777
Senior Member
- Joined
- Jan 1, 2019
- Messages
- 486
- Likes
- 360
I tested the DX3 Pro broadband spectrum with its own power supply and that of the lab.
Own supply:
View attachment 20511
Lab supply:
View attachment 20512
There is almost no difference until 100 kHz. Even after that there is not much of substance. The noise spikes are internally generated or passed through from USB. Either way they are well above frequencies of interest.
There is much more noise with adapter, we saw on the oscilloscope but it is in higher band. That high frequency noise isn't random noise, it is in burst tones. That burst tones has 32khz frequency. So, if you can see Mhz, tens, hundreds of Mhz(harmonics of the noise) then you can see that burst tones too, from the lower frequency, at 32khz.
So, all depends of how big is the bandwidth of the FFT measurement.
Now become obvious, a linear external power supply and a better internal power supply decoupling, with proper capacitors and a proper grounding, will pushing Dx3Pro in highend class product at a small price.