@wklie (Peter Lie)
Hi Peter - would be interested in getting your perspective on this. First let me start off with the good news - last week I worked directly with a Lumin support engineer who had the team fix my problem by creating a beta firmware update for the U1 Mini. So, thanks to the engineering team for the quick turnaround on a solution.
The problem was whenever I tried upsampling any of the Hi-Res files from Qobuz, the built-in DAC module, DA2, in my McIntosh C53 amp, while capable of DSD512, would display the PCM kHz equivalent of the DSD and all that could be heard was hissing and barely a whisper of the song being played. However, when I would play downloaded DSD files stored on a thumb drive plugged into the Lumin, my preamp would correctly display DSD & size, and it sounded glorious.
After installing the beta firmware update, either DSD64 or DSD128 now displays and it sounds good. But after playing around with it for another week, I’ve noticed some anomalies. Even if I have upsampled the Qobuz file to DSD128, the McIntosh “most of the time” will display DSD64. But then… occasionally, it will display nothing - just a blank line. And even more occasionally, it will actually display correctly, DSD128 - and this can be from any Qobuz file size but the most recent time it displayed 128 was when a 48kHz file was playing. I contacted support again and they said it is probably just cosmetic and as long as it sounds good there’s nothing to worry about.
While I’m very thankful the beta now allows me to hear files upsampled to DSD, the inconsistency still bothers me - would you happen to have any ideas? I assume there might be something going on with the Lumin handshaking with McIntosh’s DA2 DAC. (specs on the DA2 are on the web, but it’s a Quad Balanced, 8-channel, 32-bit DAC with USB native playback of up to DSD512 and DXD up to 384kHz.)