Inductor on tone pot?

Pickups, wiring schemes, switch techniques and onboard active electronics for guitars and basses
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mugician
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Post by mugician »

So, instead of coil-tapping to get that particular tone, you could essentially get it (hum canceling as well, and no volume drop) by having an inductor on a pot to ground... right?

Wait. Am I missing something here?

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mugician
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Post by mugician »

I should elaborate... my goal here is to cut mids.

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Post by Fuzzer »

if you put an inductor in place of a capacitor in a classic guitar tone circuit, then it would be more like a bass cut.

Regarding the hum... To be effective, the cancelling coil has to be very close to the pickup, besides having the number of wire turns.
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Post by mugician »

Really? Huh... is there anyway to passively cut mids? A combination of said components maybe?

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Post by Fuzzer »

Actually, did some calculations and you would have an effective mid cut that way (my bass-cut asseveration was hurried); try it with different caps in series with the inductor.
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mugician
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Post by mugician »

Any ideas on inductors? Would a simple wah-worthy inductor do? What value caps should I consider? What's the reason for caps in series?

Sorry for bogging you down with Q's, I'm a newbie.

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Post by Fuzzer »

¿At what frequency do you want to make the cut?
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Post by mugician »

Good lord, I don't know!

I have absolutely no idea. I'm playing on some pretty standard humbuckers, and I'd like to achieve a similar tone to what you get when you coil tap. So I guess a pretty wide mid range cut? I just don't know what frequencies that would be.

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Post by HydrozeenElectronics »

this sounds like a neat idea. Would I be able to get a Mid Range Boost using an inductor? I would like the boost centered on 500HZ.

Thanks

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Post by HydrozeenElectronics »

biffa wrote:Hi Hydro,
Was it my post you're referring to?
If so,then yes,the kit that I put on my guitar has 6 posistions
From treble to bass,and inbetween
You turn it on with a push-pull pot that replaces the 2nd tone pot
The 6 way replaces the 1st tone pot
You still get all your normal tone control,but with fuzz etc...,it comes into it's own
Torres do it
If you buy his stew 62 pickups,you get it free!
If you're really interested I could open up my guitar & photo it,I guess?
I have to say tho',that the very-tone does all you'd need & more
A bit dear for what you're after tho' probably?
do you have any schematics?

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Post by HydrozeenElectronics »

I found this schematic and this article, looks pretty good.

Image

http://guitarnuts2.proboards.com/index. ... thread=644

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Post by Fuzzer »

HydrozeenElectronics wrote:this sounds like a neat idea. Would I be able to get a Mid Range Boost using an inductor? I would like the boost centered on 500HZ.

Thanks
You can't get a boost usindg passive electronics.

In other thread here, there were these Villex tone circuits discussed which allegedly give the impression of a boost.

I believe this is because they use a transformer to bring up the output of your guitar, but the problem is, a pickup doesn't have much current for driving, so I don't know until which point that particular circuit will work constantly.

However, As far as I know, all was speculation, we haven't had one to dissect or try so...
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Post by kleinberger »

What about Bill Lawrence's Q filter?

http://guitarsbyfender.yuku.com/topic/2 ... actly.html

I have one in a tele. Pretty cool.

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Post by HydrozeenElectronics »

Fuzzer wrote:
HydrozeenElectronics wrote:this sounds like a neat idea. Would I be able to get a Mid Range Boost using an inductor? I would like the boost centered on 500HZ.

Thanks
You can't get a boost usindg passive electronics.

In other thread here, there were these Villex tone circuits discussed which allegedly give the impression of a boost.

I believe this is because they use a transformer to bring up the output of your guitar, but the problem is, a pickup doesn't have much current for driving, so I don't know until which point that particular circuit will work constantly.

However, As far as I know, all was speculation, we haven't had one to dissect or try so...

right, It would just cut bass and highs leaving mids. I was thinking of something like a way in a fixed position. But how would you calculate the right caps and inductor to get it to the 500HZ notch?

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Post by Fuzzer »

With the following formulae:

f = 1/{[2*pi]*[(L*C)^(1/2)]}

For example, if you had a 1 [H] inductor, putting it in parallel, to ground, with a 0.1 [uF] capacitor, you would dump frequencies away from 500 [Hz], to the treble and the bass side.

On the other hand, if you put them in series, to ground, you would get the effect of scooped mids as it has been mentioned here.
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Post by HydrozeenElectronics »

Fuzzer wrote:With the following formulae:

f = 1/{[2*pi]*[(L*C)^(1/2)]}

For example, if you had a 1 [H] inductor, putting it in parallel, to ground, with a 0.1 [uF] capacitor, you would dump frequencies away from 500 [Hz], to the treble and the bass side.

On the other hand, if you put them in series, to ground, you would get the effect of scooped mids as it has been mentioned here.
Thanks this is exactly what I was looking for. I'm not very good at algebra so could you maybe plug the numbers into that equation and post if for me so I can figure out other frequencies?

Thanks


Edit:

Never mind I figured it out with this cool program
http://www.deephaven.co.uk/lc.html

according to that if I use a easy to find Wah Wah inductor and a .2 Cap I can get a 500HZ notch like I want. This is going to be pretty cool.

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Post by mojah63 »

biffa wrote:I already said you can't get a boost with passive gear
Read the posts
Actually you can get a mid boost in a passive guitar circuit but there's a very steep fall
off after the cutoff frequency. You'll lose all your highs... As you roll your tone control
down on a standard guitar you'll cut your highs until you get to zero then you'll have a
peak with a sharp cutoff after it. Lower your cap value .02 to like .002 .0002 and you can change your peak higher into the upper midrange. A clever person could have a tone control that accomplishes both...

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Post by Fuzzer »

I don't know if that can be understood as a 'boost', it's the resonance peak. You get that just by using your cable, though.
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Post by TDR1138 »

Ok, I’m looking to build a passive mid control for a bass. I want it to be cut only (i.e. no fake “boost”) and to roll off somewhere around 400Hz-600Hz (I will have to play with the values once I get it built).

I’m putting this in a G&L bass, which is wired with passive volume, tone and bass controls (all cut only). I will be replacing the bass control, so it will essentially be volume, tone, mid.

I’m pretty new at this (I have a pretty good understanding of a basic passive vol/tone circuit, but the mid cut is new to me), but I’m adept at soldering and just need a little guidance. :? So, my questions are 1) what parts/values do I need and 2) how do I put them all together?

Any help is appreciated.

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Post by HydrozeenElectronics »

You are going to loose some volume with a mid-scoop like that. You could build a big muff style tone stack and tweek the RC's to get the scoop you want though.

Just my two cents.

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