耳机放大器电路 (Headphone Amplifier)

耳机放大器电路 (Headphone Amplifier)

Amplifier parts:

P1_____________22K Log.Potentiometer (Dual-gang for stereo)

R1____________560R 1/4W ResistorNotes:

Can be directly connected to CD players, tuners and tape recorders.

Tested with several headphone models of different impedance: 32, 100, 245, 300, 600 2000 Ohms.

Can drive old 8 Ohms impedance headphones, but these obsolete devices are not recommended.

Schematic shows left channel and power supply.

Numbers in parentheses show IC1 right channel pin connections.

A correct grounding is very important to eliminate hum and ground loops. Connect in the same point the ground sides of J1, P1, C2, C3 C4. Then connect separately the input and output grounds at the power supply ground.

Technical data:

Output voltage: Well above 5V RMS on all loads

Sensitivity: 250mV input for 5V RMS output

Frequency response: Flat from 30Hz to 20KHz

Total harmonic distortion @ 1KHz 10KHz: Below 0.005% on 32 Ohms load and up to 4V RMS output (typical 0.003%)
Total harmonic distortion @ 1KHz 10KHz: Below 0.005% on 100 to 2000 Ohms load and up to 5V RMS output (typical 0.003%)

Unconditionally stable on capacitive loads