Khadas Tone Board

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Khadas Tone Board

Hi-Res Audio Board Designed for Music Fanatic.

Khadas Tone Board is an amazing USB external Hi-Fi sound card in Khadas family.
Its excellent performance and compatibility will take the listening experience into a whole new level.
And that’s just the beginning…

Inherit Khadas Consistent Breakthrough Design.

We integrated XMOS advanced multi-core RISC architecture microcontroller and ESS flagship 32-Bit stereo mobile audio
DAC ES9038Q2M in such a small PCB. And, we choose 3 independent high performance OPA and
4 ultra-low phase jitter oscillator for best noise reduction. The same as you think,
each power supply path is powered by an independent, ultra-low noise
power supply and the OPA is powered up to ±5.5V.
There are a lot of examples of such designs, but in general,
we try our best to get better performance through optimal design.

Flexible Interfaces Support Secondary Development

Khadas aspires to help the DIY enthusiasts grow by achieving their ideas and dreams step by step, as well as Tone Board.
Khadas Tone Board has 2 RCAs for analog output @ 2.0Vrms
and 1 RCA for S/PDIF in or out.

For Extension:

  • One 30-Pins FPC connector for 8 channels analog output extension
  • Two 10-Pins FPC connectors for OLED display and I2S extension

And Others:

  • One 40-Pins female header is used for connecting VIMs
  • One 20-Pins SMT header for debugging XMOS and VIMs

Of course, users can enjoy Tone Board via USB-C interface and Tone Board is a ideally choice for audio developers for obvious reasons.

More good News:
Khadas new heatsink can fit with VIMs and Tone Board.
Convenient for customers to develop and Mold/Enclosure/Case design
So that the customized product can evolve from idea to reality ASAP.

  • Khadas Tone + VIMs connected through GPIO Pins
  • Generic Edition won't have GPIO Pins on board.
  • Tone + VIMs will have GPIO Pins

Key Performance Parameters:

THD+N ≤ 0.000337%

Tone Board has excellent THD+N parameter that means we can

barely hear the distortion over the THD+N signal ratio.

Khadas Tone Data1

SNR ≥ 120dB

The higher the SNR means the clearer the sound in audio system.
Generally, the SNR need to be lower than 110 dB in Hi-Res audio system.

Khadas Tone Data2

DNR ≥ 120dB

The DNR which let’s hear a wide range and very subtle sounds,
meanwhile, the sound field is horizontal and vertical,
and the sense of space and layering is like a live concert.

Khadas Tone Data3

Crosstalk (Channel Separation) ≥ 127dB

The higher the crosstalk separation, the higher the isolation level of the
left and right channel so that you can get stunning stereo effects.

Khadas Tone Data4

Frequency Response ± 0.08dB

Tone Board can output stable enough signals at each frequency point. For the bass,
the low frequency sound is enough but not boom and no dryness, and the alto,
the person’s Voice of middle frequency is close to the front,
the tooth sound is clear and it has the high definition and
the degree of separation, finally the treble is not sharp
and it’s transparent with depth.

Khadas Tone Data5

Sample Rate and Compatibility.

The XMOS USB audio to ensure a rock-solid connection. We selected to use the
XMOS XU208 microcontroller for its stability, powerful functionality,
and its reliability. You can be sure that the Tone Board will just
work when connected to most audio sources,
such as computers and mobile media terminals.

Khadas Tone board Compatibility

Ultra-low Phase Noise Clock Jitter.

The SiTime ultra performance oscillator SiT820&8209 series with just 0.5ps phase jitter
and output frequency stability as low as ± 10PPM. We chose it as a reference clock
in our audio system so that the data clock jitter < 30ps.

Khadas Tone board Sitime ultra low phase noise clock jitter

Multiple Audio Formats.

Tone Board supports mainstream lossless audio formats such as

Khadas Tone Board Format

More Design Details.

As we known, Tone Board is an amazing audio sound card with excellent audio architecture and very elegant
material selection, there are more design details that we can’t help sharing with you.

Outstanding PCB Design:

one Board has reasonable PCB stack-up and layout,

which was designed with 4 layers immersion gold PCB process

in order to get better analog signal quality and excellent power integrity.

Professional Tuning:

Professional instruments APx555 has high-performance and modular two-channel audio analyzer, which is the new standard-performance and versatility in audio analysis to test and tune Tone Board.

Khadas Tone board tuning instruments

Different Components and Solder Wires:

In order to study the influence of different material resistance, capacitors and solder wires on audio quality, we have tested many times and finally chose the most suitable

Khadas Tone board tuning Components and solder wires

Hardware & Software Optimization:

We iterated over 4 times hardware design and many times software upgrade until Tone Board is finally released.

Khadas Tone board tuning instruments

Music Fanatic Audition:

Thanks for the music fanatics giving us many valuable advices !


Specially Customized Cables.

For different audio cables and connecters, we did lots of tests. Finally we specially customized
RCA-3.5mm cables and 3.5mm extension cables.

Khadas RCA Cable

Customized Headphones and Earbuds.

Finally, there is an exciting news that we specially tuning and customized headphones and earbuds for music fanatics.
It is worth having it.

Khadas Headphone

Focus on Ergonomics, KH series is a comfortable headphone that can be accompany
you enjoy music for a whole day.

Khadas Earbuds

KE Series are Triple Drivers Hybrid Earbuds for music fanatics.

10 Tone Package

Khadas Tone Board Specifications
 VIM_Edition  Generic_Edition
Edition VIMs Edition Generic Edition
XMOS XU208-128-QF48
8 xCores, Core Share up to 500 MIPS
32-Bit Stereo Mobile Audio DAC
THD+N ≤ 0.000337% @1KHz
SNR ≥ 120dB @ 10Hz~20KHz
DNR ≥ 120dB @ 10Hz~20KHz
Crosstalk ≥ 127dB @ 10Hz~20KHz
Frequency Response ±0.08 dB @ 10Hz~20KHz
Sample Rate   PCM: Up to 768KHz @ 32bit
DSD: Up to DSD256 @ 1bit
Clock Jitter      Reference Clock Jitter < 3ps
Data Clock Jitter < 30 ps
Line Out 1x Red RCA for Right Channel, 1 x White RCA for Left Channel
Indicator White LED x1
Mounting Holes Size M2 x 5
FPC Connector 30-Pin 0.5mm Pitch: for 8 Channels Extension
FPC Connectors 10-Pin 0.5mm Pitch: for VIMs I2S Extension
10-Pin 0.5mm Pitch: for OLED Display
S/PDIF IN Up to 192KHz Up to 192KHz
S/PDIF OUT Yes Not Support
USB-C Port NC Power Supply(5V/500mA) & USB 2.0 Data
40-PIN Header 2.54mm Pitch Female Not Soldered
20-PIN Header 2.54mm Pitch Not Soldered
Dimensions 82.0 x 74.5 x 24.0 mm 82.0 x 74.5 x 17.0 mm
Compatibility Android [1]
Linux Distros(Support Volumio)
Windows PC
Linux PC
Raspberry Pi [2]
In the Box Tone Board VIMs Edition
Screws set
Tone Board Gerneric Edition
Screws set
Header: 40 PIN Female
Header: 20 PIN
[1] Android support only 44.1KHz output due to the Sample Rate Conversion(SRC) resampling implementations.
[2] Should also support other Single Board Computers(SBCs)