Tone, harmonics, pickups and pots - Question??

aristeas · Post by **aristeas** » Thu Sep 26, 2002 6:37 pm

Tracy Sands posted this on a previous topic:

"Remember, the more turns, the more distributed capacity, the less harmonic content. Before you buy or trade, check out the pickups!"

This is both fascinating and new to me (I'm a newbie at the electronic side) and it certainly backs up the argument for lower impedance on 'scatterwound' toaster pickups.

On a related subject - how do the impedance(?) values of the volume and tone pots affect tonal/harmonic output? I've seen a posting elsewhere that said:

"pots "load" the pickup, and reducing the values of the tone/volume pots reduce the upper resonant peak that give the pup it's character. So you might lose more than you bargained for.. "

Does this mean that low impedance pickups (greater harmonic conmtent) wired through high impedance pots (500k?) would give the best range and harmonic depth to a guitar?

TIA, Aristeas
The Jewel is in the Lotus to ISO9000

tracy · Post by **tracy** » Mon Sep 30, 2002 3:49 pm

In most guitar applications, the value of volume pot is not overly significant. Although it does represent a small 'load' on the pickup, if you consider a 10K pickup with a 500K pot, you have what amounts to a 50 to 1 ratio. The pot would be virtually invisible to the pickup, assuming the guitar is wired correctly.

I have experimented a great deal with Rickenbacker pickups, having rewound and reconfigured dozens of them over the years. Great tonal differences exist between short and long magnets, not because of their gauss, but on account of their shape. Short magnets are essentially 'square' and have a rather flat pattern, while long magnets have a more elevated or pronounced field. Short magnets allow you to easily achieve that "Cry for a Shadow" tone.

Wire size is also a critical component. Typical #43 wire can range all over the place, from closer to #42 or #44 depending on a myriad of manufacturing nuances. Most #43 that I have measured on Rickenbacker pickups from the fifties more closly resembles #42 when compared to textbook wire tables.

My personal favorite 'cure' for ailing Rick pu's is 5200 turns #42. Pure magic. All gremlins disappear and the pickups come alive with lots of spectrum. This works well with those pesky hi-gains as well.

Good luck, let us know how you fare!

Tracy

eddier · Post by **eddier** » Mon Sep 30, 2002 4:23 pm

Tracy:
Does the 5200 #42 formula work for bass pickups also? And do you have any "tricks" for boosting the neck pickup volume in a 4003?
Thanks
Ed

aristeas · Post by **aristeas** » Mon Sep 30, 2002 6:07 pm

Thanks Tracy, much appreciated.

So magnet shape affects sound shape, that's logical.
And 5200 x #42wire is the recipe for classic Ric sounding p/ups.

I'm still not quite sure about the pots thing, but that's mostly because I asked a question I didn't really understand in the first place. Do higher-'k' volume pots increase volume? Or am I missing something here? - and what about tone pots?

It's intriguing because in the past I've put higher output p/ups in various guitars (DiMarzio et al) when what I wanted was better tone, not more volume, and more harmonic range, not narrow-band punch.

Is there somewhere I can look this up on the net so I can ask a smarter question? After all I'm about to look up what 'gauss' means, and then try to find out what tone pots actually do, and then .. etc.

Thanks again, Aristeas

bluedave · Post by **bluedave** » Thu Oct 10, 2002 1:11 pm

Aristeas,

Here's an informative link about pots: http://www.geofex.com/Article_Folders/potsecrets/potscret.htm
(it's a little silly, but the info is there.)

Like anything you put in an electrical circuit, it can't add, it can only take away (unless it's powered in some way). So, the normal way to think of a volume knob is to imagine that it starts at 0, and when you turn it up, you're increasing the volume. A more accurate way to look at it would be to think of it as starting all the way up (not really affecting the volume at all) then making the guitar quieter as you turn it down. The link above does a pretty good job of explaining how the pot actually works.

Tone pots are exactly the same as volume pots, but they have a capacitor in front of them. So the only difference between tone and volume pots is where they're wired in the circuit.

I really hope that helps. I realize it's written in a confusing way.

aristeas · Post by **aristeas** » Fri Oct 11, 2002 11:21 am

Thanks Dave

tracy · Post by **tracy** » Mon Nov 04, 2002 9:37 am

Hi Lee. To hopefully answer your question about pot values: a volume pot appears as a load to the pickup. The higher the resistance, the higher the voltage drop across the resistance as seen at the output. There are practical limits to this however. Pots above 1 megohm tend to be very noisy in any application, but especially when used with amplifiers that have D.C. present at the input jack (such as most tube Fenders and Voxes). Actually, 250K and 500K are very popular values. Why not try one of each, and see which one you like best?

tracy · Post by **tracy** » Mon Nov 04, 2002 9:47 am

Edmond: Yes, this pickup 'cure' works great for Rickenbacker bass pickups! The solution for the neck/bridge pickup balance is to add the .0047mf series capacitor to the bridge pickup.