I’ve now had the chance to spend the last few days with the Simaudio Moon 230HAD DAC/Amp. Here is my review of the 230HAD, for your reading pleasure.
 
I was in the market for a great DAC/Amp in the sub-$2k range for my HD800 headphones, so I jumped at the opportunity when Todd initiated this 230HAD loaner program. Other DAC/Amps I have been considering include the Sennheiser HDVD800/HDVA600, the Ayre Codex, the upcoming Questyle CMA600i, the NuPrime DAC-10H, and this piece, the Moon 230HAD.
 
To avoid repeating myself, please refer to my review of the Ayre Codex, where I detailed my criteria, my associated equipment, my music selections, and my findings comparing the Ayre Codex to the HDVA 600 (amp only). I came away from that comparo with a great appreciation for the little Codex. Luckily, my Ayre dealer was able to lend me his demo Codex for the weekend, so I had it on hand alongside the 230HAD.
 
Here're all the goodies lined up for some sweet listening!
 

 
 
Objective
I had two objectives. First - I wanted to know if the 230HAD would fit the bill for my requirements. Second - how did the 230HAD compare relative to the Codex in my environment?
 
Review Approach
Being a scientist, I like to define my methodology and design my experiments carefully. Accordingly, my approach was as follows:

• Establish a baseline impression using the 230HAD.
• Compare with the Codex, varying one thing at a time, and note subjective impressions
• Finally, compare the best configurations of the 230HAD with the Codex for an overall assessment.

 
Operational impressions of the 230HAD
The 230HAD is a very impressive piece of kit. The chassis is quite elegant, and laden with digital inputs of all flavors (USB, coaxial, optical), and an analog input. All analog inputs and outputs are single-ended, with no balanced mode.
 
It also has a set of red LED indicators on the front panel to display sample rates and input selection. The sample rate indicators may be confusing to anyone without an arithmetic bent, but to me made complete sense.
 
The unit accepts resolutions up to 32/384 (DXD) PCM, as well as DSD256, both via the USB input. There is no sample length indicator to distinguish between 16, 24, or 32-bits, however. The highest resolutions I had in my collection were some 2L samples of 24/352.8, and DSD256. These played just fine with the 230HAD.
 
I did run into a head-scratcher with DSD, but chose not to pursue. My Auralic Aries Mini streamer was configured to deliver DSD-over-PCM (DoP), and this worked perfectly. However, I did try to feed native DSD to the 230. While I got audio out just fine, the sample indicators instead of lighting DSD, lit up the PCM indicators for 176kHz. This made no sense to me, as the Aries Mini has no ability to transcode DSD to PCM on the fly, so I have no idea what I was hearing. I chose to leave the DoP setting enabled the rest of the time.
 
Listening impressions of the 230HAD
Enjoyed in isolation, the 230HAD sounds fantastic. The two adjectives that came to mind as I spent some hours listening to it were: neutral, and powerful. This amp is about as neutral and uncolored as it gets. And gain is prodigious: I did most of my listening with the volume knob between 9 and 12 o’clock. Imaging and soundstage were spacious, although not the best I’d heard. Tonally, you really get the sense you are hearing exactly what is going in, with no undue boosts or dips.
 
Listening on the HD800, the bass is reassuringly solid, but the mids do have a somewhat polite and laid-back character. This amp does nothing to mitigate the slightly bright character of the HD800, but never sounded harsh or tiresome. Rhythm and pacing were very engaging.
 
Given that the S-PDIF inputs (coax, optical) were limited to 24/192 PCM, I assumed that Simaudio considered the USB input to be the preferred and the best-sounding input choice. To be honest, I was hard pressed to hear a difference between coax and USB. I convinced myself the USB was a tiny bit better, but would be hard pressed to defend it.
 
BTW - I wasn’t sure how much burn-in time this unit had experienced already, so I gave it about 50 hours of burn in using surf sounds, which according to my Ayre dealer, can accelerate burn in relative to just music. He claims none other than George Cardas gave him this tip. Who knows!
 
Honestly, if I had just acquired this piece and never compared it to anything else, I could have been quite happy with it.
 
The importance of auditions and comparisons
I don’t know about you, but my aural memory is pretty lousy. I can’t listen to a component today, and accurately compare it with something I heard even an hour ago, let alone days or months. And yet, the only way to compare equipment is to listen to them side to side with sensibly designed experiments.
 
We live at a time where the “local dealer” is a vanishing concept, so these types of loaner programs, along with purchases from retailers with generous return policies, are the only way to assemble equipment comparos.
 
In my case, having the Codex and the 230HAD side-by-side was invaluable.
 
Comparing the 230HAD with the Ayre Codex
 
Experiment 1: DAC comparison, using the 230HAD as Amp
Here is the setup:
 
Aries Mini ---- optical ---> Codex --- RCA analog ---> 230HAD --- stock SE cable ---> HD800
               |___________  coax ________________|
 
The Codex DAC is quite something. The music seemed to snap into focus, as if it were blurred before. Instruments were much easier to distinguish from each other. And the soundstage seemed to grow wider and deeper. It just sounded more relaxed. It’s hard to find the words for these sonic differences.
 
Experiment 2: Amp comparison, using the Codex as DAC
This setup looked like this:
 
Aries Mini ---- optical ---> Codex --- stock SE cable ---> HD800
Aries Mini ---- optical ---> Codex --- RCA analog ---> 230HAD --- stock SE cable ---> HD800
 
The 230HAD has the Codex amp beat on power. In SE mode, I routinely had to run the Codex to gains in excess of 95 (out of 100 max). BTW - running the Codex balanced gives you an extra 6dB of gain, and boy, does than come in handy! I suspect the Codex is right at the edge with the somewhat inefficient HD800s (at 300 ohms), and would have a hard time driving inefficient 600 ohm headphones.
 
And yet, on sonics, the Ayre had sweeter mids, and airier treble (yeah, pun intended!). Instruments like triangles, cymbals, tambourines, high hats, etc sounded more like the real thing on the Codex.
 
This also explains why the Codex made the HD800 sing better than the 230HAD.
 
Kicking in some extra gears on the Codex
The impressions so far were with the Codex being driven through the optical input, in single ended mode. However, the SQ of the Codex rose significantly further with each of the following steps:

1. USB input: on the Codex, the USB input sounds much superior to the optical. It’s hard to describe, but it’s just more of the good stuff - articulation, soundstage, air, etc.
   
2. Balanced mode/Balanced headphone cable: these two changes had to be evaluated together, since I don’t have the stock Sennheiser balanced cable. Instead I used a Moon Audio Black Dragon HD800 Premium cable (a $450 upgrade).
   
   The combination of the balanced mode and cable really added yet another quantum increase in SQ. The Black Dragon is known for both its clarity and warmth, which gives the bass a nice solidity that is lacking in SE.
   

 
All together now
At this point, I compared the 230HAD and the Codex in their best sounding configurations:
 
Aries Mini ---- USB ---> Codex --- balanced Black Dragon cable ---> HD800
Aries Mini ---- USB ---> 230HAD --- stock SE cable ---> HD800
 
Does the 230HAD as configured sound great? You betcha! In isolation, it sounded very musical and satisfying.
 
Does the Codex configuration sound significantly better? You betcha!
 
Such is the paradox of our hobby. But you have to look at the tradeoffs. The 230HAD is $1500 all in. The Codex plus balanced cable is pushing $2300. So yeah it sounds better. But yeah, it costs more too.
 
Which one is for you? Only you can decide. Go listen to both and have fun! Remember this is a hobby, not a job.
 
Wrap Up
Circling back to my objective - did the 230HAD fit the bill for my requirements? Not quite. I don’t think it’s a very good match with the HD800, but could be an excellent match for a more neutral headphone. And I’ve decided I really like the benefits of balanced amps and cables.
 
So what decisions did I make? Well, the more I listen to the Codex, the more I love it. Also, between the time Todd initiated this loaner program and my turn arriving with the 230HAD, I attended CanJam SoCal, where I was BLOWN AWAY by the Cavalli amps.
 
So I plan to buy a Codex, and use it as my DAC/Amp for the next few months. Come the fall, I hope to take delivery of a Cavalli Liquid Gold (LAu) amp. We’re talking serious dough here - which is both scary and exciting. I sincerely believe the combo of Codex DAC and LAu amp will be an end game configuration for me - or at least for some years to come.
 
Once again, a big THANK YOU to Todd for this opportunity to audition a fine piece of gear like the 230HAD.

Introduction
 
I have had my eye on the Ayre Codex ever since I saw Jude’s review of it on Head-fi TV. Ayre’s high-end credentials in both the DAC and amp space are impeccable, with iconic products like the QB-9 DSD, but this is their first foray into the headphone amp space, and quite frankly, into this low a price point. ($1795)
 
Similarly, I have had my eye on the Sennheiser HDVA 600, due to it’s beautiful design, and the excellent reviews it’s been getting.
 
My Objectives
 
I have been searching for the ideal DAC and amp to complete my system, which is bookended by the Auralic Aries Mini streamer/DAC as the source, and the Sennheiser HD800 (with Anaxilus mod) as the transducer. I had found the Aries Mini’s DAC surprisingly nice, and so have been wondering which system combinations would be right for me within a budget of ~$2000:

1. Use the Aries Mini’s own DAC along with an amp like the Sennheiser HDVA 600
2. Use a DAC/Amp like the Codex, the Moon 230HAD, NuPrime DAC-10H, or the Questyle CMA 600i
3. Use a separate DAC and a separate headphone amp. This could get pricey!

 
While I have not come even close to comparing all these options, I was fortunate to have a long weekend with both the Ayre Codex and the Sennheiser HDVA 600 gracing my rig. Many thanks to Casey McKee of Ne Plus Ultra in Austin for the Codex loaner, along with some assorted high-end cables. This review covers my impressions of the two pieces in my system. I had already had several weeks to acclimate to the HDVA600/Aries Mini combination, so that was my baseline. I should also mention that all the gear - listed in the System Description section below - had been burned in for several hundred hours, so nothing I heard should be attributable to insufficient burn-in.
 
What I expected to hear
Based on reviews I had read, I completely expected the Codex DAC to be outstanding. More unclear to me was how the Codex would fare as a headphone amp - especially against a dedicated amp like the HDVA 600 that is acclaimed to match well with the HD800. Needless to say, what I expected to hear and what I actually heard were completely different. 
 
Sonic Impressions
The music I used in my listening is listed in an appendix below.
 
My baseline system for several weeks had been the Aries Mini streamer+DAC feeding the HDVA 600. The HDVA 600, in turn, had replaced a Benchmark DAC-1 HDR, which had been doing duty as a pure headphone amp. Compared to the Benchmark, the HDVA 600 elevated the sound quite remarkably. Once burned in, the HDVA 600 had a rich, warm palette with excellent articulation. I could see why it was such a good match with the HD800. By warm, I mean a pleasing solidity in the lower registers, and the midrange had a sweetness that was lovely. But it was in the treble that the HDVA 600 really shone compared to the Benchmark. Where the DAC-1 could make all but the best recorded music sound quite harsh, the HDVA 600 removed that etchiness remarkably. Most impressive about the HDVA 600 was the prodigious amount of power on tap. Even with the input gain on the back set at 10 o’clock, I rarely had to dial the volume above the 50-60% mark.
 
Several upgrades happened after the HDVA 600 was in place, and each step (replace stock power cables, Black Dragon headphone cable, balanced mode) yielded a small but noticeable improvement.
 
How ironic then that the addition of the Codex yielded improvements over the HDVA 600 that could be described in very similar ways! In the optimal configuration:

1. Aries Mini —> Cardas USB cable  —> Codex DAC/amp —> balanced Black Dragon cable —> HD800

 
the Codex was a revelation. I could not believe how much it further improved over the gains I had previously made with the HDVA 600! There was a feet-tapping rhythmic “rightness” to the music. Maybe this is what people mean by PRAT. It’s hard to describe, but I heard it. Instruments were much easier to isolate because there was more air around them. The soundstage was much larger. And finally, the tonality. I would still give the edge on the low bass to the HDVA 600. The HDVA 600 was no slouch on the midrange either, but I felt the Ayre added an almost liquid character that was beguiling. However in the treble, just like the improvement of the HDVA 600 over the DAC-1, the Codex completely outclassed the HDVA 600. Until I heard the Codex, I had been rather pleased with the HDVA 600. With the Codex, I realized how much more relaxed and, yes, airy - or is it Ayre’y - the high notes sounded. Astoundingly, I found myself describing the HDVA 600’s treble as edgy and harsh. The difference was most apparent on music with tambourines (Cossack Dance), cymbals/high hat (Take Five), brass (Mahler’s 5th), but was apparent on every piece.
 
My final test was to have my emphatically non-audiophile wife - who is ironically blessed with golden ears - have a listen. She reinforced my opinions in about 10 mins. After listening to Why Worry by Dire Straits on the Codex, she declared it to be a goose-bump inducing experience, the best she had ever heard. In fact, after that she found the HDVA 600 “unlistenable,” which is terribly unfair to such a great piece of gear. 
 
This is the irony of high-end audio. Sonic differences in gear can be small, BUT - once heard, going back is really hard!
 
So how much of the overall differences I heard can be attributed to the Codex’s DAC versus it’s headphone amp? To attempt to answer that, I did two comparisons:

1. Amp comparison - Hold the DAC constant - use the Codex - and compare these two setups
   1. Codex —> Black Dragon balanced cable —> HD800
   2. Codex —> Cardas XLR interconnects —> HDVA 600 —> Black Dragon balanced cable —> HD800
2. DAC comparison - hold the amp constant. Since only the HDVA 600 has multiple analog inputs, I had to use it as the amp, and compare the following
   1. Aries Mini —> RCA interconnect (single ended) —> HDVA 600 —> Black Dragon balanced cable —> HD800
   2. Aries Mini —> Cardas USB cable  —> Codex —> Cardas XLR interconnects —> HDVA 600 —> Black Dragon balanced cable —> HD800

 
Amp Comparison
Essentially all the differences I described above in the overall section were evident even if I used the Codex DAC into both amps. This just floored me. I was not expecting the Codex to be such a better sounding amp. I should reiterate the superior low end of the HDVA 600. Also, maybe it’s because I like to listen to my HD800’s rather loud, but on some classical pieces, I was dialing up the volume on the Codex to >95%. This could mean with some particularly inefficient cans, the Codex may not have enough power. For me, with the HD800, I tried enough music from my collection to feel satisfied that I wouldn’t have that issue, but it could be a concern.
 
DAC Comparison
Here again, I had a surprising finding. I found it extremely hard to tell the Codex apart from the Aires Mini. This too was unexpected - I expected the Codex to smoke the Aries Mini. Perhaps the HDVA 600 was limiting the DAC differences. I don’t know. Since the Codex didn’t have any analog inputs, we’ll never know if the differences in the two DACs would have been more noticeable with the Codex as amp. This to me is the other limitation of the Codex - the lack of an analog input. In any case, I had nothing better by way of amps to do this DAC comparison.
 
Conclusion
The Codex is an outstanding DAC/amp, especially at its $1795 price. I could easily see it as an end game DAC/Amp solution for a large segment of headphone users. It may even be the end game solution for me. It does have some limitations: no analog input, no coaxial or AES/EBU digital inputs, finite power capacity with the HD800, lack of DSD256 support, and no stated plans for MQA. Maybe future Ayre products will address these things. Ayre has a pretty good track record of doing right by its customers to provide upgrade paths where possible. If these limitations are not showstoppers, you owe it to yourself to audition the Codex.
 
System Description
 

1. Source:                            Auralic Aries Mini network streamer, with Auralic LPS
2. Music server:                   Synology DS213 NAS, running MinimServer 
3. DACs under test:             Aries Mini built in DAC, Ayre Codex
4. Head amps under test:    Sennheiser HDVA 600, Ayre Codex
5. Headphones:                   Sennheiser HD800 with Anaxilus mod
6. Cables
   1. Headphones          Moon Audio Black Dragon Premium HD800 balanced 4-pin XLR
                                        Black Dragon adapter 4-pin-XLR to 2x3.25mm balanced (for adapting to Codex)
   2. Interconnects         Cardas XLR (older generation from current Clear)
                                        Kimber PBJ RCA
   3. USB                       Cardas (not sure which one)
   4. Power                    Pangea AC-9 MkII, AC-14SE MkII
7. Power conditioner           PS Audio Dectet

 
Music Selections

1. Mahler - Symphony No. 5, 3rd movement, Benjamin Zander, Philharmonia Orchestra, Telarc, DSD64
2. Dire Straits - Why worry, Brothers in Arms, Mobile Fidelity DSD64
3. Tchaikovsky - Cossack Dance from Mazeppa, Erich Kunzel, Cincinnati Pops, Telarc, DSD64 and 24/44.1 PCM
4. Dave Brubeck - Take Five, Time Out, Analogue Productions, DSD64
5. Ottmar Liebert - La Luna, Up Close, 24/96 PCM binaural
6. Talvin Singh - untitled piece #2, Accidental Powercut 3, B&W Society of Sound, 16/44.1 PCM binaural
7. Yes - The Revealing Science of God, Tales from Topographic Oceans, 24/192 PCM
8. Supertramp - School, Crime of the Century, 24/192 PCM
9. Buena Vista Social Club - El Cuarto de Tula, 24/96 PCM
10. Berlioz - Harold in italy, 3rd movement, Gergiev/LSO, 24/96 PCM