Upgrading The Nest Desk Further & GR8er ~ New Black Ice DAC & Tube Roll 06Sep24

With speakers and headphones driven well on the Nest Desk with the FX10H and the miniDSP 2x4HD, soon enough I considered what else Black Ice might do for me. It's all designed and built in Maryland, USA and mostly higher end tube stuff. However, they make an "entry level" footprint compatible & stackable (with the FX10H) DAC called the Black Ice Glass FX Tube DAC_DSD WiFi (a mouthful and dubious to put all the features in the name IMO). It's been lauded and awarded multiple times and has even defeated much more expensive DACs in blind bakeoffs. I guess the only question is whether to get an alternative multi-bit DAC instead, like the Schiit Bifrost MB or Denafrips Enyou. Nah... I bought the matching Black Ice DAC. It has more consumer digital input connectivity (like 32bit/192KHz AirPlay WiFi, and optical & coax, in addition to USB) than the Woo Audio (though they'd rarely be used beyond test & verification I suspect). And it has more decode capability, like SACD/dsf!  I do have a modicum of SACD titles I ripped to .dsf files but I rarely play them as the DACs in my Schiit & Woo Audio primary headphone setups do not have DSD decoders ~ but I will be able to play them @ the Nest Desk now. The 12AX7 output tubes are underlit with a blue LEDs for glow, and the logo glows orange in the middle of the top of the unit, all badging is completely different than the FX10H... all this is weird, but, Ok. At least the power button is on the front.

My first listening was in COS, which allowed a direct compare to the Schiit Gungnir MB DAC. The full Schiit stack is balanced all the way to my ears so it immediately sounded "more powerful" than when using the Mjolnir 2 as the amp for the Black Ice DAC ~ I had to adjust volume on comparisons. First impression was that the BI Glass DAC was not as forward, defined, or wide a sound as that from the Gungnir MB.  Yet, while it was way more reserved, it was fine and musical with 32bit/192KHz decoding and DSD & WiFi none the less. The headphone amp driven by the stock Psvane ECC83s was excellent... though I did have to go from 3.5mm pin to 1/4" plug to balanced XLR connectorization to get there... but why not 1/4"? I'll enjoy comparing the headphone amp in this DAC with the one in the integrated FX10H when back @ the Nest.

While to me a DAC often makes less a difference in a digital audio chain than do amps & transducers, this thing sets a decent standard for my Nest Desk not unlike my Gungnir Multibit does in COS or the Pontius R2R does in the NestMT. I can tell the difference between some good and bad DACs. For a delta sigma DAC, the Black Ice is the shizzle. It is very musical and fun and "analog sounding," like the Pontius, despite not being multi-bit. However, it's not nearly as fine as my Schiit Gungnir MB or my Pontius (MB), but costs a lot less too. I did test the COAX & fiber SPDIF digital inputs and they work fine. I also used the new DAC to play some SACD/.dsf files ~ it syncs quickly to that mode and they sound great. I also tested the AirPlay features; after connecting the WiFi DAC to my network via the Mac's AirPort Utility, and putting my phone or other computer on that same net, I got the DAC connected and could easily choose it as a "speaker" in AirPlay on iOS or macOS. It works (and passing the Apple certification alone is a good system engineering feat).

I did another DAC-off (A-B listening compare) of the Black Ice Glass FX DAC vs the miniDSP 2x4HD DAC. The Black Ice was smoked by the Schiit Gungnir MB in the last compare and I was completely ready to return it... I have 45 days. I used the Black Ice FX10H as the amp for both headphones and the Blanda 108NSs. It was a dead heat driving the speakers... I could hear little difference between the decoders. Perhaps that's in part due to my source material being 24bit/96KHz that's native to miniDSP and below the 32bit/192KHz rez of the Black Ice, but I doubt it. The processors are very different: miniDSP uses Analog Devices SHARC DSP and a lot of their own code and Black Ice uses a more classic DAC part Burr Brown PCM 1795 part. Equality is not sufficient enough to keep it though, despite the extra features (DSD, WiFi, integrated tube headphone amp) and keen stacking fit with my nice BI amp. On headphones (Audeze LCD-2 planars) though, I did get a noticeably cleaner low end and a smoother overall feel from the Black Ice than the miniDSP. Phew. I like the soft volume start when reapplying sound too. Let's be honest, the miniDSP is much more than a DAC anyway; it is a very cool, very powerful, signal processor for sophisticated EQ and filtering in the digital domain... and it's 25% the price of the BI DAC, so to even hold court in this application for a bit was great. "Final" verdict: winner Black Ice Glass FX Tube DAC_DSD WiFi; I decommissioned the miniDSP 2x4HD from the Nest Desk.

Of course I measured the Nest Desk system again with the Black Ice DAC in the audio path. It shows up slightly better than the miniDSP, as hoped... but now I won't get to use digital signal processing (DSP) to tweak any issues... NP, it is great as it is. As to which headphone amp I prefer, I don't like one over the other and did not hear a big difference in sound; the 1/4" connector is better but then I have to turn the FX10H on even for just headphone sessions ~ I'll probably use the headphone amp in the DAC for those sessions.

The closeness of the DAC-Off listening among delta-sigma contenders and lack of closeness vs the Schiit multi-bit R2R ladder variant makes me want to try another bakeoff with other "entry level DACs:" the Schiit Bifrost "True Multibit" and/or the Denefrips Enyo (24bit R2R multi-bit). The only "con" I can sense with my new configuration is that I cannot separate the headphone from the speaker setup anymore... NP, it's all for the Nest Desk anyway. The NAD D3045 was gifted by MLC to Eline and the Woo Audio WA7/WA7TP was sold on eBay, so the recent Nest Desk upgrades were almost fully paid off.

Tube Rolling The FX10H To Tung-Sol 7189 Power... My matched quad of current production 7189s is a reissued tube built to the same specifications as the original 7189 Tung-Sol for HiFi 7189 amplifiers built in the 1960s... the originals are rare and expensive. It has higher plate voltage than the stock Psvane EL84s and gets another couple watts to 14w/chan. A-B listening of Psvane vs Tung-Sol on the Nest Desk didn't reveal a lot in the short term. Maybe there's more punch in the low end and perhaps the mids are a bit hotter... they are good across a range of vocals, acoustics, and electric rock. I'm leaving the 7189s in the amp for a while and will see if there's any change. I did measure without much burn-in (supposed there was some of that done already by the vendor) and again nothing huge was revealed.