Khadas Tone2 Pro Review (DAC & Amp)

[Gouwa]

Thanks. I have tried with input set to auto sense as well as USB. The issue remains. I have also tried to power it up with an external power source. It doesn't help. My unit still drops the USB connection after some random period of time, typically several hours.

Does the 'disconnection' event happen during power on/off or sleep/suspend process?

 

[Massimo]

Does the 'disconnection' event happen during power on/off or sleep/suspend process?

It occurs during sleep/suspend.

 

[Gouwa]

It occurs during sleep/suspend.

Thanks for the confirmation, can you help to take a check if you are with same situation below:

 

[diegtria]

@Gouwa
Do you know when the line volume control or preamp mode will be implemented? I have active monitors and due to lack of knowledge I bought the KT2, I am new to the whole world of DACs and it seemed like a versatile option at a reasonable cost to start with.

At the moment I have only been able to enjoy with headphones, and going from a USB dongle to KT2 is impressive the improvement of the sound.

Hopefully, for those of us who have KT2 of the 11xxxxxx or 0Cxxxxxxx series, they confirm the improvement with respect to the measurements made by amirm.

I have a KT2 11xxxxxx series and in the 2 weeks of use it has been great.

Both with Audirvana and with the proper settings in Foobar2000, the recognition and playback of PCM, DSD and the famous MQA decoding have been successful.

Thanks.

DSD256

MQA Studio 192Khz

PCM 352.8KHz

 

[Gouwa]

Do you know when the line volume control or preamp mode will be implemented?

Should be sometime in the end of this month.

And good to know you are enjoying with the Tone2 Pro device.

 

[olivier salad]

@Gouwa Do you know when Tone2 Pro will be available on Aliexpress?

 

[Grooved]

Hi all,

first post here, been reading Amir reviews for a while but didn't have an account. I won't be first to saying it, but congrats to you for this incredible website!

So, received my Tone2 Pro and tested it a bit, mainly enjoying it but I hope for some little improvements (even via separated firmwares) like volume control on RCA outputs, SPDIF output (with MQA post-processing signal to be able to send it to another DAC),...

Everything is working with Foobar, Tidal app, Roon, UAPP,... and it made me discover that the Amazon Music HD app seems to not be bit perfect (could have been able to see this before but I just tested it one time before getting the Tone2 Pro) : even if I select "exclusive mode" on the app, a 24/96 track will be shown as "track quality = 24/96 - device capability 24/192 (I set it at 24/192 from playback device menu on Windows) - currently playing at 24/96" but the Tone2 Pro shows a 192khZ sampling rate, so the Amazon app is upsampling it up to the device capability instead of adjusting the sample rate of the device).

At this moment, the only point that hurts me a bit is not enough power on the headphones amp, I may be wrong but I think it's what makes the low end not as punchy and detailed than on two other headphones amp I have.
Tested with the same part of a song, I got 0.9V at best on the headphones output of the Tone2 Pro, while i got more than 2V on the other headphones amp.

Additional note : I built my own balanced cables with the special RCA plugs ordered with the device, two for analog outputs, and one for the future SPDIF output. Choose to build it myself as I have a lot of XLR plugs and cables. Even if I'm not the best at soldering in the world, I have done soldering since I was a kid and I have to admit it was a bit tricky to do, the three parts being very close

I've been waiting for an ASR review for a while and of course I got busy with my move and actually stumbled upon the Youtube video! (guess those algorithms aren't so far off...) I'm not on top of all the reviews so if there's another comparable product (around the $250 price range with balanced cables), I'd love to know what it is. Otherwise, once things settle down for me in a few months, I look forward to playing with a Tone 2 Pro!

At this price, the main thing to know is if you want to use MQA, because there are not a lot of products doing MQA decoding+rendering in this price range.

 

[flAked]

@Gouwa any rough estimation on when the Tone 2 NonPro version will be available?
In the FAQ it says Tone2 will use the older XMOS chip and I wonder if that will influence the sound? Will it use the same Opamp stage as the Pro? I would rather have the same device as the Pro, just without Amp and MQA.

 

[Dr Schweinsgruber]

I also analyzed the T2P...but more from an applied angle. Thanks to @amirm for answering some questions on power supplies.

https://www.audioreviews.org/khadas-tone2-pro-review-jk/

 

[flAked]

HiFiGo support told me the new batch will be released next week. I would presume this includes a new firmware for the co-processor. Unclear if this is a new hardware revision with the ability to also flash it via USB for later updates.

 

[TimW]

For those of you who own one of these, how does the knob feel when turning? Mine is mostly smooth but there is a scraping feeling also.

 

[anon2k2]

For those of you who own one of these, how does the knob feel when turning? Mine is mostly smooth but there is a scraping feeling also.

I'm not feeling a scratch. It's nicely damped with subtle "clicks" but nothing scratchy.

 

[TimW]

I'm not feeling a scratch. It's nicely damped with subtle "clicks" but nothing scratchy.

Yeah I imagine it isn't supposed to be this way. The scratch doesn't happen when I try to operate the volume knob from the top, but there isn't enough grip that way. If I pinch the knob between my forefinger and thumb the knob scrapes on what feels like the side edge.

 

[courtesy]

I'm not feeling a scratch. It's nicely damped with subtle "clicks" but nothing scratchy.

Mine operates the same.

 

[Dr Schweinsgruber]

For those of you who own one of these, how does the knob feel when turning? Mine is mostly smooth but there is a scraping feeling also.

Yes! Same here. Every so often during a turn there appears to be a small obstacle.

 

[Dr Schweinsgruber]

Attempted a video...underilan by stripper music:

 

[MacCali]

This is a review and detailed measurements of the Khadas Tone2 Pro portable USB DAC and balanced headphone amplifier. It was sent to me by the company for testing. As configured, it sells for $199 from the company website direct.

From the pictures, the unit didn't look all that nice but in person, it looks pretty good:

View attachment 114512

I thought the rotary control is just for volume. It does that but if you push it forward different ways, it engages various configuration mode. They are incredibly hard to decipher. The manual is of no help but there is a video that walks you through it. After watching it, I could sort of change things but this is by far the most overloaded functionality I have seen in an audio device, next to horrible Chord interface. The fact that the light is below the rotary control makes it doubly hard to figure out what is going on. I rather not have all the functions than having to cycle through them this way. It is truly maddening.

Anyway, there is innovation on the back side as we have discussed before in the form of an RCA jack that can be used with an adapter cable to get balanced out as well:
View attachment 114513

Hopefully you can see the inner ring inside which gives you the third pin. Connector has a qualify look to it. I don't think you could have both balanced and unbalanced in this size package with any other option.

Dual USB-C connectors are provided. I tested with the primary one on the right. The other is marked I2S but can also provide auxiliary power which takes priority over the USB-C data connector.

Like the original Khadas Tone Board, there is a bare board option available:

View attachment 114514

I could not however find the price for it or even the listing.

Khadas Tone2 Pro Measurements
Let's start with the dashboard view using the balanced "RCA" output:

View attachment 114515

Wow, I must stay, I didn't expect it to be this good. This is just a couple of dBs short of state-of-the-art.

I expected unbalanced out to be a bit worse but it is actually worse than that:
View attachment 114516

Here are our two rankings then:
View attachment 114533

Unbalanced has more high frequency noise as we see in dynamic range test:

View attachment 114517

From here on, tests are with balanced RCA out.

IMD vs level was excellent:
View attachment 114518

Linearity was perfect:
View attachment 114519

Multitone test showed how low the distortion products are:
View attachment 114520

Jitter test showed problems though:
View attachment 114521

There is some kind of clock selection but frankly, I got so lost in the settings I could not get to change it. Maybe that fixes it, maybe not. If it does fix it, it should be the default. Fortunately these are not audible distortions so practical implication is not there.

Filters were a nightmare to cycle though but I think I got them right:
View attachment 114522

I don't understand why there is such high noise floor for out of band response. Something is not right there. This naturally screws up the THD+N response using its default (low) sample rate of 48 kHz:
View attachment 114523

Switching to high sample rate (brown/green) removes the effect of the reconstruction filter and shows extremely nice performance.

Headphone Amplifier Measurements
The default mode is low gain so you have to suffer through the menus to switch on high gain. Without it, you have "phone dongle" level of power. There are both balanced and unbalanced modes. I tested both in low gain but only balanced in high gain:
View attachment 114524

View attachment 114525

These are respectable power levels for a USB powered, portable device.

Khadas Tone2 Pro Headphone Listening Tests
I used balanced out to drive my Drop Ether CX low impedance headphone. There was good level of power here for satisfying listen. Turn it way up though and distortion sets in so that clipping point is real.

I then switched to Sennheiser HD-650 using unbalanced output. There is not enough power here to do this headphone justice. Sound was Ok but for any type of real use, I would upgrade to balanced cables for it.

Conclusions
As a plain balanced DAC, the basic performance of the Tone2 Pro is superb with one notable miss: the reconstruction filter. I hope this is something they can fix in firmware. I am usually not harsh on performance of this subsystem but this is just not good. I don't know how you can fix the user interface given the mechanism and feedback LEDs available but hopefully they can figure something out. What is there, is not usable.

The Tone2 Pro has the potential to get my highest recommendation but I can't go there due to usability issues and filter problem above. Still, as a plain DAC that you plug in and use, its performance cannot be denied. So I am going to put it on my recommended list.


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As always, questions, comments, recommendations, etc. are welcome.

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what about the unbalanced graphs, curious to know and if it's available please post, thanks.

 

[W1ll1eTheP1mp]

Hey. Any updates on the Tone 2 pro? Firmware etc? Is it stable?

 

[Nango]

Why can't all these Chinese manufacturers produce problem-free device? It seems that in most cases there are some bugs and sometimes they aren't fixable by a firmware update. Customers don't have to beta test hardware at their own expense.

This is highly debatable as you always pay way less than for western items, at least in theory.

 

[Nango]

True... it's far, far less likely for a small team or single engineer to accomplish what your are suggesting. I also wouldn't call this a "half-baked" product... more like "mostly baked" - but fair enough. My real point was that although I've also had my share of bad experiences with smaller Chinese manufactured devices... I've had some which worked flawlessly without compromise - and plenty of half baked (or less) results from domestic manufacturers with far more resources to work with.

Nevertheless they all got ASR's golfing champions panther seal winning award.