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tremoloman
May 19th, 2006, 11:46 AM
I’m certain some of you can help enlighten me on the subject of 250K & 500K pots. I've read various contradictions on this subject so I’m going I've got a few questions I'm hopeful you could answer for me.

Why did Fender use all 500K pots in MIM Standard Strats back in 1994?
I recently acquired a MIM Strat from 1994. The guitar was bone stock and the electronics were toast. I took it apart to inspect the beast and much to my surprise it had been equipped with 500K pots. I asked my cousin to look at his 1994 MIM Strat - his also has 3 x 500K pots. If conventional wisdom says to use 250K pots in a S/S/S configuration, why did Fender use 500K pots back then? Was there a reason they went back to all 250K which is the standard now?

For a H/S/S setup – would you use a 250K or 500K volume pot?
According to Fender’s wiring diagrams, 3 x 250K pots are the standard with their guitars assembled with this arrangement. Since there is a humbucker installed, would a 500K pot be more appropriate?

250K vs 500K for tone controls? Any substantial difference?
My H/S/S Strats are setup with 500K pots for volume and 250Ks for tone controls. Is this standard or should I have 500K pots across the board? I've always been told to just upgrade the volume pot to 500K, but considering my 1994 MIM has all 500K pots with a single coil setup, I'm befuddled which is the proper setup. I don’t know what benefit or change in sound these would make, so if you could fill me in I’d appreciate it very much!

Tim
May 19th, 2006, 12:01 PM
Tremolo,

See Bloozcats excellent post on this subject here:

http://www.thefret.net/showthread.php?t=600

Bloozcat
May 19th, 2006, 12:33 PM
I'm not sure why Fender chose to use 500k pots in their earlier MIM Strats. Knowing what the resistance of the pickups is, might help in understanding it. Perhaps the single coils that were being used were too dark for 250k. Difficult to say without more information.

For a H/S/S setup I personally would choose a 300k volume pot and a .010uf to a .022uf cap, depending on which sounded best. For a number of years, 300k pots were used by Gibson with their humbuckers. As far as single coils go, I find that I like pots in the range of 275k-300k. They add a little sparkle and brightness...kind of a presence to the tone. Most commonly though, I think you'll find 500k pots used in this configuration.

A pot is nothing more than a variable resistor. It regulates how much signal is bled to ground. In the case of a tone control, it's bleeding high frequencies to ground through a capacitor which regulates the frequencies that are grounded. A vintage single coil pickup with a 500k pot will probably be very bright, or even ice-pick to the ear sounding with the pot wide open. You'd probably want to turn the tone pot down just to play it...unless you like that tone. Other single coils are voiced specifically to go into a mixed wiring like a H/S/S set-up.

There is an alternative, but it requires additional parts. For my Squire '51, I wanted seperate volume controls for the neck and humbucker pickups. The wiring diagram I chose utilized a stacked concentric pot for the volume and a single pot for the tone. I chose a pot of 250k/500k for the volume and a single 500k pot for a universal tone (both pickups). Since I rarely use the tone control on a neck single coil, this would work for me. Additionally, I chose a slightly overwound neck pickup which sounded fine with the 500k tone pot.

A good example of the difference between a 500k and a 250k pot with single coils are the Carvin AP-11 pickups. They come standard with 500k pots in the bolt guitar (and other models as well). Most of the complaints I've heard and read about the AP-11's were that they were "too bright" and "too spikey". Most of those complaints were with the pickups and their 500k pots. Wire these same pickups up with good 250k pots, and they sound really good...entirely different than with the 500k pots. Smooth, mellow, full ranged, and musical as I've noticed. The only difference?...the pots.

Anybody else with information and/or experiences on this?

tremoloman
May 22nd, 2006, 08:23 AM
Bloozcat:

Thank you! Thank you! Thank you!

Your detailed explanation clarifies why my Squier Strat sounded so damn bright to me once I completed the electronic component upgrades last week. Clean it sounded nice but lacked bass. With any kind of distortion, it resulted in ear-piercing treble without serious EQ adjustment. Since the guitar came with 500K pots stock I just opted to do the same when I upgraded the electronics. I took the guitar apart yesterday to install a DiMarzio humbucker to tone it down but instead I’ll try changing the tone pots to 250K to see how much difference it makes.

Thanks again!