Whether you’re a gamer, music lover, or just enjoy kicking back at your PC for a Netflix binge, upgrading your audio setup is one of the best ways to improve your experience. Today, we’re looking at a tiny DAC/amp combo courtesy of HiFi Go with the Khadas Tone 2 Pro. At roughly the size of a pack of cards, it’s small enough to fit into any desktop setup and uses an ESS Sabre DAC to deliver a high-end listening experience. It also supports all of the latest formats for high-end audio, including MQA and DSD, so is ready to take on those Master Quality tracks over Tidal.
Specifications
- Current Price: $199 (HiFi Go)
- Key Features
- DAC + Headphone Amplifier - Tone2 Pro combines the ESS ES9038Q2M with x4 OPA1612 operational amplifiers that deliver superior audio quality.
- High Performance - Up to 32bit 384KHz sample rate, bit-perfect DSD512, and -118dB THD+N (line-out).
- Hardware MQA Decoding - XMOS XU216 processor for full MQA decoding, enabling next-gen "original master quality" web streaming and audio playback.
- Balanced RCA - Next-generation "balanced RCA line-out" with 3-pin output, sets a new interface standard for the Hi-Fi industry.
- Linear Power Supply - Tone2 Pro has a second USB-C (I2S) port that supports 5V linear power supplies for ultra clean signal-to-noise ratios.
- DAC Performance(Balanced RCA)
- THD+N- 0.000126%(-118dB)
- THD+N, A-Weighted- 0.000112%(-119dB)
- Noise- 3.5uVrms
- Noise, A-Weighted- 2.75uVrms
- DNR- 121dB
- DNR, A-Weighted- 123.5dB
- Crosstalk, 200kΩ- >120dB
- Output, 200kΩ- 4.0Vrms
- Frequency Response- 20Hz-20kHz, ±0.15dB
- DAC Performance(RCA Single-Ended)
- THD+N- 0.000158%(-116dB)
- THD+N, A-Weighted- 0.000141%(-117dB)
- Noise- 2.0uVrms
- Noise, A-Weighted- 1.6uVrms
- DNR- 119dB
- DNR, A-Weighted- 122dB
- Crosstalk, 100kΩ- >118dB
- Output, 100kΩ- 2.0Vrms
- Frequency Response 20Hz-20kHz, ±0.15dB
- Headphone Amplifier Performance(4.4mm Balanced Port)
- Output Impedance- 2.4Ω
- THD+N, 1kHz, 300Ω- 0.000158%(-116dB)
- THD+N, 1kHz, 150Ω- 0.000158%(-116dB)
- THD+N, 1kHz, 32Ω- 0.000282%(-111dB)
- Noise- <4.2uVrms
- DNR- 121dB
- Max Output @300Ω- 83mW(5.0Vrms)
- Max Output @150Ω- 167mW(5.0Vrms)
- Max Output @32Ω- 211mW(2.6Vrms)
- Max Output @16Ω- 123mW(1.4Vrms)
- Crosstalk, 32Ω- >117dB
- Frequency Response- 20Hz-20kHz, ±0.15dB
- Headphone Amplifier Performance(3.5mm Single-Ended)
- Output Impedance- 1.2Ω
- THD+N, 1kHz, 150Ω- 0.000200%(-114dB)
- THD+N, 1kHz, 32Ω- 0.000282%(-111dB)
- Noise- <2.4uVrms
- DNR- 119dB
- Max Output @150Ω- 35.3mW(2.3Vrms)
- Max Output @32Ω- 125mW(2.0Vrms)
- Max Output @16Ω- 114mW(1.35Vrms)
- Crosstalk, 32Ω- >69dB
- Frequency Response- 20Hz-20kHz, ±0.15dB
- DAC Sampling Rate Support
- USB Input- PCM 384kHz/32-Bit, DSD512 Natively
- Coaxial Input- 192kHz/24Bit
- USB Processor: XMOS XU216, 16 Real-time Logical Cores
- DAC Chipset: ESS ES9038Q2M, 32-Bit Stereo Mobile Audio DAC
- Amplifier Chipsets
- I/V Stage- TI OPA1612x2
- LPF Stage- TI OPA1612x2
- Buffer Stage- RT6863Dx3
- Ultra-Low Noise LDOs: 1xESS ES9311Q, 1.3uVrms(10Hz-100kHz), 5xADI ADP151, 9uVrms(10Hz-100kHz)
- Jitter Filter Technology: Built-in Intel Altera MAX V CPLD, Pre-shaping Technology, Accusilicon AS318-B Series Professional Audiophile Crystal Oscillator
- OS Compatibility: Windows 7, 8, 10(Khadas USB ASIO driver required), MacOS, Linux(with UAC2 compliant kernel), Android(Support OTG function), iPadOS & iOS
- Rated Voltage: DC 5V
- What’s In The Box
- x1 Tone2 Pro
- x1 USB-C Cable (Type-C to C)
- x1 Instruction Manual
- x1 Warranty Card
The Khadas Tone 2 Pro is unassuming in its size and gorgeous in appearance. It features an aluminum body embossed with angular cutouts and the “tone” branding. I was sent the red version, but it’s also available in black and blue, and each is trimmed in gold accents. The unit also features a large control dial that’s knurled on the edges for an easy grip. This knob also pushes down (not in) to select different modes and options.
Around the back, we have RCA outputs to power speakers. Additionally, we have two USB Type-C ports for connecting to a power supply (a normal power brick works fine, though it’s not included here) and to connect to your PC. In its documentation, Khadas mentions that a special ASIO driver will be required for use with Windows 10, but I was able to connect it to two systems and have Windows recognize it right away. Still, I would recommend installing the driver package to make full use of the device.
Finally, along the right side, we have our outputs. The device supports a standard 3.5mm connection as well as a 4.4mm balanced output. If you’re not familiar with balanced output, don’t worry. The Tone 2 Pro has enough power to drive most consumer headphones beyond comfortable levels. Balanced output does allow for more power, however, so if you have high impedance cans, it might be worth looking investing in a balanced cable to drive them to their fullest.
Under the hood is where the real magic happens, and why you might want to consider this device over your computer’s onboard audio.
But let’s back up: what exactly does the Tone 2 Pro do? In essence, it takes all of the audio processing out of the computer and puts it into this tiny, palm-sized box. If you’ve never considered audio before, you might wonder why something like this would be necessary, and that’s an excellent question. Your computer is a jack of all trades. It does its own audio processing (digital to audio conversion or DAC), but it does so on a noisy electrical path alongside all of the other operations it takes to run your PC.
A separate DAC like the Tone 2 Pro has one job: to deliver great audio. It has its own top-tier silicon and electrical components to weed out interference and process audio at a much higher level than your average motherboard. Now, some motherboards have their own high-end audio chipsets, and they can be quite good, but it’s rarely apples to apples even when those components sound like they should be on par with one another.
So let’s break it down. The Tone 2 Pro uses an ESS ES9038Q2M DAC. This is the popular Sabre DAC you’ve probably heard of on other audio components or high-end gaming motherboards. This chipset supports 32-bit, 384kHz audio files. CDs, for example, use 16-bit audio, so it should be immediately clear that the resolution here is outstanding. Unlike the masses of cheap dongle-DACs on Amazon that claim the same, the Tone 2 Pro is able to deliver on that quality thanks to that ESS chip. Even at that level, the Total Harmonic Distortion is ridiculously low at 0.000126% at -118dB and the signal to noise ratio is a respectable 121dB. In layman's terms, that means it’s pristine with nary any white noise to be heard when audio isn’t playing.
That’s only one piece of the equation, however. The Tone 2 Pro also uses a three-stage amplification system, driving headphones up to 150 ohms. The heart of this system is composed of four Texas Instruments operational amplifiers. From its single-ended 3.5mm output, it can drive 125mW into 32 ohms, which is common for consumer headphones. At 150 ohms, that drops to 35.3mW, but don’t let that fool you. Depending on your headphone, you can even exceed the recommended ohm rating. My Sennheiser HD6XXs — a prime audiophile gaming can if ever there was one — are able to be driven by the Tone 2 Pro, even though they’re 300 ohms.
For the audiophile audience, the device also supports DSD 512 playback and full MQA decoding. Both are quickly becoming sought-after features for fans of lossless audio and Tidal subscribers in particular. MQA, or Master Quality Authenticated, files are used by the subscription streaming service to deliver tracks on par with the original master files from the sound engineer.
Listening and Use
Coming to grips with the Tone 2 Pro doesn’t take long, but it does have its quirks. First, don’t let the “L2S” label on the first USB port worry you — it will work fine with a generic power brick. That label simply means that it can work with a nice linear power supply but isn’t a requirement to function. Second, the knob is for more than adjusting volume.
In fact, I think it’s fair to say that it’s more of a multi-function dial than anything, and that’s pretty awesome. By pulling the knob down in single, double, and triple-taps, you can move between different modes. The first is volume, but a double-tap will shift between track control, high and low gain stages, filtering modes, and more. I do wish you could simply press in instead of pulling down since it’s a bit too easy to pull at an angle and not have your second tap register. Early on, this happened and I accidentally triple tapped and locked the device without realizing it. The system works and allows for a clean interface but there’s room for improvement here. Actually turning the knob is nice, with gentle tactile bumps and small enough steps for nuanced volume control.
Most of my listening was done using Spotify Premium as I struggle to hear the difference stepping up to true lossless. I also used it for PC gaming with Doom Eternal, Call of Duty Warzone, and Shadowlands, as well as watching YouTube videos. I listened using my HD 560S headphones, which have been my daily driver for the last month. In one situation, I compared it against the output from my Behringer UMC202HD audio interface. In another, I used it to upgrade from the onboard audio in my gaming PC, which is itself very good. My motherboard is a Gigabyte AORUS X570 Master which includes its own ESS Sabre DAC.
In both scenarios, the Khadas Tone 2 Pro really impressed me. I didn’t expect such a major jump coming from either device, but the improvement from my audio interface was big and immediately noticeable. Music and games sounded cleaner and more natural and there was a warmth and liveliness that my interface just couldn’t provide.
What really surprised me is that I could also notice a difference coming from the Sabre DAC in my gaming PC. High-end gaming motherboards often market their audio capabilities and my AORUS Master was no exception. In fact, the ESS Sabre DAC is one of the reasons I chose it. Even here, however, removing audio processing from the PC makes a difference in how clear and rich that audio sounds.
In both cases, the Khadas Tone 2 Pro flat-out sounded better. The level of components the company used really shines in how isolated the audio is. You don’t notice the bits of white noise in normal listening until they’re gone, but the Tone 2 Pro filters it right out, leaving only the source. My day-to-day setups are fairly run-of-the-mill for mid-to-high specced gamers, so I’m confident most PC users will almost notice the upgrade.
The other high point here is the level of power this tiny unit delivers, which accounts for another aspect of the listening experience. In my journey as an audio enthusiast, one of the things I’ve learned is that headphones often sound better with more power (not always, but often). The HD 560Ss blossom with a bit more juice, expanding the sound stage and dynamics in music, movies, and games. That’s something most onboard or affordable interfaces will struggle with on mid-to-high impedance headphones.
Completely subjectively, I also love the tone of this little hybrid. The ESS DAC has a warmth to it that really complemented the HD 560S and made it sound better than I’ve yet heard it. That same warmth is perfect for games, adding a rich, lush, quality that my onboard DAC and interface just couldn’t compete with.
Final Thoughts
With that said, I really, really like the Khadas Tone 2 Pro. It sounds (and looks) great, has a ton of power, and doesn’t take up a lot of space. Advanced features like DSD playback and MQA decoding are just icing on the cake. That said, at $199, it’s definitely targeting the audiophile audience that’s used to paying a bit more for their tech. Still, if you’re looking for an easy way to make your music and games sound better in a way that’s immediately noticeable, this is an excellent way to do that.
