Bass Roll Off for Dummies

Discussion in 'Tele-Technical' started by closedmri, Sep 24, 2020.

  1. closedmri

    closedmri TDPRI Member

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    I’m thinking of replacing the traditional tone knob on a new tele build in working on with a passive bass roll off rather than treble. I’ve found that I can use a linear taper pot on the volume to roll back the amount of highs I need from 10-4, and then it acts like a volume pot from 4-0.

    Does anyone have any recommendations for how to convert a traditional pot into a bass roll off as opposed to a treble roll off? I’ve read some stuff about using 1meg pots but that would change the overall impedance of the circuit would it not? I would like to use the traditional 250k pots and replace the capacitor with something that will roll off lows rather than highs if possible.

    Thanks for any advice!
     
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  2. Collin D Plonker

    Collin D Plonker Tele-Afflicted

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    Screen-Shot-2014-07-23-at-9.54.35-AM.png

    I did this mod on my Les Paul. You could do something similar.
     
  3. SuprHtr

    SuprHtr Tele-Holic Silver Supporter

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    A quick edit yields this, since you're looking to get rid of treble cut and stay with two pots. Note that bass cut is produced by placing a capacitor in series in the signal path, instead of using it to send treble to ground via a parallel path. If you're using single-coil pick-ups, disregard the 500K pot recommendation and stay with 250K. I can't vouch for how this will sound, and I'd be prepared to try all of the caps listed to see what works. Capacitors are cheap...

    Screen-Shot-2014-07-23-at-9.54.35-AM.png
     
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  4. closedmri

    closedmri TDPRI Member

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    Wow that looks like it will be relatively easy. I should have those value caps lying around from a kit I got with all kinds of values. Makes perfect sense, I wonder how I‘ll screw it up! Thanks for the replies. Is there a website or software available to draft up diagrams like the ones you guys shared or do most people just use image editing software?
     
  5. JL_LI

    JL_LI Friend of Leo's

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    I use a BOSS EQ-200 for tone shaping. With 4 memories, I have presets stored for all my needs. Bass, treble, or both can be rolled off. I can boost mid range or use the pedal as a clean boost and boost everything. I use the EQ-200 for tone shaping with all of my guitars. I use it to eliminate ice pick from single coils, increase clarity with humbuckers, and make my Telecaster richer sounding or twangier as needed. There's no guesswork about which capacitor will do what I need and there's no soldering station required.
     
  6. closedmri

    closedmri TDPRI Member

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    I’m looking to minimize what I need between guitar and amp to get the sounds I want. I think using an EQ in this instance would not have the same effect as tailoring the sound before it leaves the guitar with passive electronics.

    Just to make sure I’m understanding correctly, the change in capacitor value affects the total amount of bass that can be rolled off as opposed to at what frequency the roll off occurs, right?
     
  7. SuprHtr

    SuprHtr Tele-Holic Silver Supporter

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    Actually, it affects the frequency. The capacitor is a first order high pass filter in this configuration, with a theoretical maximum 6dB decrease in output when potentiometer resistance goes to infinity . When the pot is zeroed, there should be little or no cut.
     
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  8. Peegoo

    Peegoo Friend of Leo's

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    This is how G&L does it.

    [​IMG]
     
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  9. Boreas

    Boreas Tele-Afflicted

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    If you haven't already, you may want to check out the Fender TBX pot to see what it could do for you. It is a stacked pot which does something similar to what you described. I ordered one the other day to try on one of my Teles.
     
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  10. jvin248

    jvin248 Poster Extraordinaire

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    Generic stacked/concentric pot with concentric knob set gives you both a regular tone and bass roll off.

    Open this video in it's own tab, follow the breadcrumbs in the video notes "show more" to link to the article and wiring diagram. It's easier than the G&L which takes ordering some special parts and I found this one worked much better.



    .
     
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  11. closedmri

    closedmri TDPRI Member

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    Thanks guys! That Joe Gore video was part of the inspiration for wanting to give this a shot. The TBX knob does sound like a good idea, more versatility. For now I think I’m going to try out stock pots since I already have em and won’t need to wait for another part to ship. My guitar is just waiting for me to finish it!
     
  12. SuprHtr

    SuprHtr Tele-Holic Silver Supporter

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    Or:
    Comanche-Wiring.jpg
    I plan to use this wiring arrangement when I build with the three Z-coils I got on close-out last year.
     
    Last edited: Sep 26, 2020
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  13. adamsappel

    adamsappel Tele-Holic Silver Supporter

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    I really like the TBX tone pot I have on a Strat. I also like to set the standard tone knob on my guitars at around 5 and make amp adjustments from there.
     
  14. beanluc

    beanluc TDPRI Member

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    Is this 6db per octave, or is it really only 6db and no more than that because of the small resistance of the pot?
     
  15. SuprHtr

    SuprHtr Tele-Holic Silver Supporter

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    Sorry, per octave, yes.
     
  16. Finastbeans

    Finastbeans Tele-Meister

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    Recently did this on my dual humbucker Harmony Guitar. I would recommend experimenting with cap values using alligator clips to get the right level of high pass. I also ended up with a resistor in the circuit to maximize the usable travel of the potentiometer, otherwise most of the cut happens in the first few increments of turn. Here is the wiring diagram...

    upload_2020-9-26_10-52-45.png
     
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  17. beanluc

    beanluc TDPRI Member

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    Hypothetical. Does anyone know what difference it would make if the treble control were wired before vs. after the bass control?
     
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