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Adding more treble cut to Aguilar OBP-3

Discussion in 'Pickups & Electronics [BG]' started by Aloe, Apr 30, 2017.


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  1. Apr 30, 2017 #1
    Aloe

    Aloe

    Apr 10, 2016
    Ukraine
    Hi,

    I've swapped the preamp in my bass with OBP-3 and am really surprised how bright this preamp is (compared to the previous one). That is: I cut all the treble on the preamp and still have to notably cut it at the amp to get a tone I like. Is there a way I can make it sound darker?

    I understand that one possibility is to add a passive treble control in addition to the preamp's one. But that would need another hole in my guitar, so trying to avoid this solution.

    The guitar is Yamaha TRBX-505. Preamp is OBP-3. Wiring is 500k vol, 220k balance, stock 50k pots for the preamp. Swapping the volume for 250k would withdraw some treble, but I think I will need it darker.

    Would adding a capacitor to the treble pot help? Or something like this?
     
  5. Apr 30, 2017 #2
    ddnidd1

    ddnidd1 Supporting Member

    Mar 31, 2003
    Southern California Coast
    You can't just add a capacitor to the treble pot. The active circuitry is entirely different from passive circuitry.

    You could add passive treble rolloff circuit using a trimpot (and capacitor) inside the control cavity if you always like the high end rolled off.
     
    Last edited: Apr 30, 2017
    Aloe likes this.
  10. Apr 30, 2017 #3
    RobbieK

    RobbieK

    Jun 14, 2003
    Smellbourne, Oz...
    The trick is to add a capacitor and maybe a resistor to the volume pot. IOW, a tone pot. This can be soldered directly to the volume pot. Personally, I'd just clip in a test jig with a pot and try a few caps, then use the nearest resistor to the pot's final setting.

    As ddnidd1 said, you could also use a trimpot.

    Perhaps you can use a stacked control? Either stack your treble and bass together to leave a hole for a passive tone pot. Or perhaps switch your volume pot for a stacked concentric pot so you get the passive tone pot underneath the volume.
     
    Last edited: Apr 30, 2017
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  14. May 1, 2017 #4
    wcriley

    wcriley

    Apr 5, 2010
    Western PA
    If you can get a sound you like by cutting at the bass and at the amp, I don't see the problem.
     
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  18. May 1, 2017 #5
    Aloe

    Aloe

    Apr 10, 2016
    Ukraine
    The more time passes the more I like the resulting sound. After tweaking the EQ on other bands it does not sound as trebly. Thanks everyone for the suggestions.
     
  22. May 2, 2017 #6
    winegamd

    winegamd

    Jun 3, 2007
    Mount Vernon, WA
    Change the volumes to 250K. This will make a bigger difference than you think. I think if you added the passive tone, too, all of your problems would be solved. You could potentially change the 50K pot to a 25K and get more boost or cut, but it will also change your freq center/s, so that might not be a good option.
     
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