pickups, pots and caps

[giliad]

A couple years ago I built myself a 5 string bass with two Kent Armstrong soap bar pickups. I've built few guitars and this is the only bass so I kept the wiring simple. I bought the basic P-bass kit from Stewmac that had (2) 250K pots, a .050 cap, the jack and a little wire. I added a blend pot instead of switches for the two pickups. The blend pot was also 250K.

 

The result was a very mellow bass that was just what I wanted.

Now my son is using it on tour with a rock band. He says it's too mellow, not enough punch. He turns the treble up and EQs everything to the treble side but that doesn't give him much flexibility. He has a 4 string Fender J with noiseless pickups and really likes the way that sounds but he needs the low B playing with this band.

 

He'll be home for a few weeks around Christmas and we thought we would make some modifications.

My first idea is to change all the pots to 500Ks and use a .02 cap. I have a couple of DPDT switches we could add to so he can reverse polarity on one or both pickups if he wanted.

 

For all you who know more about this than I do, will this give it more punch?

Any better ideas?

Other than buying a new 5 string J.

[bassman1956]

Soap bars are often humbuckers. Humbuckers tend to be more mellow, and are usually set up with 500k pots, and caps of .050 to .100. I'd try swapping to the 500k pots first, they'll give you a hotter, more trebley sound. After that, maybe try the caps.

 

Last, consider switching options. For this, are your soapbars humbuckers? 2-wire or 4? There are options with this. 2-wire, not so many, but you could still do a 3-way between the pups, series-parallel-series out of phase. If 4-wire, you could do that with each pup.

[giliad]

Yes they are humbuckers with 4 wires if I remember correctly. Two wires are just connected together right now.

I guess I'll try the pots first and have the cap on hand to experiment with too.

I'll have to think about the switching. Thanks.

[NineMinuteNap]

It sounds to me like the bass is passive, so there's no such thing as turning the treble up. Passive tone controls are cut-only. When the tone knob is fully clockwise, it isn't adding treble, its not cutting it.

 

A smaller cap would raise the cutoff frequency, so it wouldn't cut as much treble. Using a 500k pot would have a similar effect.

 

In order to get the "most" sound (or the widest range of frequencies), you could ditch the tone knob and hook the volume pot straight to the output jack.

 

As far as I know, the only way to actually add treble is to go active and/or use a preamp (either installed on the bass or an external pedal/rack).

[giliad]

 

It sounds to me like the bass is passive, so there's no such thing as turning the treble up. Passive tone controls are cut-only. When the tone knob is fully clockwise, it isn't adding treble, its not cutting it. A smaller cap would raise the cutoff frequency, so it wouldn't cut as much treble. Using a 500k pot would have a similar effect. In order to get the "most" sound (or the widest range of frequencies), you could ditch the tone knob and hook the volume pot straight to the output jack. As far as I know, the only way to actually add treble is to go active and/or use a preamp (either installed on the bass or an external pedal/rack).

 

 

Yeah OK, he's turning the tone knob fully clock wise and not cutting existing treble. So I'm not adding, just not cutting as much with the changes, if it gets the desired tone then all is good.

 

An external pedal/preamp might be good alternative too