Tone tweaks on passive guitar circuitry

[crunchee]

I should probably ask this question starting at the VERY basic level, as I really don't have ANY knowledge of passive guitar circuitry, or what capacitors do (or don't do) in a passive circuit. I'm also curious to find out if maybe adding or subtracting something from a guitar's volume and tone circuit will make a less-than-stellar pickup sound better in a guitar, allowing the original pickup to be kept in place. I really don't have the fundage to play 'musical pickups' in a guitar, and a commonly-found pot or capacitor might be more cost effective for me.

For instance, EDITED TO CLARIFY: A SOMETIMES mentioned complaint I've heard here on the HFC is how the stock SD JB pickup on many Hamer USA models is too trebly, bright, or shrill. Will a capacitor, pot or some sort of tone circuit installation cure this, or make it less of an annoyance AND make it sound better? Does anybody out there have any tricks, other than replacing the pickup? Edited to add: Simple Is Better, I'm not looking for something complicated, installation-wise.

Also, a complaint about some 'vintage' guitars are that the pickups don't have much output and power. My stepdad once had a mid '60's Silvertone (made in Chicago, U.S.A.) Harmony hollowbody electric that had very feeble sounding pickups, and he used to have to turn the volume way up on the amp and guitar to make himself heard. Is there any way to increase or optimize the output on a 'vintage' guitar like that, without making pickup changes or using a volume boost?

On the other extreme (and it WAS extreme), my stepdad also had a '80's Peavey electric guitar that had passive pickup Output From Hell...it didn't make the amp overdrive nearly so much as it drove the input but HARD, which made for unpleasant sounding distortion if you tried to play at ANY level from the guitar besides clean. In order to turn up the volume on it beyond a clean (yet loud) level, you had to plug into the second, less attenuated jack. Even then, it didn't solve the problem, the bridge pickup was liveable to use (more or less, again, for clean sounds), but the neck pickup was BOOMY, boomier than some basses that I've played through guitar amps! It was a stock guitar, it wasn't a modded guitar, and it was definitely a passive pickup setup, so what the Hell caused it to do THAT? Just to add, the guitar amp was a old silverface Fender Princeton, and it seemed to do fine with my Hamers, if anything it lacked gain as it was the non-reverb circuit...but the amp and speaker was definitely NOT the problem.

TIA!

[MCChris]

For instance, a common complaint I've heard here on the HFC is how the stock SD JB pickup on many Hamer USA models is too trebly, bright, or shrill. Will a capacitor, pot or some sort of tone circuit installation cure this, or make it less of an annoyance AND make it sound better? Does anybody out there have any tricks, other than replacing the pickup?

Are you basing your assessment on the complaints you've heard or what you've heard with your own ears?

[crunchee]

For instance, a common complaint I've heard here on the HFC is how the stock SD JB pickup on many Hamer USA models is too trebly, bright, or shrill. Will a capacitor, pot or some sort of tone circuit installation cure this, or make it less of an annoyance AND make it sound better? Does anybody out there have any tricks, other than replacing the pickup?

Are you basing your assessment on the complaints you've heard or what you've heard with your own ears?

My ears, mainly. The JB is bright, IMO, I like the sound of it but I find myself always adjusting the tone control when I'm using the JB only. The '59 in the neck, on the other hand, I rarely feel the need to adjust for volume or tone.

[velorush]

Let's see: first, we need the Armitage Volume Pot graphic and his explanation of same... Then we'll need an explanation of tone circuitry. Let me do some searching and I'll post some links.

Edit: got a link to the graphic and an excellent explanation of volume and tone function (BTW: that thread got contentious enough to have been locked, but that does not diminish the value of Armitage's explanation. Also, I just realized Armitage credits the graphic to Duncan, so there you go).

[murkat]

where's Zen?

the heart of a pickup is it's magnet(s)

The soul of a pickup is it's wire / coils / windings.

The magnet's job is to translate the strings vibrations.

The type of magnet is the key of this translation.

The coil's job is to decipher the translation of the magnet.

The type of wire, how many winds, how it is wound, what size of wire, etc.,

is the key of deciphering.

Example: Duncan JB comes stock with a A5 mag. Switching out the A5 mag with a A2 mag

can, may yeild a more pleasent tone to your ear.

A ceramic magnet will yeild (to my ears) a harsh, high end, brittle tone.

A ceramic magnet will overdrive the signal into the front end of an amp, like the Peavey discribed.

Magnets can and will loose there strenght (guass rating) over time.

the silvertone guitar's pickups, magnets could have lost there charge to almost nothing,

creating a very low output to the Amp.

Heat is a magnets worst enemy. Excessive heat applied to a magnet will cause a magnet to degauss rapidly.

Thats a good primer

[crunchee]

Thanks, velorush and murkat (Jay)...I do like that primer! I'm curious, is there any way to tame the output of a 'hot' pickup (ceramic or otherwise), to where it DOESN'T overdrive the input of an amp, and allow the amp to do it's distortion magic without sounding like crap? That is, short of sticking it into a hot oven or setting it on fire?

[murkat]

mmmm.

magnet swap. But, the windings will still affect the resistence of.

Lowering the pickup further away from the strings....

[crunchee]

I had thought about lowering the neck pickup, I did it as low as I dared and it helped a little but it wasn't a cure. On the other hand, that guitar easily got the Hound Dog Taylor "Give Me Back My Wig" sound, which is great but I didn't want it ALL the time.

Edited to add: I don't think a magnet swap was possible, as I believe the Peavey pickups on that guitar were epoxy potted.

[Armitage]

I'm curious, is there any way to tame the output of a 'hot' pickup (ceramic or otherwise), to where it DOESN'T overdrive the input of an amp, and allow the amp to do it's distortion magic without sounding like crap?

A very simple thing to try is to get a resistor about the same size as your pot and solder it across the two outside tabs. If you have a 500k pot, get a 500k resistor (470k is readily available) and it'll knock down your pots value to half and lower the output some, mostly at the resonant peak. You can also get a preamp pedal, and turn just it down, but it's usually the big peak that distorts first.

[Uncle Thor's Hamer]

A capacitor is sort of a calibrated leakage in the circuit. The smaller the cap the less the leakage. The leakage starts at high frequencies, so a small cap will drain off some of the highest freqs whereas a larger cap will also leak off the less high freqs.

So if you increase the value of the capacitor you will make the guitar sound less shrill. If you go too far you will get muddy tone.

The pot in the tone circuit sort of determines how much signal gets to the cap. When you are dialed to 10 on the tone pot there is little signal going to the cap, so few of the high freqs get leaked off. When you dial in 0 on the tone pot all of the signal goes to the cap, so a maximum of leakage occurs. With tone at 0 that low value cap will roll off a lot of the signal but mostly in the higher freqs. The larger value cap will roll off even the lower freqs.

That is a pretty loose and dirty explanation. Put in a bigger cap and you'll get a less shrill tone.