For comfortable listening to music recordings, it is often necessary to adjust the tone at different frequencies. This may be due to room acoustics, speaker characteristics, or simply personal preference.

The M266 stereo equalizer is designed for this purpose, allowing smooth adjustment of the frequency response of the audio signal. Control is carried out across five bands using dual potentiometers R7–R11. The equalizer is connected between the preamplifier and the power amplifier stage. Two LA3600 ICs are used as the active elements. The output of the equalizer should be connected to an amplifier stage with master volume control.

Specifications:

• Supply voltage: 9–15 V

• Current consumption: ≤10 mA

• Input voltage: 0.2–0.7 V

• Maximum output voltage: 2 V

• Tone adjustment depth: –10...+10 dB

• Frequency bands:
  • R7 – 100 Hz
  • R8 – 330 Hz
  • R9 – 1 kHz
  • R10 – 3.3 kHz
  • R11 – 10 kHz