Well, if anyone was considering it, the factory direct price of the Aurix has been bumped up to 657 Euro.
Meanwhile, I've had the Aurix in a lot of chains, but for several weeks now, I'm exceedingly happy with the synergy it has in this particular chain:
Apple Touch 6 (an iPhone 6 without the phone) streaming Tidal HiFi to the DAC via Sonica App
or
88.2k and 96k FLAC files, read from 128 GB MicroSD cards, mounted in USB card readers at two USB ports on the Sonica DAC
>
Oppo Sonica DAC (ES9038Pro) (controlled by the Sonica App, but receiving Tidal HiFi directly from the WiFi router)
>
Audioquest Diamondback RCA interconnects (
the best kept secret in the ludicrous AudioQuest RCA interconnect lineup)
>
Metrum Acoustics Aurix (set for 10 dB gain)
>
Toxic Cables Silver Poison cable
>
Beyerdynamic DT880 Pro 600-Ohm (with Beyer's pleather pads for better seal than velour)
The typically difficult to read 6moons review of the Aurix suggests that it's a better match for high-impedance headphones than for low-impedance headphones like my Oppo PM-1 and Aureze LCD-2. I have to agree!
I had purchased both Metrum Acoustics Octave MkII and the Aurix as a "fix" for the my cankerous Sennheiser HD 800, which is definitely happy with that DAC/Amp pairing, as the HD 800 is particularly sensitive to oversampling DACs (especially ESS DACs, it seems), but also to amps that use a lot of local or global negative feedback. The HD 800 sounds horrible on the amp section of my Oppo HA-1, a multi-stage design with a ton of feedback applied to eliminate the distortion created by the amp's own architecture - an amp that sounds absolutely wonderful with Planar headphones, especially when fed with 4x the power output of the 4-pin connector. But no matter which DAC is used to drive the HD 800 with the HA-1 amp section, the HD 800 can resolve and deliver to your waiting ears the very low-energy distortion artifacts that the HA-1 amp's application of negative feedback creates down near the noise floor - which really destroys all those micro-details that expand the soundstage and improve imaging. Just about any single-ended, zero-feedback (or, at least, very low feedback) amp (even the affordable and thus, unheralded - thanks to price bias - NuForce HA-200) sounds much, much better with the HD 800, as long as you've also eliminated the use of an oversampling DAC.
Wow, I got on a soapbox there... But I was headed toward saying that if you think the passive (0 dB) or transformer-based gain (10 dB) Aurix lacks dynamic punch (as has been judged by some people), you are not giving the Aurix what it wants, in my opinion
(and that of the frustratingly entertaining Srajan Ebaen) - and what the Aurix wants is a high impedance headphone, like the 600-Ohm version of the seemingly ancient yet still venerable Beyerdynamic DT880. Wow! I am so very happy with this chain - and the Beyer (which I've elsewhere described as "the poor man's HD 800," with slightly less resolution, a slightly coarser treble (not a bad thing - it's analogous to going from the too smooth Beyer T1 to the less smooth HD 800), but also with a far more appealing bass energy and extension") has none of the HD 800's sensitivity to ESS DACs, but to be fair, even when I use the Sonica DAC with the HD 800, it is much smoother in the treble, yet chock-a-block with the resolution that an HD 800 deserves. The only thing "finicky" about the Beyerdynamic DT880 600-Ohm is that it wants lots of power and the Aurix really finds its legs to deliver that power when pushing against a 600-Ohm load. This pairing has plenty of slam that's just not there with my planar magnetics and not even with the 300-Ohm HD 800.
When you think "Aurix," think "600-Ohm load."
In my chain above, to achieve extremely an extremely low noise floor, the Sonica DAC and Aurix are powered by a 500 VA
Topaz 91095-32 isolation transformer (with an inter-winding capacitance of only 0.0005 pF, offering -146 dB of common-mode noise reduction and -65 dB of differential-mode noise reduction on the mains power). Both the DAC and the amp are plugged into the same outlet on the Topaz, for minimum impedance, and thus reduced vulnerability to audible noise from leakage currents that can evolve when a voltage potential develops between any two components. And... The WiFi router is powered by a 12V
iFi iPower DC power adapter (with a shortened cord) that itself is plugged into a
B&K 1604a isolation transformer (with floating secondary coil.)
PS> My
Metrum Acoustics Octave MkII is doing a great, NOS job of driving a $500, 24VDC battery-powered
TBI Audio Millenia MG3 Class BD power amp (32Wpc rms into 8-Ohm, which John Hoffman,
writing for Positive Feedback, describes as sounding very much like his $3000 Electra Print 300B, 8 Wpc, SET tube amp, believe it or not. I'm using the Octave MkII + TBI MG3 to drive a pair of
Definitive Technology SM45 two-way bookshelf speakers, in a near-field monitor setup - at about arm's length from my head. I'm beyond sure they're not as good as something like the coaxial-driver KEF LS50s I'd love to try, but the SM45s fit my budget and have been highly praised by
Chris Martens of Abso!ute Sound, who have often been accused of failing to review any affordable HiFi gear.
I, for one, abso!utely love what the Metrum NOS DAC is doing for this near-field monitor setup with the SET-wanna-be Class BD, TBI MG3 amp. Here, again, I use a B&K 1604a isolation transformer to provide common-mode noise reduction on the mains power for the Octave MkII. I'm driving the DAC's Anamero-based USB card (with heavy design input by Cees Ruijtenberg), with data and power coming from an Uptone Audio USB Regen, that is itself powered by a 7.0V DC TeraDak LPS on another B&K 1604a isolation transformer. The USB signal is not coming from a laptop any longer. I've recently started feeding the USB Regen with data from, believe it or not, a Sony NWZ-A17 DAP, equipped with a custom USB emulation cable that bypasses the DAP's proprietary internal DAC to create an already very clean USB audio signal for the USB Regen. Alternatively, I will drive the USB Regen with an iPad 3, using a CCK. Clean, clean, clean - low noise floor and the monitors just disappear - very hard to place with my eyes closed, except when listening to tracks that have been mixed with signals going to only one channel.
OK! I guess I felt like rambling this morning, but the big picture here is that I LOVE my Aurix with the 600-Ohm Beyer DT880!