hello,
I have finished my 2 channel AV400 using IRFP240/9240. The pre-flight test was ok for both channels. Then i solder the fet's. I have 40mv and 70mv offset (on the output without load) voltages.(the manual says 1 to 50mv) is that ok? The voltages on the 0.22 source resistors are 14-18mv on the irfp9240 but only 8-10mv on the irfp240. The fet's were matched but not the P to the N channel as manual says. Is that ok?? By the way the amplifiers sounds very well.
I have finished my 2 channel AV400 using IRFP240/9240. The pre-flight test was ok for both channels. Then i solder the fet's. I have 40mv and 70mv offset (on the output without load) voltages.(the manual says 1 to 50mv) is that ok? The voltages on the 0.22 source resistors are 14-18mv on the irfp9240 but only 8-10mv on the irfp240. The fet's were matched but not the P to the N channel as manual says. Is that ok?? By the way the amplifiers sounds very well.
Try swapping the 240s from one channel to the other, or the 9240s (whichever are easier to get to).
Offset is a little bit high but nothing to worry about. It sounds as though the mismatch between the P and N FETs is a bit high.
Offset is a little bit high but nothing to worry about. It sounds as though the mismatch between the P and N FETs is a bit high.
hello,
i just swapped the fet's between them and it seems better. Now the source resistor voltage on irfp240 is 11-15mv and on the irfp9240 12-18mv. same on the other channel. The offset remains same but i think it is ok. Now the bias voltages are ok didn't they?
i just swapped the fet's between them and it seems better. Now the source resistor voltage on irfp240 is 11-15mv and on the irfp9240 12-18mv. same on the other channel. The offset remains same but i think it is ok. Now the bias voltages are ok didn't they?
i am posting some picture of the amplifier. i build this for my new speakers: http://www.diyaudio.com/forums/multi-way/189710-my-new-diy-speakers-project.html
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