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Need some mudcutting on varitones/mid-cut coils/lo-cut options

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  • Need some mudcutting on varitones/mid-cut coils/lo-cut options

    I've been hassling out mid-cut coils for a while and have made a couple of useful observations, but I'm still fuzzy on a few things.

    Firstly, I followed the advice on another forum and bought an assortment of TL018-TL023 coils from Mouser. But I don't see how they're usable...yet. The "fattest" of them doesn't seem to have more than 600ohms resistance on a on the TL021, for example, says to use the 4kOhm side if memory serves...none of these puts out anything in the kilohm range. Now, I've also been looking at varitone circuit diagrams...I can't quite wrap my head around them. The coil comes after the capacitor in the do these lower-inductance coils become sonically useful when placed after the cap? If not, what specific effect does the coil have when used in series with the capacitor that it doesn't have on its own...if any?

    Second...after experimenting with everything from generic relays to the coils out of bug-zapper paddles, I've had some luck using gutted pickups as mid-cut coils. I've actually built a little outboard box with 4 gutted strat pups, ranging from 3.3kOhms (Squier Bullet neck, I believe) to 8kOhms (Peavey Raptor middle), and these shrill, cheap Squier pickups really do a passable job...they should have inductance ratings in about the "sweet-spot" 1.5-2H range. But so far my circuitry is pretty primitive...I simply wire the pickup to a pot as though it was a tone cap; I'd be interested in suggestions on how to get a more sophisticated result, as this tends to suck a bit more output volume than I think it should, and doesn't seem to be tunable.

    Third...I've never seen this discussed, and it seems like it should be important information. When using capacitors, it seems to my ears NOT that a higher-value cap actually reduces more treble, but rather than it begins to shelve the treble at a lower frequency. (I'm assuming it's a simple 6dB/octave cut? Or does it cut on a curve?) It seems to be a fairly consistent effect, yet I've never seen a chart listing the frequencies at which particular caps begin to shelve.

    I know that caps also work as bass-cut filters when wired in a different way. I recently discovered a terrific little p/j bass mod, in which a capacitor on the hot side of the bridge j pickup gives me a p/j tone with all of the bottom of the pre pickup and only the highs from the jazz pickup. It would be nice to know on this side as well at which frequencies particular capacitor values begin to filter out the bottom end. I'm aware that this capacitor must be affecting my bridge pickup, but since I never use it alone, I don't notice it...and I don't hear an effect on my amp. I only notice its effect when both pickups are selected.

    This mid-cut stuff seems remarkably esoteric stuff, even at this point in time, considering the value that this knowledge has. (My clumsy squier mid-cut coil does a great job of leaning-out high-output humbucker tones when dialed in judiciously. A well-selected coil value should allow for very usable pickup emulations on a LOT of guitars.) Any light you guys could shed on these mysteries would be greatly appreciated. My first exposure to this stuff came from an ancient "Tone Qube" gadget that I used in several guitars in the '80s and never fully understood...I've loved this concept ever since.

  • #2
    The mouser transformers work well for mid cut circuits.

    If you want to cut the lows, use a cap in series with the signal.

    Yes, larger value treble cut caps cut at a lower frequency. If you want a steeper cut without huge loss in volume, you have to go with an active filter design.
    It would be possible to describe everything scientifically, but it would make no sense; it would be without meaning, as if you described a Beethoven symphony as a variation of wave pressure. Albert Einstein


    • #3
      If you absolutely know the inductance of your PUP's to within ~10%, you can use the GuitarFreaks tool to show you frequency analysis graphs of your circuitry. I figured out how to get very specific adjustable mid cut/dual peak boosts with a 1.8H Wilde Q-filter by wiring a cap over the PUP and another in series with the parallel wired Q-filter and a pot. Lower inductance PUP's have more flexibility, but there is a higher value Q-filter for bass.