Roland SH-3a

via this auction

"Roland SH-3a. This is a very unique synth. It was Roland's first non-preset synthesizer, and was one of the few ever designed Analog synthesizers with both subtractive and additive synthesis.

Though it’s only a single oscillator synthesizer, the additive blend feature allows for the creation of some really fat sounds. And a chorus effect on the 8’ tone gives the same sound that most synth’s use two oscillators for anyway: detuned chorus.

The Sh-3 had a five stage diode ladder filter…the Sh-3a replaced it with a four stage transistor ladder filter. It’s often said that it was changed due to a Moog patent infringement…but I don’t think that’s correct since the Sh-3a is even closer in design to the Moog 904 ladder filter. Moog did sue Roland over filters…but I think it had more to do with other models. But anyway, when most people think of the Moog sound they think of the Minimoog, which is totally different…not like the 904 that this one resembles.

To me, there’s two things that really make this synth valuable. One, it has a CV and Gate interface for the oscillator that allows it to be controlled remotely. One Midi to CV convertor later and you’re suddenly sequencing this from your favorite DAW. That will keep it active in your studio line-up…not just a sideline tool. Second, this thing has a very vintage analog sound. I attribute several things to this, including the filter, and the fat additive section. But also, there’s something about the CV tracking on the oscillator that occasionally give’s you what sounds like a transient tracking error..so you get this slight random portamento sound now and then that somehow reminds you of how alive this thing is. Soft synths, digitals, and most analogs don’t do that... The Sh-3a weighs about 35 lbs"