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Post by navinder on Jun 20, 2016 17:52:05 GMT
Recently I have build a 4th order low pass Butterworth low pass filter using lm741, and a TDA7294 amplifier circuit. From laptop audio jack, I fed signal to filter which then is input to TDA7294 for driving a 6" and 6ohm DIY woofer. with 120k in place of 1K. Input is given from both left and right channels after adding in series 120k to each. I have skipped C1. That means 6th pin of lm741 is connected directly to 3rd pin of TDA7294. But after sometime now when i plugged my headphones to laptop, I am finding my one channel audio level very less than the other. To balance the level, I have to reduced one channel to 35 while other at 100 from 'control>sound>speaker>property>balance' option. Could any one shed some light, what hapenned? And how?
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solderdude
Administrator
measureutternutter
Posts: 4,881
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Post by solderdude on Jun 20, 2016 21:20:51 GMT
Does this happen as well when the circuit is not connected ?
What power supply voltage is used to power the opamps ?
With 120k as input resistors it is impossible to damage the output of the the laptop. Even when it would have been carrying 25V.
When omitting C1 you run the risk of having DC on the speaker. I would use a non polar cap there of at least 10uF instead. Could well be a cheap bipolar 10uF electrolytic.
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