Aune Audio A17 Headphone Amplifier

The Aune A17 is the flagship of Aune's amplifier line, a fully discrete, fully balanced headphone amplifier that delivers up to 11,500mW into 32 ohms and runs in Class A across a wide operating range. Aune's tagline for it is "Drives Anything," and the power tables below back that up.

The A17 is for listeners with hard-to-drive headphones: inefficient planar magnetics, 600 ohm dynamics, and everything in between. It is a pure analog design with no DAC inside. It takes RCA or balanced XLR from your DAC, and its preamp outputs can also run powered speakers or a power amplifier.

Output Power

The output stage runs three pairs of power transistors in parallel per channel, which lowers the output impedance to 1 ohm and gives the A17 a firm grip on difficult loads. At maximum gain the balanced output delivers 11,500mW into 32 ohms and 1,260mW into 300 ohms, with 640mW still available into 600 ohms.

That covers the hardest headphones we sell. A HIFIMAN Susvara gets the current it needs, and a Sennheiser HD 800 S uses a small fraction of what the A17 can deliver. Check any headphone against these tables with our headphone power calculator.

Class A Operating Range

In a Class A amplifier, the output transistors carry current all the time, even between notes. This avoids crossover distortion, a small error that can occur when transistors hand the signal back and forth, and it is a large part of the smooth, dense sound Class A designs are known for. The cost is heat.

Aune publishes how far the A17 runs in Class A. From the balanced outputs, it stays in Class A up to 4.32 watts into 32 ohms and 6.76 watts into 50 ohms, and headphones above 107.6 ohms balanced or 53.85 ohms single-ended stay in Class A all the way to full volume. Beyond those levels the output stage moves into Class AB to deliver the rest of its power.

For most listening, that range is wide. Four watts is more than nearly any headphone draws at loud listening levels, and a 300 ohm headphone like the HD 800 S stays in Class A on the A17 at any volume.

Split Power Supply

A higher supply voltage gives an amplifier more dynamic range, but it also produces more heat. The A17 splits its supply to manage that trade-off: the pre-amplification stage runs at plus and minus 20V for headroom, and the output stage runs at plus and minus 15V to keep temperatures under control without giving up drive.

A 100 watt toroidal transformer powers only the analog section, backed by a filter capacitor bank of nearly 80,000uF. The display and controls draw from a separate supply, and their control signals pass through digital isolator chips to keep digital noise out of the audio path. Aune measures output noise under 7 microvolts and THD+N below 0.0005%.

Twin JFET Input and MUSES Volume Control

The input stage uses Aune's twin JFET arrangement in a dual-transistor parallel configuration. JFETs are voltage-controlled devices, like vacuum tubes, and Aune credits them for the A17's natural, layered, warm character. Running matched pairs keeps that character stable as the amplifier warms up over a long session.

Volume runs through the JRC MUSES72323, a 99-step R2R volume chip that tracks all four balanced channels together, so left and right stay matched even at very low listening levels. The headphone and preamp outputs keep separate volume settings, so switching from headphones to powered speakers does not start at the wrong level.

Gain, Bias Current, and Controls

Four gain settings from 5.8dB to 13.5dB and two bias current settings, A-L and A-H, let you match the A17 to the headphone. Sensitive in-ear monitors on G-1 sit against a background under 7 microvolts, and flagship over-ears on G-4 get the full output. The upper display shows input, output mode, gain, volume, and current setting. In A-H both displays turn red, and the lower one shows the internal temperature.

The chassis is thick pure aluminum with a multi-tiered internal heatsink structure that draws heat away from the circuit and spreads it across the case. The A17 runs warm, so give it open space on the desk or rack. Every function has its own physical button, and the included remote mirrors the front panel.

How the A17 Compares

Within Aune's line, the step up from the S17 Pro EVO is large. The A17 has 11.5 watts of balanced power against 7.5, a 100W transformer against 50W, and about four times the filter capacitance. Its Class A range is roughly twice as wide, 4.32 watts into 32 ohms against 2.07, and it adds two more gain settings and the MUSES72323 volume chip. For most headphones the S17 Pro EVO has plenty of power. The A17 makes sense if you own, or plan to own, headphones like the Susvara that need a lot of current.

At $2,399, the A17 is priced against established flagship headphone amplifiers. It brings a fully discrete balanced circuit, a wide Class A range, and more power than nearly any headphone needs.

Key Features

• Aune's flagship fully discrete, fully balanced headphone amplifier and preamp
• Up to 11,500mW balanced output into 32 ohms
• Class A up to 4.32W into 32 ohms balanced; full Class A above 107.6 ohms balanced or 53.85 ohms single-ended
• Three pairs of output transistors in parallel per channel
• Twin JFET input stage in dual-transistor parallel configuration
• Split power supply: +/-20V pre-amplification, +/-15V output stage
• 100W toroidal transformer dedicated to the analog section
• Nearly 80,000uF of main filter capacitance
• Isolated control power with digital isolator chips
• JRC MUSES72323 99-step R2R volume control across four channels
• Independent volume logic for headphone and preamp outputs
• Four gain settings (5.8dB to 13.5dB) and two bias current settings (A-L / A-H)
• Output noise under 7uV; THD+N below 0.0005%
• 4-pin XLR, 4.4mm balanced, and 6.35mm headphone outputs
• RCA and XLR inputs; RCA and XLR preamp outputs
• Dual-display interface with temperature readout
• One-button-per-function controls with remote
• Ultra-thick pure aluminum chassis with tiered internal heatsinks
• 3-layer internal shielding structure
• Hi-Res Audio certification

Technical Specs

Headphone Output Power (G-4, Maximum Gain)

What's in the Box

• Aune A17 headphone amplifier
• Power cord
• 6.35mm to 3.5mm adapter
• Remote control
• Quick start guide