byoc wrote:
...FWIW, if I was going to change the volume pot, I'd use an A100k instead of an A10k, and we usually always have those in stock.
Keith raises a great point here! SteveO and I recently exchanged some email on this topic, so allow me to pass it along here. It's a VERY important fact about how pots are used in effect circuits that took me w-a-a-a-y-y too long to recognize:
Pots are almost always used in one of two ways--as a
variable resistor (i.e. a rheostat) or as a
voltage divider (a true potentiometer). In the former usage, there are only two wire connections, one to the wiper (middle lug) and one to one or the other of the outer lugs. The wiper is usually jumpered directly to the other outside lug, though not always. The resistance across the pot can then be varied
between zero and the pot resistance value. In this application, the rating of the pot is critically important for the pot's function.
But a voltage divider works fundamentally differently. The idea there is to
split the voltage (could be AC or DC) and send it to two different places. This is how a volume control works, sending a portion of your signal to the output and the remainder to ground. What is important is the
ratio of the two resistances between the wiper and the outer lugs, not the absolute value of the pot's rated resistance.
So you don't have to use a particular pot value for a voltage divider! If you happen to be out of 100K pots when needing a volume control, a 50K or a 500K will do just fine.
Just check the schematic of the effect you're building to see if a given pot is wired as a voltage divider or a rheostat. If the former, you have flexibility on the rating of the pot you use. If the latter, stick to the specified value.
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