The SIMA P-20 was the first preamplifier manufactured by SIMA back in 1980. The P-20 included an RIAA phono section for moving-magnet cartridges

The SIMA P-2001 preamplifier was manufactured for nearly a full decade, the last three-and-a-half years in a mkii version which offered minor sonic refinements through tighter internal parts matching. The SIMA P-2001 included a user selectable (via a rear panel push-buton) internal RIAA phono section for either moving magnet or moving coil cartridges. As well, this phono stage used two passive equalizers operating without any inverse feedback; one for medium and low frequencies and the other for high frequencies.

The SIMA P-3001 was the third and final preamplifier produced under the SIMA brand name. Over two years of research and development went into the design of this model which featured a no overall feedback design and a massive outboard power supply (below right) in a chassis identical in size to the actual preamplifier. The phono section (below left) was designed to accomodate any moving-coil or moving-magnet phono cartridge with adjustments to both resistance and capacitance settings made via miniature internal DIP switches, and used a pure class A, no inverse feedback circuit. The P-3001 included 5 line-level inputs (6 without the phono board) and also used a pure class A, no feedback topology, 2 tape monitor loops, 2 pairs of outputs (single-ended and fully balanced), and a headphone jack powered by an internal class A amplifier. As well, a record selector switch is included which allowed for listening to one source while recording from another.