Here are the specifications:
Power 200W (8R) 350W (4R) Voltage: DC + - 45V Rectified AC voltage range AC 12V to AC dual dual 32V; THD = 0.009% 1K HZ 50W 8R SR = 35V / US Noise 92DBU EIN = 114 DB Frequency Response 20-20KHZ + - 0.5 DB 34 times the voltage gain All resistors are 1% precision high precision resistors PCB size: 116MM * 72 MM*1.6MM All capacitors are imported original.
KEC original imported audio power tube. Promote the use of KEC B817 D1047 and Toshiba A1930 C5171 Package including: 1X L20 Mono Amplifier Board
You might note that the specifications are very poor translations. The big shock to me was the price, it was only $17.50 plus $7 shipping. That is less than the cost of two of the old TO-3 metal power transistors! The circuit board does not come with a heat sink, and the transistors certainly do not fit the old TO-3 power transistor holes. So I made a "heat sink adapter" out of a piece of aluminum.
I connected the power supply and it works. I am limited to about 150 watts by the 1 volt output of the signal generator program running on my laptop. That 1 volt input produces 25 volts peak to peak into 4 ohms with this setup.