As my kid grows older, I find I have a little more time to muck about with longstanding repair projects. I’ve been trundling around a Vox Super Continental for 23 years now, though “B flat” never worked properly (nor did it for its previous owners, Shawn Swagerty and Heather Gonsior).
And I have literally no idea where my Farfisa Compact came from…was it Tim Green’s? I’ve had that for decades too, though its sounded worse and worse over time.
In any event, the Corin Tucker Band has had more and more need for these instruments–or at least I’ve convinced the other band members that they do!–so it seemed like a good opportunity to get them working again.
Working on solid-state circuits is intimidating, at least for me. Tubes can be mysterious too, but there’s something a little more comprehensible about them. The Farfisa has a tube preamp section, which was rebuilt along with the power supply in the standard way with new electrolytics, tubes, diodes, power resistors and a thorough cleaning.
So far, so good. I lugged the organ–which is NOT light!–back to rehearsal. It sounded great, or at least as great as these pieces of junk can. But after the organ was allowed to warm up a few minutes, several of the notes would go wonky. My bandmate Mike Clark asked what was wrong, and my only answer was that it was a piece of crap that had been made in Italy 45 years ago!
Side note: My friend Steve Perrone likes to point out that these instruments were likely built by elderly Italians in a converted accordian factory (yes, Italy had a thriving accordian industry!). As he put it so well: “They gave the best years of their lives for rock and roll”….
Back to the problem: It turns out that this particular organ (like the Vox) uses germanium-based transistors on each of the oscillator cards (the section of the organ’s circuitry that actually produces a given pitch). These early transistors are particularly sensitive to changes in temperature, so after current–even relatively low current–flowed through them and heated them slightly, they would do all sorts of unpredictable things, like warble, produce grinding sounds, and so on. I do think that some of the charm of old electronic instruments is their unpredictability, but enough was enough, particularly during a recording session in which one crucial note–again, a B flat!–went way off base.
You can still find these old transistors, but there’s no guarantee they’ll be any more reliable than the originals. Fortunately, there’s a modern replacement–to wit, the BCL 214L–that will suffice. from then on, it was a matter of tracking down the bad notes and rebuilding their oscillator cards with modern components. Some of them took a bit more detective work than others, because the note would sound fine down to a certain octave, then go haywire. That’s because these organs use divider circuits, in which an oscillator produces a given pitch (in Hertz), which is then divided in half to produce the same pitch an octave lower. It took a number of tries, but finally the Farfisa was back in action.