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Mid selection on Bartolini preamps

Discussion in 'Effects [BG]' started by sheepdog, Apr 30, 2004.


  1. sheepdog

    sheepdog

    Feb 20, 2003
    Birmingham, AL
    I see that the Bart preamp can be used with a 3 way toggle for mid selection. Would it be possible to use 3 different mid pots (1 for each position) instead of the toggle. This would be if I used the 3band preamp as an outboard preamp. I wouldn't want to fit that many pots on a bass.

    side note: any reason the box for this couldn't be made out of wood? Easier to build than a metal one.
     
  2. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    no easy way I can think of doing what you suggest. The switch determines the frequency, and the one mid pot determines the cut/boost at that one frequency. It'd require some pretty extensive work to the preamp to have three separate cut/boost mid bands.
     
  3. sheepdog

    sheepdog

    Feb 20, 2003
    Birmingham, AL

    if it uses a 3 way switch, that would mean there are 3 different wires from the preamp. Instead of choosing one at a time, I would be choosing all 3 at once. Makes sense in my feeble mind, but that doesn't mean anything. :rolleyes:
     
  4. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    There aren't three wires in the switch, what happens is that the switch position selects a varying capacitance which in turn determines the one frequency range being boosted/cut.

    Look at this wiring diagram, bottom of second page, for a diagram of the mid switch wiring:
    http://www.bartolini.net/instructions/electronics/ntmb/ntmb918f.htm
     
  5. sheepdog

    sheepdog

    Feb 20, 2003
    Birmingham, AL

    ah...and 1 wire can only run 1 pot at a time. Oh well, still more flexibility than other mids...

    Can it be wired to be continually variable between the low and high mid frequencies (similar to what can be done on the Aguilar OBP3)?
     
  6. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    I think the best way you could emulate it would be via a rotary switch which selected different capacitors depending on switch position.

    The old aria pro II sb-1000 bass used this method for it's 'attack' switch.
     
  7. sheepdog

    sheepdog

    Feb 20, 2003
    Birmingham, AL

    just realized that the rotary mid selection on the aguilar could use capacitors to be cont variable from 200-800. I like the idea of using an aguilar anyway, so back to the aggie. I would stick to Bart for 2 band eq, though.

    Thanks for the help