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Positive Feedback ISSUE 53
january/february 2011


Building a Digital Music Server, Epilog Part 1, Three Digital-to-Digital Converters: What Hath Humankind Wrought?
by Andy Schaub


"Far away across the field
the tolling of the iron bell
Calls the faithful to their knees
to hear the softly spoken magic spells."

–Waters, Gilmour, Wright

First of all, this is not a technical review. So please don't expect me to explain the difference between asynchronous and isosynchronous modes used in DAC's. I understand it, I really do, and for a great albeit somewhat biased explanation, please see this page setup by Wavelength Audio:

Having made many changes to the now ADMS (Advanced Digital Music Server, not Another Dark Moon [of the] Side), I am in an experimenting mood; and thanks to Dave Clark here at PFO along with an impulse purchase I made some time ago, I have three "modestly" priced digital-to-digital converters that let me by bypass the intrinsic asynchronous USB conversion built into my trusty dCS Debussy and run my 17" MacBook Pro—with Amarra 2.1.1—into the SPDIF and AES/EBU inputs of said DAC; now in his review of the Ayre QB-9 and Bryston BDA-1, Dave says the following:

"But if the Ayre QB-9 is the sweet girl boasting an alluring innocence that is oh, so attractive on an emotional level, the BDA-1 is the tattooed busty biker-vixen that your mother always told to stay away from... cause with her, well, you are just asking for trouble!"

To me, that is a bit of an exaggeration; although I understand from listening to my dCS Debussy's direct asynchronous USB input the inclination towards a, "papery", quality in it; and I like that. However, during most of this composition, I have been listening to a 24/96 recording called "Guitar Noir" via the mini-XLR to regular-XLR AES/EBU cable provided by KingRex with their US192 and in all truth I like it. It's not exactly a biker babe; but it has tube-like warmth and I feel that I want to employ less filtration. I am, in fact, enjoying the music with my heart as opposed to appreciating it with my head.


Perhaps, however, I should go back to where the advanced digital music server currently stands and why there are two epilogs. First, I am now using a 17" MacBook Pro with a 3.06GHz Core 2 Dual processor, 8GB of RAM, a 256GB internal SSD and a Manley Skipjack source selector with all Kondo Sound Labs KSL-LP analog interconnects and—because of Amarra 2.1.1—I am no longer using an external SSD to hold the music but have gone back to the LaCie 1 TB RAID 1 drives a LaCie 2TB backup drive controlled by SilverKeeper. Although I find that Amarra 2.1.1 sounds good enough that I don't necessarily need to use it, I love the new CACHE function where I can load up to 40 tracks into RAM and play the music from RAM meaning that it doesn't really matter what I store it on; and, yes, even using CACHE playback on music coming off of an SSD sounds better than the SSD, but not cumulatively so. I love the Locus Design Vision analog interconnects but the KSL-LP's do offer a unique window into the music and allow me to level the playing field between my Ayre C-5xeMP universal disc player and my dCS Debussy-based advanced digital music server. Now we get to the reason why there are going to be (at least) two epilogs: first, the Debussy will soon have the ability to go to 24/192 and, second, I am eagerly awaiting the release of the Sonicweld Diverter 192, which I think will be a "game changer"; but onto the three USB to S/PDIF converters that I HAVE gotten to try. They are, in no particular order:

(1) The Bel Canto USB Link 24/96

(2) The Audiophilleo audiophilleo1

(3) The KingRex UC192

In all truth, I have kind of rank ordered these in terms of which I think sounds best, although the ranking is backwards, or No. 3 is No. 1 (i. e., the best). It helps me build to a climax from a narrative perspective.

bel canto

The Bel Canto USB Link 24/96 is a very solid USB to S/PDIF converter that I first got when I HATED the sound of the USB input on the PS Audio Digital Link III; and I found—using the Bel Canto USB Link 24/96 with an ALO "exactly 75 Ohms" S/PDIF cable with Eichmann Copper Bullet Plugs – that the Bel Canto made a world of difference and that even going into my original Audio Note DAC 3.1X Balanced, I got very pleasing sound. So when I sent my Bel Canto USB Link 24/96 down to Dave I kind of panicked because I didn't have my reference, generic USB to S/PDIF converter against which to compare the others. Fortunately, Dave sent it back to me quickly on request along with the Audiophilleo audiophilleo1 USB-to-S/PDIF converter. The KingRex UC192 came directly from KingRex, an apparently very kind group of hardworking engineers and other job-related folks. I should say that none of these adapters can compare to the original Sonicweld Diverter, which is now in the capable hands of Nick Gowan awaiting his experiments with a Mac of some variety, Amarra 2.1.1, the Locus Design Axis USB and Core S/PDIF cables (although Nick may experiment with more) and his tricked out Audio Note (hold your breath) DAC 5 Signature, which is really quite awesome and proof of the existence of a higher power.


As far as the Audiophilleo audiophilleo1 goes, it's really quite something as well; and I regret that I don't have a 24/192 S/PDIF DAC anymore with my Wyred 4 Sound DAC-2 having left the building in favor of the substantially pricier Ayre QB-9 which ONLY accepts USB input, but understands the native protocols built into Snow Leopard that let it naturally support 24/192. From listening to the HDtracks download of Rebecca Pidgeon's The Raven at 24/176 after about 200 hours of burn in, I would say it does it very well (in my office system). I wouldn't mind having a Bryston BDA-1 as a 24/192 capable S/PDIF converter to truly test some of these new digital-to-digital converters, isosynchronous or asynchronous; but last year was, "The Year of Spending Dangerously", so I will just have to wait for the 24/192 upgrades to my dCS Debussy, something that will come along soon enough. Getting back to the Audiophilleo audiophilleo1, I think that using it translate the USB signal into a S/PDIF, or "COAX", signal then using the S/PDIF input of the dCS Debussy does sound slightly better than dCS's own proprietary asynchronous USB algorithm; however, it does not sound SO much better that I would necessarily say buy one immediately and bypass the dCS's direct USB input; it's a matter of degrees and really more an issue of tone and texture than "better" or "worse". From my perspective, the Audiophilleo audiophilleo1 would have gone very nicely with my Audio Note DAC 3.1X. The slightly papery thin but oh so clean and sweet sound of the Audiophilleo audiophilleo1 would have complimented the warmth and slight euphony of the DAC 3.1X quite well; and that's where I think it's major strength is. It does a truly fine job of preparing the USB signal for input into a warmer, in all likelihood tube-based S/PDIF DAC.


Now we get to the KingRex. I have to say, I really like the KingRex a lot. To my great surprise, I found that I preferred using the AES/EBU input of the dCS Debussy with the generic AES/EBU adapter cable that KingRex supplied over the "COAX" or S/PDIF output (although apparently AES/EBU is a form of S/PDIF) with the Wireworld cable now supplied with one version of USB Link 24/96. I will also add that the Wireworld cable—which is just a BNC-to-BNC pigtail with an RCA adapter—sounds substantially better than the cable Bel Canto used to supply, made by Stereovox, and that in general my experience has been good with Wireworld digital cables; although, they don't fall into the same category as the Locus Design digital, analog, and power cables. I found the sound of the KingRex UC192 – after about 40 hours of burn-in—to be musically very engaging and quite warm and tube-like, again using the AES/EBU in on my dCS Debussy with the KingRex generic adapter cable. My main complaint is that damned "walwart". Can't SOMEONE design a generic power supply that uses a real transformer, sits in a box by itself and allows you to choose your own power cable? That's essentially what Manley did with the Skipjack and it's the quietest piece of audio equipment I've ever owned. Even Drew Baird at Moon Audio (and I shouldn't say "even" because Drew is a super cool and very talented dude) gives you the option of purchasing a prebuilt Welborne Labs Upgraded Power Supply for use with the Blossom Blo-0299 Balanced Headphone Amp, both of which I have and adore; in fact, I really need to experiment more with power cables for that arrangement. (I'm thinking of the Audience powerChord-e, which I am currently using with my Ayre QB-9.)


So what was my reaction when I disconnected all these USB-to-S/PDIF converters and went back to the dCS Debussy's own direct USB in? It was a simultaneous, "Ah, that sounds right again," and, "Damn, where did my tube-like warmth go?" All of which leads to me to be very excited about the forthcoming Sonicweld Diverter 192 and the 24/192 upgrade to the dCS Debussy; because I have to say that I REALLY like listening to ultra-high resolution files via my 24/192-capaable Ayre QB-9 in my office system (with a Locus Design Axis USB cable, Audience powerChord-e and Locus Design Vision analog interconnects); in fact, as soon as I am done with this article and go off to do the photography, I plan to download another ultra-high resolution album from HDtracks because I'm burning out a little on The Raven. As times goes on and I get more and more used to using the Advanced Digital Music Server, I find myself increasingly annoyed that I can't just download everything and store it on a hard disk; and although I still have an appreciation for the tangibility of vinyl, which I hope never goes away, having to get up every 20 minutes (or 15 at best at 45RPM) is getting to be a serious pain when I can program 9 hour playlists into my digital music server.

manley skipjack

Even today as I have been wrapping up this article and listening to the 3 SACD set entitled The Forgotten Kingdom performed by Jordi Savall among others (Alia Vox AVSA9873 A/C), I have found myself annoyed at having to get up and change SACD's approximately every hour, particularly when my Ayre C-5exMP is sitting on the same stand as the digital music server… and is one button away from it on the Skipjack… and doubly annoyed that no high-resolution copy of this exists that I can download nor is there any simple way of ripping the DSD data from the SACD into iTunes… so again, I hope that vinyl never goes away because we need it to remind ourselves of the roots of recorded music. Plus, it still sounds better than anything else. However, being able to download anything from a 16/44.1 to a 24/192 album from HDtracks, Linn, Etc. and play it through my Axis USB cable and Ayre QB-9 via iTunes and Amarra 2.1.1 on my office system makes a VERY compelling argument for all media except for vinyl and high-resolution digital downloads to just go away; but, to quote Pink Floyd again:

"And everything under the sun is in tune

But the sun is eclipsed by the moon"

Kindest regards,


P. S. I am now listening to the 24/192 version of Jen Chapin's reVisions: Songs of Stevie Wonder through my Ayre QB-9 in my office system using the Locus Design Axis USB cable, Audience powerChord-e, and Locus Design Vision analog interconnects and it sounds just like heaven. THIS is what the future of music downloads is all about. I can't wait for the Debussy to be 24/192 capable through its USB and S/PDIF inputs, then I'm going to collect all the 24/192 material I can because it sounds closer to analog than any digital "album" I have ever heard, CD, SACD, or otherwise. Linn's 24/192 copy of John Ward: Consort music for five and six viols by Phantasm has much the same effect.