Sanity Check PJ Bass

[Dmac252]

Need a sanity check here.

I have just installed a couple of new pickups in my custom Bass I have wired for 2 volume and 1 master tone.

I can not seem to make it work properly both volume pots are CTS 250k the tome pot is CTS 250k as well

the volume pots are bridged on position 1 the pickup hots are on position 2 respectively position 3 is grounded to the casings.
the bridged volumes are wired to the position 1 of the master tone with a .047 cam on the middle position to grn. position 3 is open.

there doesn't seem to be much wiggle room for error, but hey one never knows.

My issue is that the volumes do not work properly the become interactive in very negative way. the volume have very little sweep and engages only at the very top and when I try to bring up the bridge pickup it also engages ate the top bu cuts the volume and tone on the neck pickup and visa-versa:11::11:

 

[Funkfingers]

Re: Sanity Check PJ Bass

Welcome to the forum.

Please include some photographs of the actual wiring inside your instrument. Chances are, you have made and/or overlooked some minor error. We need to see that error in order to point it out.

Regarding the behaviour of your volume pots, what resistance taper have you used? Audio/logarithmic (A), Linear (B) or some other (D)?

Also, it is possible that you have misinterpretted the (semi-)schematic diagram. The convention is that the pots are illustrated as if viewed from below. (As you would observe them whilst soldering.) If you have, effectively, wired up Audio taper pots in reverse, they will misbehave exactly as you have described.

 

[Dmac252]

Re: Sanity Check PJ Bass

Sorry, just saw the response, been out of the shop for a bit. Anyway here are a few photos of the wiring. a little tough to shoot the master tone is in a separate cavity. I color coded the a couple of wires so to keep track. The white with the blue marker goes to the jack. the RED wire is a ground from the bridge, they are all audio taper pots.

 

[Demanic]

Re: Sanity Check PJ Bass

Your capacitor in your tone pot is grounded on both feet. See the way it's laying across the pot? The leg that's attached to the post of the pot is also grounded to the pot body itself.

 

[Funkfingers]

Re: Sanity Check PJ Bass

In the last photograph, I am struggling to understand what is happening where the capacitor "leg" meets the pot terminal. The solid wire appears to be tucked between the bent steel contact and the plastic board. Significantly, the wire DOES NOT appear to be soldered to the terminal at any point.

Hence, the capacitor is not in circuit. The pot works as neither tone nor volume.

The solid wire "leg" of the capacitor needs to pass through the "eye" of the pot terminal and to be soldered into place.

 

[Dmac252]

Re: Sanity Check PJ Bass

Your capacitor in your tone pot is grounded on both feet. See the way it's laying across the pot? The leg that's attached to the post of the pot is also grounded to the pot body itself.

No it's not, it only looks that way from the aerial view.

 

[Dmac252]

Re: Sanity Check PJ Bass

OK let me settle the cap comments the TONE works fine the cap is grounded on one leg and soldered to (through the eyelet) the tone pot on post 1 or 3 depending on you preference for naming. My issue remains volume pot functionality not a tone issue
thanks

 

[Funkfingers]

Re: Sanity Check PJ Bass

Allow me to "settle" how a conventional Jazz Bass control system goes about its business.

• Audio taper 250k pots achieve most of their volume reduction between 100% and 70%.
• Connecting the pickup signal to the central terminal and running the audio output from terminal #1 tends to further reduce the apparent "sweep" of the pot.
• The classic approach is to set one pickup to maximum volume and roll the other off until a "nasal" comb filtering effect occurs.

The imbalance between the signals of a vintage-style PJ bass pickup pair means that the comb filtering is less pronounced.

The expression "negative" is subjective and imprecise. Describing sound through words is always difficult. Hence, a sound clip would communicate more quickly.

If operating your pickups individually sounds good but operating them simultaneously sounds "thin" or "weak", you may have a phase relationship issue.

 

[BlueTalon]

Re: Sanity Check PJ Bass

Just a comment -- I love how that pickguard was designed and executed.

One thing I noticed is that in the SD diagram in the OP, the cap is wired to the center terminal, whereas you have it connected to one side. Just an observation.

 

[Funkfingers]

Re: Sanity Check PJ Bass

By Jove. He's got it.

White insulated conductors to terminal 3. Capacitor to terminal 2.