Review: AMR DP-777 DAC

Review: AMR DP-777 DAC
Review: Sparkler S306, Part II

Revised 21/1/16 (some further listening thoughts on the AMR, particularly piano)

I had barely published my article on Weiss Minerva vs Sparkler S306 (link here) when my friend Tony told me he just bought a second-hand unit of AMR DP-777 for a friend and I could have it for a month. Needless to say, I seized the opportunity as it is a Non-Oversampling (NOS) DAC with a Twist.

As I am a believer of NOS, and as the Sparkler S306 I own and just reviewed is a NOS DAC (albeit one much simpler in execution than the AMR), in that article I reviewed the Sparkler S306 and shared my general views on NOS. Please refer to it as a prelude/background to this article.

AMR DP-777 Brief Comments The AMR Official Info contains much useful technical information that is way beyond me, as well as review links. I'd think my approach and views conform most to Art Dudley's in Stereophile. My comments shall be very brief.

• Built The DP-777 is built (in the UK) like a tank. But the large size (not without its advantage) puts me off a little. Construction is a little intricate.

• 16-Bit DAC A 16-bit chip is used for 16/44.1 Playback (CD), but it is not the already mostly exhausted classic Philips TDA-1541, nor its cousin TDA-1543, the DIY favorite still used by 47 Labs and Sparkler. Instead it is one I have never previously heard of, the Philips UDA1305AT. Since spec's for this chip is not available online, it has generated some noise, controversy and speculation (designer Thorsten Loesch under the moniker "Kuei Yang Wang" has refuted these). There are 2 algorithms for this DAC; I only used the default "Bit Perfect II".

• 32-bit DAC A Wolfson chip is used for "hi-res" files.There are multiple algorithms for this DAC; I only used the default "Organic".

• S/PDIF Input Most unusually, a 6N11 valve is used for "purification" of the signal.

• Valve Analogue Output there is no solid state in the analogue signal path. One triode half of the 6N1 is used for amplification and the other for buffer. Note here that it is very hard to change valves. I tried opening the chassis but failed to access them. Note also 6N1 does not have an exact equivalent, but many people substitute 6DJ8/6922 for it. Also, I note that AMR sells the GE5670 with a special adapter to use in lieu of 6922 (see here). I'd love to try this as this tube sounds great in the iFi iTUBE (review yet to come).

Equipment Used Same as in my article Weiss Minerva  vs Sparkler S306 (link here):

CDP/Transport: Sony BDP-S190 (Belden 1694A coaxial)
Computer: Apple Macbook Pro/iTunes/Unitek USB Cable
DAC: Sparkler S306 or Weiss Minerva
Amp: Naim Nait 3
Loudspeakers: Yamaha NS-1000
RCA to DIN Interconnects: Gotham GAC-4/1 and Gotham GAC-2/1

Sonic Impressions

• In General There is little to fault in this DAC. I resort to default settings (never interested in playing with dithering/algorithms).

• CD Playback I used the coaxial input and only the default BitPerfect II. Sound was exemplary. Ambience Clues This has always been a main concern for me, and reason for my dislike of Weiss (IMHO a DAC that cannot render the recording venue correctly is useless, let alone qualifying for monitoring work). Like the classic 16-bit DAC's employing TDA1541/1543, the DP-777 renders the hall as is. Every track in the Channel CD sampler (some recorded in a church and some not) was rendered perfectly. Details Unlike some 16-bit DAC's, the DP-777 is very detailed, yet not highlighting artificially. It has the same ambience as the Sparkler, but details are mostly (but not always) just a shade clearer. Dynamics In both micro- and  macrodynamics (especially the latter) this is the among the best I have heard. Channel Classics' Stravinsky and Mahler tracks were threatening and explosive, and nothing frayed at climaxes. Marvelous!!! Tonal Balance Nothing I could fault. Piano Playback After a while I find myself listening to more and more piano discs - that is because the piano sound has such outstandingly depth! It is not often at all that one finds such majestic piano bass notes and truthful reproduction of the deeply resonating innards.

• Comparison with Sparkler S306 The AMR has cleaner leading edges and transients and better macrodynamics, but I feel the Sparkler has perhaps better microdynamics. Hence, with AMR Michelangeli's Schubert D557 (DG) is razor-sharp and exacting, but the Sparkler S306 brings out a little more tonal shades and just perhaps a more Schubertian flow (which may or may not represent this coolest of pianists). Even in Channel Classics' big Stravinsky and Mahler pieces, the Sparkler S306, although a little less forceful, conveys a sense of threat more than the AMR. With the Sparkler playing the Manger CD, Haydn (track 6) has a little more stately grace, and O-Zone's Percussion (track 15) shows more variety of touch and rhythm. This is further confirmed by Take Five: Morello's drum solo is slightly better inflected with Sparkler, and Eugene Wright's concomitant taunts and challenges surprisingly more obvious.

• CAS Please note I only have 44.1 files and no "Hi-Res" files. I tested the USB Asynchronous input with my Macbook's iTunes, essentially the same setup and files I used to test the Meridian Explorer and 47 Treasure 0547 (link here), hooked up with Unitek USB Cable (link here). I was immediately able to compare the Manger Test CD with the ripped files. I also ripped the Channel Classic Test CD into the Mac so as to compare with the CD. With multiple tracks tested, both gave identical results. Even with my imperfect setup, I'd say this is among the more musical CAS I have heard (many more serious setups than mine sound so bad that it is hard to describe). Compared to CD's, I heard almost little or no loss of details. Tonal balance is similar to CD replay. But there are distinct differences: ambience clues are a little less distinct, and Rhythm and Pace are less enticing. In fact, I was surprised that there is a somewhat polite demeanor; not as overtly exciting as when I tested the Meridian (in NYC, with a completely different setup). Take all this with a grain of salt, as when it comes to CAS, my attitude is more utilitarian than "hifi"-oriented.

Conclusion

• In many ways the AMR is the DAC for me. With CD's, it plumbs great depth with complex music, and there is not a weak link. Most desirable.

• I also come away from this with great respect for Sparkler S306. In some ways, it held up to a formidable rival. Kudos!