Less than 24 hours and mine is post number 254! This is either a Chord fan club page or hate club!
A few observations:
- Portable DACs as a rule do not have galvanic isolation on USB input for two reasons: 1- they don't really need it 2- it costs too much on battery juice.
They don't need it because, even connected to a noisy phone or tablet, but nothing else! The noise has nowhere to go, so it won't pollute the ground plane. That happens once you connect them to another grounded device, like an amp, the noise current might flow through different grounds, polluting the system.
Is there a portable device with built-in USB isolation out there??
Any noise Amir encountered on USB operation, he is responsible for! the noise came and went from his source and whatever else he connected the device to, so don't blame the device, clean up the lab.
At any rate, anyone who can afford this unit and is worried about USB noise, either use TOSLINK or the diminutive cheap Topping HS-01 isolator! size of a match-box, running on USB power, fully isolating the USB input. Problem solved (only on a noisy source) for £50.
- I find it curious that at times, one channel is noisier than the other! Specially on USB, this tells me there is something wrong with the test gear noise, as under optical connection, both channels are same.
- Optical Does lock on 192kHz with my PC, using an onboard sound card, an Amazon £2 cable and a £10 backplate connected to SPDIF pins (& +5V) on the mainboard, Every time, all the time. Perhaps Amir has an issue with his optical too.
- The different filter's effects will not show up on 44kHz & on a 100dB scale graph! Amir should know better. Use 96kHz and zoom in a bit to 5dB scale graph, then you will see them. The filter's effect can just about be heard on some hi-res materials, otherwise I agree there is not much point to them, as all Chord DACs have a very effective brick wall filter. Unlike other manufacturers that have slow filters of varying kind.
- Hugo2 was launched in Jan 2017. Still rocks with the best of them, 5 years & more later.
- I paid less than £1k for mine in used condition a year ago, today I get over 6 hours play time on USB! Longer on optical and coax.
- Desktop Mode works great on Hugo2. The remote works at any angle, even not in line of sight, an additional phone charger connected to the charge-socket keeps the unit at 80% charge and stops, adds no noise (phone chargers have no Ground).
- Subjectively, it is better than my beloved Topping DX7 pro which incidentally sounds cleaner with Toslink compared to straight USB, on a par with a Topping HS-01 in loop.