Recently I performed a couple of Elliott Smith cover songs on Solo Upright Bass with Vocals, and I needed a cheap way to amplify the bass for the show. Luckily, it wasn’t hard to do and it sounded OK, and only costed $3.
All you need is a small portion of 2 conductor wire, a 1/4″ jack and a Piezo Transducer from Radio Shack. I used part # 273-0073, which cost $2.50. Basically, this transducer comes wrapped/ covered in a black plastic piece which needs to be removed carefully. I used some wire cutters and just pried the small hole larger and larger until I saw the element inside then carefully removed it since it was glued in place. I wrapped the element in electrical tape, then I soldered on a short section of 2 conductor wire to the Piezo Transducers existing wires. Last, I connected a 1/4″ output jack. I went the extra mile and grabbed a scrap of metal to mount the jack on, and wrapped it so that I was able to install it semi-permanently like the commercial options.
There are 2 important elements to get a good tone with this pickup. One is placement. I tried various spots, but ended up mounting it to the bridge as seen in the video. This gave me a decent tone, but even more importantly, let me clamp it on with a C-clamp. The second important element is the amount of pressure on the piezo. That is why I used a C-clamp which allows me to squeeze it, which improves bass response. The piezo also has a small rubber piece between the clamp and it to help evenly distribute pressure.
Here is a quick demo. I am plugged directly into an MXR Super Comp pedal and recorded direct. I EQ’d the mids out and boosted certain lows and highs to get this tone.