The Steel Guitar Forum

Hi All

Just checking to see if anyone has recent experience or thoughts using (550k?) volume pot and (.047?) caps on a tone pot using a GeorgeL 10-1 on a lap steel. Just had an active pickup completely die after a day (reason undetermined yet) so I'm swapping to passive and hoping to avoid future problems.

cheers!

Hey Kevin, I have a Melbert 8 lap with a George L's SS-10, which is the same as the 10-1 except the rails are stainless instead of iron, so it's just a bit brighter. These are well-balanced humbuckers with lots of bass and mids, usually wound around 18-19 kohm and 9H, and not too bright at all (kind of like me.) Mine works well with 500k pots for treble and volume. 250k might be a bit too dark. I do recommend experimenting with a smaller value tone cap, maybe in the range of 5 to 10 nF instead of the traditional 47 nF which I've never thought was very useful. That will give you more usable range without getting muffled, and you can roll it all the way down to take the edge off. Easy to change if you don't like it, but I think you will.

Hey Mike

Thanks for the feedback. The active came with 250k pots; I was thinking the same on using 500k for passive pots; don't want dark combined with tone control. It came with a .22uF (they say unless that's a misprint from .022) ceramic cap, which has a lot of range, but that's active. I frequently see .047uF (I think) combined with 500s - all those p's and n's and u's get confusing; you are correct, don't want muffled, just be able to take the edge off. Your suggestion is about 1/5; I assume a lower value provides a more restricted range, so it's a finer increment on the tone.

I don't have electrical expertise to know beyond the math what they really do, or which variety is the most applicable or reliable. I see a lot of ceramic caps, but read that they can be microphonic (maybe not in this small range) and non linear compared to film. Stewmac has very inexpensive .01uF, 100v film caps.

cheers

Hey Kevin, here's the equivalence for caps: 1,000 nanofarad = 1 microfarad (1,000 nF = 1 uF). So the traditional guitar tone caps are 47 nF = 0.047 uF, and 22 nF = 0.022 uF. In a tone control turned down all the way, larger cap values cut more treble, smaller cap values cut less treble. Tone caps also have an effect with the knob all the way up, by changing the resonant peak (smaller cap = bigger peak.) Since tone caps are only exposed to the output voltage of a pickup (millivolts for passive pickups, less than 3V for active pickups) any cap with a voltage rating over 5V is fine for longevity. Yes, single layer ceramic caps can be microphonic, like a piezo pickup, generating voltage spikes when tapped. I doubt you'd hear it in your lap steel, but even good caps are cheap so there's no reason to use a ceramic cap if you're rather not. If you'll PM me your address, I'll send you a bunch of different values to try. All that matters is using what sounds good to you.