PM-AB1 error correction amplifier

This amplifier was developed in 2004 to verify one of the possible error correction circuits for MOSFET output stage. It is a small, simple amplifier with 25W/4 ohm power output. The main advantage is spectral purity of output signal even for low power levels.

The amplifier uses an opamp as a voltage amplifier and MOSFET output stage with error correction. Idle current is 300 mA approx. The error correction circuit improves dynamic behaviour, increases power frequency range, reduces distortion and output impedance.

Technical parameters

• input resistance 47 kohm
• gain 20x
• frequency range 2Hz - 150kHz (-3dB)
• output power 25W/4 ohm
• harmonic distortion <0,003% 20W/4 ohm/1kHz
• intermodulation distortion 13+14kHz <0,005% 20W/4 ohm
• supply voltage 2 x 24V to 2 x 27V

Distortion spectrum at 20W/4 ohm

CCIF IMD 13+14kHz for same output amplitude, 4 ohm load

20kHz square wave response, 4 ohm

PCBs

PCB dimension is 170 x 71 mm. The PCB is double-layer, with non-solderable mask and silkscreen print. PCB's are not available now.

contact

Pavel Macura 10/2010