I planned to write this a lot later... after at least a week or so, but then my notes would have stacked up, so here they are thus far. Please check back on the first post for more impressions later on, as I'd like to keep things coherent and continuous. 10/05/2015, got the Gungnir Multibit (hereby shortened to Gumby for convenience) from the mailman, and I immediately plugged 'er in. Immediate impression compared to my Macbook's built-in DAC (yes, I'm serious!) is that... Gumby is thicker, and kinda murky? But not as bright or strident. That's good. Though I wasn't wowed. Tried to change sampling rate and all but that didn't seem to help. So... I decided to just leave things the way they were and just listened sporadically. Here are the notes on the same day: 1 hour later, I swear I could start to hear a bit more of something coming from my music, but... it was still a little murky. 2 hours later, at that point, I think the soundstage started opening up, and I could hear things coming from the far right or far left. Still not much depth. 3 hours later, I think I'm hearing things a bit further into the soundstage. Still not sure what to make of it. 4 hours later, I gave up and went to do other stuffs instead. Will try again tomorrow. 10/06/2015, I waited until exactly 24 hours have passed since I turned the Gumby on to listen. At this point... I'm starting to notice how certain things like guitar, vocals, violin, piano, etc... still retained the same full-bodied warmth and thickness from yesterday, but now there is tangibly "air" or "silence" in between the parts where those things don't happen. Suddenly there is much more contrast between the "no sound" and "something" parts of my recordings. That's awesome! Oh, and this also happens with Youtube and MP3s, so it's not limited to highest quality lossless. Just to confirm, I switched back to my Macbook's DAC again, and... wow... the sound collapsed in every dimension, and everything was pulled closer to me by a large margin. It was a lot harder to distinguish between guitar and violin. This isn't brain burn-in. I swear Gumby was only marginally better than my Macbook's DAC yesterday. Very very very cool! Also, at this point, I started noticing flaws in certain recordings like... say... Eagles' Hotel California in their Hell Freezes Over album (K2HD version). In that song, the guitar at the very beginning has a weird buzzing sound whenever the track is played. I'd guess... I'm hearing the recording/mixing artifacts? Note that I've heard that before, but I thought it was grain in my amp/headphone. Now it's clearly sounding more like a recording/mixing artifact rather than a flaw in my amp or headphone. 10/07/2015, 2 days later... at this point, with some of my recordings, including the closed-mic acoustic ones, I can "feel" strings being plucked close to me, the vibration and presence of the singer's vocal in front of me, piano notes ringing in space with the thump and weight of each stroke, and each one of those sounds is distinct and projected in their own space. It's a very holographic experience that I'd never experienced before! Do note that I have listened to Yggdrasil systems before, but it meet and show conditions and with music that were not my own, so I could not make out what it was. Now I know for sure that it's not the music. It's the Gumby that's doing this. And the effect is not exclusive to the HD800. I can hear this with my HD600 as well, and it makes some recordings so much more involved to me. And the crazy thing is... I still have a feeling it's not quite there yet. Gumby may still be able to pull even more out once it has had a few more days. 10/08/2015, on this day, I actually didn't post anything because I was so enthralled with the music now. At this point, it didn't matter anymore. Gumby simply sounded excellent and "real" to me. To be able to listen to Youtube, to movies, to some of my lesser recordings this way? It was simply bliss! 10/10/2015, I got my Wyrd in today, and so... I hooked it up to Gumby. Without exaggerating, I think... the improvements come down to a little bit more tightness, transients are a bit faster, a bit more blackness in the sound, and lower frequencies are slightly fuller. But honestly, I think it's a fairly small improvement compared to what Gumby was already able to do by itself. Or maybe it's because I have only my HD600 now. I don't have the HD800 with me. Maybe I'll revisit this (do a with-Wyrd and without-Wyrd comparison) again at a later time. But IMO, this is worth it if you want that extra 1-2%, and you can afford an extra $100. Otherwise? Gumby should be good enough on its own already. Foot note: listened with modded Sennheiser HD600 and HD800 (except for when I hooked Wyrd up). Amp-wise, I was using my DIY solid-state op-amp-based amplifier and the Bottlehead Crack. I've got OJ's CKKIII as well. Macbook's DAC was used as a comparison for you "all DACs sound the same" folks. Foot note 2: yes, this is a "how does Gumby sound like as it warms up" post in disguise.