Converting Fender 9 volt system to 18 volts?

Discussion in 'Pickups & Electronics [BG]' started by jayman121, Jul 1, 2008.

  1. jayman121

    jayman121 Supporting Member

    Sep 13, 2003
    I have a Fender MIM Deluxe Active Jazz bass 5 string with vintage noiseless pickups and Fender's 3 band active EQ/ preamp. I think it's the same preamp that comes in the American Deluxe models, the difference seems to be that the American series preamps are 18 volts while the MIM models are 9 volts. My question is: Can the 9 volt system be converted to 18 volts? The preamps seem identical in specs. I'm not getting enough headroom with 9 volts and seem to be clipping the preamp especially when slapping. I get a loud popping sound when slapping hard and I think it's the preamp OR could it be the vintage noiseless pickups? I like the preamp so I'm thinking of replacing it with an 18 volt preamp OR trying to convert the 9 V system.
    Does anybody knows if it can be done or maybe have tried? Thanks.
  2. Nighttrain1127

    Nighttrain1127 Supporting Member

    Nov 27, 2004
    Near Worcester MA
    Just route for a second battery box and connect pos to neg and neg to pos of battery boxes and leave the original battery box connected as it originally was. The only difference between 9 and 18 volt systems is a bit more head room So you can push the pre a bit further before you overdrive it. Not sure how the pre will like the extra voltage.
  3. bongomania

    bongomania Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    That's kind of important there. ;) It will vary from one pre to the next, not all are designed to be able to handle 18V.
  4. jayman121

    jayman121 Supporting Member

    Sep 13, 2003
    Thanks for the feedback guys. I'm not sure if you can add a second battery to this preamp but judging from the specs it seems that it might be the same preamp without the second battery. I'll try and hook up another battery and see. Routing the cavity deeper will be the hardest part.
  5. Nighttrain1127

    Nighttrain1127 Supporting Member

    Nov 27, 2004
    Near Worcester MA
    You could always route wider and use a double battery box
  6. that would be more similar to the american deluxe models which are in fact 18volts (some of them anyway.. mine is)
  7. ReidK

    ReidK Jst sy n t lsy cmprsn.

    The MIA and MIM active jazzes use the same preamp (Fender part number 0054137000), and the MIAs use two batteries, so the preamp should be able to use the extra voltage without a problem.

    I've got one of the MIMs myself, and I've been planning to try this out. While I'm at it, I'll draw a schematic for the preamp and post it here.