Hello, I would like to know if anyone knows, the idle consumption of this amplifier, and the factory value it should have in offset on the output channels.
thank you very much
thank you very much
he amplifier was purchased broken, one channel with dc output of 20v, 2 irf540 damaged, and lm833 damaged, I restored it, but not knowing if the old owner has touched the bias trimmers, I wanted to know if of service the values are in the normal.
Every time you repair the output stage in an amplifier, you have to reset the bias. I set the bias pot fully CCW then rotate it until I just see the idle current increase. If you have a Flash capable browser, this will show you what I mean.
http://www.bcae1.com/temp/ausettingbias.swf
http://www.bcae1.com/temp/ausettingbias.swf
ok i opened the file, the bias as current, should you adjust for each independent channel? if i connect to the positive power supply the idle current is marked as total of all 2 channels.
I made a test both bias trimmers left and right channel at minimum, absorption 0.36A.
I increased the right channel until I had an increase of 0.15A same thing for the right channel with a total of 0.6 A idle.
I increased the right channel until I had an increase of 0.15A same thing for the right channel with a total of 0.6 A idle.
It should be OK. Drive it with a sine-sweep to see if you see any notch/crossover distortion if you're still concerned whether it's right.
At least in the next gen Rockfords, bias was suggested to be a 0.05A rise per channel, so 0.15A is a bit excessive.
Rockford has high bias specs (too high IMO) for their amps. The specified idle current for the 200DSM was 1.4A (attached). The 0.6A of idle current is much lower than what Rockford gave for this amp.
In many of their schematic diagrams, they specify 2mv across the 0.1 ohm source resistors. For large amps, that causes high current draw and excessive heating.
Running a sweep and confirming that there is no crossover/notch distortion is the definitive test for sufficient bias current (for me).
In many of their schematic diagrams, they specify 2mv across the 0.1 ohm source resistors. For large amps, that causes high current draw and excessive heating.
Running a sweep and confirming that there is no crossover/notch distortion is the definitive test for sufficient bias current (for me).