Tone pot question
- Thread starter T50
- Start date
line6man
Epic Member
- Messages
- 6,443
A tone pot is simply used as a variable resistor between the capacitor and ground.
When the pot is turned all the way down, the capacitor is directly inserted in the circuit with zero ohms resistance between the capacitor and ground.
When the pot is on full, the full value of the pot is applied between the capacitor and ground. The greater the resistance,the less treble is cut.
A 500K tone pot set to the 250K point (Usually about 4/5 of the rotation on an audio taper.) is identical to a 250K tone pot turned all the way up.
When the pot is turned all the way down, the capacitor is directly inserted in the circuit with zero ohms resistance between the capacitor and ground.
When the pot is on full, the full value of the pot is applied between the capacitor and ground. The greater the resistance,the less treble is cut.
A 500K tone pot set to the 250K point (Usually about 4/5 of the rotation on an audio taper.) is identical to a 250K tone pot turned all the way up.
Cagey
Mythical Status
- Messages
- 24,425
Larger pots do several things in both tone and volume controls. They present less of a load on the pickup, so frequency response improves and output increases. Also, the output response curve changes. The improved frequency response and output is not dramatic, but it's perceptible even to a casual ear. The change in response curve can be problematic, though. You may end up with most of your control at one end of the pot's throw, rather than evenly spread throughout the pot's rotation. With some pickups, it'll behave as though you've put a linear taper pot in place of a log (audio) taper pot. With the tone control, you can often mitigate that behavior by changing the value of the filter cap, but you could end up with too much cut, making the thing sound dead.
Any pot at all is going to load the pickup(s), though, which is why there's such a thing as a "no-load" pot. With those, they actually open the pot up at one end so when you're at that extreme, the pot isn't even in the circuit anymore. It's essentially an "infinite megohm" pot, which = no load at all. Lets the pickup fly free. "No-load" pots aren't easy to find, though. You can make them yourself, but I don't know if it's worth it. If you really want to dump that load altogether, it's easier to put in a mini-toggle.
Another side effect of high resistance or no-load pots is that your guitar's output impedance goes up some, so it's a little more susceptible to noise. But, since you're getting more output the S/N ratio probably doesn't change much. Still, the amp will see it and amplify it.
Any pot at all is going to load the pickup(s), though, which is why there's such a thing as a "no-load" pot. With those, they actually open the pot up at one end so when you're at that extreme, the pot isn't even in the circuit anymore. It's essentially an "infinite megohm" pot, which = no load at all. Lets the pickup fly free. "No-load" pots aren't easy to find, though. You can make them yourself, but I don't know if it's worth it. If you really want to dump that load altogether, it's easier to put in a mini-toggle.
Another side effect of high resistance or no-load pots is that your guitar's output impedance goes up some, so it's a little more susceptible to noise. But, since you're getting more output the S/N ratio probably doesn't change much. Still, the amp will see it and amplify it.
bbl4ck
Hero Member
- Messages
- 1,974
Cagey said:
The 250K no load pots are around. I know that Fender sells them under their brand name. However, the 500K no load pots are really hard to find. I finally came across some at Singlecoil.com. This shop is in Germany, but their shipping is really fast. I have normally received my parts from then in ~1 week. Dirk, the guy that runs the place is really nice and will help you with any of your electronic needs. Shoot him an email and he replies quite quickly.
http://www.singlecoil.com/shop.html
AutoBat
Hero Member
- Messages
- 3,589
i've got 1meg pots, and they're quite touchy on the extreme ends. 0 to about 2.5 on the knob is nothing, then when the volume comes in around 2.75, it's noticable.
i like them, but if you have a high gain amp and you use volume swells, it won't be as pretty (a la Somebody Get Me a Doctor)
i like them, but if you have a high gain amp and you use volume swells, it won't be as pretty (a la Somebody Get Me a Doctor)
