Transistor integral amplifier Musatoff PA-20
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The main difference of this amplifier is an incredible accuracy of the transfer music material.
To achieve it required to apply a number of both known and new techniques, such as:
  • War with heat distortions in active and passive components
  • Make minimum phase distortion by using only one voltage amplification stage
  • Exclude from signal path of interstage capacitors and amplification upto DC
  • Failure to use an integrator that affects the transmission of virtual DC
  • Static and dynamic stabilization of operating mode of output stage, coupled with its thermal stability
  • Three-step stabilization of power of pre-amplifier minimizes noise penetration
  • Distortion minimizing of complex and stochastic signal including the signal coming from the speaker
  • The central signal ground is connected to the input terminals

  The sound amplifier so transparent and not painted, you can not see it on the background sources and speakers even more the high price group. Due to the high and independent of frequency damping ratio, amplifier controls speakers good.
  The amplifier has a rich functionality that makes it easy to use:
  • Control via the multifunction encoder.
  • Full remote control. With it all the functions done in one click
  • Concealer for MM cartridges with the ability to adjust its parameters for the characteristics of the head.
  • Four universal line inputs.
  • Sensitivity adjustment on all inputs, including the MM input, to preserve the volume level when switching between inputs
  • Ability to operate as an integral amplifier, a power amplifier and pre-amplifier
  • Ability to customize for each input operation without interstage capacitor.
  • Adjust the volume by 1 dB and the balance in the range of ± 8 dB.
   • Select the type of correction between MM RIAA and RIAA-78.
Technical specification:
  Nominal output power   120 W / 4 Ohm и 75 W / 8 Ohm
  The maximum output power is limited by the clipping (depending on the voltage at the wall outlet)   155 W / 4 Ohm и 94 W / 8 Ohm
  THD on nominal output power(0 dB)   0,005% 
  THD on power level -10 dB   0,001% 
  IMD on half power (-3 dB)    0,002% 
  The level of intermodulation products of any order of the sound spectrum in the test 10 frequency signal with frequencies ranging from 20 Hz to 20 kHz (non-stationary signal emulation) at full power 0 dB   85 dB and higher (105 db on middle frequencies, where hearing is most sensitive)
  No delay after exceeding the maximum level (clipping)    
  Output impedance at low and medium frequencies of approximately   0,002-0,003 Ohm 
  Damping factor   1500-2000
  Amplfication band   0 Hz - 240 kHz
  The frequency of high-pass filter to work with the sources to the presence of the dc output voltage   1,7 Hz
  The band amplifier is limited to the top by two passive filters: Inlet and outlet. Without them, the bandwidth of amplifier more than   2 MHz
  Amplfication factor   30 (29,5 dB) 
  Amplfication factor of preamplifier   ftom -127 dB to +18 dB
  Amplification step   1 dB
  Balance ajusting   +-8 dB with 1 dB step
  Input inpedance of preaplifier   10 kOhm
  Input impedanse of power amplifier   20 kOhm
  Dimensions excluding terminals and control knobs   420х325х145
  Weight   about 15 kg
  Another photo of amplifier