Pepper rev2 defect? 0V output at 1V

jayrope

On Pepper rev2 my oscilloscope shows, that the 0v line jumps to 1v, when audio codec is running.
Effectively this leads to a level range of approx. 0v to +2v, instead of -1v to +1v.
(edit: my oscilloscope has very tiny display...)

I guess that isn't normal, no?
(edit: shouldn't the whole range be 10v on rev2??)

giuliomoro

hmm the output should be -5V to 5V. Do you have a way of testing it with a voltmeter in case there is something weird with the vertical scale of your scope? Use a 50Hz sine wave as a test signal (as that will surely fall within the range of the multimeter's AC sensing bandwidth).

jayrope

giuliomoro
okay, so i used
[osc~ 50]
|\
[dac~]

result on a voltmeter (voltcraft)
Out-L 0.657 V
Out-R 0.662 V

However, when using a single dac~ as the only object without any input whatsoever to it, then i get DC
Out-L +1.354 V
Out-R + 1.356 V

giuliomoro

jayrope result on a voltmeter (voltcraft)
Out-L 0.657 V
Out-R 0.662 V

Right, so it seems that you are using the line outputs from the cape, bypassing the NE5532 opamp. J21 and J22 allow you to select between the non-amplified ("Bela audio out") configuration and the one using the NE5532 ("Amplified audio out"). Make sure the latter is selected.

jayrope

giuliomoro Embarrasing (i hope to have a little more understanding of music, than what i show here of programming/building): I set the jumpers wrong.
This not only solved the level issue.
It also solved the DC issue. Subsequently the cause for the request mentiond in thread below isn't that urgent/big anymore: https://forum.bela.io/d/1836-soft-mute-upon-patch-change/

Thank you much, Giulio. You rock.