Up until recently I was using the Digilent Analog Discovery 2 to perform audio measurements on my DIY audio projects - with 14-bits of resolution, it's a surprisingly powerful and cost effective little device. And while still an exceptional and blisteringly fast scope - I honestly can't see myself using a "traditional" oscilloscope when these insane USB devices exist! - the bottleneck is the noise floor, which doesn't get much lower than around -80dB. So while I could verify that my projects were relatively clean, I couldn't really plumb the depths of their noise characteristics.
I recently picked up the Clarett 2Pre to take over FFT/spectrum duties, freeing up the Analog Discovery as a full-time scope (and logic analyser) and giving me much more dynamic range to test out designs.
Apart from the abysmal software - "Focusrite Control" - I couldn't be happier. Great build quality, and effortless to integrate into my setup. My chain is as follows:
While I'm still fairly new to best practices regarding sound interfaces and loopback measurements, here are some quick results:
Setup
REW @ -6dBFS 1KHz sine:
That third harmonic hops around a little, somewhat larger than I'd like. Although massive nitpicking (it's ~125dB down!).
And for what it's worth, RMAA:
Very happy with the results! Not quite the rock-bottom distortion figures seen elsewhere in the Clarett range (I've seen -116dB noise figures), but an absolutely razor sharp frequency response. Lovely.
If anyone has any tips about how best to perform loopback tests, software choices, setup (particularly the godawful Focusrite Control software) I'd appreciate it!
I recently picked up the Clarett 2Pre to take over FFT/spectrum duties, freeing up the Analog Discovery as a full-time scope (and logic analyser) and giving me much more dynamic range to test out designs.
Apart from the abysmal software - "Focusrite Control" - I couldn't be happier. Great build quality, and effortless to integrate into my setup. My chain is as follows:
DUT -> Dummy Load -> Passive Attenuator -> Clarett 2Pre
While I'm still fairly new to best practices regarding sound interfaces and loopback measurements, here are some quick results:
Setup
- Balanced 1/4" to balanced 1/4" cable from Line Out 3 to Input 1
- Focusrite Control set to Direct Routing (the only way I could find to prevent a feedback loop - still getting to grips with the software)
- Line Output at -6dB in Focusrite Control
- Input pot at 10-o-clock
- Mono only - didn't have a second cable on hand
REW @ -6dBFS 1KHz sine:
That third harmonic hops around a little, somewhat larger than I'd like. Although massive nitpicking (it's ~125dB down!).
And for what it's worth, RMAA:
Very happy with the results! Not quite the rock-bottom distortion figures seen elsewhere in the Clarett range (I've seen -116dB noise figures), but an absolutely razor sharp frequency response. Lovely.
If anyone has any tips about how best to perform loopback tests, software choices, setup (particularly the godawful Focusrite Control software) I'd appreciate it!