mminutel
500+ Head-Fier
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- Jan 7, 2007
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I recently built a Pimeta and didn't think there was a problem until I was listening to a soft song. The right channel has a weird noise. I cannot describe it. It is not a hiss or a crackle, it just sounds almost like the buzz of electricity (if that makes sense). It is only in the right channel.
I have single buffers. AD8610/20 as OPAmps. Class A biasing.
The amps do not seem like they are oscillating. The 8620 seems a little hot but I could hold my finger on it for as long as I want so it isn't really hot like my other amp got when oscillating. There are no solder bridges. I have also checked with a multimeter. Each channel has around 20mV of offset. The only thing that has a significant voltage difference is the Left Buffer which is a difference of around .2V but it is in the right channel.
I have checked about everything that I can think of. No pics right now but I cannot see any solder bridges even under magnifying glass.
Has anyone had this problem before and fixed it? I will keep tinkering with it but I have checked everything I can possibly think of. I have checked resistor values to make sure they are the same and everything. Also, what is the main cause of offset? I get around 21mV which is higher than I would like but I don't know how to minimize it. The last thing is that when I turn off the amp, there is a "pop". It isn't like it hurts my ears or anything but I measure around 1V when I turn it off but it slowly depletes.
Thanks all. Like said, I have tried everything I can think of just looking for further advice.
I have single buffers. AD8610/20 as OPAmps. Class A biasing.
The amps do not seem like they are oscillating. The 8620 seems a little hot but I could hold my finger on it for as long as I want so it isn't really hot like my other amp got when oscillating. There are no solder bridges. I have also checked with a multimeter. Each channel has around 20mV of offset. The only thing that has a significant voltage difference is the Left Buffer which is a difference of around .2V but it is in the right channel.
I have checked about everything that I can think of. No pics right now but I cannot see any solder bridges even under magnifying glass.
Has anyone had this problem before and fixed it? I will keep tinkering with it but I have checked everything I can possibly think of. I have checked resistor values to make sure they are the same and everything. Also, what is the main cause of offset? I get around 21mV which is higher than I would like but I don't know how to minimize it. The last thing is that when I turn off the amp, there is a "pop". It isn't like it hurts my ears or anything but I measure around 1V when I turn it off but it slowly depletes.
Thanks all. Like said, I have tried everything I can think of just looking for further advice.