Hello, I am working on two ppi pcx2400 amplifiers. One of them had shorted outputs (in one ch.), shorted windings on the transformer, burnt mosfets, burnt gate resistors, and bad HIP4081s. The other had a shorted toroid choke, burnt mosfets, burnt gate resistors and bad HIP4081s. Both now power up normally, idle @ approx 2.65amps and sound normal. My question is the current draw. Using an 80hz signal and a 4ohm load bridged mono both amps draw approx 10amps @ 3.3v output, 12.5amps @ 4.4v output and 15amps @ 5.7v output. I don't have the data for each channel driven individually but I know each respond nearly equal. Is the current draw excessive or are these amps that inefficient at lower volumes (I'm not that familiar with the large PPIs with h-bridge power supplies)? Can anyone tell me what's normal? And what I should check, if it's not? Any help would be
appreciated!!! Thanks!!
P.S. I can't(at the moment) give readings @ >15 amps, I'm currently long on power
supply and short on amp meter. Also I changed the SG3525 in one of the amps, it
made no difference.
appreciated!!! Thanks!!
P.S. I can't(at the moment) give readings @ >15 amps, I'm currently long on power
supply and short on amp meter. Also I changed the SG3525 in one of the amps, it
made no difference.
Do you mean the PCX-21400 by chance?? If so its like the A1200 and PC2350 and I just worked on a A1200 and it drew 80 amps per channel into 2 ohms each channel driven independently just below clipped output < I.E. one channel at a time > Output power fell short of the 600 watts per its rated at @ 2 ohms, but it meet its 4 ohm power output easily.
I test output power into test loads and the max current draw at the un-clipped < O-Scope validated > full power output if your testing for final repair quality related issues.
Also you can use ohms law to calculate output power by using this equation:
P = E 2 / R
or just use this link to a online calculator :
Ohm's Law Calculators
This will give you output power RMS as long as you use true RMS voltage readings and know your load values like a 4 ohm dummy load resistor would provide. < speakers vary too much to be certain in this test > Then you can calculate your power input to the amp as opposed to its output into load and check to see if the amp is between 50 and 55% efficient < typical class AB efficiency > which will pretty much answer your questions about current draw and output power I think.😉
Oh subtract idle current readings when you do this math so the numbers work out properly...😱
I test output power into test loads and the max current draw at the un-clipped < O-Scope validated > full power output if your testing for final repair quality related issues.
Also you can use ohms law to calculate output power by using this equation:
P = E 2 / R
or just use this link to a online calculator :
Ohm's Law Calculators
This will give you output power RMS as long as you use true RMS voltage readings and know your load values like a 4 ohm dummy load resistor would provide. < speakers vary too much to be certain in this test > Then you can calculate your power input to the amp as opposed to its output into load and check to see if the amp is between 50 and 55% efficient < typical class AB efficiency > which will pretty much answer your questions about current draw and output power I think.😉
Oh subtract idle current readings when you do this math so the numbers work out properly...😱
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