This Mustang bass initially came in as a fretless conversion, which came out great. Pretty routine: pull the frets, clean the slots, fill with maple veneer, glue, plane the board, sand it out to about 1500, then set it up and you’re off to the races. However, the customer wanted tapewound strings, and that proved a challenge for establishing an effective string ground.
This is not a new problem, with both coated strings and tapewounds being frequent non-conductive culprits. Some tape wounds are more conductive than others, but these did not want to provide a consistent string ground, so first we shielded the pickguard and cavities. That took care of most of the excess hum, even without a string ground, however this particular player plays with an extremely clean sound and direct into the board when recording, so any extra noise wasn’t going to work.
That’s when the idea for the conductive thumb rest appeared, to provide essentially a hum kill switch that would stand in the place of a traditional string ground. His thumb was already going to be there, so why not make it multi functional? So I found a piece of zinc machine key stock that was about the right size and drilled a few holes, polished it out, and had a nice little shiny rectangle. I ran a small lead under the pickguard that was soldered onto the shielding tape and voila, Bob was my uncle. So now the customer has a stylish thumb rest, a quiet bass, and should they decide to swap out the tapes for flatwounds, the thumb rest will be a redundancy and it’ll still be quiet as a mouse.
I did this job for Harlan Silverman (read his testimonial here), who is an incredible musician out of Portland. Harlan is a very talented multi-instrumentalist who creates some of the most calming ambient music I’ve come across. I’ve included a link to his website here where you can learn more about him and the music he creates.