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Built-in Overdrive Project - HELP

Discussion in 'Pickups & Electronics [BG]' started by croftyttl, Jul 30, 2012.

  1. croftyttl


    Jul 30, 2012
    So the idea is to buy a Jazz Bass kit from http://www.diyguitarshop.co.uk/kits.htm#jb and modifying it with a built-in overdrive circuit.

    From a purely "where will it all go?" stand point, I've decided to have a friend rout some cavities for me underneath the scratchplate (space for the OD circuit between neck join and neck pickup, and a 3-way switch on the lower horn, and channels for all the wiring running to join the pickup wire channels) and will move the jack socket to a side mount ala Telecaster.

    I want to use an OD pedal that has a small-ish circuit that will be simple to remove pots and connect new pots in the control panel. I was planning to use a Boss BD-2 if I could as this pedal is woefully underrated, so will ebay/b stock it where possible.

    My question is this - I can competently read wiring diagrams and follow them, however I know very little about PCB circuits. I want to use a stacked pot for tone/gain and a push/pull to control level and on/off, and then single neck/bridge volume controls for the pickups.

    What is the best way to wire the existing pot contacts on the board with the pots at the control panel, and what type of pot would be best to use?
  2. bassbenj


    Aug 11, 2009
    I'm not a huge fan of OD on a bass (I use a Bad Monkey for some "grit" but it's pretty mild) but I love the idea of built in effects in a bass.

    First thing is you want to be sure you have a pedal that doesn't have a huge battery drain. And install one of those flip-out battery holders to make changing batteries easy.

    Then I'd wire it pretty much the way you would if it were a pedal. What I mean is you wire the jazz bass as if it were a jazz bass first. I happen to prefer volume/blend but that's up to you. Then you take THAT output and direct it to the OD pedal. Obviously you don't need all the heavy case/battery stuff/ foot switch etc. from the pedal. But you DO need to replace the foot operated switch with a toggle switch of the same type and wiring on the bass. This may or may not be easy. If the foot switch uses one of those standard push button toggle switch, just get a bat handle toggle switch of the same type and wire it the same. However. if the foot switch is a micro switch on the circuit board you'll do the same thing (only now the same type may be a momentary type switch). You'll have to pull the switch off the PC board and use wires to extend the circuit to the new switch.

    Hint: When working with circuit boards NEVER over-heat them! The copper foil will come loose! And buy a relatively cheap device known as a "solder sucker". It's a spring-operated suction tube for pulling solder out of the contacts of whatever is soldered into the board. You heat the joint, apply the sucker to it, and press the button (usually takes about three hands!). And voila! The solder (or most of it...sometimes takes a few tries) is pulled out and with a little wiggling and heating you can get the part free without damaging the board.

    The other place you may need this is the pots on the pedal. Now MY choice would be to leave the pots on the circuit board (usually they are mounted on the board) and then mount the whole thing under the pickguard with the row of pots (that used to be across the top of the pedal) down along the edge of the bass. If you really, really, want one of those pots on the control plate, then pull the pot off the board and mount it over there and run wires from the board to the pot. SAME pot. Just wrap wires around the circuit board pins on the pots, solder them, and cover with shrink tube.

    Since I have a TRS phantom 9 volts to power my active basses a built-in pedal would work great and take no batteries. Indeed I actually OWN such a bass I built MANY moons ago. It has a built in vibrato and a special Hammond organ Leslie speaker imitating circuit. I still have it, but it is MUCH too noisy for modern use because of the ancient technology in it. However, it's basically like I just described. There is a row of 4 knobs along the upper horn that adjust the effects (speed, depth, etc,) and there are three mini toggle switches by the control plate. These turn the Vibrato on and off, the Leslie on and off and the tone knob on and off (off is max bright, on is the knob setting). Uses a 9 volt battery under a plate (as I indicated, less than optimum) and I thought it was quite an advance at the time. Adding in the fact that it's short scale it has quite an unusual tone.

    Good luck.
  3. croftyttl


    Jul 30, 2012
    With respects to powering it all, I would be using a 9v with a flip out box on the back of the bass, and was thinking of basing the battery section on the EMG system of powering things (once the jack is plugged in, the circuit is completed and can be switched on and off, the jack removed results in no battery drain) but not using active pickups.

    As for the pots, I'd quite like to have it all on the control board to keep it aesthetically a Jazz bass, no extras visible. I was thinking of a stacked pot for tone and gain, and a push/pull for level and switching which should allow me quite a lot of control without having extra knobs all over the bass.

    With respect to the circuit of the pedal I want to use (see attached photo for an image pulled off google), the pots appear to be attached to the circuit by a cable that reminds me of old pc to printer cabling. I think it might be simpler to use new pots, but am uncertain what the lugs would do. Any suggestions? Kee4.
  4. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    You'd be better off using a very small circuit like this GuitarFetish Mod Board "tube distortion". That stomp box has all the foot switch stuff associated with it, and I'll assume that might be an electronic for switch.


    I've installed over drive circuits in guitars in the past. I like having them on the floor better since I can use them with different instruments.
  5. croftyttl


    Jul 30, 2012
    I've looked into the Modboards before, and although I like the soundbites they have with guitars, the BD-2's sound works really well for what I have in mind. Thanks for the input though!

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