Y.A.S.F. Is a transistor ladder filter in the early Moog style. Offering two completely independent filters and audio paths for stereo applications, while also offering normals across from left to right channels for stereo handling of mono sources.
Y.A.S.F. has inputs for two cutoff control CVs per channel. One equipped with an attenuator, and the second equipped with an attenuverter. These two CVs are mixed before finally being applied for the filter cutoff allowing for unique stereo effects that change the filters response across the stereo field. Basically it sounds really good when you manipulate the left and right channels independently.