is that Gibson puts linear volume pots in the production guitars, and many (including me) hate that taper.  There are a number of companies selling custom taper pots that are more like the vintage Gibson's pots in taper (it's a specific audio taper), and changing to one of those pots will make the taper of the volume pots more gradual.  With the Gibson linear volume pots, especially if you are using distortion, there is not much change as you turn the volume down until you hit about "2" on the knob, then there is an abrupt cut in volume.  The custom taper pots are available from RS, Dimarzio, Hamer, and other companies.  They are generally good quality CTS pots that are ordered with a custom taper and high tolerance, not the 20% tolerance in value that common CTS pots have.  Also, Gibson is now selling their new Historic pots, which have the vintage taper and high tolerance (also made by CTS), they are only available in short shaft as far as I know, but they are excellent.  I got mine for about $10 each, but most places are selling them for around $12.  I got mine here:

http://www.darrenriley.com/GibsonPickups.htm

They are down near the bottom of the page.
Gibson Historic Spec 500k short shaft pot  $9.95
Gibson part# PPAT-059

I will add that his shipping was extremely fast.

Al

[pinkjimiphoton]

really depends on the guitar. i tend to  like 500k's on my necks, and 250's on my bridge in most guitars...a little more glass is nice on the neck.
my old sg89 has a 500t bridge with a 500k pot...treble that will tear your head off. i ended up using a big freakin' cap in there, like 22mf or something to bypass it, that knocked the treble down enough. weird guitar!

on my 66 firebird, i got 3 500's for 3 humbuckers, and added a 1 meg as a master volume for my pinky. sacrilege? sure. but i got spoiled by my strat.

[shredgd]

That thing Mark posted about the Anderton "load switch" deal is kind of funny.  Most guitars come with a continuously variable one of these built in.  It's called a Tone pot!

It is not exactly the same thing. If you still want the same response in tone when turning your tone knob, but you want more or less overall treble, then you have to change the value of your volume pot. Also, if your pickup/volume pot combo is just too bright, even if you might get the same final result by turning down the tone knob "a little", then you might not like to search for that sweet spot everytime you play and you might prefer to be able to put both knobs at max and instantly get your tone.

Giulio