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Why does Windows require the Khadas USB driver?

The Khadas USB driver provides ASIO support and removes the latency and sample rate conversion issue experienced with the default Windows USB driver for DACs.

What does MQA stand for?

MQA(Master Quality Authenticated) is an award-winning audio codec technology. The master MQA file is fully authenticated for high sample rate audio and is small enough to stream and download. 

What is balanced-RCA?

A new balanced audio connector standard, designed by Khadas for small form-factor desktop DACs. It is backwards compatible with standard RCA plugs and cables, more details visit

How do I use my existing XLR-3 equipment with Balanced-RCA?

Purchase the Khadas Balanced-RCA to XLR-3 adapter, it is a male Balanced-RCA plug connected to a male XLR-3 plug.

What is the maximum headphone impedance supported by Tone2 Pro's headphone amplifier?

3.5mm Single ended: 150ohm

4.4mm Balanced: 300ohm

How do I use “S/PDIF” input?

Attach a standard RCA cable to the orange-coloured RCA jack, and set the input mode to “S/PDIF”. Alternatively, set the input mode to “AUTO”and stop music playback from other sources.

How do I connect my smartphone to Tone2 Pro via Bluetooth?

Attach a Khadas bluetooth module to the USB-C (I2S) port, and set input mode to “I2S” or “Auto”.

Why doesn’t my USB-C to Lightning charging cable work with the Tone2 Pro?

Connect an Apple C78-USBH Lightning to USB-C cable to Tone2 Pro’s USB-C (USB) port for data communication, then connect a 5V power source to the USB-C (I2S) port.

Can the USB-C input be used with the USB-C output of Android phone?

Yes, Tone2 Pro can be powered by most Android smartphones via USB-C.

Does the Tone2 Pro support native DSD decoding?

Yes, DSD512 native decoding can be enabled by installing the Khadas USB driver.

What is the voltage level of the Balanced RCA connection?

4.0Vrms for balanced RCA mode, and 2.0Vrms for standard RCA mode (single-ended).

What are the priorities when input mode is set to “Auto”?

Priority from high to low: Bluetooth, USB ( disconnect the Bluetooth module) , and finally  “S/PDIF” (the USB-C cable must still be attached to supply power).

How can I play MQA music?

one2 Pro supports full hardware decoding of MQA data. Stream or play music from a software or app that contains  music that uses MQA encoding. Visit to learn about MQA-supported software and apps.

When inserting headphones during RCA output playback, will RCA playback be interrupted or will it play through both RCA and headphones concurrently?

The RCA playback will not be interrupted, Tone2 Pro will play through both RCA and headphone jacks concurrently.

Can I use the Tone2 Pro to receive a signal from the TV via coaxial and send it to the amplifier via RCA?

Yes. Set the input mode as “S/PDIF” or “Auto”, Tone2 Pro will output to both the RCA and headphone jacks.

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