Mark Dirac
New Head-Fier
- Joined
- Jan 7, 2015
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Well I finally got around to buying a USB C otg adapter for my new LG G6, and am thrilled to report that it plays to the S2D.I've successfully connected the Pre Box S2 Digital to an Android phone and the UAPP app, via a UTG adapter cable. However, I needed to put my USB REGEN between them. My externally-powered Schiit Modi 2U connects fine with or without the USB REGEN, but the Pre Box needed the REGEN's help.
Power: My phone is a Pixel XL. When connected directly to the Pre Box I get the Android "USB Supplying Power to Attached Device" message, but the phone does not supply enough power and the Pre Box does not turn on. Powering the Pre Box with the supplied wall-wart didn't work either: the Pre Box powered on, but UAPP could not find it. But after disconnecting the wall-wart and inserting my USB REGEN, the Pre Box powered up and UAPP found it.
Play: I used UAPP to play several HDtracks hi-res files, and the Pre Box reported the sample rates perfectly. I then tried streaming from Tidal and Qobuz using UAPP, and found that unless I enabled bit-perfect in Settings anything above 44.1 kHz would stutter. I used UAPP to test Tidal HiFi, MQA, and Qobuz low + Hi-Res. Everything was detected and sounded as expected, with one minor exception that I suppose is due to the way MQA works: during MQA streaming, UAPP showed 48 kHz which is what it sees in the package it's sending, and the Pre Box displayed 192 kHz which is the result after unfolding in the DAC.
Success. Not a portable solution without a better power source, but interesting. I'm looking forward to seeing someone try this with an iPhone or iPad. I tried an Android tablet, a Pixel C, and couldn't even get the "USB Supplying Power to Attached Device" message, but I assume with the USB REGEN inline I would be able to do the same as above with my tablet.
And yes, I get the popping noise in this app too. Can't wait for the firmware update.
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Edit: clarified "my Schiit Modi" is "my externally-powered Schiit Modi 2U".
Playing Tidal, the S2D's display reports 96kHz, which puzzles me. I would expect it to show 44.1kHz or the Android's native sampling rate of 48kHz. (MQA is not available on the Tidal Android app. And I cannot believe that the app is sufficiently sophisticated to decide to upsample to 96kHz. So what is upsampling? Puzzling.)
The wall wart is needed to get the S2D to power up, but thereafter the wall wart can be disconnected, and the S2D is happy to be powered from the LG G6. Battery drain of the LG G6 is pretty high - I guess a 100%-full battery would be drained in about 4 hours. Battery drain is reduced a little by plugging back in the wall wart. (I can still hear no change in sound, on my LCD 3 headphones, with the wall wart connected or disconnected.)
It's a pity that we never found out what the wall wart is powering. Clearly, the S2D needs not only voltage but a fair bit of current over the signal USB from the host, particularly when starting up. But the wall wart seems to be powering only a proportion of that current through the power USB, and is not essential.
I am curious as to how it would sound if I found a USB C otg adapter with a power-injection socket. The S2D seems to be well-designed to smooth away noise from the wall wart on the power-input USB socket, but would it be able to smooth away noise from a switching wall-wart supplying power into the signal (host) USB?
I have updated the summary document slightly.