4P1S directly heated tube dual-channel preamplifier, 6Z5P+6F3 vacuum tube DC high-voltage adjustable regulated power supply, LM317 dual-path filament adjustable regulated power supply, simply connect to 220V to operate.
Schematic diagram is shown below, for reference only. 
Vacuum tube high voltage regulationLine,Vacuum tube 6Z5PRectified, electrolytically filtered, 6F3Sampling to adjust the regulated output, output DC 155VThe current is more than 40 mA,forTwo 4P1S tubes are used. 
The internal resistance of the electronic tube circuit is low ripple and small gall taste, which is a good match for the pre-biliary biliary amplifier. The effect is excellent and better than that of the ordinary biliary voltage regulator circuit! The W sampling potentiometer on the adjustment board can change the output voltage. See the picture below for the enlarged board. See the picture below for the finished machine.
See the picture below for the finished product.
beauty National CMC 816U plated thick gold RCA socket, aluminum alloy feet, thick iron casing, silver-gray paint color beautiful. The chassis shell is produced by our own mold opening.Cold tie iron plate stamping production. machineThe volume is 320mm long, 320mm deep, and 98mm high.The finished machine weighs 5.71KG.
