I'm putting together my "AMZ Mosfet Boost" by Jack Orman.One of Jack's suggestions is to use a 5k "reverse taper".I've got a 500k reverse taper pot.What size of resistor what i need to solder to the 2 lugs to bring it down to 5k?
The pot will do 0.0 ohms up to what the potwafer measures, about 500k.
5k is within that range, but it would be hard to hit that setting which is about 1/32nd of the shaft rotation range...fine tuning will be impossible or difficult, the other 31/32nd [almost all of the shaft rotation range] will be useless.
Start with...10k or smaller, use tapering resistors, or try to find the right pot.
IIRC I used a 5k log, but reverse connected [so a CCW turn increases gain] and although it wasn't perfectly smooth and even, it was usable/easily enough to adjust/set.
The 500K is too high as petemoore noted. I believe you can get close to a 5K antilog with a 10K R across a 10k linear pot
http://www.geofex.com/article_folders/potsecrets/potscret.htm
http://music-electronics-forum.com/attachments/737d1181440399-pot_taper_amz.pdf
A 5051 Ohm resistor in parallel with your 500k pot would yield an 'effective' 5k pot - but it'll screw up your taper vibe.
If you've got a regular 5k audio pot just wire in backwards to get the proper taper but with backward knob action.
dave
Quote from: davent on October 09, 2011, 02:20:05 PM
but with backward knob action.
...& if you need any more input, I'll ask my missus - by now she's an expert.
Hello! :icon_eek: ;D
It's important to remember that a resistor across the outside lugs of a pot does not magically turn it into a different value.
What it does is put another resistor in parallel with it, loading the signal source. This may be helpful if the loading on the source is critical.
But it doesn't help at all with the impedance the pot presents to whatever load is attached to the wiper.
Ok cool.I guess i should have read your "Secret life of pots" first R.G. I learn something new everyday!Thanks to everbody for your comments!I really appreciate it!