Help regarding sweepable mids to mids switch mod

Discussion in 'Pickups & Electronics [BG]' started by evermelon, Jan 8, 2014.


  1. evermelon

    evermelon Previously srvlives4evr Supporting Member

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    I know that the Aguilar OBP-3 can have the mids wired in multiple ways including switching, a sweep control and stand alone no selection. This is really a curiousity of mine, but I got this old ibanez varimid preamp soley with the idea of trying a similar idea by modding it to just a switch between two frequencies. I have gone so far as to figure out what each wire connects to as you can see in the pic [brown, yellow, green connect to the mid cut/boost (TOP shaft, B20k), and the orange, white, grey to the sweep (BOTTOM ring, Dual C100k)]. I can wire up the mid control no problem to an individual eq pot, but I am not even sure how to go about trying to figure out wiring the sweep wires in a switchable manner. Not sure if its possible, but like I said, I'm drawing inspiration from the OBP-3. Any ideas?
     

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  2. RockBoxBass

    RockBoxBass Supporting Member

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    I've personally never heard that sweepable mids are possible with the aguilar. I've got at least15 basses with aguilar obp's. I'd love to have sweepable mids. Where did you hear that? Did you draw that diagram?
     
  3. therhodeo

    therhodeo

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    I've yet to wire it up but I have an OBP-2 that I'm putting in a bass and I have an EMG VMC circuit to put with it.
     
  4. RockBoxBass

    RockBoxBass Supporting Member

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    Hmmmm. I'm thinking that would work...have you heard of it working for someone else?
     
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  6. Aguilar/Dave B.

    Aguilar/Dave B. Aguilar Amplification

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    Technically it is possible to wire up sweepable mids using a dual taper pot. However, the change in frequency is subtle and hard to discern because of the fairly wide bandwidth of the mid boost/cut.

    The preamp is designed to work with a switch, and that's the way we sell it. It may have been poor judgment on our part to illustrate the sweepable mids wiring as a response to the question of "is it possible".

    Hope this helps!

    Dave B.
     
  7. evermelon

    evermelon Previously srvlives4evr Supporting Member

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    The PDF wiring diagram (last pg) for the OBP-3 from Aguilar shows a bunch of different configurations for the midrange and the last one on the page is a 'continuously variable' option. I've never done it (I have an OBP-3 as well w/switch) but I thought maybe since it apparently can be done, maybe this 'vari-mid' preamp I have can be done too, well from a sweep to switch that is. It might not be able to because circuts can vary and whatnot, but I am not knowledgable enough to wrap my head around what exactly is going on circuit-wise with the sweep portion of this stack pot. Its a stack with a B20k (bottom 3 lugs) for the midrange and dual C100k (above 6 lugs) for the sweep. It has 9 lugs total soldered to a board, and 6 wires connected to the board and that's it (no micro components). I made that diagram/pic based off what it looks like and the connectivity paths and thats an image of the pot for reference.
     
  8. RockBoxBass

    RockBoxBass Supporting Member

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    Thanks Dave! I've never really explored it to date, just because I never really felt it necessary. On all my obp3's I either have a switch, or pp and it gives me a wide variety of tonal options. I have noticed...I tend to boost using 400, but tend to cut while using 800 . It's such a great sounding circuit already, sweepable might just overload my brain!
    Robert M. , New Orleans
     
  9. evermelon

    evermelon Previously srvlives4evr Supporting Member

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    Ok, so after some time trying to figure this out, I came up with something. After an initial test (wired everything up, just not on a bass) it seemed to work! Now to actually install into a bass and really try it out. I will post up my solution if it works.
     

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