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Positive Feedback ISSUE 42
march/april 2009


redwine audio

Isabellina DAC

as reviewed by Dave Clark






Reimer Speaker Systems Tetons (with the Hi-Vi Isodynamic Planar tweeters and series crossovers) heavily treated with Marigo VTS Dots, with Townshend Audio super-tweeters.

Clayton Audio M-200 monoblock amplifiers, Sutherland PhD phono stage (treated with Marigo VTS Dots), and a Cary Audio SLP-05 preamplifier w/Pope 6SN7s.

EMM CDSA SE and Cary CD-306 SACD/CD player treated with Marigo VTS dots and Shakti Onlines and Stones. Transrotor 25/25/60 Leonardo turntable with a Shelter 901 MC cartridge w/Marigo dot. Sennheiser HD540 headphones and Meier Audio HA-2 headphone amplifier.

Kubala-Sosna Emotion, Purist Audio Proteus Provectus, Audio Magic Clairvoyant 4D, Soundstring, and Dual-Connect interconnects. Kubala-Sosna Emotion, Purist Audio Proteus Provectus, Dynamic Design Nebula THD, and Audio Magic Clairvoyant 4D speaker cables. Kubala-Sosna Emotion, Dynamic Design Nebula Digital (CD player), Soundstring, Elrod EPS2 Signatures, Audio Magic Clairvoyant 4D (preamp), and JPS Aluminata (amps) AC cords.

Audio Magic Transcendence power conditioner, Nanotec Nespa #1, Furutech RD-2 demagnitizer, Bybee XLR Golden Goddess Tails and Slipstream Magic Bullets, Blue Circle BC86 Noise Hound (amp circuit) and Audio Prism QuietLines (throughout the house). Dedicated 20 (amplifiers) and 15 amp (everything else) AC circuits. Tons of Shakti Stones and On-Lines, and Original Cable Jackets (frig's AC and on DSL phone line). Various Marigo VTS Dots used extensively throughout the system and room (window behind listening seat). EchoBuster acoustical treatments and Shakti Hallographs. BDR cones and board (turntable), BDR cones and Jumbos (under speakers). Blue Circle Cones, DH Jumbo cones, Stillpoints, Vibrapods, Mondo racks and stands, and Townshend Audio 2D (amps) and 3D Seismic Sinks (CD player, preamp, and Transcendence). Walker Audio Ultimate High Definition Links and SST. Various hard woods placed here and there along with numerous Peter Belt treatments. audioexcellence az AudioDharma Cable Cooker for all cables.


Redwine Audio is the brainchild of one Vinnie Rossi… an Electrical Engineer by intellect, but an audio designer at heart. Vinnie started Redwine a number of years ago with the idea of making simple off-the-grid components (meaning they are battery-powered only and simple in that he kept things ….well, simple) that offer the listener great musical enjoyment without breaking the bank. The Redwine line is composed of a preamp, amp, integrated, and the topic of this review, the Isabellina DAC. All Redwine products share the same case-work which no doubt helps to keep costs down… as does the choice of a battery-power supply since a 'regular' power supply would necessitate extensive parts (and no doubt of an audiophile pedigree grade as well, also that means way more cash) along with additional space and whatnot to get it to work as it should … or at the very least, as one wants it to! So going battery allows one to ignore a lot of the issues of a regulated power supply in terms of filtration, stability, etc., and simply put, batteries done right are downright solid with respect to stability and being immune to outside contaminates that dirty up our AC. I would think that batteries should be a perfect match for digital in that they can keep things as clean and stable as the proverbial rock. Yeah, there are issues with batteries, such as charging and being green (got to put them somewhere when the time comes… and it comes for us all in some way, way sooner that we expect)… and well… like I said you got to get batteries done right as well.

So Redwine chose to go with their custom-designed SMART battery-circuit module to make sure that the Isabellina is always ready to play. The SMART circuit ( SLA battery Monitoring and Auto Recharge circuit) continuously monitors the voltage of the batteries so if the voltage drops to a point where it can't deliver the juice, the SMART module automatically turns off the Isabellina and begins the recharging the batteries. Now that is simple and clean. Worked like a charm here and I found that one could use the Isabellina for a good 12 hours or more before it needed to be gassed up …which only took an hour or two for a full-charge recovery. Wish I could recharge that fast!

Other than batteries, what makes the Isabellina that different than other DACs on the market? Well, several things: one the Isabellina is one of the NOS-type DACs; meaning its uses vintage non-oversampling 16/44.1 DAC chips; two, there is no digital-filtering; and three it features a proprietary discrete Class A transistor output stage (there are no opamps to deal with) with high quality parts and short signal paths throughout (the DAC/analog board is the size of a decent coaster—though a nice neat one with carefully chosen parts and is feed via the batteries as simple and as direct as one can get).

The Isabellina has three digital inputs all selectable from a three-position mini-toggle switch that is located on the rear above the digital input jacks …from the Redwine website:

1. USB that converts directly to I2S to feed the internal DAC chip (no intermediate S/PDIF conversion). This input offers optimal sound quality and requires the use of a computer (music server) with a USB port. The power bus from the computer is not used. We instead provide our own clean, on-board +5V line.

2. Coaxial (S/PDIF) with a Vampire 75-ohm BNC input jack followed by a digital pulse isolation transformer that isolates noise and gives precision 75-ohm impedance matching.

3. Toslink (optical S/PDIF) that naturally offers noise isolation and avoids ground loops from the source component via the optical transmission cable.


Based on the DAC's design, I choose to use the Isabellina as a stand-alone DAC for my computer-based system. This is comprised of a Mac Book (2.4GHz Intel Core 2 Duo with 2GB DDR3 Memory) with the music files being saved on a Raid 5 NAS (1.5TB) drive on its own AC line (housed in another room). Files are ripped and played back via iTunes 8 (error correction on) as Lossless files. I used either a van den Hul Optocoupler II Toslink cable or the Locus Design Nucleus USB cable to connect the Mac to the Isabellina.

Redwine Audio… huh, is there a wine connection here or what? While we consider ourselves to be decent wine drinkers (our wine cellar usually has a good hundred plus bottles from our favorite California wineries—though pretty much only red varietals: Cabernets, Merlots, Pinots, Zinfandels, and several chosen blends) we make no allusions to grandeur. While we know what we like, we ain't wine snobs in that we much prefer drinking wine as opposed to talking wine! But talk about wine… err… the Isabellina I will!

Like a premium bottle of a red varietal, the Redwine Isabellina possesses the best of what the better red wines offer the vinophile….

The Isabellina has a wonderful bouquet, like a great bottle of wine where its bouquet of aromas are particularly complex and in harmony. That is, the Isabellina delivers a complex musical tapestry with a harmonious balance across the frequencies. Nothing is spot lit or thrust onto the listener… nothing is amiss or absent …no, the Isabellina is all about tonal evenness. The Isabellina presents this by offering the listener a complex musical presentation where harmonic textures and colors (or with respect to wine, aromas and flavors) harmonize in a way that is sheer musical enjoyment. The opposite would be "simple" or one dimensional where a DAC would sound like "this or that" …for example a DAC that is referred to as being primarily analytical or whatever …one with a characteristic that overshadows anything else the DAC is offering to the listener.

Sure, the Isabellina does possess to a great degree that sound or style from years past…one that is a bit less resolving or transparent of the finest details and minutiae, but then again, not having that does little to detract from the overall musical experience. Even so, I would not say that the DAC has a certain or specific characteristic… just that it has certain qualities that are far-reaching as well as being reflective of a certain origin… like a good Cabernet. After all it is an NOS DAC, so I would expect the DAC to posses that 'NOS' characteristic to a greater degree than not possess it, and I have found very similar 'sound' from all the NOS DACS… smooth and organic, warmer than colder, richer than leaner, darker than lighter, less presence or resolution than more… etc.

Even so, the Isabellina gets music across in a way that is very rewarding in terms of its complexity of tonal and harmonic 'rightness'. This complexity reveals itself as there being sense of "depth" or density to the music; not only in how the Isabellina portrays the sonic tapestry of the music, but the overall "presence" of the music as well. The Isabellina presents many layers to explore and does so with an ease and elegance that is very beguiling. There are no hard edges to the music …no grain or glare to turn one away from spending hours listening to one's collection. No, the Isabellina is very refined while being rich, smooth, lush, and silky, all in the sense of being easy on the ears …as opposed to hard, thin, bland, closed-up, or austere. Perhaps it is more forgiving than being relentless and intolerant of poorly recorded music. Is this a fault or something to cherish? I found it rewarding and not a detriment to my listening experience as this quality is not present in a fashion that draws attention to itself… it is just there. There in way that is most musically enjoyable.

The Isabellina is also quite ethereal in that while it is complex with wonderful sense of density, it is also quite light on its feet. Not light in the sense of being light-weight… that the Isabellina is clearly not, but light in that it is not overly rich and dark. The Isabellina allows one to hear or "see" deep into the soundfield. There is enough information and resolution to get things moving along quite nicely, so light it is with respect to timing and pace. The Isabellina swings and sings… on many occasions while the music was playing through the DAC I was drawn into the living room to enjoy the feel and presence of musicians having a ball.

In terms of the bottom-end, the Isabellina presents the bass frequencies with slam, articulation, and depth. There is a rock-solid 'feel' to the bass frequencies that may be related to the use of batteries for power as opposed to that of a regulated power supply, but not being the technical guru, I can't say unequivocally if that is the reason, but I can say that the Isabellina is as firm and weighty as all get out. Not in an over-blown way… and certainly not in a way that is boomy, flabby, or ill-defined.

Yeah, for sure it won't go as slammingly-deep or with the same control, presence, and feel as other players in house, but then again, these are at the top-o-the-heap in that respect (Cary 306 Professional, EMM CDSA/SE, and the Playback Designs MPS-5). Nor is it nearly as resolving or tactily palpably revealing as these stellar players… but then again they are of reference quality and cost several times as much as the Isabellina …and they are coming from a completely different ideology of how a digital product should be engineered, let alone sound. Any of these three will be more dimensionally 'real' and provide considerably more resolution or 'tactile information' than the Isabellina … you just get a different perspective or presentation with them as opposed to that of the NOS DAC. So yeah, the Isabellina does give up a bit in many 'key' areas to the bigger boys, but it is no less enjoyable for its sins of omission. Choose your poison.


Well… it is 16/44.1 so forget higher-rez formats. USB trumps S/PDIF though I did find things to sound "better" via S/PDIF if I used an outboard re-clocker (the Empirical Audio Pace Car, the new Empirical Audio Off-Ramp Turbo 3, or the Bel Canto 24/96 USB). Using either was better in the sense that the Isabellina opened up a bit more… with more resolution …and well, more of everything in a good way from the mids on up …I would even say that what I heard was in many ways more like the bigger boys (which I do like), though not to a degree that would make anyone go hmmm… what should I do? For the most part it is a matter or preference or taste, so just stay with USB and relax even though having less jitter will make for me at least, an audible change or improvement in the Isabellina's presentation. Though one may find this as added glare or whatever …not real, but an artificial presence or detail. (Redwine does say that the DAC is not necessarily designed to "remove" jitter to the same degree as some other products that feature SOTA re-clockers or whatever simply because the DAC's design makes it less "sensitive" to the ill effects of jitter. That is, being of NOS heritage without any up- or over-sampling, the DAC sees jitter in a way that is not as detrimental to the sound as heard from other non-NOS DACs … who am I to say? It does sound quite good as it is, but yes… like I said above, using a re-clocker from either Empirical or Bel Canto does "change" or improve the sound in ways that one may or may not appreciate.)

Your choice of interconnect cables might also be an issue in that even Redwine suggests one avoid "darker" cables with the Isabellina to avoid potential "sonic" issues. I tried several here and settled on some new ones from England—the Artisan Silver Cables. Yeah, adding a touch of silver to the mix made the Isabellina sing a slightly different tune—a tune that possessed a bit more light, more sparkle… a bit more more! Not that the other cables did not, no they worked quite well too, it was just that pairing the Isabellina with the $2500 Kubala-Sosna Emotions was not how I saw the DAC being used out in the real-world. The Artisan Silver Cables retail for about $160 (a meter) and showed themselves to be a real-world beater …sweet, musical, and oh-so naturally… well, nice! Yeah, the Artisan Silver Cables are something that any serious music lover should put on a short list of cables to audition if price is an issue… as is attaining sheer musical enjoyment (I will have more these wonderful cables soon).

Anyhow, the Isabellina is a wonderfully musical DAC that allows for hours and hours of stress free musical enjoyment—like a glass or two of wine! The Isabellina possesses no edge, grit, or grain… no harshness or hyped presence or detail to detract from your listening pleasure. Tonally even with a rock-solid like presence, the Isabellina is like a fine wine; drink it in and enjoy the day …err, music. Way to go Vinnie! Dave Clark

Isabellina DAC
Retail $2500

Redwine Audio
web address: