Aune S17 Pro Headphone Amplifier User Manual

1. Introduction

This manual provides detailed instructions for the setup, operation, and maintenance of your Aune S17 Pro Headphone Amplifier. The S17 Pro is a Class-A, fully-discrete, fully-balanced headphone amplifier and pre-amplifier designed for high-fidelity audio systems. It features multiple headphone outputs (6.35mm, XLR, 4.4mm) and preamp outputs (XLR, RCA) for versatile connectivity.

2. What's in the Box

• Aune S17 Pro Headphone Amplifier
• Power Cord
• 6.35mm to 3.5mm Adaptor
• Remote Control
• Quick Start Guide

3. Product Overview

3.1 Front Panel

Image: Front and Rear Panel Overview of the Aune S17 Pro. The front panel shows the display screen, multifunction knob, headphone jacks, and remote control receiver. The rear panel shows various input and output ports.

• Balanced 4-pin XLR Headphone Socket: For balanced headphone connections.
• Balanced 4.4mm Headphone Jack: For balanced headphone connections.
• 6.35mm Headphone Jack: For single-ended headphone connections.
• Remote Control Receiver: Infrared receiver for the included remote control.
• Display Screen: Shows volume level, input selection, gain level, and quiescent current mode.
• Multifunction Knob: Controls volume, input selection, and gain/current settings.
• Power Indicator Light: Indicates the power status of the unit.

3.2 Rear Panel

• XLR Line In (R/L): Balanced audio input.
• RCA Line In (R/L): Single-ended audio input.
• XLR Preamp Out (R/L): Balanced audio output for connecting to power amplifiers or active speakers.
• RCA Preamp Out (R/L): Single-ended audio output for connecting to power amplifiers or active speakers.
• Power Switch and Power Input: Main power connection and on/off switch.

4. Setup

1. Placement: Place the S17 Pro on a stable, flat surface with adequate ventilation. Ensure no objects block the rear panel heat emission holes.
2. Power Connection: Connect the provided power cord to the power input on the rear panel and then to a suitable 110V AC power outlet. Caution: This device operates on 110V. Please verify your local voltage before use.
3. Audio Input: Connect your audio source (e.g., DAC, CD player) to either the XLR Line In or RCA Line In ports on the rear panel.
4. Headphone Connection: Connect your headphones to the appropriate jack on the front panel (6.35mm, 4.4mm balanced, or 4-pin XLR balanced).
5. Preamp Output (Optional): If using the S17 Pro as a pre-amplifier, connect the XLR Preamp Out or RCA Preamp Out to your power amplifier or active speakers.
6. Power On: Flip the power switch on the rear panel to the 'ON' position. The display screen will illuminate.

5. Operating Instructions

1. Volume Control: Rotate the multifunction knob clockwise to increase volume and counter-clockwise to decrease volume. The current volume level is displayed on the screen.
2. Input Selection: Single press the multifunction knob to cycle through available inputs (RCA, XLR). The selected input will be shown on the display.
3. Gain Level Adjustment: Long press the multifunction knob to switch between Low Gain (G-L) and High Gain (G-H) modes. Low gain is suitable for sensitive IEMs, while high gain provides more power for demanding headphones.
4. Quiescent Current Mode: Double press the multifunction knob to switch between 50mA and 100mA quiescent current modes. The selected mode is indicated on the display. The 100mA mode offers a richer sound but generates more heat.

6. Key Features

6.1 Twin JFET Design

Image: Close-up of the Aune S17 Pro circuit board highlighting the Twin JFET components. This design contributes to the amplifier's sound characteristics.

The S17 Pro incorporates a Twin JFET design, utilizing two JFET transistors per channel. JFETs are known for their high input impedance and a sound signature often compared to vacuum tubes. The Twin JFET implementation ensures consistent performance and stable mid-point voltage. The final output stage uses 2 pairs of output transistors in parallel, totaling 16 output transistors for the entire device, providing a maximum output of 7.5W to drive various headphones and IEMs.

6.2 Class-A Operation with Adjustable Current

Image: The Aune S17 Pro front panel with text indicating 'Class-A Current Adjustable Two Levels'.

The S17 Pro operates in Class-A mode, offering two selectable quiescent current levels: 50mA and 100mA per transistor. With two pairs of transistors in parallel per channel, the quiescent current can be as high as 100mA or 200mA per channel. Class-A amplification is characterized by a mellow, warm, and smooth sound. The two gain levels (low and high) allow for optimal driving of both sensitive IEMs and power-hungry headphones.

6.3 R2R Electronic Volume Chip

Image: Detailed view of the Aune S17 Pro circuit board, highlighting the R2R electronic volume chip and surrounding components.

The S17 Pro utilizes an R2R electronic volume chip from JRC, combined with dedicated op-amps, to implement a 4-way balanced R2R volume control. This design provides high control precision, excellent channel balance, a wide soundstage, and accurate sound positioning.

6.4 Advanced Cooling Structure

Image: Internal view of the Aune S17 Pro, showing the complex 3-dimensional cooler structure and various high-quality components.

To ensure stable Class-A operation, the S17 Pro features a complex 3-dimensional cooler structure. This system integrates the heat sink on the transistors, a heat plate at the bottom, and the chassis to form an efficient cooling system. Heat is dissipated through the rear panel heat emission holes, maintaining Class-A stability. The unit also includes overheat protection, which automatically switches the quiescent current to 50mA if the internal temperature reaches 69°C.

6.5 Power Supply and Component Selection

Image: The Aune S17 Pro showing its multi-connectivity options on the rear panel and the multifunction knob with remote control on the front.

The S17 Pro is equipped with a 50W low-ripple toroidal transformer and a dual-power design, ensuring digital and analog sections operate independently to prevent interference. A 19200 μF capacitor array further contributes to the amplifier's powerful and rich sound. High-quality components such as electrolytic capacitors, ceramic capacitors, organic thin-film capacitors, and communication-grade PCBs are carefully selected for optimal audio performance.

7. Specifications

8. Troubleshooting

• No Sound:
  • Ensure the power cord is securely connected and the unit is powered on.
  • Verify that the correct input source (RCA/XLR) is selected on the S17 Pro.
  • Check headphone connections and ensure they are fully inserted into the correct jack.
  • Confirm the volume level is not set to minimum or muted.
  • Check the audio cables connecting your source to the S17 Pro for damage or incorrect connection.
• Unit Gets Hot:
  • The S17 Pro operates in Class-A mode, which naturally generates heat. A slow temperature rise is normal.
  • Ensure adequate ventilation around the unit. Do not place it in an enclosed space or stack other heat-generating devices directly on top.
  • If the temperature reaches 69°C, the overheat protection will automatically switch the quiescent current from 100mA to 50mA to prevent damage. This is a normal protective function.
  • If excessive heat is a concern, consider operating in 50mA quiescent current mode or ensuring better airflow.
• Remote Control Not Responding:
  • Check the battery in the remote control and replace if necessary.
  • Ensure there are no obstructions between the remote control and the receiver on the front panel.
  • Point the remote directly at the receiver.

9. Safety Information

• Do not expose the unit to rain, moisture, or extreme temperatures.
• Avoid placing the unit near heat sources or in direct sunlight.
• Do not open the casing. Refer all servicing to qualified personnel.
• Use only the provided power cord or a suitable replacement.
• Ensure proper ventilation to prevent overheating.
• Avoid listening at excessively high volume levels for prolonged periods to prevent hearing damage.

10. Warranty and Support

Aune products typically come with a manufacturer's warranty. Please refer to the warranty card included with your product or visit the official Aune website for specific warranty terms and conditions. For technical support, product inquiries, or service, please contact Aune customer service through their official channels.