For Rob,
I was thinking about HMS and the way it can be powered by an external powerbank. I then had a very strange thought that if an external powerbank could somehow be charged and powered up 24/7 and connected to hugo 2 then hugo 2 might effectively be kept in desktop mode without a mains powered charger connected and benefit from being off the grid with the powerbank. I will not under any circumstances try this and will use chord's supplied charger of course. Could you explain why the powerbank with H2 in this context is a very bad idea (and should not be tried) as one member already replied stating he had experimented with a smartphone powerbank and H2 with bad results. Many thanks mk.
Power banks are actually very good devices to use for audio, even if they employ switch mode regulators. The sound quality issue with RF noise on the mains is from 10 MHz to 10 GHz, and in this band a battery power bank is very much better than mains supply. And before anybody starts saying LPS, these devices provide no rejection from 10 MHz and above, as they do not employ RF filters- but a SMPS must employ filters, both on the OP and back to the mains.
As you know, RF noise creates noise floor modulation, as the intermodulation distortion from random RF noise is a white noise modulated by the wanted signal. This then results in noise floor modulation, and is very very audible. It accounts for the things sounding brighter and less smooth; additionally, when you reduce RF noise, things sound considerably warmer and darker, and one consequence of this is perception of tempo - more midrange gives the impression of a slower tempo, as individual instruments have much more body.
Now if somebody prefers the brighter sound from more noise floor modulation, then fine - that's their taste and preference. But it's not accurate.
Another benefit of battery bank operation is disconnection from the mains supply, and so no ground loops (or RF ground loops from non-grounded supplies). THis is a considerable advantage, as it is RF noise injected into the DACs ground plane that is the issue for the source of noise floor modulation; and if the PSU is isolated from the mains, then there is no RF ground loops, and so no current flowing into the ground plane - and then no problems.
As to Hugo 2, I would not worry - with HP operation, I can't hear the effect of adding the supplied charger, nor is there any measurable change either.