"The Wire" Ultra-High Performance Headphone Amplifier + DACUp for sale is my reference dac/amp combo, which includes:
•    A fully assembled ‘The Wire” SE-SE (a hard-to-find, if not unobtainium, headphone amp with a cost-no-object design)
•    DENON DA-300USB (a matching USB and S/PDIF DAC that is electronically isolated all the way by galvanic isolation)I intend to sell them as a combo because "The Wire" would not work with non-isolated DAC (see below for details). As you might know, "The Wire" was designed by Owen, a Canadian electrical engineer that frequents diyaudio.com. He designed a number of amps and DACs, but the most sought-after design is this headphone amp. It has attracted a lot of attention, including the attention of the now-missing NwAvGuy. Indeed, NwAvGuy (his user name is RocketScientist there) admitted himself that “The Wire” was the reason he designed the O2 (he missed The Wire board’s groupbuy and wanted a cheaper but good enough option). As he himself wrote, he was aiming for ‘"hard-to-beat measured performance at any price" sort of amp rather than a cost-no-object design.’So what’s so special about “The Wire”? According to Owen, “The Wire” has the following characteristics:
•    Perfectly flat FR from DC to over 100kHz
•    No phase shift from 0-100kHz
•    No capacitors (except for PSU)
•    Extremely low harmonic distortion
•    Extremely low IM distortion
•    Extremely low noise floor
•    Ability to drive down to 4 ohms with no load dependence
•    Enough voltage swing to drive any reasonable headphone set
•    Excellent input CMRR
•    Simple circuitry using the best parts availableThe above claims are supported by objective facts. Owen published a set of Audio Precision measurements to prove the performance. Indeed, the measurements are so impressive that Agdr, a fanboy of NwAvGuy and put in enormous efforts to improve the O2 by a Objective Desktop Amp (ODA), admitted that “OPC's Wire measurements beat the O2 in all areas”.Below is a thread comparing the two if want to read further:
h*t*t*p* : / / w*w*w.diyaudio.com/forums/headphone-systems/230646-diy-amp-dac-better-measurements-than-o2-odac.htmlAs NwAvGuy himself admitted in one of his blog posts, the Wire outperforms the O2. Now you might wonder, if it is so awesome, why isn’t “The Wire” the most popular headphone amp in the market? Two things. First, Owen has been busy in the past year. So groupbuy for boards and kits has been discontinued the last time I check. Second, it's also a full surface mount design making it much more difficult to build, even for experienced DIYers. In short, it’s basically a hard-to-find, if not unobtanium, ultra-high performance headphone amp. The wire with a gain.Now a few things about this implementation of “The Wire”:
•    It is set up with all 1K resistor (instead of the 10k), which gives a 1.8x gain.
•    Case is built of Cheery wood stained and top is removable (4 side screws) for easy access
•    Professionally built. Used Neutrik RCA for inputs and Neutrik NJ3FP6C-B securely locking chassis phone jack for output. Used a 5 mil copper foil glued to the bottom plate (FR4 material) and connected to the earth ground.
•    110v (you will need to replace the internal transformer or get an external one for 220v).
•    Dimensions are 11"x 5"x 4" (D x W x H).And two more important notes for those who are not familiar with “The Wire”:
•    Please be aware that it’s a fixed-gain amp. There’s a constant debate about the merits of analogue vs. digital volume control. Owen prefer volume to be controlled digitally and hence the design. In other words, you would have to use your DAC and/or software to control volume. Of course, you could also add a passive preamp in the chain if you insist on analogue volume control, but that would defeat the “wire with a gain” design intent IMO.
•    Also aware that the inputs cannot take DC offset at all. There is no isolation; signal goes directly from the RCA to the input of the OP amp. A design choice made by Owen, but it means that this headphone amp would not work with sources with any DC. Because of the above, and because “The Wire” refuses to work with all the sources I have paired it with except Denon DA-300USB (tried OPPO BDP-105, Sony HAP-Z1ES, different CD players, and a few Resonessence and Apogee DACs), this combo includes the former as a matching DAC.“The Wire” does work with portable devices like iPod and PonoPlayer but since you likely are to pair it with a desktop DAC, you’ll need a totally electrically isolated DAC. The Denon DA-300USB included in this combo is such a DAC. Both the USB and the S/PDIF are totally electrically isolated (by galvanic isolation) from the rest of the DA-300USB’s electronics. The signals are also isolated (by Analog Devices ADUM1285CRZ dual channel digital isolator) circuits. MSRP at $549, this DAC is probably the cheapest DAC in the market with electronically isolated digital inputs. DENON comes with all accessories, paperworks, and manual. Condition is Used -- Good on Amazon scale. "The Wire" comes with a power cord, but you could have the WireWorld USB and SONY OFC RCA cables captured in the photos for an additional $49. Headphones not included : ) Condition of “The Wire” is also good, for a DIY, non mass-produced, non assembly-line-made item.Shipping includes fully insurance. Let me know if you have any question!