vari tone in a box

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Greg Martin
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vari tone in a box

Post by Greg Martin »

Im going to start winding my own pickups and thought a 12 way varitone switch box could help dial in the tone when used on a surragate bench body. I have all the varitone parts but one. The inductor. On guitar wiring many used a mouser 42TL021-RC mini transformer for the inductor. Do I need to use one in my varitone in a box? What is the purpose of this inductor? Ive read 1.2-3henrys will work, but Id like more info. Also how is a decade switch different than the varitone?? thanks

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Mark Swanson
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Re: vari tone in a box

Post by Mark Swanson »

Greg, can I ask why you need the varitone? if you are winding pickups, the best way to get the tone you need is to make the pickup to sound the way you want it to right "out of the box". In other words, if you wind it right in the first place the tone will be there right from the start, making it much easier to get the sound you want when things are done.
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Greg Robinson
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Re: vari tone in a box

Post by Greg Robinson »

Greg, if I understand you correctly, what you are hoping to do is to compare different capacitors with the pickups you wind to select what you feel best matches them for use in a tone control, is that right?
If that's the case, I think you're a bit confused as to the function of a varitone. Both a varitone and a conventional "tone control" are passive filters, but they work very differently.
A conventional tone control is an RC filter (resistor capacitor), which forms a low pass (rolls off the highs).
A varitone is an LC filter (inductor capacitor), and forms a band pass filter (from memory, I haven't looked at the circuit for a while), so effects the frequency response differently.

A decade box allows you to easily select different capacitor values, and would be what you want if I understood you correctly, although, you will likely find that the conventional values will work best with most conventional styles of pickups.
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Greg Martin
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Re: vari tone in a box

Post by Greg Martin »

LOL Man I didnt want to start a brain fest here. I want the 12 way varitone box so I can hear the result on my own pickups when using a certain tone cap, thats it? I want to wind a few different pickups using different wire and different magnets. I would like to know if I should use a xion 42tlo21 transformer as an inductor or a different one or none, and what does the inductor do to the varitone curcuit? ,is there an advantage to using it in the varitone curcuit or not?. The one I made for my EBO did not have the inductor, it sounds great,just curious ??????????????

Bill Raymond
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Re: vari tone in a box

Post by Bill Raymond »

Greg M, I think you should re-read Greg R's post above. He describes very well the difference between a "varitone" and a decade box which selects various capacitors. It _sounds_ like you simply want a tone control in a box, or a decade box and not a varitone with inductor. Greg also explained the varitone very well. It's really up to you to decide what kind of circuit you may want to put in a box to try.

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Greg Robinson
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Re: vari tone in a box

Post by Greg Robinson »

Ok Greg, no need to get worked up.
Well that definitely sounds like you want a decade box, not a Varitone.
You mention that you made a "varitone" for your EBO, but that it didn't use an inductor, well, without an inductor, it's no longer a Varitone, but a tone capacitor selector switch.
A Varitone is a completely different control that affects the entire frequency response of the pickup (pass bands), rather than just the high frequencies (low pass) like a tone control (larger the cap, the more highs are rolled off).

Easiest way for you to understand the difference would be to try out a guitar that has a Varitone, and compare it's differences with a conventional tone control.
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Beate Ritzert
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Re: vari tone in a box

Post by Beate Ritzert »

Mhmm, i always thought the varitone was a band attenuation filter, not a bandpass. The maximum of attenuation is somewhere in the range of about 200 Hz to 2000 Hz.

IMO 12 steps is overkill. You should chose capacitor values increasing by a constant factor from step to step in order to obtain steps equal to the ear. Then You will probably find that 5 steps + "off" are more than enough. (same for RC-switches controlling the pickup resonance on its damping)

BTW have You ever thought of building a PI-filter for that purpose (the circuitry of the AMZ tone control, to match passive guitar pickups with impedances scaled upward by a factor of 5)?

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Greg Robinson
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Re: vari tone in a box

Post by Greg Robinson »

Yes, you're right Beate, I just had a look the circuit again, and it's an RLC band stop (notch) filter.
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Bill Raymond
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Re: vari tone in a box

Post by Bill Raymond »

I believe that's correct, now that I think about it; I should have looked at the circuit before posting. The technicalities aside, what our excited questioner needs to know is "it ain't a Varitone if it ain't got an inductor!"--or, in standard English (for our foreign members and visitors) it isn't a Varitone if it doesn't have an inductor. I think what he wants is simply a selector switch that will connect various values of capacitor in the circuit.

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Beate Ritzert
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Re: vari tone in a box

Post by Beate Ritzert »

Please see my remark on these Switches above. My experience with parallel Cs is that You need to add additional damping by a parallel R, especially for the larger values of C. My first build was actually such a switch - constant factors between the capacities, and 5 values + "off" proved more than enough to cover the range from "off" to darker than ever needed" in very natural steps. Since then i am using switches with no more than four selections.

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David Schwab
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Re: vari tone in a box

Post by David Schwab »

Varitone circuits are notch filters that cut out the midrange. If you remove the inductor, then they are decade controls that cut out the high frequencies. Some instruments, like the L6-S guitar and L9-S Ripper bass, used a potentiometer as a midrange control, instead of the rotary switch with the assorted caps.

If you make either, be sure to install 10Megohm resists from the "hot" side of the cap to ground, so that you wont get pops when you switch it.

Greg Martin
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Re: vari tone in a box

Post by Greg Martin »

thanks everyone great info

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