Digital processor P-1A, external DAC unit P-3A, power supply unit for them P-3B of the American company Perpetum Technologies.
The P-1A is designed for converting digital audio formats. At the output of the processor, you can get digital digits 16, 18, 20
or 24 bits at 44.48, 96 or 192 kHz clock rates.
The P-1A uses ultra-fast 32-bit SHARC chips. The algorithms themselves are entered into the EEPROM hard memory (EPROM).
The second function of the P-1A is the correction of amplitude-frequency distortions of acoustic systems. The company "Perpetual Technologies" has at its disposal a large data bank on almost all models of ACs of various manufacturers. It is only necessary to enter into the processor a set of correction coefficients, which can be purchased from "Perpetual Technologies" or even obtained via the Internet. With the help of these coefficients, a characteristic is formed, which
compensates for the peaks and troughs of frequency response of acoustic systems. At the same time, there are no phase distortions, which are inevitable in ordinary analog filters and equalizers. The third function of the P-1A processor - full correction of the "room + speaker" system - is implemented with the help of an additional spectrum analyzer and a measuring microphone. This function is especially necessary in "bad" rooms. Quite in an acoustically good room
it is enough to correct the frequency response, i.e. the P-1A performs its second function.
The P-3A DAC external unit is recommended for use with the P-1A processor. In combination with it, the P-1A acts as an external digital
filter. The P-3A is assembled on the same chassis as the P-1A, and is its main companion - a converter. P-3A uses "Crystal" microcircuits: CS4397, CS8420, the output stages of the analog signal work in class A. The possibility of inverting the signal phase allows you to optimize the character of stereo panoramas and localize sound images.
The P-3b is a power supply designed to get maximum performance from the P-1A digital signal processor and P-3A digital-to-analog converter. It has separate transformers for each device, ultra-fast rectifier diodes, built-in AC line filtering.

Technical characteristics of the P-3B
AC Input Voltage: 115~230 Volts / 50~60 hz
DC Output Voltage: 12 Volts @ 2A (P•1A )
AC Output Voltage: 9 Volts @ 2.5A (P•3A )
Size: 8.5″ x 6″ x 2.5″
Weight: 8 lbs
Technical characteristics of the P-1A
Digital converter: 24 bit
Digital Inputs: Coaxial, AES/EBU
Sampling Frequency: 16 to 24 bit, 44, 48, 96, 192kHz
Line output: 0.5V
Dimensions: 5.5 x 8.25 x 1.75 inches
Weight: 4lbs
Technical characteristics of the P-3A
Inputs: I2S, AES/EBU, Coaxial S/PDIF, TosLink
Input impedance: 75 Ohms
Outputs: Coaxial RCA pair
Output impedance: 100 Ohms
Output voltage: 2.5 Volt
Input bit resolution: 16–24 Bit
Output bit resolution: 16, 18, 20, 24 Bit (selectable)
Input sample rate: 44 KHz–192 KHz.
Size: 5.5” x 8.25” x 1.75”
Weight: 4 lbs

The sound of this set is characterized by softness, unobtrusive insight. It is similar to the sound of gramophone records. Original packaging and instructions.