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Running pickups straight to jack, through a cap

ElectraPhoenix

ElectraPhoenix

Jan 10, 2010
407
4
Houston, TX
#1
Ok. So, I have an interest in running my bass without a volume pot, going from volume to a switch I have installed, then through a cap and to the output jack. So, no tone knob. My question is - what value cap works best in this setup?

Using a Fender Jazz Bass in a P/J setup.
 
#3
Ah, sort of. I've found that I never really use the tone control - all the way down is useless, and it's almost always just wide open. I just use my amp to EQ in my tone. I'm re-vamping this bass I have (that is my only bass) and so I'm making it completely custom. I'd like to just get rid of the tone control entirely, but I'd still like to wire in a cap so I get basically the same effect as a wide-open tone knob.
 
#4
And if I remove the cap entirely, I'll get a more treble-y sound, right? This might be ideal b/c I'm considering using the DiMarzio model P/J set... what is a smaller value cap I could wire in that would still cut treble but not as much as other caps? In other words; what are common cap values that will cut less treble relative to other common cap values that cut more?
 
#6
M0ses said:
If you put it pup>cap>output, it will have the same effect as having the tone control all the way closed i.e. max treble cut.
Click to expand...

That would be my thought too. If I were you, I would just forget about the cap, and run the pickup straight to the output (notice I said output line6man ;)) jack. Yeah it's a little brighter, but the added brightness is almost insignificant.
 
#7
Ok; I was just wondering because I've read on here that if you wire it the right way, it'll function as a low pass filter and cut a little treble but not all of it. It is probably just simpler to wire it w/o the cap entirely, though.

In fact I think I'll do that... thanks very much for the help/information. I'm pretty new to wiring; you can probably tell.
 
#8
If you wanted to, you could wire it so that a resister took the place of the potentiometer, resulting in a fixed amount of treble cut. Or you could do like line6man does, and wire in a resistor or two without any cap, getting rid of that tiny bit of brightness capnsev is talking about.
 
#9
M0ses said:
If you wanted to, you could wire it so that a resister took the place of the potentiometer, resulting in a fixed amount of treble cut. Or you could do like line6man does, and wire in a resistor or two without any cap, getting rid of that tiny bit of brightness capnsev is talking about.
Click to expand...

That's an interesting idea... I've heard that the added brightness is pretty unnoticeable (and not necessarily undesirable) so I'll probably just keep it simple.
 
#12
M0ses said:
It sounds to me like what you're looking for is pups straight to jack, no nonsense. Although with a P/J configuration, I'd suggest a three-way selector switch.
Click to expand...

Yeah, that's more what I'm looking for. I have a switch in there and it's wired nicely right now.. but I'm looking to get a better volume pot and output jack, remove the tone pot and possibly install better pups (just revamping all the wiring, basically). So I'll need a diagram, eventually.

I actually have a 4-way switch so I have "neck/series/parallel/bridge". But I'll need to rewire it when I get all the new parts, so I'll be needing a diagram... P/J config that goes "single volume knob - switch - jack" (so no tone knob or caps involved). Would you mind, line6man? That would be simply amazing...

http://www.guitarelectronics.com/product/SWR41/4-Way-Rotary-Guitar-Pickup-Selector-Switch.html
this is basically what my switch looks like (it's a rotary rather than a Tele/Strat style switch
 
#13
ElectraPhoenix said:
Yeah, that's more what I'm looking for. I have a switch in there and it's wired nicely right now.. but I'm looking to get a better volume pot and output jack, remove the tone pot and possibly install better pups (just revamping all the wiring, basically). So I'll need a diagram, eventually.

I actually have a 4-way switch so I have "neck/series/parallel/bridge". But I'll need to rewire it when I get all the new parts, so I'll be needing a diagram... P/J config that goes "single volume knob - switch - jack" (so no tone knob or caps involved). Would you mind, line6man? That would be simply amazing...

http://www.guitarelectronics.com/product/SWR41/4-Way-Rotary-Guitar-Pickup-Selector-Switch.html
this is basically what my switch looks like (it's a rotary rather than a Tele/Strat style switch
Click to expand...

Sure.

Just a neck/series/parallel/bridge rotary toggle and a volume, right?
 
#14
line6man said:
Sure.

Just a neck/series/parallel/bridge rotary toggle and a volume, right?
Click to expand...

Well, I'd like there to be an output jack too ;)

But yes, that'd be awesome. Thanks very much. Also, quick note... the volume control has to be in the first position and the switch in the second (I have a 4-hole control plate) because the switch is pretty big and I had to hollow out the spot for the switch so now it fits perfect. Also, I know that now I'll only have three holes filled in the control plate and one empty, which is fine.
 
#15
Also, if I switch to using the DiMarzio P/J set... what kind of volume pot do I use? 250k or 500k? Since I'm getting rid of the tone pot (thus boosting the brightness a little) would the 250 be better?

Also... audio taper has the smoother tapering, right? So that's the better kind to use?
 
#16
ElectraPhoenix said:
Also, if I switch to using the DiMarzio P/J set... what kind of volume pot do I use? 250k or 500k? Since I'm getting rid of the tone pot (thus boosting the brightness a little) would the 250 be better?

Also... audio taper has the smoother tapering, right? So that's the better kind to use?
Click to expand...

You can use either, but 500Ks will be a bit brighter.

I personally prefer linear taper volume pots, but it's a topic of much debate around here.
 
#17
line6man said:
You can use either, but 500Ks will be a bit brighter.

I personally prefer linear taper volume pots, but it's a topic of much debate around here.
Click to expand...

250s are supposed to be "warmer" so I think I'll go with those... I'll be getting a little added brightness since I'm bypassing the tone control anyways.

As far as the linear vs. audio taper... I don't suppose it matters too much, since it's mostly just going to be all the way off or all the way on for me (although I do play with my volume on occasion).
 
#18
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#19
ElectraPhoenix said:
Ah, sort of. I've found that I never really use the tone control - all the way down is useless, and it's almost always just wide open. I just use my amp to EQ in my tone. I'm re-vamping this bass I have (that is my only bass) and so I'm making it completely custom. I'd like to just get rid of the tone control entirely, but I'd still like to wire in a cap so I get basically the same effect as a wide-open tone knob.
Click to expand...

A lot of people find the "toy" tone controls nearly useless. But there is a bit more to this than you think. A passive pickup is a coil of wire and as such it has three electrical properties: Inductance, resistance, and capacitance. These three circuit elements combine to form what is called a "resonant circuit". Such a circuit does not respond equally to all frequencies. In fact it has a "resonant frequency" at which it produces more output. And above that it produced less and less. Hence the frequency response of a typical passive pickup is NOT "flat". It is set not only by the inductance, resistance and capacitance of the pickup itself, but also by those parameters in the external circuits. Those external values include the volume control resistance, the tone resistance and capacitance (depends on tone setting) and the cable capacitance. It also depends on whether more than one pickup is wired in series or parallel.

The bottom line is that the "adjustment" of these things by pickup makers is what gives each brand/model it's certain tone.

Where this is going is that if you strip out all the external circuit, you may want to wire back in some parts to simulate what was there before. I do not believe you need a series capacitor. The main function of that would be to reduce the bass response and it could shift the resonant frequency to an undesirable place. The tone cap when the tone control is set to minimum effect is virtually out of the circuit anyway so is not important. The value of the volume pot (usually 250k or 500k) on the other hand is important and is widely known to change the tone (500k being brighter).

So what I suggest to pursue what you are trying to do (and I've thought about doing this myself. would be to remove all the wiring and pots. wire the pickup directly to the jack. (If there are two pickups, I'd feed them out seperately on two jacks or a TRS jack.) Then wire a fixed resistor across the jack(s) simulating the value you were using for a volume control previously. Now you pretty much have a direct feed to your amp from the pickup.

Now here's the thing to try. Get a multiband parametric EQ unit and substitute that for all the component value adjustments usually used to change pickup tone by inserting it in the effects loop. You can shape the frequency response of the pickup just about any way you wish with this set up.

I think this *MIGHT* be an interesting way to control your tone from a "direct drive" bass.
 

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