Re: One of the best!

I just acquired a later rev Sonic Six myself. It needed a new negative voltage regulator and a buss bar cleaning, but beyond that it works fine.

I read that you converted the CV scaling to 1V/oct. Does the Sonic6 use another scaling standard? Any tips on what you did?

Just to share:

- I also found the envelope very limited, so I modified the EG Bypass switch. Instead of now giving you the choice of "Contour-to-VCA" and "VCA-always-open," I routed the internal Gate signal to the VCA when the Bypass switch is in the "VCA-always-open" like the Roland Juno series. It was only lifting one resistor and adding one wire. This lets you use the EG for just the filter and you can get nice full sweeps!

- Even though the Sonic6 uses the uA726 for it's VCO's, I took Paul Schreiber's advice on the AH list on further improving the temperature sensitivity of the Moog VCOs. He says that the resistors used in the early Moogs are 'RN60D' which have awful tempco specs and recommends replacement with 0.1% Holco 25ppm resistors in the VCO CV summing circuitry. He also recommends the LT1006 to replace the op amps in those summing circuits. Well, those Holco's ARE expensive, so I replaced all the CV summing resistors with 1% 50ppm (even the 5% resistors), and I did replace the 741's with LT1006. I left all the other waveshaping, filter, and amp circuits intact, though. I now need to do a test to see how stable the oscillators are over time...