My friend Jeff and I have a running joke about guitarist Eric Johnson who said that he wanted to write a book on cables, such a notion seeming to epitomize the indulgence of obsessive musicians and engineers more interested in eliminating every last bit of noise than in making compelling music. I haven't yet become an Eric Johnson fan, but am now more convinced about the value of good audio cables.
So far, I've built all of my pickups by chopping guitar cables in half (so I don't have to resolder the plugs) or by using scrap, balanced, 1/4 " microphone cable. These cables work fine but they're heavy and tend to get twisted. They pull on the piezo element and the plug or jack, which are taped on, resulting in noise from extra vibration or the pickup becoming detached altogether.
Again following the lead of
David Fittell's site, as I did when I built a piezo film pickup, I purchased some lightweight Mogami cable. I bought three types from
Redco Audio:
- W2368 - miniature unbalanced microphone cable, only 2 mm in diameter;
- W2697 - miniature balanced microphone cable, only 2.5 mm in diameter; and
- W2319 - guitar cable built for high impedance things, only 5 mm in diameter.
I've only built two pickups with this cable, using about 2" lengths of the two microphone cables with a $0.40 Murata piezo disc at one end and an 1/4 phono jack at the other. I didn't do a good job with the Plasti-Dip or the soldering and so have left these as rough-looking prototypes, i.e. I haven't added any foil or heat shrink, but I haven't heard any hum yet. I also haven't heard any difference between the balanced and unbalanced cable.
These pickups are excellent. I modeled them after the designs of the commercial pickups I discussed in my last post. Each unit is so small I can tape it in its entirety almost anywhere I want on the guitar. There is little stress on the pickup and no resulting vibration. Also, in the pickups made with guitar cables, the cable itself, attached directly to the piezo element, is very sensitive and will make noise when touched or rubbed. In these new pickups, the cable between the pickup jack and the amp or preamp is not so sensitive and doesn't make any noise when touched. I haven't recorded anything yet with these but will soon. And, the cost for each, given the cheap Redco prices, is about $1. Subarashi!
The sound from the balloon is surprisingly good, but as Hopkin wrote, some high end is missing. Although there are certainly better ways to mike a guitar amp, I suspect this would make an interesting microphone for vocals. Imagine a group of singers standing around the balloon.
