"JLH Germanium" part 1 While powerful high-frequency transistors were on the road, I decided to try to build an amplifier on the powerful germanium low-frequency transistors P215. Here is on such a set of transistors: The P215 transistor is a powerful but very low frequency transistor. Its upper frequency is 10-12 kHz. We make a new PCB Prepare the radiators for the installation of transistors. The old transistors have mysterious pinouts on the body, so I had to work a little. Print and cut the template Attach the template to the radiators Drill Attach and prepare transistors Solder one channel on the Board. Turn on and measure at different frequencies. The lower sine wave is the input signal At a frequency of 1 kHz: At a frequency of 10 kHz: At a frequency of 20 kHz: In all measurements, the quiescent current of the transistors was equal to 1 A Surprisingly, the JLH circuit made the transistor P215 work well at a frequency at which it should not work . In appearance, the sound of the sine wave amplifier on the transistor P215 is likely to be similar to the sound of a tube amplifier. But it should be checked for hearing.