Here's a weird one: v/v/t/t, both vol knobs have to be on...

[Basschair]

I just finished my first passive wiring job on a new build of mine. Here's the specs:

2 Nordstrand dual coils
Each DC -> 3-way switch (Series/single/parallel) -> V/T with .1 microfarad caps. See here for the 3-way switch diagram I followed, half way down the page.

See here at the bottom of the page for the diagram I followed for the v/t circuits. The only thing I didn't do was run a string ground to the bridge.

Grounds are to backs of pots, with grounds terminating at the jack ground. If you look at the Stew Mac diagram (bottom of linked page), whenever it says "From Pickup" and "From Ground," I ran the hot and ground wires from the 3-way switches.

The setup sounds amazing: crisp, clean, quiet, and strong from low to high. I played for a while plugged in to my Acoustic Image Contra I.


Here's the problem:

If either of the volume knobs is all the way down, there is no sound. I can have the neck all the way up, but if the bridge is all the way down then there's no signal. Vice versa with exactly the same results. Now, if I have the neck all the way up and turn the bridge vol up just a bit, then it sounds like I get all the signal from the neck pup with the slightly fatter sound you'd expect. If I have the bridge vol up all the way and the neck pup up just a bit, I get that tighter bridge sound. So, both volume knobs have to be up at least somewhat in order to get any signal. Is this a grounding issue? A wiring issue? An amateur wirer issue? By the way, changing the 3-way switches to different settings has absolutely no effect on this at all.

Thanks for any advice: for now, I'll be playing it anyway, pretty much non-stop .

[Lobster11]

There was a lengthy and very informative discussion recently about the problems involved in wiring a passive bass V/V/T/T here:

Best way to wire VTVT

Turns out to be much more problematic than almost anyone would've guessed!

[maurilio]

in a dual vol conf, the pups need to be wired at the center lug of the pot (the opposite of your diagram).

[slyjoe]

Originally Posted by maurilio

in a dual vol conf, the pups need to be wired at the center lug of the pot (the opposite of your diagram).

Why?

[maurilio]

if you want to have the volume ctrls working separately from each others.....

[slyjoe]

With one end of the pot grounded, the two wiring schemes are equivalent.

[Basschair]

Right on, thanks for the link and comments guys: I'm too wiped out right now to change it, but the next time I've got to do some soldering I'll crack it open.