Modding a custom jazz 5 string bass w/ Alembic electronics


I was considering adding a Q-switch to my recent bought custom built sandwich body jazz set neck with Alembic electronics, but I first removed the original cap and then rigged up some wires with alligator clips to try out some of the many odd and vintage caps I have to see what they would sound like. I found 5 I like and do not sound like each other. I also tried many others that sounded bad or made horrible squeals of various frequencies while plugged into my amp.


I am now thinking of crafting a 6 position varitone switch with the 5 caps instead of a 2 or 3 position Q-switch, just for something to do. The adding of 1M resisters to eliminate pops when turning the switch will add a lot of work, but what the hey.


I wonder if anyone else has messed with this idea. I know the series 2 variable Q is kinda like this idea.

so the old time analog circuit engineer guy in me says you may get different results between an alligator-clipped prototype and a neatly soldered, trimmed and shielded final result so you may want to make a couple of intermediate trials before you button it up to make sure nothing changes from version to version.

other than that, it sounds like a cool idea, good luck with it.  nice looking bass btw. :-)

Don't forget to shield that puppy!

Here's my little board with the various caps on it. After some sound testing I decided I did not like the tone of the setting where no cap is in the circuit, so I am adding another old cap in there. Now to decide where to put the 1meg anti-pop resistors.

Yeah, I know that the cavity needs some shielding paint. Odd that whoever built it skipped that part.
Thanks Mica!

Quote from: gtrguy on January 20, 2022, 01:04:59 PM
Yeah, I know that the cavity needs some shielding paint. Odd that whoever built it skipped that part.
Thanks Mica!

Perhaps the builder used EMG pickups. I know some luthiers who do not shield the cavity when using EMG electronics.

Very cool bass and mod idea! Kudos!
Cheers, Oliver

Finishing up my Q-varitone switch. I decided to not use the circuit board and just solder the caps onto the 6 way switch (finicky job) to save room in the control cavity. Now I have a wide variety of tones in the various positions!