Gooday,
Is it possible that an intermittent faulty bias pot can cause intermittent Dc offset on the output of an amplifier ? When cold, there is no problem but when the amp heats up there is some intermittent DC offset now and then.
It is a slight scratching on the speakers, when measured it is between 80 and 120mv .
Is it possible that an intermittent faulty bias pot can cause intermittent Dc offset on the output of an amplifier ? When cold, there is no problem but when the amp heats up there is some intermittent DC offset now and then.
It is a slight scratching on the speakers, when measured it is between 80 and 120mv .By "bias pot", I typically think of the pot that sets quiescent current in the output stage. While a faultybias pot that sets output stage current could change the offset voltage, I'd more likely suspect the offset voltage correcting pot.
Does the amp have two adjustments, one for bias current in the output stage, and a second for offset voltage?
Akitika GT-101 Audio Power Amplifier Kit
Does the amp have two adjustments, one for bias current in the output stage, and a second for offset voltage?
Akitika GT-101 Audio Power Amplifier Kit
djoffe,
No, there is no DC offset adjusting pot. I have replaced all the electrolytic caps on the amp, thought it could be some of them. It is a Nad 214. The bias pot is very sensitive and the bias drifts a bit with 2-4mv +/- in both directions on the problematic channel, that's why I suspect the bias pot.
No, there is no DC offset adjusting pot. I have replaced all the electrolytic caps on the amp, thought it could be some of them. It is a Nad 214. The bias pot is very sensitive and the bias drifts a bit with 2-4mv +/- in both directions on the problematic channel, that's why I suspect the bias pot.
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