Fosi Audio FY29 829B Tube Class A Amplifier Bluetooth 5.0 Hi-Fi Parallel Single End

The supplied Russian tubes are in FY29. North American tube identification is 829B.It is a composite tube in which two Cambodian tetrodes are packaged in the same glass shell. Using it in a power amplifier with push-pull output can reduce the trouble of tube selection and match. The FY29 filament voltage is 6.3V, the current is 2.25A, the screen voltage is 600V, the curtain grid voltage is 200V, the zero letter screen current is 40mA, full letter current is 110mA. The grid bias voltage is -18V, the optimal load impedance from the screen electrode to the screen grid is 13750Ω, and the output power (effective value) reaches 50W when the signal is full. In order to further simplify the circuit, this unit uses a composite tube 6N3 for preamplification and inversion. In this way, a single 6N3 and an FY29 can be used to complete the power amplifier task, and it has a 10W power output. The sound is soft and smooth, warm and delicate. This is why the tube amplifier has not been compl