I STILL OWN THIS DAC, SO I FIGURED I'D COPY THE CONTENT FROM CHANGSTAR OVER TO HERE. Many of you would never have guessed, but I’ve been listening to the Gungnir (1) instead of the M7 (2) DAC since I’ve gotten the Ragnarok racked up in the speaker rig. Speaker listening presents a slightly different set of criteria than headphones. The power to sensitivity ratio with speakers is much lower than with headphones, therefore any kind of dynamic compression inherent in the DAC will be made much more obvious. Unfortunately, one of the weaknesses of the M7 is macro-dynamic capability. The M7 is good, well above average, but not excellent in this area. Also, speakers, assuming they are set up properly, have a much greater potential for demonstrating soundstage depth. Most unfortunately, with stage depth from the M7 is mediocre at best, even with the whizz-bang USB gadgets employed to improve this. Basically, what I am saying is when DACs are within closing distance of each other, there is really no such thing as A is better than B and B is better than C. It really depends on the situation. Of course there are situations where D is simply not in the same league. For example, the Hugo DAC does not merit discussion here. The only reason I bring up the Hugo is because people keep reminding me of the Hugo. How popular the Hugo is. How the Hugo can actually compete with full sized desktop DACs (it can’t). I just want to let it rest and go about my way; but no, someone had to remind me, yet again, that I was being too harsh in judging the Hugo’s sound quality just three nights ago. So I figured I'd say shitty things about the Hugo DAC again. But enough of the Gungnir; as this is really a comparison between the M7 and the Sonic Frontiers SFD-1mk2. By the way, Sonic Frontiers no longer exists. The only way to obtain an SFD-1 is through the used market. Every now and then they do pop up on the ‘gon or at pcX. Good luck if you want one. I used both speakers (Fostex 6” Sigma wide range drivers in a back-loaded horn enclosure) and the Sennheiser HD800 from the Schiit Ragnarok for this comparison. The speakers were augmented by a slightly modified Hsu subwoofer. Room modes in the bass region were accounted for in the subwoofer processor. Parametric EQ in JRMC19 (3) was applied to the frequency response at the listening position to meet a target similar to Figure 5 on page 6 of this document:http://www.bksv.com/doc/17-197.pdf Let’s get right to it shall we? The SFD-1mk2 has replaced the M7 and it only took two nights for me to make that decision. (It took me about a month to decide if I wanted to replace the PWD2 with the M7.) The first night, I tested both the singled ended SPDIF coaxial and AES3 balanced outputs from the OR5. I didn’t have a digital AES3 cable on hand, so I resorted to re-purposing an XLR patch cable for this task. The balanced XLR connection sounded best, so I went with this arrangement. Yup, upon initial listen, it’s an UltraAnalog module based DAC alright: http://www.changstar.com/index.php/topic,1801.msg48465.html#msg48465 Craig Uthus (Eddie Current) two Moth HyperDACs have UltraAnalog modules. He used to bring one of those DACs to the headphone shows. Donald North brings his SFCD-1 to the headphone meets. My experience with these DACs, especially with Donald’s Sonic Frontiers SFCD-1, was instrumental in my quick decision to nab one right after DaveBSC informed me of its availability. The SFD-1 was on another level of smoothness compared to the M7. The M7 has always had some level of minor upper midrange harshness or lower treble stridency. This can be easily heard with the earlier USB firmware versions. The use of the OR5 mitigates this issue tremendously, but it cannot completely remove what is inherent. Since the M7 was my reference DAC, I had already adjusted to his behavior (it's an extremely very minor issue) and really did not notice it outright until a friend pointed it out. This was of concern to him because he wanted to be sure that the Ragnarok was not the cause of it. In the end, we both concluded that the slight harshness was probably the fault of the M7 and not the amplifier. (It should still be noted that on a relative scale, the M7 with the OR5 is still smoother sounding than almost all other modern DACs.) The SFD-1 smoothness only confirms this conclusion. Finally, we are not talking about the artificial, dull, or intrusive kind of smoothness which glosses everything over. The SFD-1mk2 achieves a deeper tonal density that even other new production R2R DACs such as the Metrum do not have. The tonal density reminds me of the M7 running in NOS mode bypassing the DSP. Except in the case of the M7, bypassing the DSP collapses the stage depth and eliminates a significant amount of low level information. I don't know if the SFD-1 is a non-oversampling DAC or not. I did not begin to truly appreciate the SFD-1 until the second night where I used a "real" balanced digital cable. No, I did not buy an expensive cable. Instead I terminated some CAT5e Ethernet cable with XLR connectors. (CAT5/6 Ethernet cables are magical and make excellent speaker and headphone cables as well.) Awesome. A huge difference and now we are talking. Let's first start with how the M7 is better. The M7 is cleaner. The SFD-1 sounds a little "dirtier" in comparison. The M7 has more delineated lines and precise imaging. The SFD-1 isn't quite as precise. Not really unexpected because of the tube output. However, I do want to point out that the SFD-1 does not sound tubey. At least with this setup including the OR5, cables, and Philips JAN 6922 tubes. If I hadn't had known tubes were in the SFD-1, I could have just as easily assumed that it was a solid-state DAC. Despite the "dirt", the SFD-1 manages to have a blacker background than the M7. ("Blackground" was another M7 weakness, made much better by the OR5.) As an aside, I hate overly tubey DACs. The California Audio Labs DAC I heard about twenty years ago made me assume anything with tubes in it was shit for the next twelve years. Surprisingly, the the SFD-1 resolves low level information as well as the M7, at least with the Ragnarok, which is incredibly resolving for a solid-state amp. I had to go back and forth a few times to confirm. Initially it seemed that the M7 reproduced more microdetail, but every time I went back to the SFD-1 for a reality check, there never seemed to be any less microdetail. It could probably be accurate to say that the M7 brought up the volume level of the microdetails or perhaps accentuated it with a certain sharpness (more an effect of tonal balance, timbre, etc.) Now in terms of macrodynamics, microdynamics and soundstage depth, the M7 gets spanked by the SFD-1. As I've hinted at above, ultimate macrodynamic capability in terms of hitting hard was never a strength of the M7, and thus why I had been spending more time with the Gungnir (at least with speakers.) Ability to slam and hit hard was something that I missed from the PWD2; and in retrospect, I've always felt the PCM1704s (the chips in the M7) were kind of soft. In terms of microdynamic contrasts, the ability to make small changes in volume and to swing or throw sound with speed and authority, the difference between the DACs is even larger. The M7 sounds flat, almost lifeless, in comparison. Finally, although the SFD-1's imaging isn't as clear, the three dimensional aspects such as depth and even height is far superior. There's a spooky quality in how the SFD-1 throws sound from the stage towards you. Tonally, the SFD-1 doesn't seem more bassy than the M7. (I think it's fair to say both DACs are on the bassier and warmer side.) I did have to bring back the super tweeters with the SFD-1 which seemed a touch more rolled in the last octave. I almost want to say that the SFD-1 has a thicker sound, but that would implying something negative. For reference, the SFD-1 certainly does not sound as thick (even muddy) and rolled-off as the one Moth HyperDAC that Craig brings to the meets. (With the SPDIF or the makeshift AES3 cable, the SFD-1 did sound more like that. I'll stick with the tonal density thing. I mean, I'm hearing guitars, bass, piano growl. I mean fuck, no modern DAC I've heard has ever growled that like. Low notes on piano have this weight, this body, where you actually get a palpable sense, the shaking of the sound board inside the piano doing its job in magnifying the sound of the strings. Violins and harmonicas would shriek with deep tones to make the hairs on my back stand up. Now that's music. A bunch of colors and textures and tones flying all over the place. The M7 does not quite do these things. The modern DACs do none of these things. Finally, getting back to tonal balance, the SFD-1 is more similar in tone to the Gungnir than the M7. Mainly less strident and more forward (upper-mids) than M7. Absolutely the least digital sounding DAC I've heard yet in the past decade or so. What's amazing is that the SFD-1 does so without removing microdetail, like the nature of the little grains in tape or guitar pickup noise. What's really sad and depressing is that in the last twenty years, we've generally moved backwards in DACs with all this cost-cutting delta-sigma shit. (1) The Gungnir DAC this time around was vastly superior to when the initial DAC-Off tests were conducted with the PWD2 (upgraded 1), Invicta, X-Sabre, etc. The USB receiver was upgraded with the Gen 2 board. The Wyrd USB power cleaner and data reclocker was installed in line. The DAC and Wyrd were plugged into a power condition. These efforts removed harshness and “tension”, increased microdynamics and microdetail, and deepened the soundstage. (2) Audio-GD Master 7 DAC. The i2s interface was upgraded with a custom-built HDMI interface by DACLadder. Digital output was from PC USB to an Empirical Audio Off-Ramp 5. The HDMI i2S interface and used from the OR5 to the M7. (3) J River Media Center 19.