I had a chance to play with the HS01 today on both my headphone desk system and home office system.
It seems a little finicky to set up, it will work if I first connect it to the DAC then power it, give it a few seconds to boot and then connect to the source. At first I couldn’t make it work with my Pi. With the Pi, I powered the Pi after everything else was powered. It will rapid blink the red LED for a second to give you feedback it has recognized the input.
The two setups are as follow:
Headphone system
MacBook Air M1 running the Roon client app -> Apple USB/HDMI dongle -> HS01 powered by an Allo Nirvana (5VDC) -> Modius -> Magnius -> Hifiman Sundara
Non generic cables are DIY, balanced, with Neutrik termination. Headphone using Canare microphone cable, analog XLR using Supra DAC cable.
Speaker system
Pi 3B+ running RoPieee XL -> HS01 -> X-SPIDIF 2 -> Genelec 8330A
Power supply is an Allo Shanti with two 5VDC outputs. The 3A output powers the Pi and the 1A is connected to the HS01 and powers the X-SPDIF 2. Without the HS01, I only use the 3A output to power the Pi and the X-SPDIF 2 is powered by USB from the Pi.
The sonic differences are subtle but audible. The systems did not sound different tonally (thank god!), but there was a sense of greater clarity and transparency, especially on the high frequencies. I went back and forth a few times (level matched on the headphone system - I did not touch the volume knob or anything else in the amp). For this initial comparison I mainly listened to Dave Brubeck’s Take Five first track from the album Our Favorites (I think my favorite performance and recording of Take Five).
With the Modius DAC on the headphone system I compared 3 configurations:
1- Powered by the MacBook Air USB port - sounded more fatiguing and not as clear as other configurations.
2- Powered by the Nirvana PS (no HS01) - sounded smoother overall, no obvious listening fatigue.
3- Powered by the HS01 (powered by the Nirvana) - still smooth, but with more apparent clarity on the high frequencies, music felt more engaging.
These are my subjective impressions of course, but it seems that there are some subtle improvements when isolating DAC from computer.
I’ll spend sone time listening with the HS01 in the speaker system for the next 2 weeks and switch with and without back and forth a few times for longer periods of time to see if my long term impressions are the same.
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