Posted on May 3, 2017 3807
The two ECC83 lamps make the pre-enhancement. The potentiometer R1 is used to adjust the volume of the voice. Output transformer T1 has an impedance impedance of 10KΩ. The primary wire is for 100mA and this transformer must have a core for 30W power transfer. If its secondary transformer T1 is to be connected to a loudspeaker, it should have an impedance of 8Ω. If used as a modulator then it must have a 10KΩ impedance. The power adapter has a primary 220V and a secondary 2X 350V for 150mA, 6.3V for 3A and 5V for 2A. The smoothing filter choke is 10H for 150mA.