Tone doesn't work

-executor- · #1 03-14-2009, 08:28 PM

I just switched my bass from active to passive.
I wired it with new pots and the volume works but the tone doesn't. Its a vol/vol/tone/tone setup, so it can't be that both the tone pots are bad.

Does anybody have any ideas about what could be wrong?

This is the diagram I used to wire it(since its 2 volumes and 2 tones, its just two of these):

megadan · #2 03-14-2009, 08:38 PM

Did you use a common ground for the whole system?

I would look into getting a full 4 pot schematic.

-executor- · #3 03-14-2009, 09:00 PM

Theres a ground wire from the bridge soldered onto the casing of one of the volume pots. The other pots are connected to the casing of this pot.

Even with only one tone and one volume connected, the tone doesn't work. In that case, my wiring looks exactly like the picture.

ErebusBass · #4 03-14-2009, 09:20 PM

Shouldn't the final hot lead wire to the jack be coming from the tone pot? I'm pretty sure that's how mine is wired. I see the hot/ground from the volume pot to the tone pot, but it looks like the hot lead goes from volume pot to jack.

I don't think your signal can go from your volume pot, to the tone pot, BACK to the volume pot, and then to the jack... Maybe I'm wrong. Maybe your drawing is wrong. Otherwise, there's your problem Jim.

seanm · #5 03-14-2009, 09:28 PM

The cap and hot lead on the tone pot are reversed. Put the hot to the center tap.

-executor- · #6 03-14-2009, 10:19 PM

Quote:

Originally Posted by seanm

The cap and hot lead on the tone pot are reversed. Put the hot to the center tap.

I did this and I think it helped, because I hear a difference now, but it seems like it just barely changes the sound when I turn the knob now.

Quote:

Originally Posted by ErebusBass

Shouldn't the final hot lead wire to the jack be coming from the tone pot? I'm pretty sure that's how mine is wired. I see the hot/ground from the volume pot to the tone pot, but it looks like the hot lead goes from volume pot to jack.

I don't think your signal can go from your volume pot, to the tone pot, BACK to the volume pot, and then to the jack... Maybe I'm wrong. Maybe your drawing is wrong. Otherwise, there's your problem Jim.

Can you tell me all the changes I'd have to make to how its wired now?

ErebusBass · #7 03-14-2009, 11:15 PM

Like this... But I would switch the posts that the cap and the hot are wired to on the tone pot. Hope this fixes you up.

Edit: wow, my lines look like they were drawn by a toddler.

seanm · #8 03-14-2009, 11:29 PM

Quote:

Originally Posted by ErebusBass

Like this... But I would switch the posts that the cap and the hot are wired to on the tone pot. Hope this fixes you up.

It actually doesn't matter where the grounds go, as long as they are all connected together.

ErebusBass · #9 03-14-2009, 11:31 PM

Quote:

Originally Posted by seanm

It actually doesn't matter where the grounds go, as long as they are all connected together.

Good to know, thanks for that.

seanm · #10 03-14-2009, 11:32 PM

Quote:

Originally Posted by -executor-

I did this and I think it helped, because I hear a difference now, but it seems like it just barely changes the sound when I turn the knob now.

What is the value of the tone pot?

RyreInc · #11 03-15-2009, 08:05 AM

The original drawing is fine. Sometimes it can be hard to get a solid connection to the pot body--use a multimeter to test for continuity between the ground points on the pot body. Also using a single solder point to connect both the ground wire and the cap together will help.

Seanm's suggestion about cap value could be a good clue as well.

-executor- · #12 03-15-2009, 10:35 AM

Okay, I rewired it like Erubusbass's drawing and the tone definitely has more of an effect now.

By the way, the tone pot is 500k (audio taper) and the capacitor is .047uf. If these were different would the tone have more range?

EDIT: actually when its wired this way, now the volume pot doesn't do anything.

Ideas anybody?

GlennW · #13 03-15-2009, 12:42 PM

The way you had it in post #1 should work. If it doesn't it might be a bad pot.

The way you have it now bypasses the volume pot; that's why it doesn't do anything. The center lug of the volume pot should be connected to the hot side of the jack.

seanm · #14 03-15-2009, 01:33 PM

This is what you want:

-executor- · #15 03-15-2009, 03:36 PM

Okay, the tone and volume work when wired that way.

However, when I try to put a second volume and a second tone in for the other pickup, neither of the tones work.

Another strange thing that happens is when I turn down the volume knob for one of the pickups to 0%, it cuts off the sound for both pickups. I don't know if this has anything to do with my other problem, and I'm definitely more concerned about the tone not working than this.

And by the way, I really appreciate all the help everyone's given so far.

seanm · #16 03-15-2009, 04:52 PM

Quote:

Originally Posted by -executor-

Okay, the tone and volume work when wired that way.

However, when I try to put a second volume and a second tone in for the other pickup, neither of the tones work.

Another strange thing that happens is when I turn down the volume knob for one of the pickups to 0%, it cuts off the sound for both pickups. I don't know if this has anything to do with my other problem, and I'm definitely more concerned about the tone not working than this.

And by the way, I really appreciate all the help everyone's given so far.

That is correct, you can't just wire the two together. Either volume control will short out both. You need to look at a wiring diagram for a J bass.

GlennW · #17 03-15-2009, 05:23 PM

I hate the standard JB wiring...just another way for Leo to save a few bucks. Many love it, but having to turn two knobs to switch pickups is for the birds (IMO, of course).

-executor- · #18 03-15-2009, 05:37 PM

Basing it off of the j bass, how would I wire it with two tone controls?

GlennW · #19 03-15-2009, 05:40 PM

What are you trying to do?...individual V and T for each pickup without a selector switch?

-executor- · #20 03-15-2009, 05:42 PM

Yeah. Does that not work?