Like Esoteric’s disc players, the N-05 can function as a stand-alone DAC, with SPDIF inputs on RCA and optical TosLink jacks, and a USB Type B input. There is also an Ethernet input to connect the N-05 to your LAN and a second USB Type A input into which you can plug an external USB drive (hard drive or flash drive). There is also an RCA digital output jack that enables you to use a DAC other than the one built into the N-05, but of course, it’s limited to the highest speed of SPDIF output (192kHz sampling rate/24-bit word length), too slow for the highest-resolution music files.
I can’t complain about having external digital inputs, but in my view, since the player part of the N-05 does exactly the same thing as a computer or external digital music player, those inputs seem less useful than those on Esoteric’s disc players or DACs. Actually, the fact that the N-05 is not a computer (or at least doesn’t look like one) is precisely why it will appeal to many users, who just want to turn it on and play music. The N-05 will play DSF, DFF, FLAC, Apple Lossless, WAV, AIFF, MP3, and AAC music files—virtually all commercially available files except MQA, a very new format with (so far) limited music file availability. Both balanced (XLR) and unbalanced (RCA) output jacks are provided to connect the N-05’s analog output to your amplifier or preamplifier. The volume control is in the app, allowing you to drive a power amplifier directly. Esoteric recommends leaving this volume control at the maximum setting, and adjusting the volume with a preamplifier or integrated amplifier.
Esoteric recognizes the sonic superiority of a really high-quality digital clock, so the N-05 uses a high-precision VCXO (voltage-controlled crystal oscillator) to supply “a highly accurate reference clock signal to the digital circuitry. The N-05’s large, custom-designed VCXO was jointly developed with Nihon Dempa Kogyo (NDK), a leading manufacturer of crystal oscillators, exclusively for high-quality audio playback. The cornerstone of quality sound, its large crystal element realizes both excellent center accuracy (±0.5ppm, as shipped from the factory) and extremely low levels of phase noise to ensure exceptional sound playback quality.”
But that’s just a start: Esoteric makes two even more accurate external clock units, the G-01 and G-02, both with styling identical to that of the N-05. The lower-priced $5000 G-02 would probably be matched to the N-05. The N-05 has input and output jacks for the external clock.
A music file player is only as good as its remote control app, and Esoteric’s app is called Esoteric Sound Stream, which runs only on iPads and is available free from (where else?) Apple’s App Store. I’ll discuss Esoteric Sound Stream in detail in the next section.
Esoteric marketing specialist Scott Sefton said that “the N-05 uses most of the same designs and circuitry as the K-05X SACD Player/DAC.” That means it uses dual Asahi Kasei Microdevices AK4490 DAC chips, which according to Esoteric’s website “are configured in four parallel and differential circuits (8 outputs) driving each channel.” Also, “technology developed for the Grandioso C1 (Esoteric’s $40,000 top-of-the-line linestage) is also employed in the DAC’s power supply, which features Electronic Double-Layer Capacitors super capacitors. This regulated power supply boasts a total capacity of 500,000µF per channel for exceptional low-frequency sound reproduction.” That’s more than many power amplifiers have!
Since the player and DAC share the same chassis, there’s no need for a connecting cable; and the two sections can share the same clock through an I2S connection, which is the least sonically degrading connection—it’s used internally on most CD players.
The actual sound of the player is affected by the settings used, which include upconversion to multiples of the input sampling rate, as well as conversion of incoming PCM files to DSD. You can also set the output of the renderer to a specific sampling rate up to DSD256. Like many DACs, the N-05 has several available filters, as well as an off position which doesn’t use a digital filter for PCM playback. There are two Finite Impulse Response (FIR) filters, with sharp and slow filter slopes, and two short-delay filters with sharp and slow filter slopes. There is also a filter that cuts off frequencies over 50kHz when playing DSD. If you’re worried about ultrasonic noise produced by DSD, that filter should reduce it. Other settings let you select which analog output you want to use, if any; and whether you want to use the digital output (I didn’t, so I turned it off). There are also a setting that automatically darkens the display after playback has stopped for 30 minutes, an automatic power saving setting, and a dimmer for the display. A very complete assortment of controls.