[SOLVED] [Moved] unable to pass signal through LM833 opamps connected in series...

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brochington

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Hello!

I hope this is not too basic an issue, and if there is an easy fix or a topic I'm skipping then please let me know. I'm very much a beginner, and getting my electronic feet wet in some basic audio signal design. The issue I'm running into at the moment is getting signal to pass from one opamp output(with a basic non inverting voltage divider on the negative feedback loop) to another setup in a similar fashion. Both separate opamps process signal correctly on their own, but if I connect the output of opamp 1 to the noninverting input of opamp two, I get no output. thoughts?

also, if you don't mind, I have another question. I find that an audio signal doesn't pass through the opamp unless I use a capacitor at the input. Why is this? Decoupling?

Please let me know if you need any more info on the setup, and I'll happily reply.
 


The LM833 works properly if the input(s) are biased with roughly ½ of the supply voltage, so, for example, if your supply is +Vcc/- Vcc the input should be connected via a resistor to GND .. see attached drawing ..
The audio signal is AC, so you have to get rid of the DC component, and one easy way is to use a coupling capacitor that will only pass the audio signal but will cut off any DC component ..

:wink:
IanP
 

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Thanks IanP, that pretty much solved my issue!

If I may ask, Is this a factor is most opamps, or just the LM833?

I think I had seen the schematic you posted before, but thought the resistor and cap after was some weird Highpass filter.
 

Thanks IanP, that pretty much solved my issue!
If I may ask, Is this a factor is most opamps, or just the LM833?

If you work with audio signals the last thing you want to worry about is the dc offset.
From that point of view, the LM833 is not different to any other opamp ..
:wink:
IanP
 
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