Après avoir entendu les démos de Synthwalker de la Taurus 3 et lu l'article qui suit, je pense que c'est le synthé Moog à avoir en 2012 !
Why can't modern synthesizers or softsynths duplicate the creamy fat sounds of the Source or the Minimoog? Some people think it's the filter, some people think it's the oscillators. The real reason is the Minimoog's discrete VCAs and the OTAs sprinkled throughout the circuitry of the Source. In order to implement microprocessor control in the Source, many passive components formerly used in the Minimoog (such as pots) had to be replaced with OTAs.
An OTA - Operational Transconductance Amplifier - is a rudimental opamp with an extra input that controlled the gain of the opamp. I use the term rudimental because the OTA can't handle large signals, has a weak current output stage, and can only perform a subset of traditional opamp functions. OTAs do have other talents because they can be configured as a voltage controlled variable resistor (to replace a passive component) or as a VCA. However OTAs were not high fidelity audio devices - they have a linear low distortion region only for very small signals, and if you exceeded this region your distortion would increase. This distortion also varied by frequency. This was the best that technology had to offer in the 1970s. And although the Minimoog did not use OTAs, the VCA was a crude design that wasn't low distortion high fidelity either. Back when it was designed in 1969 that was the best that technology had to offer.
Today high fidelity VCAs are readily available and they are easy to implement in softsynths. What they missed out is the distortion of the classic OTA which is a direct contributor of that "vintage sound". Modeling dynamic distortion in softsynths is a big challenge because the exact mathematical model is not easy to derive and it is a major number cruncher to implement on a microprocessor. Many owners of Moog Voyagers have noticed that when you opened the filter all the way, it was missing that Minimoog high end "sheen". I was able to confirm that the Minimoog VCA was the contributing factor by routing the Voyager output to the Minimoog external input which put the Voyager through the Minimoog VCA and - wala - instant Minimoog "sheen" on the Voyager. The Voyager VCAs are too clean!
The same OTA distortion was responsible for that big Oberheim sound on their early polyphonic synthesizers. By the time the OB-8 was designed, the OTAs were replaced with clean VCAs and they lost "something" in the sound. OTAs contribute more to the "vintage sound" of synthesizers than designers care to admit.
When Moog Music set out to re-issue the Taurus I bass pedal synthesizer in their Taurus III, they even duplicated the dirty sounding OTA in key circuits. Taurus enthusiasists all over the world were delighted at how close the Taurus III sounded to the original.