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I bought a Topping D10b for equipment measurements a while ago but never really used it because I couldn't get ASIO4ALL working initially.
Yesterday I managed to achieve exactly that, so I decided to take some measurements.
My input device is an RME Fireface UC which I have measured a lot lately too, just to get used to its distortion behaviour and levels.
Both devices were set to 96khz sampling rate. The D10b was in 32bit mode.
Let's look at the output spectrum of the D10b at -1dbFS, which equals to about 3.7V (0dbFS produced 4.11V):
That doesn't seem quite right. 3rd harmonic is at -74db or so, pretty far off Amir's measurements. To make sure that the Fireface is not the issue, I measured it at the same output voltage and it resulted in much better stats (as I expected), which I forgot to save, so let's look at an actual comparison next.
The Fireface performs best at 0,5V input, which produced the following results:
Not sure wha the bad THD+N value is about, but ignoring that we have pretty clean THD and there is no garbage below our fundamental.
The D10b produces 0,4V at -20dbFS, which is what can be seen in the next measurement:
THD and THD+N are as good or better as the Fireface itself, but the graph looks way worse to me.
That tone at 375hz could already be seen in the first measurement of the D10b, which I why I turned off the generator to see how the sub 1k noise reacts:
Well, it didn't react much at all. The D10b seems to be outputting this on its own. Graph now with actual voltages.
I have one more measurement, which is THD vs output level. It is quite limited by the Fireface (it's not an APx555 after all), but it clearly shows the issue at hand.
I typically have a bit of confidence in my measurements when they show consistency and repeatability, but I often discover new things and I hope somebody will point out a mistake I made, because dealing with a broken device would be much more bothersome.
Distortion shows unusual behaviour at levels beyond 1V output and there are lots of tones being generated at all times.
I tried a lot of different settings in ASIO4ALL, but they didn't change anything. The latest Topping driver is installed. I tried rebooting. The D10b is connected to the Fireface via ~10m of balanced cable (runs through the patchbay in my outboard rack; Fireface-only measurements were also taken through the patchbay).
Yesterday I managed to achieve exactly that, so I decided to take some measurements.
My input device is an RME Fireface UC which I have measured a lot lately too, just to get used to its distortion behaviour and levels.
Both devices were set to 96khz sampling rate. The D10b was in 32bit mode.
Let's look at the output spectrum of the D10b at -1dbFS, which equals to about 3.7V (0dbFS produced 4.11V):
That doesn't seem quite right. 3rd harmonic is at -74db or so, pretty far off Amir's measurements. To make sure that the Fireface is not the issue, I measured it at the same output voltage and it resulted in much better stats (as I expected), which I forgot to save, so let's look at an actual comparison next.
The Fireface performs best at 0,5V input, which produced the following results:
Not sure wha the bad THD+N value is about, but ignoring that we have pretty clean THD and there is no garbage below our fundamental.
The D10b produces 0,4V at -20dbFS, which is what can be seen in the next measurement:
THD and THD+N are as good or better as the Fireface itself, but the graph looks way worse to me.
That tone at 375hz could already be seen in the first measurement of the D10b, which I why I turned off the generator to see how the sub 1k noise reacts:
Well, it didn't react much at all. The D10b seems to be outputting this on its own. Graph now with actual voltages.
I have one more measurement, which is THD vs output level. It is quite limited by the Fireface (it's not an APx555 after all), but it clearly shows the issue at hand.
I typically have a bit of confidence in my measurements when they show consistency and repeatability, but I often discover new things and I hope somebody will point out a mistake I made, because dealing with a broken device would be much more bothersome.
Distortion shows unusual behaviour at levels beyond 1V output and there are lots of tones being generated at all times.
I tried a lot of different settings in ASIO4ALL, but they didn't change anything. The latest Topping driver is installed. I tried rebooting. The D10b is connected to the Fireface via ~10m of balanced cable (runs through the patchbay in my outboard rack; Fireface-only measurements were also taken through the patchbay).
