Gil Ayan
 | Re: presence pot
quote:
"Dave:
The main problem with this little trick is that the impedance seen by the driving source will vary greatly as you turn the pot.
Are you sure about that? I'd been using that trick for many years in my guitars without any problem. There was an article posted on the AMZ site last June and I've been using that trick ever since. In one of my amps I wanted to stretch out the mid-gain range of the pre-gain pot so I added a 510k resistor from the wiper of a 1MA pot to ground to create a "super" audio taper 500k pot. So instead of having the middle gain sounds right at 3 or 4, I get them from maybe 3 to 7. 8 to 10 gives me the higher-gain distorted sound that used to take up half the span of the knob.
BTW the article didn't explain how adding the resistor changes the net resistance. When you add a 200k resistor to a 1M linear pot, the net resistance is ~167k. (A resistor of 20% of the pot value was recommended for the most accurate representation of a typical audio curve.)
Thanks!
Steve Ahola
" |
In the case of a presence pot, not really. The driver sees only whatever portion of the presence pot is working (presence pot is wired, typically, like a variable resistor and not a voltage divider), which varies as you turn the blooming knob. If the case in point was a volume control wired as a voltage divider, then Dave's point would apply, since the driver network would always see the full value of the pot to ground.
Gil |
11/5/1999 8:53 AM