WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
First test is the level hum of the machine. Amateur environmental manufacturing, has 0.7mv hum. From the size point of view, it is not very good, from the frequency analysis, the hum from the power supply filtering. 350uf electrolytic capacitor two, there is no power filter choke hum 0.7mV100Hz bring to final output, from a practical point of view, this is already small enough. 93db sensitivity JBL4425 ear does not hear.
The first hole machining is completed. It takes approximately 4-5 minutes. Everything is in accordance with a pre-set program automatically. The whole process takes approximately 4-5 hours. Until this side completely finished processing.