Jazz VM Series Parallel mod..does not sound good

jazzmik

New member
Hi Folks, I've done this mod on my Squire Jazz VM Bass and its doesn't sound good. Its very noisy and the bridge pup is hardly noticeable as well as the tone, btw the push/pull pot is A250k. The only difference is my Seymour duncans have 2 black wires and 1 white ea compared to the drawing. I've grounded the second pair of black wires as they previously were. Don't know if I have a bad push/pull or if the wiring is not right but I'm considering removing this mod and going back to VVT setup. I hear good things about this mod but it doesn't sound good to me, Any ideas before I go ahead??
Thanks
 
Re: Jazz VM Series Parallel mod..does not sound good

Welcome to the forum!

Would it be possible to post the drawing you are using? It might help me (and others) understand what is going on.
 
Re: Jazz VM Series Parallel mod..does not sound good

Yeah we need a diagram of what you did, and maybe some pics.
 
Re: Jazz VM Series Parallel mod..does not sound good

Hi guys, I didn't get around to taking actual shots of the mod yet. The first pic was the original wiring from the VM bass, the second(below) is the series/parallel wiring mod. I left the original cap which I believe is a 0.22uf as I did not have a 0.5uf like the drawing.squire-jazz2.jpgjazzB_VVT.jpg, Jazz_VVT_SP.jpg
any help appreciated, thank you
 

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Re: Jazz VM Series Parallel mod..does not sound good

Your SD pickups have 3 wires (1 white, 2 black?)? They could either be tap-optional pickups (although IIRC those use a red wire), or one black wire is an isolated ground while the other black wire is the (-) side of the coil. If you don't experience any of the same problems when switched in parallel which is running the "stock" wiring, then you wired the switch wrong - JB pickups in series should not sound as described. If you do experience the same problems when switched in parallel (which would definitely be a tell-tale - but not so conclusive if the statement is not so), then swap one (or both) of the pairs of black wires. If you have one of the iso ground wires reversed and touching the hot signal (via serial wiring), that would introduce all of the excess ground noise, while grounding the side of the coil that should be in the series link. From your wiring schematic (which should work), both black wires on the bridge pickup should go to ground, the neck's isolated ground should go to ground, the other black to the corresponding switch terminal, and white to the vol pot. One way to check which wire is which is with a multimeter: if you get a reading between one pair of white and black wires, those are your coil wires and the remaining black wires should go to ground.
 
Re: Jazz VM Series Parallel mod..does not sound good

Yeah, I was pretty surprised when I saw those extra black wires, tap optional?? that should give me more options but I wasn't able to find any info on them anywhere. 1 wire follows the bridge and the other two they seem to follow the pups and as you can see they were grounded on the volume pot's casing together with the pups black wires. I will test them with a meter to see which give me a reading. Also, I do get the same noise either in parallel or series, that's why I said it sounds terrible(very weak) and noisy, btw, the original setup worked just fine. Will do some testing tonight to find out what's going on. thanks
 
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Re: Jazz VM Series Parallel mod..does not sound good

Well I re-worked the pup wiring and all those extra black gnd wires, and its now much better, no more noise. Only thing is the Master tone seems to have no effect at all.
Should I be changing that original cap to 0.5uf? as the original has no more effect on the tone??
thx
 
Re: Jazz VM Series Parallel mod..does not sound good

It's either bad joints or bad pot, probably not the cap.
 
Re: Jazz VM Series Parallel mod..does not sound good

My guess is a bad pot or solder connection. I myself have never had a cap go bad. Doesn't mean it can't happen, just not likely. I have had bad pots and lots of bad connections, though.
 
Re: Jazz VM Series Parallel mod..does not sound good

My my,,where does the time go.. I really haven't had the time to look at it. I will make some time this weekend to check things with the multimeter.
Since my last post where I said there was no more noise, well that only lasted a few minutes. the noise came back but its not as bad as before, maybe a bad pot??
I also observed that with the original VVT setup each pup together seemed louder than the current (down)parallel mode but there is a nice boost in series mode. I'm not entirely satisfied with this mod. anyways I will re-check everything. thanks for the advice.
 
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Re: Jazz VM Series Parallel mod..does not sound good

Well, looks like a bad pushpull, makes sense why I get a boost when pulled and only noise when down(parallel). all pots and caps tested good. I'm ordering a new replacement part.
 
Re: Jazz VM Series Parallel mod..does not sound good

Congrats on finding the issue! I hate diagnosing problems like this in my own guitars. Usually by the time I get to that point I am tired and cranky and just want it to work.
 
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