I know I am beating a dead horse on this one but if DAVE is galvanically isolated and the USB issues in terms of better or worse SQ stem from RF noise either from the USB signal coming in via the USB cable or from the AC power cord, is there a way to measure this RF interference with some external device?
As Rob points out when asked: So what are the best USB cables?
“Firstly, be careful. A lot of audiophile USB cables actually increase RF noise and make it sound brighter, and superficially impressive - but this is just distortion brightening things up. Go for USB cables that have ferrites in the cable is a good idea.”
So for those who claim that putting 20 + clamp on ferrite cores on the USB cable can reduce RF to the extent that a cheap USB cable can sound as good as a $700 cable, why not just measure this RF and reduce with adding the ferrites if there is a way to measure this beyond simply listening subjectively?
Rob was also asked if better AC cables make a difference?
“In the 1980's, people started talking about mains cables making a difference to the sound quality - and I didn't believe it either - particularly as my pre-amp had 300 dB of PSU rejection in the power supply. But I did a listening test, and yes I could hear a difference. Frankly I still could not believe the evidence of my own ears, so did a blind listening test with my girl friend. She reported exactly the same observation - mains cables did make a difference to SQ.
To cut a long story short, I proved the problem was down to RF noise. RF noise inter-modulates with the wanted audio signal within the analogue electronics, and if the RF noise is random, then the distortion is random too and you get a increase in noise floor with signal. This increase in noise floor is noise floor modulation, and the brain is very sensitive to it...”
So once again why not just add enough ferrite cores on the power cable to get rid of all measurable RF noise?? How can this be measured objectively??
Finally when asked if
DAVE benefits from mechanical isolation (Stillpoints, etc)? The answer was “Yes all products do”
So what relatively inexpensive options are there for DAVE for mechanical isolation? I assume this isn’t required for just headphone use but when DAVE output is to efficient speakers like Alnicos or an amp?