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Old 10th June 2006, 11:00 PM   #11
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Thank you for the help everyone.

The pot was not the problem. It was either the chip, resistors or damage done to board by soldering. But I think it was the chip. It made some extremely loud sounds when i was soldering the board that scared the **** out of me I think I might have left it plugged in, while soldering. I had another board and chip around from a setup where one channel didn't work, probably the chip again. And I used the channel that still worked from that pair of boards. It's a little different it has a resistor across 2 pins the chip, should I put a resistor on the other channel?
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Old 13th June 2006, 08:18 PM   #12
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it could be the DC offset.
try to measure it, the speaker running louder should have an higher dc offset (i guess).
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Old 13th June 2006, 09:06 PM   #13
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DC offset I don't know the terminology Is that the rectifier? Converts AC to DC, that thing?

All I changed was the chip, PCB board, and resistors and it works. Only thing is that the chip has a resistor across two of it's pins, was wondering if I should remove it or put the same one on the other chip.
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Old 13th June 2006, 09:53 PM   #14
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Quote:
Originally posted by Jimmy154
DC offset I don't know the terminology Is that the rectifier? Converts AC to DC, that thing?


No, it's not about that.
i don't know exactly where dc offset comes from (maybe it's due to the dc rail voltage that 'enter' in the signal path), but surely it's not good to have a huge dc offset (hundred of mV).
try to put your multimeter (set on 200mV dc) across the speaker binding posts of one channel (or between chip pin 3 to ground) and see what it measures.
do the same with the 'dumb' channel.
the louder channel should have an higher dc value.


Quote:
All I changed was the chip, PCB board, and resistors and it works. Only thing is that the chip has a resistor across two of it's pins, was wondering if I should remove it or put the same one on the other chip.
I guess it's the feedback resistor.
Is it across pin 3 and 8? If it's so, you'd better don't remove it!
You should have another feedback resistor on the other channel chip.

I hope to have explained myself in a decent way and that it helps
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Old 13th June 2006, 10:36 PM   #15
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Yes the resistor is across pin 3 and 8. I don't hear any difference between the 2 channels. I guess I will put the resistor on the other channel when I get the chance or maybe it is already on there. I have to look, but the channel I removed did not have one. And also see what it does.
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Old 25th June 2006, 05:21 PM   #16
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Ahhh yes much better!

There was a difference between having the resistor and not. I noticed it a few days ago.

I used to get "feedback" (don't know what that means exactly) or slight humm sometimes very noticeable (at night esspecially) and sometimes not so noticeable, on both channels, cause I forgot to put those resistors in. I noticed that the problem stemmed from the signal inputs going past the power input wires to the transformer or maybe some other wires too or maybe the transformer inself. I'm pretty sure the term feedback refers to this effect (interacting with the electromagnetic field maybe?), but I'm not sure.
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