Bass pickup blend: traditional dual ganged or...

[ubersam]

I gutted my bass to replace the onboard preamp. I'm keeping the stock unit intact for easy re-installation so I won't be re-using the pots. So instead of getting a dual-ganged B500K pot for a blend pot, I thought I'd try a snippet from the B-blender circuit instead. I haven't built it yet so I want to ask firs, will this work as an alternative bass pickup blend pot?



EDIT: it's not a snippet but rather inspired by snippets of the B-Blender and the Bass Paralooper

[bassmannate]

Unfortunately, no. You need to turn the volume down on the pickup you want to fade out and to do this, you have to short it to ground. Otherwise, some of the signal will still pass through the resistor element of you pot and make it to the wiper.

I used to think the same would work years ago until someone explained the electronics to me. Best way to do it is with a dual ganged pot.

[ashcat_lt]

I suppose it depends how important it is to you to know that you're not getting any contribution at all from one pickup when turned toward the other.  How good is good enough.  You'll have 16.8/126.8 x the one pickup mixed in with the full output of the other.  Is that too much?  I'd tend to think that it will be fine for bass guitar.  Something is telling me that the "3:1 Rule" - which I prefer to call the "at least 9db rule (of thumb)" - applies here.  If one is 9db or more louder than the other you probably won't notice the quiter one's contribution enough to care.

A bigger pot will give more separation.  Another important question, though, is what happens in the middle of the pot's rotation.  You need to be somewhat careful picking values of resistors and the pot in order to keep a fairly constant volume through the sweep.  Wouldn't do much good to have a whole bunch of separation at the ends if the middle is half as loud as either!