One bit of advice I had read regarding resistor-string keyboards was that one could get enough closely matched resistors by buying 100 or so 5%'ers, measuring them with an ohmmeter, and selecting the ones closest in value to each other. Bad advice, since the value required for the RTL Synth was low -- 10 ohms or so -- and I had only a crummy RadioSchlock V.O.M. that wasn't precise enough in that range. I gave up, and went to Canal Street to find another solution. (This was when you could actually find electronics parts on Canal Street, before it became Hong Kong West.) I knew I probably wouldn't find 1% resistors, and even if I did, they'd have to be measured and selected as well. I didn't know exactly what I was looking for, but I knew it when I saw it: Adjustable wire-wound power resistors. These have a metal slider that can be moved to contact the exposed resistance windings at different points. I bought three 100 ohms @ 75W. They were each about 6" long and when placed end-to-end they'd be approximately the same length as the 2-1/2 octave keyboard. I removed the sliders and mounted the resistors on a piece of 1x2 pine with pan-head sheet metal screws through the solder lugs at each end. Then I cut lengths of guitar string, bent a small loop at one end, and screwed them into the 1x2 as contacts to the exposed resistance and wired them to each keyboard switch. After adjusting the highest-note and lowest-note trimmers, (tuned against my Hohner electric piano,) I nudged each guitar-string contact to the correct position for each intervening key.