I've owned or had for extended audition quite a number of DACs over the past two years.
Channel Islands VDA2, PS Audio DL 3, Benchmark DAC1, Zhaolu 2.5, Bel Canto S300iu (integrated amplifier with DAC input), Electrocompaniet ECD-1, Citypulse DA 7.2, Scott Nixon JFET NOS USB DAC, iRock NOS USB DAC, AudioSector/AudioZone NOS USB DAC.
I haven't heard everything, but I've heard a number of DACs over a relatively short time period. Nothing exotic like Mark Levinson, and no top shelf CD players like, say, Ayon.
I've also heard the Wavelength Brick v2, and the Wavelength Cosecant, but the audition was at a dealer and I've always found that it's very hard for me to really understand how good a component is or how well it will work with the rest of my system without actually having it in my home for a couple of weeks. When I auditioned the Wavelength products, I came away with the impression that although the Brick was possibly better than my AudioSector/AudioZone DAC, it was a close call and I wasn't willing to pay 4x more money for it. As for the Cosecant, it really was quite simply out of budget so I didn't seriously consider it. A little bit of a listen, and then back on the shelf please.
My favourite oversampling DAC was the Electrocompaniet ECD-1. It is slightly warm, texturally dense, throws a wonderful sound stage, very dynamic, has an extremely low noise floor, and bass is very, very musical with an impressive amount of slam. When I sold my Antique Sound Labs integrated valve amplifier and bought the Signature 30.2 integrated, I found that despite the obvious warmth of the 30.2, it is also very transparent, and this transparency together with the oversampling nature of the ECD-1 contributed an edginess to the music that gave me significant fatigue after only an hour of listening. I don't think everyone will necessarily feel this way, perhaps it's just me as I have found that I'm very, very sensitive to digital. I wasn't willing to give up the dead quiet background of the RWA 30.2, and I had by now heard great things about NOS DACs, so the ECD-1 had to go.
Around the same time I also decided to go the iTunes route as I had an old Apple Powerbook G4 12" I hadn't used for more than 2 years, and I figured using the iPhone as a remote control would be a real kick. Hence, a USB NOS DAC would be in my future.
I started with the Scott Nixon because it's really quite affordable, and then tried an iRoc. I liked the iRoc better than the Scott Nixon, but on the recommendation of other AudioCircle members Bucky and Pardales, I took the AudioSector for a spin. The AudioSector (with USB) is more romantic than the iRoc and also more dynamic. So I settled on the AudioSector, which is identical to the AudioZone DAC that Paul Candy on 6moons likes so much, except this one has USB input rather than SPDIF. I like it too, it's really quite musical, and frankly I would have been quite happy with the AudioSector long term if the Isabellina hadn't come around and I hadn't thought longingly of its 100 ohm output impedance and predicted positive effect on dynamics.
NOS DACs are characteristically: non-fatiguing, natural sounding, tonally accurate.
Oversampling DACs, on the other hand are: detailed, accurate, dynamic, throw a great sound stage.
As for the Isabellina, the first 2 hours were miserable, after 5 hours things got quite a bit better, and after 20 hours the DAC started to hit its stride. After 48 hours now, I'm pleased to report that the Isabellina DAC (using the Powerbook G4 via USB as source, and RWA 30.2 integrated amplifier) is the best NOS DAC I have ever heard. It is utterly and completely non-fatiguing, effortless and natural. It is tonally rich and texturally dense. At the same time it is very dynamic, throws a deep and wide sound stage, and detailed without being overly detailed or analytical. And (I'm sure this is because it's battery powered) it is dead, dead quiet. No AC grunge here. If you're already familiar with the benefits of battery power as applied to amplification, I think you'll find that there's a similar benefit to digital-to-analog conversion.
After having previously paired a Modwright SWL 9.0SE (tube recitified) with the 30.2, and now after hearing the Isabellina source direct to the RWA 30.2 integrated, I am perfectly content and in fact prefer the Isabellina and 30.2 without preamp. Funds allowing, a world class preamp like the Isabella, Dodd, or Modwright LS might change my mind, but the Isabellina, no doubt because of its outstanding 100 ohm output impedance makes me miss an active gain stage not at all.
In summary, what the Isabellina does very well is balance. If you're looking for euphonic then get a tube DAC and do some rolling, if you're looking for detail get a Benchmark. If you're looking for tone, density, neutrality with a touch of warmth, detailed but not too detailed, dynamic but not hi-fi sounding, a dead quiet, black as midnight noise floor, and a sound stage which is wide and tall and deep ... and none of these things in excess, and all of these things in the correct proportion and balance, then I think this is what the Isabellina does exceedingly well.
Vinnie says there's dramatic improvement all the way to 100 hours, and then a little increment improvement after that. I'll wait another 100 hours, but if first impressions count, I believe I'll be keeping the Isabellina; it's terrific, and I can finally stop searching.
