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Help! Trying to hook up new preamp to existing pickups

Discussion in 'Pickups & Electronics [BG]' started by bassistnc, Jun 28, 2014.


  1. bassistnc

    bassistnc

    May 27, 2013
    Hi all, I just recently bought a 1994 Ibanez SR506 off of ebay and when I got it, some of the electronics don't work as they should and I can tell that some items have been replaced/doctored. Instead of trying to problem solve 20 year old electronics, I bought a new preamp and am having trouble installing it. Each pickup has 3 wires that come off of it and the instructions don't offer any help when I have such a situation. There is a red wire, a white wire, and a third wire that has a cloth covering. I am assuming that they are +, -, and ground in that order. The instructions that I have (Tone Monster SEB3 v.2 Active preamp) Only give me info for the + and the GND on the blend control. Am I supposed to hook up the GND's or the -'s to the GND on the blend control? And what am I supposed to do with the other wires? Thanks for any help.
     
  2. You likely have pickups with separate shield grounds. The shield and the negative-phase lead from each coil needs to be grounded.

    The other explanation would be active pickups. If that is the case, the red wire goes to the battery's positive terminal.
     
  3. LoveThatBass

    LoveThatBass

    Jun 28, 2004
    Question: Did you look at how the pickups were connected to the original preamp and controls? I have seen some that the red and white tie together and the shield goes to ground or back of pot control or side of the blend pot. The 506 originally came with Bartolini MK1's
     
  4. JustForSport

    JustForSport

    Nov 17, 2011
    Pickups on that year SR506 (if original) are ADX6's which are active. DX6's are passive and only have signal and ground (2) wires.
    I'll try to get a photo of cavity up.
    Also, I'll try to attach a wiring diagram.
    What pre are you installing?
    The red and white *do not* tie together on these active pickups.
    Photos shortly...
     

    Attached Files:

    Last edited: Jun 28, 2014
  5. JustForSport

    JustForSport

    Nov 17, 2011
    SR506 cavity shots- with EMG, the pickup red is straight from the battery. With this preamp, the pickups are supplied power from the PCB.
    From the schematic, they could be powered straight from the battery as EMG's are.
    Hope the photos show enough- I don't like moving old wiring that 'works just fine' around too much.
    I'd be interested in your old SR506 pre for parts- pm me.
     

    Attached Files:

  6. JustForSport

    JustForSport

    Nov 17, 2011
    Just re-read the OP and the red is power from the battery, the white is signal to blend pot, and cloth-covered remaining wire is ground.
    Some people prefer not to ground the blend pot (don't know if it matters with active pickups) in which case you can run the pickup grounds to the vol pot and tie in to the system ground.
     
    LoveThatBass likes this.
  7. LoveThatBass

    LoveThatBass

    Jun 28, 2004
    Yes, looks like you have a handle on it! Tell us how it works out for you
     
  8. bassistnc

    bassistnc

    May 27, 2013
    Well, I tried it with the red wires going straight to the battery, the whites to the signal contacts on the blend pot, and I tied both grounds together and connected them to the ground contact on the blend pot. I got no sound at all other than the preamp turning on and off when I plugged and unplugged the guitar cable in. I have sent an email to the manufacturer in hopes of getting schematics for hooking up this preamp to active pickups. Maybe I will get a response in a day or two. I will try tonight moving the pickup grounds to the volume pot ground to see if that makes a difference. If that fails and I don't hear anything from the manufacturer maybe I will break down and buy some nice passive pickups since the stock pickups are apparently not much to write home about anyway. I look forward to any advice and will post any progress. Thanks
     
  9. Connecting pickups to batteries without verifying that they are active is not a good idea! Fortunately, the current through the coils would not be enough to melt the insulation, but it is a risk of damage to the pickups.
     
  10. LoveThatBass

    LoveThatBass

    Jun 28, 2004
    Leave pickups hooked up and pull the pots and output jack from the control cavity. Now connect a guitar cable up to it and the amp. If you have sound then something (pot or output jack) was grounding the signal to the shield (assuming it has shielding) in the cavity. I used tape under the pot terminals to eliminate mine and installed one at a time, tested and moved to the next one. If it doesn't have sound then suspect a wiring problem.
     
  11. JustForSport

    JustForSport

    Nov 17, 2011
    + ^^
    If no sound after that, connect the pickups to the bal pot, to the volume pot, to the jack, by-passing the pre. They may not be real loud, as they're designed to be used with the preamp, so...
    The EMG active 40 series are fairly hot, and can be run w/o a preamp.
    Re-check all grounds from pickups, vol pot to jack.
    It is a stereo jack?
    If the signal is grounding out somewhere, it won't matter if they're active or passive pickups- same result.
    If they're the original ADX6 pickups, they're split 'P' inside, humbucking, quiet, and clean sounding.
    Do the pickup leads look like the ones in the photo that I prev posted?

    Edit: Just tried a set of ADX5's- by passing the EMG pre that's in that bass, and the ADX5's are plenty hot to be run w/o a preamp. ADX6 and ADX5 differ only in coil length. (This was brought up recently on another thread, so I had to see if they'd be hot enough by themselves.)
     
    Last edited: Jun 29, 2014
  12. JustForSport

    JustForSport

    Nov 17, 2011
    I found the schematic and a photo of the PCB for you preamp.
    After checking the above, connect as per the diagram, and good luck.
    Also, be sure your 9v batt is hot.
     

    Attached Files:


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