sndscientist
- Jul 10, 2013
- 47
- Joined
- Jul 10, 2013
- Messages
- 47
usually i am on top of things, but this has me baffled. i bought a certain amplifier for a permanent instal job i have from a notoriously cheap manufacturer. the price was right so i figured I'd buy a test unit to see if it would do what i needed done. it seemed to work very well. but it was ridiculously light so being the nebby person i am i cracked the case. now i am used to seeing switching power supplies in these things and smt transistors on huge heatsinks. but this one seemed different. it had 2 output devices per channel one pnp and one npn. i started thinking that there is no way on earth this can output nearly the claimed 500 watts per channel. so i started metering it. the power supply to output board had a rail to rail voltage of 100 Volts. (+/-50 to the Ground) so i began being a bit more skeptical. the output devices are a single A1941 and a single C5198. which according to the datasheet are rated 10Amps continuous at 140VDC. resistor to the output is .25 ohms.
According to my math this setup is capable
(6.06A) 303 watts at 8.25 ohms figuring 50 volts and
(10A) 500 watts at 5 ohms again with the 50 volt supply.
understandably the power supply will limit the output by not being able to produce a solid 25 amps. however the rectifier is a nice 12 amp unit.
so like i said mathematically it checks out. on the meter it checks out but i have taken apart and tested amplifiers rated the same power with 12 devices per channel and power supplies that weigh more than 3 of these units
According to my math this setup is capable
(6.06A) 303 watts at 8.25 ohms figuring 50 volts and
(10A) 500 watts at 5 ohms again with the 50 volt supply.
understandably the power supply will limit the output by not being able to produce a solid 25 amps. however the rectifier is a nice 12 amp unit.
so like i said mathematically it checks out. on the meter it checks out but i have taken apart and tested amplifiers rated the same power with 12 devices per channel and power supplies that weigh more than 3 of these units