Twochannel Reference Build — Detail-Forward Headphone Rig

For the solo listener who values transient detail and a wide open-back stage over bass slam or isolation. It leans on a near-zero output-impedance amplifier feeding an efficient 38-ohm headphone, with the streamer relegated to transport duty so the converter sets the resolution.

This is a private, near-field listening rig organized around one measurable idea: keep the amplifier's output impedance far below the headphone's, and the frequency response the driver was voiced to produce survives to the ear. The Grado GS3000X is a 38-ohm, 99.8dB open-back headphone with a stated driver bandwidth of 4Hz to 51kHz. Because it is 99.8dB efficient it needs almost no power, so the question is never watts, it is the character of the stage driving it. The Benchmark DAC3 HGC answers that with a headphone output whose source impedance sits well under one ohm. Into a 38-ohm load that is a damping ratio above 40 to 1, so the driver's motion is controlled by the amplifier rather than interacting with it; a tube stage of 30 or 40 ohms output impedance would tilt this same headphone's balance audibly. That control is the foundation the detail-forward voice is built on. The source chain is split on purpose. The Bluesound NODE 2i is used only as a transport here, passing bits over coaxial or optical into the Benchmark rather than using its own converter. That hands the DAC3's ES9028PRO stage a signal to reclock and convert on its own terms, with the DAC3's measured distortion sitting near the floor of what the format allows. The result the listener hears is not extra brightness added anywhere; it is the absence of the softening that a higher-impedance amplifier or a noisier front end would introduce. Leading edges on plucked strings and brushed cymbals arrive intact, and the open-back baffle keeps the presentation wide rather than pressurized against the ears. The load-bearing pieces are the amplifier's output impedance and the Grado's efficiency together. Pair the same headphone with an output-transformer-coupled amp and the treble the design is known for shifts; pair it with a low-sensitivity planar and the NODE-plus-DAC3 volume budget tightens.

This rig is deliberately narrow in scope. The open-back Grado leaks sound in both directions, so it is unusable around others and offers no isolation. Its forward upper-midrange and treble reward clean masters and expose bright, heavily compressed, or sibilant recordings rather than smoothing them. Low-bass output rolls off early, so electronic and film material that lives below 40Hz will not have physical weight. And it serves exactly one listener at a time; there is no room presentation, no shared session, and no path to loudspeaker playback without replacing the amplifier stage.

• 01

  Swap GS3000X → HE1000 V1 (−$895)

  For a more relaxed, extended presentation with better sub-bass reach, the HiFiMan HE1000 planar trades the Grado's forward treble for a smoother tilt; at 90dB and 35 ohms it asks more of the amplifier, which the Benchmark still supplies.

• 02

  Swap DAC3 HGC → RME ADI-2 FS (−$1,450)

  For built-in parametric EQ and tone control at lower cost, the RME ADI-2 lets the listener tame the Grado's treble in the digital domain, giving up some of the Benchmark's outright transparency.