Apeech Resto 500 Series Mic Preamp Module

Apeech Resto is a one channel microphone preamp for the 500 series format.
I wanted to create a microphone preamp that on the one hand would be clear and transparent, but not too sterile and tough in sound. The second task was to reduce the circuit's own noise to a minimum. For this purpose, low-noise resistors, ultra-low noise transistors and a low-noise operational amplifier were used. Transformerless balanced input and transformer-coupled output with complex winding were used for low phase distortion and audio signal losses.
This preamp is one of the quietest preamps (with transformerless input)  on the market with a very pleasant and transparent sound revealing the sound of ribbon and dynamic microphones.  
Designed and Manufactured in Moscow, Russia.

The main features of the Apeech Resto include:
Gain more than 60 dB
Pad -20 dB
48V phantom power
Phase reverse
low pass filter -3 dB at 12Khz
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Input impedance 3 Kohm
Output 600 ohm