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Hi all,

I measured SHD output voltage from XLR and RCA outputs, and they are much lower than I expected.

I use poor man's method: use the SHD as an USB sound card, set volume to -0, turn DIRAC off, generate a 0 dBFS sine wave to SHD, and use a multimeter to measure AC V at the outputs.

I got 1.7 V rms on XLR outputs and 1.1 V rms on RCA outputs.  Aren't they supposedly 4V and 2V?

What can be wrong?

Thanks in advance.

What was the indicated output signal level shown in Device Console (or an older SHD plugin if you're still using this)? What frequency signal did you use?

Device console showed -1 dBFS.  I tried 300Hz and 1000Hz and the results were the same.

 

Many AC voltmeters don't have frequency response much higher than 60Hz. 
I would suspect that's your problem.

Dave.

I did detailed measurements of the SHD when I got it and found clipping (0dBFS) at a level of 2.0Vrms on RCA and 4.0Vrms balanced.  The analog in to analog out frequency response was right on 0dB gain and was very flat with a roll off of -0.2dB at 10Hz and 20kHz. The -3dB corners were at 2Hz and 45kHz.

Let me know if you need any further details.

Steve

Hi guys,

Thanks for all the help.  I figured out what went wrong: I didn't unplug all other output connections when I measured.  If other things are connected, the measurement will be affected.

 

slm3654 wrote:

Let me know if you need any further details.
 

we probably don't 'need' more details but that doesn't mean we wouldn't be interested in seeing learning more of what you've measured!

dreite wrote:

Many AC voltmeters don't have frequency response much higher than 60Hz. 
I would suspect that's your problem.

Dave.

Indeed. Need to use a 'scope.

edmundpan wrote:

Hi guys,

Thanks for all the help.  I figured out what went wrong: I didn't unplug all other output connections when I measured.  If other things are connected, the measurement will be affected.


 

If you're loading the outputs such that the expected voltage is dropping significantly, it might be indicative of some interfacing issue.

Dave.