IQAudio I2S Pi-DAC+

I received this a while back but had not had time to set it up previously.

IQAudio Pi-DAC+

Setup

I had a new RPi3, set it up with Rune which is a Volumio equivalent on a different Linux platform (ArchLinux - only 32 bit) but already compatible with Pi3. Works wonderfully well, doing everything  I set up for myself with MPD etc. in a flash. The Pi3 built-in wireless works a treat, but has crappier reception than the USB plug-ins.

Rune does UPnP OOTB, so I was able to test with the headphone output and the MinimServer on my Mac as a music data source. Very impressive that it all worked perfectly in a stress-free manner.

Plugged the DAC+ into the RPi GPIO pins no problem, using the supplied stand-offs and screws. Powered up - recognised immediately by Rune interface, told it to use it.

Plugged my USB drive into the RPi, restarted things. Drive and music recognised, Rune UI showed Library updating. All good.

Evaluation Approach

My approach to evaluating DACs is simple.

1. Plug the DAC for evaluation into the Disc2 input of the Chord pre-amp
2. The Naim CD2 is meanwhile plugged into the Disc1 input
3. Disc1 and Disc2 have the same gain setting - this makes sense as long as the DAC and Naim have the same nominal output, I check this in the specifications
4. Using the 80s vintage HiFi News Test Disc, which has some very nicely recorded music on it, play the same track on both my Naim CD2 and the DAC, starting at approximately the same time
5. Switch between Disk1 and Disk2 using the Chord preamp remote control, sitting in the main listening position 

This allows me to A/B the two sources pretty easily, and when there's an interesting bit, switch conveniently from one to the other. "Interesting" usually means spatially amusing, or transiently brisk.

Observations

In isolation, the DAC sounds fairly bright, and does have space around instruments. I've only listened to some classical at this point, including some Hildegarde of Bingen, as that is probably more critical than most rock in respect of the factors I'm interested in i.e. soundstage, spatial location, "air", timing.

Listened to against the Naim, the Naim sounds dull initially, and not so immediate, almost boring. However, listen harder and for longer, and the acoustic of the Naim sounds deeper and more detailed. The instruments sound woody, and less brazen, sibilant. This is on only two tracks so far, so it's a bit unrepresentative, so more listening to do.

At this point, I'd not swap the Naim out for this DAC. at least, not for the main stereo setup.

I also have to compare this to the ObjectiveDAC (a USB-connected unit) - I'll be able to do that from the Pi directly, as it allows for both to be plugged in at the same time, and switched between. Cables are a bit of a problem as I don't have two identical sets of RCA cables, so I'll have to try with one setup and then switch the cables and try again.

How much have I allowed Rob Watts' presentation to influence me? Quite a bit probably, but then, he is a long-time listener and digital dude, so that's not necessarily a bad thing. Of course, I'd like to hear Mojo/Hugo/Dave in this setup. Maybe I can if I nip along to Audio-T...