Need help with J + MM pickup config.

[Philthy]

I'm a bit experimental with bass building and revamping. I have a jazz bass in which I routed out the bridge pickup to fit a MM style humbucker. I installed a 2-band active preamp. Here's my dilema. I have both a bartolini Jazz bass neck position pickup and a bartolini MM style bridge pickup. I have everything wired correctly (so I think). I'm getting good sound out of the bass however I notice when I turn the blend pot to only have the neck pickup (Jazz pickup) on, play a note and bend the string; the volume kinda cuts out when the string is bent. It's weird. It's kinda sounding like a wah, flanger effect. Any reason as to why this would happen. It doesn't happen when I put full blend on just the MM pickup.

Do I just have a bumb neck J pickup? Any ideas?

Thanks for your help.

[FBB Custom]

what is the model number on the neck pickup?

[Philthy]

ok....this is what is carved on the bottom of the pickup 9W544-L

[FBB Custom]

Well, I don't know if this is the reason or not, but the 9W4 is a quadrophonic pickup. There are 4 coils in it, spaced for a jazz bass. It may be that you are moving the string enough to get out from over any one coil. The "L" also usually indicates a bridge pickup, so this might make the problem more noticeable if it were used as a neck pickup.

I also seem to recall someon e mentioning that the 9W's were somehow inappropriate for MM+J setups. I also recall not understanding why, but I have seen a post somewhere indicating that. Might be worth trying to scare up a 9J1 to see if things get better. Bartolini would know best, obviously, but they can be hard to get in touch with.

[Philthy]

Thanks alot. That makes alot of sense about bending the strings past the coils. You've been very helpful. I'll see if I could get my hands on another bartolini.