MattPete
New member
The conventional wisdom is that 250k volume pots smooth out the highs, whereas 500k (and 1meg) let more of the highs through. Recently, I was swapping pickups in my Flying V, and the Seth was a bit too bright. So I wired in a switch to the volume pot that allowed me to externally switch a resistor in-or-out. Sure enough, 250k was smoother and 500k was brighter. Both were usable in their own ways, so I'd figure I'd replace the volume pot with a push-pull that could allow me to do this on the fly.
After many pickup and magnet swaps, I finally settled on a Seth bridge with an UO A5. I had a 250k push-pull pot lying around (I had some 500ks that would arrive a few days later), so I decided to use that until the 500ks came in. I wired it up so that it would add (or remove) a 250k resistor in between the pot and ground (i.e. in series with the pot). This meant that it would behave like a 250k or 500k volume pot (except the 500k could never be turned down all the way).
Sure enough, it worked, in that I could never turn the volume pot all the way down in the 500k setting. But, perceptually there was no difference when switching the resistor in-and-out. I tried different amps, clean, dirty. I was stumped, so I waited on my 500k pots.
The 500k pots arrived, and I wired it so that it would add a 500k resistor in parallel (outer lugs) to the pot. I tested it before it went into the guitar, and it seemed good to go: with the switch in one position, there was 500k resistance between input and ground, and with it in the other position, there was 250k.
Perceptually, I could hear no difference. WTF?
Next I grabbed my PRS Soapbar SE and used alligator clips to jumper a 500k pot between the outer lugs of the volume pot. This allowed me to have a 500k volume (unclipped), 250k (parallel with external pot set to 500k), and inifinitesmally small resistance. Frankly, it wasn't until I cranked the external pot down into the 80k range -- which means the parallel resistance was around 70k -- that I could hear a difference.
Now I'm scratching my head. What was it that I did when I originally wired up the external switch to cause the tone to change? Could I have been doing it correctly all along, and the effect is pickup-specific, such that a pickup with a relatively flat curve is largely unaffected, whereas one with a high resonant peak (at least one in the auditory range) is highly affected?
P.S. For what it's worth, the V's volume has been changed to the 50s mod (I'm not sure if I had made the change before or after the first test) and the PRS has the stock treble bleed on the volume.
After many pickup and magnet swaps, I finally settled on a Seth bridge with an UO A5. I had a 250k push-pull pot lying around (I had some 500ks that would arrive a few days later), so I decided to use that until the 500ks came in. I wired it up so that it would add (or remove) a 250k resistor in between the pot and ground (i.e. in series with the pot). This meant that it would behave like a 250k or 500k volume pot (except the 500k could never be turned down all the way).
Sure enough, it worked, in that I could never turn the volume pot all the way down in the 500k setting. But, perceptually there was no difference when switching the resistor in-and-out. I tried different amps, clean, dirty. I was stumped, so I waited on my 500k pots.
The 500k pots arrived, and I wired it so that it would add a 500k resistor in parallel (outer lugs) to the pot. I tested it before it went into the guitar, and it seemed good to go: with the switch in one position, there was 500k resistance between input and ground, and with it in the other position, there was 250k.
Perceptually, I could hear no difference. WTF?
Next I grabbed my PRS Soapbar SE and used alligator clips to jumper a 500k pot between the outer lugs of the volume pot. This allowed me to have a 500k volume (unclipped), 250k (parallel with external pot set to 500k), and inifinitesmally small resistance. Frankly, it wasn't until I cranked the external pot down into the 80k range -- which means the parallel resistance was around 70k -- that I could hear a difference.
Now I'm scratching my head. What was it that I did when I originally wired up the external switch to cause the tone to change? Could I have been doing it correctly all along, and the effect is pickup-specific, such that a pickup with a relatively flat curve is largely unaffected, whereas one with a high resonant peak (at least one in the auditory range) is highly affected?
P.S. For what it's worth, the V's volume has been changed to the 50s mod (I'm not sure if I had made the change before or after the first test) and the PRS has the stock treble bleed on the volume.
