Jazz tone cap

[RoKuLiKa]

I borrowed a MiJ jazz bass and it needed a little maintenance. I cleaned it up. Neck volume wasn't working well so deoxited it check connections all that good stuff. It worked but I noticed the tone knob worked but it wasn't as bright a sound as it should've been and when tone was turned all the way down it cut the volume to almost nothing. So I sprayed it, re soldered it but it stayed the same.

So I come across a thread on another place and this guy was saying he had the same problem. So he took the capacitor leg off and it worked fine so I tried it and it worked. I took off the cap leg that was soldered to the back of tone pot and let it hang without touching anything and now it works as it should.

So why is this?
Thanks!

 

[RSBBass]

By removing the cap leg to ground you disabled the tone control. The tone control shunts some frequencies to ground. The cap controls which frequencies go to ground and the pot controls how much of them go to ground. Now none do, so it is brighter. A better fix would be to play around with different value caps until you get one you like.

 

[RoKuLiKa]

But the tone control is not disabled, it works like it is supposed to now. It is brighter. But when I turn the tone know down the tone gets darker as it should. So the tone pot works and sounds like it should brand new without the cap.

Before the sound was muffled when tone on ten, then when I turn tone all the way down instead of getting even darker it would lose volume instead.

 

[Matt Liebenau]

Pictures of the wiring?

 

[RoKuLiKa]

Pictures of the wiring?

I will post when I get home from work

 

[SulzerType2]

The tone might still get darker due to the loading of the pot? The cap is doing nothing if one leg isn't grounded at all.

 

[Marty Forrer]

Impossible for the tone to work if the cap is disconnected. It defies logic.

 

[MidlifeBeginner]

Regardless of why it is working the way it does, leave it that way if you are happy.

If you ever sell it, likely someone will curse your name for not wiring it standard.

 

[Ostie]

Regardless of why it is working the way it does, leave it that way if you are happy.

If you ever sell it, likely someone will curse your name for not wiring it standard.

Well, it’s a pretty easy fix, assuming there’s some leg left to solder back to ground.

 

[RoKuLiKa]

 

[RoKuLiKa]

So there is the pic. And again the all both volumes and the tone control work as they are supposed to. This fixed the problem. I have another capacitor I can put on but I don't know if I want to. It sounds fine as is. No buzzing nothing. It's as good as new.

So why? Is the cap just for certain frequency roll off? It's a 250k pot. I'm just curious as to how and why? Not trying to fix it because it already fixed like this.

 

[sissy kathy]

I don't see the cap lead going to the center contact on the pot; it looks to me like the cap goes to the top contact. If that's the case it's no wonder the tone didn't work, as the Cap was never in the circuit. The mystery now is WHY DOES THE TONE CONTROL WORK NOW?

 

[yeasty]

You don't have a tone control; you have an inline "master variable resistor" which is a new one to me.

The tone control adds an RC filter (resistance and capacitance) to the hot leg , with the amount of bleed from the hot side controlled by the potentiometer to ground. Through the cap.

Your circuit has the hot leg (center leg, rightmost pot) going through another pot to go to the hot output.

Connect the hot output to the middle leg of the tone pot -- move it from where it currently is.

TL;DR -- Connect the big dab of solder to the cap -- and the ground path.

 

[J-Bass RMR]

Mis-wired.
the white wire connected to the output jack should be connected to the center terminal of the adjacent pot.

@Artman had it right 1st - I didn't see your post, then it was there, then it was gone...

 

[Matt Liebenau]

A bit late but, as said above, the tone control is miswired. If the tone is changing it’s because of some odd loading from the potentiometer.

 

[SulzerType2]

I don't see the cap lead going to the center contact on the pot; it looks to me like the cap goes to the top contact. If that's the case it's no wonder the tone didn't work, as the Cap was never in the circuit. The mystery now is WHY DOES THE TONE CONTROL WORK NOW?

The output from the volumes is running to the centre lug of the tone pot. An outer lug of this pot is connected to the output jack. Turning down the tone control puts the resistance of the pot in series with the output. It is essentially an ungrounded volume, like the 5th 'blend' knob on some Rickenbackers. In doing so some highs will be lost.

 

[Tommy Sparks]

If you like it leave it as is.
There was some witchcraft (not the band) going on with the existing wiring. It never worked
Correctly wired that way.
Also I enjoy the band Witchcraft very much.

 

[39-Bassist]

I am curious to know if you wire it correctly, will it sound better or worse than what it does now?

Hmmm...the world may never know...lol

 

[Tim Skaggs]

Looks like it should be acting as a master volume as wired. The signal wire coming from the pickups is on the center lug of the tone pot, one outside lug has the disconnected cap and the other lug appears to be grounded. Turning the pot max one way should do nothing and the other way should ground the signal. The pot is probably NOT getting down very close to zero ohms when turned in the direction to ground the signal, so the volume isn’t going to zero. With the flaky pot, you are probably getting some high end reduction without losing signal completely. If you keep messing with the tone pot, it might “turn into” a master vol control….

Edit; the lug opposite the cap appears to be connected to nothing when I gave it another look. I was seeing the reflection of another wire in the chrome control plate. So now, the middle lug would be going to low resistance to each outside lug when the pot is turned to the max in either direction. Since the lug with the cap also has the wire going on to the jack, when you turn the pot one direction, the signal is passing through. When turned the other way, you are adding the pot value resistance between the pickups and the jack. That probably affects highs most, so it’s acting a little like a tone control by accident. If you move the wire from the jack over to the center lug and reconnect the loose leg of the cap to the pot case (ground), you should have a normal tone control

 

[JeezyMcNuggles]

I borrowed a MiJ jazz bass and it needed a little maintenance. I cleaned it up. Neck volume wasn't working well so deoxited it check connections all that good stuff. It worked but I noticed the tone knob worked but it wasn't as bright a sound as it should've been and when tone was turned all the way down it cut the volume to almost nothing. So I sprayed it, re soldered it but it stayed the same.

So I come across a thread on another place and this guy was saying he had the same problem. So he took the capacitor leg off and it worked fine so I tried it and it worked. I took off the cap leg that was soldered to the back of tone pot and let it hang without touching anything and now it works as it should.

So why is this?
Thanks!

It sounds to me like the hot was being affected by the pot. Which could be a couple things, but usually that the hot is ran on the left node instead of center. In my experience. It ends up acting like a volume pot, where it attenuates the hot signal as you turn it down.