pickups and pots

[chukra]

I recently finished making a copy of a gibson flying guitar from scratch. I used african ribbon stripped mahogany for the body because i didn't want a pickguard(never liked the 1/2 or 3/4 pickguards on the v's).i wanted the wood to shine thru. I put 2 EMG EMG-ZW Zakk Wylde 81/85 Humbucker Set from musicians friend and they came with 25k pots(short shank or shaft which ever you prefer) i couldn't find long shaft 25k so i replaced with 500k long pots. short shank or shaft you can use with a pickguard but not really mounting thru the back of the guitar.Am i taking away from the pickups by using different ohmed pots?

[Meelo]

Should be.
I know it's so in passives - then again, a 25K in a passive guitar is way out of line.

IMO, the principal should remain the same - a higher value pot will get you more treble and fizz, while a lower one will cut on the low bass (you'll be hard pressed to notice any difference in that part, though) and the high treble.

And congrats on the guitar! Post a pic, let us enjoy it too.

[icarus579]

Originally Posted by chukra

I put 2 EMG EMG-ZW Zakk Wylde 81/85 Humbucker Set from musicians friend and they came with 25k pots(short shank or shaft which ever you prefer) i couldn't find long shaft 25k so i replaced with 500k long pots. short shank or shaft you can use with a pickguard but not really mounting thru the back of the guitar.Am i taking away from the pickups by using different ohmed pots?

If you want the long shaft 25k pots, AllParts sells them.

ALLPARTS guitar parts, bass parts, guitar amplifier parts

[brandondrury]

i couldn't find long shaft 25k so i replaced with 500k long pots.

I'd expect this to sound like complete shit with EMGs. I could be wrong, but you've replaced a resistor with a value 20x the original. This is a recipe for disaster in every way possible and I couldn't recommend it less.

I'd spend the extra money to get the long 25k pots.

Brandon

[chukra]

Originally Posted by brandondrury

I'd expect this to sound like complete shit with EMGs. I could be wrong, but you've replaced a resistor with a value 20x the original. This is a recipe for disaster in every way possible and I couldn't recommend it less.

I'd spend the extra money to get the long 25k pots.

Brandon

i have recently found out that if i just put 25k resistors the 500k's act like 25's true or false? its cheaper to solder a resister than change a pot.

[Tony Ramone]

Originally Posted by chukra

i have recently found out that if i just put 25k resistors the 500k's act like 25's true or false? its cheaper to solder a resister than change a pot.

Not really...

Audio pots work on a logarithmic scale, so if you just strap a lower value resistance across the terminals (in parallel), then sure, where it was once 500K it will now be closer to 25k, but as you turn the pot, it pretty much all goes to shit.

Think of it like this: a high resistance in parallel with a low resistance will give you a value much closer to the low resistance, OK? Well, if you have a 500k log pot, most of the swing will be much higher than the 25k, so you end up with a 25k resistance along most of the track - i.e. the resistance is constant as you turn the pot, so you'll get no change in volume (or tone if that's what you're using it for). Then, as you pass the 25k point and head towards 0, you get a big jump in volume change in a very short length of the track.

I tried this myself in a preamp I just built (using the THAT 1512 IC). I had accidentall ordered a bunch of 500k pots, when what I needed was about 10k, so I tried the trick you mention, but what happens is you get almost no discernible change in volume until the last millimeter or so of a turn, when all of a sudden the volume rockets up (as the resistance approaches 0).

I hope I've explained this well enough (with my limited understanding, plus it's really early in the morning - I'm not fully awake yet. I'm breaking my own rule of not posting before midday )...

On a slightly different note, when I originally read this, I though the 25k was a typo - aren't standard guitara pot usually 250k as opposed to 25k? That said, I've never used an active guitar so maybe there's the difference...