What is the best way to use mono input to both ADC's

Hardware questions and issues with the FV-1

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ice-nine
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Post by ice-nine » Sat Oct 17, 2015 7:14 am

I know it has been a while since I asked about if the inputs should be directly tied together or if they would be better kept separate with the signal being fed to both inputs via their own filter network. I have managed to test out both options now and find no real difference in noise when the two are directly tied together.

Sweetalk
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Post by Sweetalk » Tue Oct 20, 2015 5:40 am

ice-nine wrote:I know it has been a while since I asked about if the inputs should be directly tied together or if they would be better kept separate with the signal being fed to both inputs via their own filter network. I have managed to test out both options now and find no real difference in noise when the two are directly tied together.
Great!, just what I thoughted, did you tried to leave the unused open?.

ice-nine
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Post by ice-nine » Thu Oct 22, 2015 11:00 am

Sweetalk wrote:
ice-nine wrote:I know it has been a while since I asked about if the inputs should be directly tied together or if they would be better kept separate with the signal being fed to both inputs via their own filter network. I have managed to test out both options now and find no real difference in noise when the two are directly tied together.
Great!, just what I thoughted, did you tried to leave the unused open?.
Yeah, I tried with pin 2 input open as well. the code I was using processes signal from both inputs (an echo) everything sounded just as it should apart from the fact that the right input processing was missing at the output, as expected of course.

sandromatik
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Post by sandromatik » Mon Nov 02, 2015 4:27 am

I think the best way is to work with balanced lines,
with a mono program you can use the FV1 stereo in and outs as balanced mono.
Of course your program must be adapted to receive and send balanced signals.

Since I tried this will never go back to unbalanced,
both common mode noise rejection and converters S/N are widely improved.
Especially when using an external oscillator any leak of the VCO into the audio is gone.

It's also a very cheap and straight forward improvement,
can be done with 2 op amp sections, a few resistors and 3 lines in the dsp...

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