Would this be a reasonable thing to do?

[jglunt2112]

I love my Fullerton SB-2, but I'm partial to basses with one volume control. (Probably the result of playing a P-bass for a thousand years.) The SB-2 has two, one for each pickup, and the balance between those pickups is how you set the bass's tone. (Of course, you all know that.) So if you have to turn volume up or down during a song or set, you have to do it by adjusting one pickup at a time and, at least for me, tweak it several times to get that tonal sweet spot back. Of course, said tweaking also changes the volume as well, so it can all start over. I thought of this possible solution that wouldn't require any routing or other "heavy lifting." Run the volume for both pickups through the first pot, making it a master volume. Change out the second pot for a fader control to dial in how much of each pickup goes to the output. The bass would look exactly the same as it does now, but volume adjustments would be simpler and more consistent tonally. Could this work? Has anybody tried this? Is there a diagram showing the wiring for this with pot values, etc.? Diagrams I can follow; an electronic innovator I am not. Thanks...Jim

[Ken Baker]

Reasonable? Sure!

Here you go. Click the image for a PDF suitable for printing.



Pots are both 250KA (250KΩ Audio taper). Those downward pointing arrow thingies represent a connection to ground. Arrange the leads as needed. The final connection to ground is to the sleeve connection on the jack.

Ken...

[jglunt2112]

Beautiful. I just might have to give this a try. Thank you...Jim

[jglunt2112]

I have had no luck finding a 250k-250k audio taper blend pot. Everything I find is linear. I've checked All Parts, Stew Mac, Amazon, and even G&L. Does anyone have an idea where I can find one of these? Thanks!...Jim

[Ken Baker]

I have had no luck finding a 250k-250k audio taper blend pot.

I was working off a really old set of notes.

A standard 250K-250K blend should be fine.

Sorry about that.

Ken...

[jglunt2112]

No problem. Even the diagram you sent me states plainly a 250kA pot for the blender. I was wondering if I was going crazy. Now there's no more need to wonder...I know for sure that I am. Thanks...Jim

[Ken Baker]

The diagram was hand scrawled by yours truly.

Just get a 250K blend pot.

Ken...

[jglunt2112]

I finally installed a 250k blend pot into my SB2, so it's wired as master volume & blend. I used a linear taper pot, as I couldn't find an audio taper pot. (See previous messages.) I had a hum problem, which I figured out thanks to you guys, but it just isn't acting right. The blend is not smooth at all. It kind of changes as if it were a notched switch, not changing at all, then taking a jump, then repeating that. Is that because of the linear taper? It also somehow seems to have affected the volume control, as it very slowly increases volume until it's about 3/4 full, then it jumps up much louder. I tried an MN taper blend pot, which was a disaster. It literally sounds like I have a 3-way switch installed. I did find a seller on Ebay that had one 250kA blend pot, which I ordered, but I'm curious if any of you might have some thoughts on this...Jim

[jglunt2112]

Here is a follow-up question (or two) to my follow-up question (see previous post on this thread). Ken, I notice on your wiring diagram that the ground from the "X" on the blend pot just shows going to ground. Is it supposed to be connected to the chassis of the blend pot? I read some articles elsewhere that say not to do that, but (1) doesn't that introduce the possibility of hum, and (2) isn't the blend pot grounded anyway because it's against the foil on the back of the pickguard, as are the jack and the volume pot, both of which are grounded? I grounded both the "X" to the blend pot chassis and ran a ground wire across from the volume pot chassis to the blend pot chassis. I also grounded the bridge pickup and the bridge to the chassis of the blend pot. Am I wrong in doing all that? My feeble and inquiring mind wants to know ....Jim

[Ken Baker]

I finally installed a 250k blend pot into my SB2, so it's wired as master volume & blend. I used a linear taper pot, as I couldn't find an audio taper pot. (See previous messages.) I had a hum problem, which I figured out thanks to you guys, but it just isn't acting right. The blend is not smooth at all. It kind of changes as if it were a notched switch, not changing at all, then taking a jump, then repeating that. Is that because of the linear taper? It also somehow seems to have affected the volume control, as it very slowly increases volume until it's about 3/4 full, then it jumps up much louder. I tried an MN taper blend pot, which was a disaster. It literally sounds like I have a 3-way switch installed. I did find a seller on Ebay that had one 250kA blend pot, which I ordered, but I'm curious if any of you might have some thoughts on this...Jim

Sounds like there's something odd going on in the pot. Possibly taper, but impossible to check without a replacement. You have one coming, so we'll wait for that.

Here is a follow-up question (or two) to my follow-up question (see previous post on this thread). Ken, I notice on your wiring diagram that the ground from the "X" on the blend pot just shows going to ground. Is it supposed to be connected to the chassis of the blend pot?

Any ground point that connects to the sleeve of the jack is good.

Ken...