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VVT troubles (Jazz Bass pickups)

twinjet

twinjet

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Sep 23, 2008
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#1
Hey gang.

I am having an interesting time with my J. I can run pickups full on or soloed. I can't seem to blend the two together. Additionally, my tone knob doesn't seem to alter the sound very noticeably. It's either tone off, somewhat off or wide open.

There is no 80/20'ing the neck & bridge, etc. It's either both full on, or a pickup is soloed.

I noticed this issue as soon as I installed the first set of new strings. It doesn't change if I'm going through an amp or headphones. It's just weird. I'm sure the solution is simple, though...
 
#10
Slater said:
Emerson pots are just pricey CTS with a little tighter tolerance.
Click to expand...
That's basically what he told me, yeah.
BassWaffle said:
It's not super clear to me how you aren't able to blend them, do you mean that when you back off one of the volumes it doesn't change at all until it is all the way down? Same with the tone, are you describing sudden shifts?
Click to expand...
Yup, you got it. Tone is similar, but changes are not so sudden.
 
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#12
bigtone23 said:
How is the harness wired? What are the values and taper of the pots?
There is a pretty standard way to wire a VVT J bass. FWIW, with typical passive pickups, using 250K linear taper volumes and a 250 or 500K audio taper tone makes a VVT most easily finessed.
Click to expand...
Honestly I have no recollection of what he used aside from using cheaper CTS pots. I can try and find out later.
 
#13
I think what we're more interested in is how it was wired, not necessarily the specifics on the pots. Can you post clear photos, and or make decent enough drawings so we can learn what's going on better?
 
#14
I'm having the same issue with my MIJ Jazz V/V/T harness, get (what sounds like an) 85-90% volume level drop when the tone's backed off. Pickup volumes seem to work fine tho far as blending. I braved a newbie self-installation job with a set of Aguilar HC J-pups a few months ago & am just now getting to follow-up on my blunder. Also changed the mini-pots for 300k CTS audio pots for volume & a 250k 0n the tone (I think). Anyone have a clue as to what I"ve done wrong here? IMG_0001.jpg IMG_0002.jpg IMG_0004.jpg IMG_0005 2.jpg
 
#15
Stringkill said:
I'm having the same issue with my MIJ Jazz V/V/T harness, get (what sounds like an) 85-90% volume level drop when the tone's backed off. Pickup volumes seem to work fine tho far as blending. I braved a newbie self-installation job with a set of Aguilar HC J-pups a few months ago & am just now getting to follow-up on my blunder. Also changed the mini-pots for 300k CTS audio pots for volume & a 250k 0n the tone (I think). Anyone have a clue as to what I"ve done wrong here?View attachment 3576009 View attachment 3576010 View attachment 3576011 View attachment 3576012
Click to expand...

You may be shorting a connection against the shielding (if any). I had that problem with a P bass where turning the tone control down killed the volume. A bit of rejiggering the connections and/or the output jack might fix that.
 
#16
ahc said:
You may be shorting a connection against the shielding (if any).
Click to expand...

You mean, the copper shielding inside? I'll look into that, there IS a ground screw that I added into the control cavity & soldered connection to see if the original bridge ground was an issue (the striped lead on tone pot that looks like Beetlejuice's sleeve is bridge). Though the drop was very present before adding that & no uncovered parts are touching the cavity inside when closed.
 
#17
Stringkill said:
I'm having the same issue with my MIJ Jazz V/V/T harness, get (what sounds like an) 85-90% volume level drop when the tone's backed off. Pickup volumes seem to work fine tho far as blending. I braved a newbie self-installation job with a set of Aguilar HC J-pups a few months ago & am just now getting to follow-up on my blunder. Also changed the mini-pots for 300k CTS audio pots for volume & a 250k 0n the tone (I think). Anyone have a clue as to what I"ve done wrong here?View attachment 3576009 View attachment 3576010 View attachment 3576011 View attachment 3576012
Click to expand...
Photo #3 shows a close-up of the neck volume pot...that center-lug connection (pickup Hot); the wire looks rather long and can be shorting out to the pot case.
Same thing can be said for pic #4 - the wire from center lug of the tone pot (which goes to the bridge volume pot) also looks rather long and can be shorting to ground...this might be the actual cause of your problem.
 

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