gres
Full Member level 4
Most important assumptions was to create cheap amplifier. To do that I used as little elements as it is possible. It’s a prototype, but also final version that means that any upgrades are not necessary. Amplifier should work with 4 subbases 18” sometimes in hard situation like wetness, short circuits, shakes.
Power amp is very similar to bipolar 2x550W/4R. consist 6 pairs of bipolar transistors 2SC5200 and 2SA1943 per channel.
Power supply:
Filtration of amplifier is 16x3300uf/100V. rectify bridges 25A/1kV per channel. At condensers is 2x94-97V DC. Power transformer 1500VA and voltages 2x67V/2x11,5A and 2x15V/1A
Cooling system
Heart of cooling system for transistors are 2 radiators. Dimensions of them are 33x13x3,5cm per channel + angle bars. But I’m going to put 4 ventilators 10x10 because with big load radiators get worm. But only radiators, rest of elements are cool.
Secure system
Are much faster and better than at previous construction of bipolar 2x550W. Making secure system I didin’t use any integrated circuits. So we have:
- thermic 90*C
- shorting
- overloading ( e.g. wrong impedance of speakers or branch broke)
- against DC ( start work with 1,5V up to 100V)
- soft start ( time = 2s) and fast speakers disconnection
- soft start of transformer
Besides there are 3 indicator lights for each channel:
Green – property work of transformer, columns are on
Yellow – thermic warning and overloading
Red – short circuit, DC, overloading, temperature.
More information you can find at https://www.elektroda.pl/rtvforum/topic1541184.html/
