Warmth With Numbers: Why Desktop Tube Amps Still Matter
A tube headphone amplifier is a desktop audio device that uses vacuum tubes instead of solid-state circuitry to drive headphones, prioritizing a warm, harmonically rich sound while still aiming for measurable fidelity in power delivery, distortion control, and frequency response across demanding loads. In the age of clean, portable solid-state gear, that may sound like nostalgia. Yet for many serious listeners, tubes are less about retro aesthetics and more about shaping music in a way silicon rarely does. The Auris Audio Euterpe and Feliks Audio Elise MK II are not toys: they are high-end headphone amps built for people who want obvious tube character without throwing measurements in the bin. The key choice is not whether tubes are valid, but which implementation of tubes best fits how you listen and how you build a system around your headphones.
| Spec | Auris Audio Euterpe | Feliks Audio Elise MK II |
|---|---|---|
| Role | Tube headphone amplifier with integrated DAC, can act as headphone amp and pre out | Tube headphone amplifier and preamplifier, OTL design |
| Tubes | 2 x PL95, 1 x ECC81; designed for ECC81, ECC82 possible with sensitive headphones | PsVane 6SN7 driver tubes, 6N13S NOS power tubes |
| Amplifier topology | Single-ended, pentode ultra-linear with output transformers | Output transformer-less (OTL) design |
| Power output | 0.9 W RMS | 200 mW |
| Inputs | USB, RCA analog | Analog input (with 100 kΩ input impedance) |
| Outputs | 6.3 mm headphone out, RCA pre out | 6.3 mm headphone out; pre-amp outputs for other amplifiers |
| Impedance handling | Low 32–80 Ω / High >150 Ω switchable | Broad range, including 32 Ω headphones |
| Frequency response | Not stated | 10 Hz – 60 kHz +/- 3 dB (300 Ω) |
| THD | Not stated | 0.4% (300 Ω, 20 mW) |
| Dimensions | 270 mm W x 210 mm L x 230 mm H (main unit) | 11.6" D x 8" W x 6.5" H |
| Weight | 4.1 kg main unit, 1.1 kg PSU | 13.2 lbs total |
Auris Audio Euterpe: The One-Box Desktop DAC Amplifier
The Auris Audio Euterpe is the answer for listeners who want a single desktop DAC amplifier that handles both music files and analog sources without feeling like a compromise. Its integrated asynchronous DAC based on xMos and ESS Sabre lets you feed PC or mobile devices over USB, with support for DSD64, DSD128, and PCM up to 32-bit/384 kHz. That matters: you are not bolting tubes onto a mediocre digital front end; you are getting a coherent, high-end headphone amp whose digital section is designed for serious use. Sonically, Auris promises deep soundstage, strong tonality, and top-level dynamics, backed by a single-ended pentode ultra-linear circuit and output transformers for controlled delivery. With switchable low and high impedance ranges from 32–80 Ω and above 150 Ω, plus 0.9 W RMS of power, the Euterpe is tuned to drive a wide span of demanding headphones while staying firmly in the tube warmth camp rather than chasing solid-state neutrality.
Feliks Audio Elise MK II: System-Focused, OTL Tube Flexibility
Where the Euterpe aims to be your all-in-one digital hub, the Feliks Audio Elise MK II takes a different stance: it is a pure analog, output transformer-less tube headphone amplifier that doubles as a preamplifier for the rest of your system. The OTL approach and choice of PsVane 6SN7 and 6N13S tubes lean toward transparency with tasteful warmth rather than thick coloration. Feliks describes it as sitting between euphonic tone and detail retrieval, with a focused soundstage and strong vocal presence and extension. Crucially, this is not a finicky tube toy; the Elise MK II offers broad frequency response from 10 Hz to 60 kHz +/- 3 dB at 300 Ω and a low 0.4% THD at 20 mW, plus “virtually no background noise” and improved noise-reduction circuits. Add its pre-amp gain of 20 dB and ability to drive both tube and solid-state power amps, and you get a high-end headphone amp that is as much a control center as it is a listening seat.
Build, Ergonomics, and the Desktop Trade-Off
Both units wear their high-end ambitions on their sleeves. The Euterpe is described as “artfully designed,” using original mechanical and electrical concepts to chase deep soundstage, great tonality, and dynamic punch. The use of ALPS volume potentiometers in a custom implementation shows Auris is paying attention to tactile control as much as sonic effect. Elise MK II, meanwhile, is “beautifully hand-crafted,” with a new high-end audio class transformer for improved stability, more power, and better resistance to external interference, plus input/output safeguards to kill turn-on pops. On the desk, they occupy different kinds of space. The Euterpe’s main chassis sits at 270 mm wide, 210 mm long, and 230 mm high, with a separate PSU adding its own footprint. The Elise MK II spreads horizontally at 11.6" deep, 8" wide, and 6.5" high. Choosing between them is partly deciding whether you want vertical sculpture with an external PSU or a more traditional, heavier single block.
Choosing Your Tube Path: Integrated Convenience vs System Ambition
Ultimately, the question between Auris Audio Euterpe and Feliks Audio Elise MK II is not which tube headphone amplifier is “better,” but what kind of audiophile you are. If you want a desktop DAC amplifier that lets a single chassis serve as source, analog hub, headphone amp, and pre-out, the Euterpe’s integrated xMos/ESS Sabre conversion, impedance switching, and strong 0.9 W RMS output make it an appealing centerpiece for digital-first listening. If you are building a broader system—matching power amps, exploring tube rolling, and treating your headphone amp as a reference pre-amp—the Elise MK II’s OTL layout, 20 dB pre-amp gain, extended frequency response, and quiet noise floor argue for it as a long-term anchor. Both clearly target high-end listeners who prefer tube-driven sonic character over strictly neutral solid-state sound; the real decision is whether your ideal reference-grade rig starts with an elegant all-in-one or a flexible analog heart built to drive whatever you add next.
