Schiit Unison USB

Unison draws effectively no power. I used a split USB cable to test some issues with the xDuoo unit I mentioned above, its USB into Unison makes extremely loud popping noises during loud recordings, probably something to do with clipping (SPDIF is totally fine, great actually, and if there's no clipping(?) in the track, the USB is superb). I used a data/power split USB cable and plugged in a portable charger for power. After 5-6 hours, the battery hadn't gone down by a single percent--and made no appreciable difference in sound. (EDIT: D'oh, I forgot Modius is USB powered)

I edited my comment above but I'll say it again, if you can, isolate the DAC on its own USB hub, and if you can't, keep USB peripherals at a minimum.

 

@ohshitgorillas Thank you for your suggestions. I had not considered the xDuoo, will look into it. RPi4 with Pi2AES is definitely more versatile but also more money.

Yes, I agree. It seems that laptops are generally the bottom of the barrel of audio transports. My old desktop machine with USB card was much better.

I have my own custom ALSA configuration set up for bit perfect, equalisation, etc. So I'm pretty comfortable with the ins and outs. But I will check. DeaDBeeF (music player) and VLC (movie player) are using the same ALSA config path.

I don't remember it sounding so bad with the Gungnir Multibit and Gen 5 USB. Maybe Unison on Modius is not so super in comparison. Also, my Neumann NDH 20 headphones, that I'm currently using, maybe more revealing than my usual HD 650. May be will listen again with HD 650 tomorrow.

Much to think about.

Edit: I will also try unplugging the other USB peripherals / isolating the hub.

@Yethal I'm using the separate micro usb port for power Thanks.

 

It's not about the Unison power draw it's about not powering the dac using laptop's noisy motherboard.

@mrflibble Dunno how much difference would it make if you're already using ALSA but can you check whether the same issue occurs with Strawberry? It can output directly to alsa sink and uses gstreamer under the hood.

 

Just an update on my USB issues.

I tried the Strawberry player (I was not previously aware of this, thanks @Yethal) and unplugging all other USB devices, but it was no help.

I then managed to pick up an RME ADI-2 DAC for a reasonable price. This was a minor improvement over the USB implementation in the Modius, it helped slightly with the nasty treble (almost like a constant hash in some tracks) and the sibilance issues . However, it did not actually fix the problem and still sounded like ass (just a bit less ass).

Next, I managed to find an Intona filter, again for a reasonable price. This did the trick! No more nasties I therefore surmise that Bifrost 2 with its galvanically isolated Unison USB would also fix this problem.

The blanket effect on the sound (particularly noticeable with speech) was caused by something different. It is a combination of the Neumann NDH 20 headphones and the Harman EQ I am using. I need to so some further work to optimize the EQ for these headphones. The Neumann sound even worse without any EQ (very poor tonality, IMO). Sennheiser HD650 (non EQ'd), on the other hand, sound fine.

 

Turns out the issue I had with USB Audio Player PRO and Unison USB (no sound after a sample rate change) can be fixed by enabling the "Free USB bandwidth after playback" USB audio tweak.

 

I added Unison USB to my Yggdrasil A2. Everything is out of my PC.

Having used Unison on Modius for a moment, I immediately recognized some of the qualities of the interface when adding it to Yggdrasil. What I hear is the SPDIF optical has a bit more veil and rounder transients. Unison adds a bit of clarity and sharpens the transients. Unison is probably the better technical performer but I find myself often preferring the softer SPDIF presentation.

The relative delta is on the level of differences between different brands of good interconnect cables around the same price point.

 

Spdif reference is from optical not coax ?

 

Yes. The mobo doesn't have a coax spdif output.