Vermes
Advanced Member level 4
This design is based on N-mosfet power amplifier on two pairs of transistors IRFP250. The PCBs were made in thermal transfer method. Quiescent current was set to 50mA.
Power supply:
Power supply consists of 800VA transformer with a voltage of 2x50V. There are also bridge and capacitors 30mF for a side. Voltage without load is 70V, and when both power amplifiers are maximally drived, it drops to 55V. Transformer is equipped with a softstart.
Preamplifier:
Preamplifier is inspired by a good amplifier (Revox). It is supplied by symmetrical voltage 18V from power supplies on Zener diodes and transistors.
Cooling:
Cooling is carried out by two heat sinks with dimensions of 20x10x5cm. Recesses were milled for the fans in the heat sinks. It is recommended to use quiet fans.
Housing:
Housing was made of aluminum sheet with a thickness of 3mm. Sheets for walls were cut with a laser. The whole was screwed with chromium angles and chromium Hex M4 and M5. Ventilation holes in the bottom and top of the housing were laset cut.
Link to original thread - Wzmacniacz N-mosfet irka by Haker