HOLO Audio Spring DAC: Affordable discrete R2R Multibit Dac, could be a winner.

The Schiit Yaggs is much more technically advanced in its actual 21 net bits... patented AD -Bruz technology

Huh? Not sure where you're getting 21 net bits from since the Analog Devices AD5791BRUZ DAC they use is a precision 20 bit DAC. Feed it 24 bits of data and the last four are rounded off. If anything, the Spring DAC is closer to 21 bit, given their claimed SNR of 126 dB. I also think you're confusing Schiit's oversampling digital filter (which is proprietary, not patented) with the DAC chip itself. 

True that the AD DACs themselves are 20 bit, but the way they implemented the design with two DACs per channel gives them a claimed 21 bits of resolution.

I see - dual differential. Still, I don't think it makes much sense to claim that. The input register doesn't even accept more than 20 bits for data. But what do I know? I'm just a regular schmoe... And not that it matters all that much anyway since we're talking about deafness at this amount of dynamic range.

A good friend of mine received the Holo Spring DAC a few weeks ago and has accumulated just over 300 hours in his bedroom system. He invited me over today to hear it in his primary system. Which is comprised of computer-Bricasti SE DAC-Absolare Altus Line Stage-Krell FPB 600 mono blocks-Rockport Altair speakers, he uses Echole cable loom. Needless to say that he has a fabulous sounding home audio system.

We listened to several very familiar recordings all 16/44.1 with the Bricasti SE we then listened to the same music with the replacement Spring DAC level 3. Well I’ll say this, the Holo Spring DAC is very good sounding. Natural character with good tonality and sense of musical ease. Dynamics,bass weight and impact as well as sound stage presentation and perceived dimensions were near equal to the Bricasti, this is a compliment.

Where th Bricasti SE is superior is refinement, nuance and inner/micro details or information. Bass texture, vibraphone, piano and guitar harmonics, overtones and timbre are superb as they’re more completely fleshed out and distinct. The Holo does these sonic things very well to be perfectly clear. The Bricasti raises the bar higher yet. In no way or manner is the Holo embarrassed in direct comparison, not at all. You are made aware of differences between components when heard back to back.

When cost is factored into the mix you have to acknowledge that the Holo Spring DAC level 3 represents very substantial value. Without question this is an exceptionally good sounding DAC. Three points to clarify.
1 The Distributor strongly recommended the Audio Horizon Platinum fuse upgrade based on his personal experimentation. I’d trust him on this. We replaced the stock fuse with a Synergistic Research Black fuse and there was genuine improvement. Take that as you like.

2 The sound was also improved with the use of an Intona high speed USB isolator between computer and the DAC.

3 The Distributor is sending my friend a Singxer SU-1 USB digital converter which he insists is very beneficial. We’ll see if that is the case once it arrives.

Initial impression, This DAC is very well built, solid and reflects high quality workmanship. Best ofall It sounds like music if you know what I mean. It held its own in an exceptionally fine and highly resolving (yet superbly musical) audio system. It is a legitimate high end product.
Charles,

Thanks Charlies, very nice review of A/B comparison with Bricasti SE. 
Do you think this 3rd level Spring DAC has improved \ exceed in every areas than the Yamamoto DAC ? Thanks!
-philip