To get to a subtler tone control, which pots get bigger & smaller?

[stubhead]

Bill Lawrence L500 pickups put out a whole lot of highs, a whole lot of mids, and a whole lot of lows. And in a situation where you have it in a “normal” tone circuit – 500K volume pot, 500K tone pot, and a .022uf capacitor – the tone control often seems to behave almost like a cocked wah or something, sampling one narrow range of the output. You can choose from a wide spectrum, but you can't get it all at once. This works great when blending pickups – fantastic, stupendous etc. - but it can be almost shocking  by itself.

I'm setting up the new one with two completely separate circuit paths, so I can experiment with just this stuff. What I'm hoping to do is find a combination of pots + cap that will always have a wide tone range, and the tone control will subtly roll off rasp and squeal – at “0” I want it warm and cello-y. Just lose the icepick and rasp, but still keep a wide range of signal available.

What my brain is telling me to try first is – a 1 meg volume pot (log), and a little tone pot, 300K (linear) say, and a really light cap, a .015uf or even .0082uf. But do I have these pot values backwards?

Dirk Wacker at Premier Guitar is adamant about using really, small caps, 1/10 the value sometimes! And I will end up trying that, this entire guitar is designed as a test base. There is no “right” or “wrong”, but in regards to which pots get big and small, there is still a little bit of “forwards” and “backwards.” And “retardo” - always make room for retardo! :tard: :toothy11: :toothy12:

http://www.premierguitar.com/articles/auditioning-tone-capacitors-part-ii-1

here is a uF-pF-mF converter chart to B-M:

http://www.justradios.com/uFnFpF.html

 

[Cagey]

You could stick with the 500K tone pot, but a linear taper is probably better than log for that, then take Dirk's advice and lighten up on the cap. Or, you could just stay with the .022uF and go to a linear 1M.

Log tapers are good for volume controls because of the way the human ear works, but for tone controls linear will give you just that - a linear response to your tender ministrations on the control. Most people have no way to judge an amount of cut, so they play the tone control by ear. In that case, log/linear matters not and manufacturers know this so they don't bother stocking two different parts and training people to know the difference.

Since it's a low-pass filter we're talking about, the smaller the cap the farther up the bandwidth it'll be before you start hearing the effect.

It's a balancing act. A set of jumper wires w/ alligator clips and a pile of different components will save you a lot of wear and tear and time. Be aware you'll likely hear a lot more noise until you finally install what you find you like, as the test leads won't be shielded and will be out hanging around like antennae.

 

[stubhead]

Those guys with the little piece of cardboard with 8 capacitors taped around the edges and alligator clips.... sigh. I mean, we KNOW humans hear what they want to hear, what works in your bedroom may be very different that what works in a room with a drummer, or even a room full of pesky bar customers standing around, absorbing high frequencies. Human beings, being basically a walking talking water balloon, are great high-frequency absorption devices. Hey, remember when Hannibal Lecto... no never mind.

The point is, I'll have TWO independent tone circuits. With one, I'll wire it bang-o normal, 500k  + 500k +.022uF and the other circuit will be the weird one, but I'll have my own baseline one switch away. And the other circuit's for fiddling, and if/when I get that one to work better, that's the new #1 son and the other circuit is now the playground. Being a human, I'm really sure I wouldn't be able to make minute, shaded judgments about tone with a bunch of crap hanging out of my guitar.

Being able to easily COMPARE one thing to another is, umm, sort-of, like, a necessary (though not sufficient) basic REQUIREMENT for making good decisions.  I really can't figure what's going through the minds of the senior editors at Premier Guitar, Guitar Player etc. when a young flunkie gets his assignment, "Here - test these pickups."

And the flunkie turns in a piece saying that they put the new D'almatiophatgorino BoomBoom Grande Primo Skunksnappers in their Strat, and "now" it has more sustain, dirtier distortion, cleaner cleans, higher highs and lowers lows than their old stock Fender PU's - but they didn't record the old ones, or get one single other opinion! You would get booted from "Consumer Reports" SO fast for wasting their time on nonsense like that - and it's the NORM for guitar rags & websites. The worse part of it is, these guys do know what "objective journalism" looks like.

At least what I will be able to do is direct side-by-side comparisons of pots, caps, resistors, q-filter, and plot further directions from that. I figure a Tonestyler, a preamp and some kind of sustainer  are in the mix eventually, more for my own education than for anyone else's.

 

[Jumble Jumble]

You don't have to hang a bunch of crap out of your guitar really though. Just don't wire any controls, and come straight out through the normal jack. Make yourself a little breakout box with some tone controls, volume controls, switches and whatnot, and plug your guitar into that. It'll be electrically identical to having the controls on the guitar, but without weird crap hanging out. Just a box sitting on top of your amp you can reach out and tweak.

Of course, if you still can't tell whether you like it or not unless the controls are physically attached to the guitar, then yeah you're gonna be out of luck.

 

[Patrick from Davis]

I have used down to a 0.006 uF cap.  Not what you are looking for, kinda a weird wah effect.  I like 0.015 to 0.018 uF for more of the tone spectrum, but I have never used it with the linear pots.  I just didn't have any handy, otherwise, wheee!
Patrick

 

[Dan025]

is this the l500xl? there are 4 l500 pups, the c, r, l, and xl. yes, bill has a way of making high inductance pickups that can still be shrill because of his research in core material and eddy current testing. the thing that high inductance will bring is a really strong resonant peak and when directly shunted with a cap it will be lower in the spectrum compared to other pickups. you should choose a cap half or smaller of what normally goes on a humbucker because the l500xl has a huge inductance value and the same overall effect can be had with not much cap at all, if you can't find the right values just wire 2 or 3 caps in series, you might also like a resistor in series with the cap. something between 5k and 50k ohms so the control never goes to "0" which will spread out the usable range over more of the rotation..

if you keep both pots at 500 k try both audio/log taper and linear for the tone but always log for the volume (then again you talk about mixing, linear volumes may help with that but make the lower part of the range very sensitive.) the results for tone pot taper may vary on the listener and the rig. if everything was buffered and the amp was "hifi" the answer of log vs linear would be easier but there are so many nonlinearities and response curves to worry about it's more of a trial/preference thing.

you may also like a smaller volume pot which will make it darker, but it should also make the bump in response more subtle. a 250k may be too small for an l500l or l500xl but bill himself would be a better person to ask. maybe modify a 500k with some resistors for 400k or 330k. the volume pot does 2 things, it creates a low pass filter with the pickup inductance, and it loads the pickup and helps absorb high voltages in frequencies where the impedance is high (resonant peak) the higher the pot impedance the higher the corner frequency of the low pass filter and the more pronounced the resonant frequency is.

if you are using an l500c or l500r then you might just want to lower the volume pot value and not mess with the cap. an l500c might be good with a 250k r lower volume pot.

 

[Dan025]

why not put a prototyping breadboard in the cavity to load the pickup differently or change the caps quickly. you could even use dip switches and have all the resistors and caps installed from the beginning. then you could try different things over a few sessions that you can choose before the gig and not be fumbling with a mess of knobs and switches on stage... once you settle on something you can either just seal up the cavity or write down the best settings and wire it in permanently.