Topping E1x2 OTG Professional Audio Interface

1. Product Overview

The Topping E1x2 OTG is a versatile audio interface built for professional audio production and live streaming. It features ultra-linear microphone premodules, multiple OS support, and zero-latency monitoring, making it suitable for various creative needs.

Key features include OTG direct mobile connection, ultra-linear mic premodules, multiple OS support, four 12-channel simultaneous mixes, 6*LOOPBACK, zero-latency monitoring, and high sample rate support up to 192KHz/24Bit.

2. Package Contents

Please check the package for the following items:

• E1x2 OTG Host Unit
• Type A to Type C Cable
• Type C to Type C Cable
• 6.35 mm to 3.5 mm Adaptor
• Quick Start Guide

The image displays the E1x2 OTG unit, a Type A to Type C cable, a Type C to Type C cable, a 6.35mm to 3.5mm adapter, and a Quick Start Guide. Dimensions are 14.5cm x 12.9cm x 5.0cm.

3. Parts and Controls

Front Panel

Detailed view of the front panel with labeled controls.

1. IN (Combo Connector): For connecting microphones (XLR), instruments (6.35mm TS), or line-level devices (6.35mm TRS).
2. INST Button: Toggles between Line input (light off) and Instrument input (light on).
3. 48V Button: Activates 48V phantom power for XLR microphone inputs when lit. Caution: Only use with condenser microphones that require phantom power. Ensure all volume levels are at minimum before activating.
4. Input Gain Knob: Adjusts the gain level for microphone, instrument, or line input. Monitor LED meters to avoid clipping (red CLIP light).
5. MON Button: Enables direct monitoring, routing input signals directly to the headphone output for zero-latency monitoring.
6. LED Meters (IN/OUT): Displays input (IN1) and output (OUT1&2) levels. Red CLIP light indicates clipping.
7. Power Indicator: Solid light (working), off (power off), breathing light (standby). Flashes when in standby mode with power signal but no USB/OTG/Analog input.
8. OTG Indicator: Solid light (OTG device connected), off (no OTG device connected).
9. Input Monitor Mix Knob: Adjusts the balance between live input signals and computer playback streams during direct monitoring. Does not affect recording levels.
10. Headphone Volume Control: Adjusts the volume level for headphones.
11. 6.35mm Headphone Output Jack: Connect your headphones here.
12. GAIN Button: Headphone amplifier gain setting. Low gain (light off), high gain (light on).
13. MONITOR Knob: Adjusts the level sent out of LINE OUT to your monitors.

Rear Panel

Detailed view of the rear panel with labeled ports.

14. LINE OUT (6.35mm TRS Balanced Jacks): For connecting to active speakers or an amplifier.
15. OTG Port (USB-C): Connect mobile devices for recording audio from or sending audio to the mobile device.
16. USB-C Port: Connects the E1x2 OTG to a computer for data transmission and power.
17. POWER Port (USB-C): Connect to a DC5V power supply if the USB-C port (16) cannot provide enough power (e.g., when connecting a mobile phone/tablet). In this case, USB-C port (16) is for data only.
18. Power Switch: Turns the unit on/off.

4. Setup and Connection

Before connecting or disconnecting any external device, ensure all volume levels on the E1x2 OTG are set to minimum to prevent hearing damage or equipment damage.

USB Mode Setting (PC / Mobile)

The E1x2 OTG can operate in PC mode or Mobile mode depending on the connected device.

• To enter setup: Press and hold the 48V button on the front panel while powering on the device.
• To switch modes: Press the 48V button again. 8 lights on indicates PC mode; 4 lights on indicates Mobile mode.
• Save setting: Power off and reboot the device.

Connecting to a Computer

Connect the E1x2 OTG to your computer using the provided USB-C cable. This setup allows for PC synchronization during mobile live streams.

Connecting to a Mobile Phone

Use an OTG USB cable to directly connect to your mobile phone for lossless sound quality transmission during live streams. Auxiliary power supply is needed when mobile phone OTG is directly connected.

Dual Mobile Phone Livestream

Connect a second phone to play accompaniment or audio material while one phone is live streaming, enabling synchronized dual phone live streams.

5. Operating Instructions

Independent Mixer Control

The E1x2 OTG features a four-channel input mixer for precise audio management. It includes 8 DAW channels and 6 LoopBack channels for recording, mixing, and playback.

Direct Condenser Microphone Connection

The 48V phantom power switch ensures compatibility with both condenser and dynamic microphones.

High-Resolution Production Experience

Equipped with an XMOS chip, the E1x2 OTG supports high-specification audio recording and playback from 44.1KHz/24bit to 192KHz/24bit, compatible with Windows, Mac, iOS, Android, and other operating systems.

Ultra-linear Microphone Preamp Module

The self-developed ultra-linear microphone preamp module boasts an EIN as low as -130.5dBu, ensuring extremely low background noise and precise audio signal transmission.

Low Noise Reference Voltage Module

TOPPING's unique LNRD module provides a reference-level stable power supply for the AD/DA chip, ensuring audio purity. Input DNR (ADC) is 118dB, Output DNR (DAC) is 115dB, and ADC THD+N is <0.0003%.

Analogue Volume Control

The volume control knob for Line Out and the headphone amplifier uses an analog potentiometer, allowing for accurate volume control. Line Out analogue dynamic range is 127dB, and Phone Out analogue dynamic range is 132dB.

Three Type-C Ports

The E1x2 OTG uses Type-C for both transmission and power supply. It is recommended to connect the auxiliary power connector if the E1x2 OTG is frequently fixed to a desktop or if 48V phantom power is required to avoid signal interference. External power supply is recommended when using with a phone, and a specific cable is recommended for OTG livestreaming.

Powerful Headphone Amplifier

With only 1uVrms of noise floor and 1 ohm output impedance, the NFCA-LE headphone amplifier module ensures distortion-free and noise-free monitoring for high-sensitivity headphones. The E1x2 OTG offers two gain adjustments (up to +17dBu) and a powerful output of 580mW x 2@RL=32 Ohm, capable of driving professional headphones up to 600 ohms.

Zero-latency Hardware Monitoring System

The zero-latency design allows real-time monitoring of audio effects during recording or mixing.

Software Control (TOPPING Professional Control Center)

The E1x2 OTG can be controlled via the TOPPING Professional Control Center software. For detailed instructions on using the software, please refer to the dedicated guide available for download from the official TOPPING website. (Refer to the PDF manual for the link).

DAW Audio Settings

The E1x2 OTG is compatible with any DAWs that support Core Audio on Mac or ASIO on Windows. Ensure that E1x2 OTG is selected as the ASIO driver (Windows) or Core Audio driver (Mac) in your DAW's preferences/playback settings. Consult your DAW's user guide if you are unsure where to find these options.

6. Maintenance

Factory Reset

To restore the E1x2 OTG to factory settings, press and hold the MON button at the top left corner while powering on the device until all meter indicators light up.

Precautions

• Do not expose the unit to high temperatures, humidity, or strong impacts.
• Do not open the casing; doing so will void the warranty. Repairs should only be performed by qualified personnel.
• This product is for indoor use only.
• TOPPING is not liable for any direct or indirect loss or damage resulting from product failure.
• Specifications are subject to change without prior notice for product improvement.

7. Troubleshooting

No Power

• Ensure the rear panel power switch is in the ON position.
• If power is insufficient, connect a DC5V power supply to the POWER input.
• Check the USB cable for damage; replace with a new one (max 2 meters).
• Try different USB ports on your computer, preferably rear ports.
• Test with another computer if possible.

No Playback Sound

• Check speaker connections and volume settings.
• Adjust E1x2 OTG Line output and headphone output volume.
• Verify settings in the TOPPING Professional Control Center.
• Connect E1x2 OTG directly to the computer, bypassing any USB hubs.
• Remove unused USB devices from your computer.
• Close all unused applications.

Recorded Audio Too Loud, Too Quiet, or Silent

• Adjust the E1x2 OTG input gain level.
• If using a condenser mic, ensure 48V phantom power is enabled.
• Verify settings in the TOPPING Professional Control Center.

Sound Breaks Up

• Increase the buffer size (latency) in your audio application or TOPPING Professional Control Center (Windows only).
• Test with another computer if possible.

Distorted Input Sound

• Monitor the input meter and reduce the input gain level if the CLIP indicator is on.

Cannot Play or Record

• Confirm E1x2 OTG is selected as input/output device in your software.
• Ensure E1x2 OTG is correctly connected to the computer.
• Close all applications using E1x2 OTG, then unplug and re-plug the USB cable.

Mobile Phone Does Not Recognize Unit

• Some phones require OTG function to be enabled manually.
• Ensure the USB cable supports OTG functionality.
• If power is insufficient, connect a DC5V power supply to the POWER port.
• If connected via USB-C, ensure the unit is set to mobile mode.

8. Specifications (@24bits/96kHz)

The image provides detailed specifications for Microphone Input, Line Input, Headphone Output, and OTG Output.

Microphone Input

• Equivalent Input Noise @A-wt, 150 Ohm: -130.5dBu
• THD+N @A-wt: -110dB (0.0003%)
• Dynamic Range @A-wt: 118dB
• SNR @A-wt: 118dB
• Frequency Response: 20Hz-40kHz (±0.2dB)
• Maximum Input Level: 8.6dBu
• Input Impedance: 1.5K Ohms
• Available Gain: 58dB + 20dB (20dB digital gain)
• Phantom Power: 48V
• Connector Type: XLR connector of the combo socket

Line Input

• THD+N @A-wt: -107dB (0.00045%)
• Dynamic Range @A-wt: 118dB
• SNR @A-wt: 118dB
• Frequency Response: 20Hz-40kHz (±0.1dB)
• Maximum Input Level: 23.9dBu
• Input Impedance: 9K Ohms
• Available Gain: 58dB + 20dB (20dB digital gain)
• Connector Type: TRS connector of the combo socket

Instrument Input

• THD+N @A-wt: -108dB (0.0004%)
• Dynamic Range @A-wt: 118dB
• SNR @A-wt: 118dB
• Frequency Response: 20Hz-40kHz (±0.3dB)
• Maximum Input Level: 14.8dBu
• Input Impedance: 1M Ohms
• Available Gain: 58dB + 20dB (20dB digital gain)
• Connector Type: TS connector of the combo socket

Line Output

• THD+N @A-wt: -100dB (0.001%)
• Dynamic Range @A-wt: 115dB
• Analogue Dynamic Range @A-wt, -40dB attenuation: 127dB
• SNR @A-wt: 115dB
• Frequency Response: 20Hz-40kHz (±0.3dB)
• Maximum Input Level: 14dBu
• Noise @A-wt: 1.8uVrms
• Output Impedance: 100 Ohms
• Connector Type: 6.35mm TRS balanced jack

Headphone Output

• THD+N @A-wt: -100dB (0.001%)
• Dynamic Range @A-wt: 115dB
• Analogue Dynamic Range @A-wt, -40dB attenuation: 132dB
• SNR @A-wt: 115dB
• Frequency Response: 20Hz-40kHz (±0.3dB)
• Maximum Output Level: 0dBu @ Gain=L, 17dBu @ Gain=H
• Noise @A-wt: 1 uVrms
• Output Impedance: 1 Ohms
• Connector Type: 6.35mm stereo headphone jack
• Output Power:
  • 580mW x 2 @32Ω THD+N<1%
  • 380mW x 2 @64Ω THD+N<1%
  • 198mW x 2 @150Ω THD+N<1%
  • 105mW x 2 @300Ω THD+N<1%
  • 55mW x 2 @600Ω THD+N<1%

OTG Output (@OTG 24bits/48kHz <-> TypeC 24bits/44.1kHz-192kHz)

• THD+N @A-wt: -130dB (0.00003%)
• Dynamic Range @A-wt: 138dB
• SNR @A-wt: 138dB
• Frequency Response: 20Hz-40kHz (±0.1dB)
• Maximum Output Level: -0.5dBFS
• Connector Type: OTG (TypeC)

Note: The above data is the result of tests conducted in the TOPPING laboratory.

9. Warranty and Support

For comprehensive warranty information and further support, please refer to the full user manual PDF available at: Topping E1x2 OTG User Manual (PDF).

You can also visit the official TOPPING Professional Audio Store for product information and customer service.