Can be directly connected to CD players, tuners and tape recorders. Simply add a 10K Log potentiometer (dual gang for stereo) and a switch to cope with the various sources you need.

Q6 & Q7 must have a small U-shaped heatsink.

Q8 & Q9 must be mounted on heatsink.

Adjust R11 to set quiescent current at 100mA (best measured with an Avo-meter in series with Q8 Drain) with no input signal.

A correct grounding is very important to eliminate hum and ground loops. Connect in the same point the ground sides of R1, R4, R9, C3 to C8. Connect C11 at output ground. Then connect separately the input and output grounds at power supply ground.

Technical data:

Output power: well in excess of 25Watt RMS @ 8 Ohm (1KHz sinewave)

Sensitivity: 200mV input for 25W output

Frequency response: 30Hz to 20KHz -1dB

Total harmonic distortion @ 1KHz: 0.1W 0.014%? 1W 0.006%? 10W 0.006%? 20W 0.007%? 25W 0.01%
Total harmonic distortion @10KHz: 0.1W? 0.024% 1W 0.016% 10W 0.02%? 20W 0.045%? 25W 0.07%