The P-4001 and P-4002 were the first preamplifiers in the Simaudio Celeste series. The P-4001, introduced in 1993, was a simpler single chassis unit. In 1996, the "se" version of the P-4001 was introduced, featuring better internal parts matching. The P-4001 features included a pure class A, no feedback design with a separate headphone output stage, as well as six line-stage inputs, two tape monitor loops and an optional RIAA phono section (MM or MC).

The P-4002, introduced in 1996, was a more advanced design, also operating in pure Class A with no feedback, using balanced ciruitry, an outboard power supply, six line-stage inputs (five single-ended & one balanced), two tape monitor loops and an optional external RIAA phono section (MM and MC) in a matching chassis.