Khadas Tone2 Pro Review (DAC & Amp)

[Grooved]

What's the difference between Windows volume control and hardware? How big is the drop in sound quality?

If you use ASIO driver, you won't be able to change anything. If WASAPI with exclusive mode, you won't too. You need to use non-exclusive and change it in the player app, but you loose bit perfect, and you can't do that with MQA tracks, or it won't be recognized and processed (unless you use Roon as player and let it decode MQA, add a level change and transmit it with MQA signaling, so the DAC will render it).

 

[dsnyder0cnn]

What's the difference between Windows volume control and hardware? How big is the drop in sound quality?

Windows volume control runs the signal through the O/S mixer, which often results in the signal being resampled. Volume adjustment is implemented by decimating the samples, which reduces signal to noise ratio. While all of this may seem disconcerting, most listeners will not notice any significant loss in sound quality during casual listening. But for critical listening in a carefully calibrated system, you'll want a better solution.

 

[TheTalbotHound]

If i buy a new unit from Khadas right now is it guaranteed to ship with the updated firmware that Wolf measured or might i have to update the firmware myself?

 

[DeepSpace57]

2nd USB C input seems a bit confusing. The manual says it runs on I2S protocol and is for LPS.

So, is it supporting power input and data input at the same time? I could not find also any I2S to Type C Cable.

 

[dsnyder0cnn]

If i buy a new unit from Khadas right now is it guaranteed to ship with the updated firmware that Wolf measured or might i have to update the firmware myself?

It may depend on where you buy it. For example, I believe units in Germany still have the v1.1 firmware. If you order directly from Khadas or from Amazon in the US, you'll get a unit with the v1.2 firmware.

Edit: more info here

 

[dsnyder0cnn]

2nd USB C input seems a bit confusing. The manual says it runs on I2S protocol and is for LPS.

So, is it supporting power input and data input at the same time? I could not find also any I2S to Type C Cable.

I agree that this is confusing. I think the main idea for this port is to provide a place to connect the optional Bluetooth receiver that should be available soon. It can also be used to provide power to the DAC, but this requires a cable with PINs A4/B4 and PINs A9/B9 separated. I have no idea where to buy or how to build such a cable, but this is described here.

I have not heard of anyone successfully using the I2S port as a digital input to the Khadas Tone2 Pro DAC.

 

[Gradius]

Firmware in case you missed:
https://www.khadas.com/post/tone2-pro-firmware-v1-2-for-xmos-mcu

Fix issues with the Audio Filter and Noise Floor measurements.

 

[cheapmessiah]

Would it be a bad idea to use the balanced headphone out instead of the 3 pin RCA since a pentacon to pentacon/XLR cable might be easier to come by, cheaper DIY or already in posission of possible buyers?

 

[dsnyder0cnn]

Would it be a bad idea to use the balanced headphone out instead of the 3 pin RCA since a pentacon to pentacon/XLR cable might be easier to come by, cheaper DIY or already in posission of possible buyers?

Welcome. Not sure. Depends on what you are trying to do…

 

[cheapmessiah]

Welcome. Not sure. Depends on what you are trying to do…

Of course, I forgot the important part, my bad, I meant to plug from the bal headphone out of the tne borad into the bal input of a headphone amp.

 

[dsnyder0cnn]

Of course, I forgot the important part, my bad, I meant to plug from the bal headphone out of the tne borad into the bal input of a headphone amp.

The output impedance of the 4.4mm jack is stated as "< 0.3Ω" compared with 200Ω from the balanced RCA outputs. I can imagine that noise floor might be a few dB higher when going out of the 4.4mm jack (worth measuring), but otherwise, it should work fine.

 

[drplinker]

Comparing results to that of Allo BOSS 2(Cirrus Logic DAC CS43198), how does Khadas Tone 2 Pro (ESS ES9038Q2M) perform so well ?

Allo Boss2 is unbalanced, and does better than Khadas Tone 2 Pro's unbalanced output, and T2P balanced output performs way better than Allo Boss2.

My question (and my surprise) is due to what I see on PCB of each of them. Boss2 has 2 super capacitors, numerous filters/regulators. Khadas T2P must have some voltage regulators, but I don't see any non-SMD like capacitor.

I am not convinced that ES9038Q2M is so much better than CS43198, as there are many other DACs with these same chips that perform better and worse.

How can Khadas T2P perform so well with so few DAC related components (ignoring AMP + knob stuff + XMOS) and with just ordinary (Aamir mentions this in video) USB power ?? (Allo Boss2 needs dedicated power supply - Nirvana SMPS / Shanti LPS)

BOSS2: (also has RPi4)

Khadas T2P:

 

[JohnYang1997]

Comparing results to that of Allo BOSS 2(Cirrus Logic DAC CS43198), how does Khadas Tone 2 Pro (ESS ES9038Q2M) perform so well ?

Allo Boss2 is unbalanced, and does better than Khadas Tone 2 Pro's unbalanced output, and T2P balanced output performs way better than Allo Boss2.

My question (and my surprise) is due to what I see on PCB of each of them. Boss2 has 2 super capacitors, numerous filters/regulators. Khadas T2P must have some voltage regulators, but I don't see any non-SMD like capacitor.

I am not convinced that ES9038Q2M is so much better than CS43198, as there are many other DACs with these same chips that perform better and worse.

How can Khadas T2P perform so well with so few DAC related components (ignoring AMP + knob stuff + XMOS) and with just ordinary (Aamir mentions this in video) USB power ?? (Allo Boss2 needs dedicated power supply - Nirvana SMPS / Shanti LPS)

BOSS2: (also has RPi4)

Khadas T2P:

Khadas tone2 uses two 9038q2m. And single 9038q2m is already a bit better than cs43198 in terms of THD+N. Our coming D10 Balanced only uses one 9038q2m and achieved same performance as khadas tone 2.

 

[JinxDynamic]

Khadas tone2 uses two 9038q2m. And single 9038q2m is already a bit better than cs43198 in terms of THD+N. Our coming D10 Balanced only uses one 9038q2m and achieved same performance as khadas tone 2.

Actually Khadas Tone2 only use 1 x ES9038Q2M.

 

[Phorize]

I’ve been using one of these as my desktop dac/amp set up for about a week. The encoder is intimidating at first try, but after a little while it becomes more intuitive. Most of the settings are ‘set and forget’ anyway. My akg 371s are fine with the high gain setting, going well beyond comfortable listening levels. When I have sourced a balanced cable that doesn’t cost as much as the tone 2 itself I’ll give my hd 6xxs a try. Overall it’s very good value in a narrow use case, which means my use case I think.

@amirm out of interest can you see any reason for Khadas’ recommendation of avoiding switching power supplies with this. They say it’s possible to end up with a low frequency hum, but I can’t see why that would be.

 

[treuben]

+1 on the psu since Khadas themselves seem to recommend better power than USB for SE operation and utmost performance to specs - though on reading about the wierd cable requirments I'm not sure how to do that practically - maybe a properly spec'd usb-c port rather than USB3 with adapter is better for SE especially? Also, I guess now (noticing on the Topping E30 thread) that feeding a nonsense (like multichannel) signal that can't be properly decoded to the E30 results in noise rather than muting. Does anyone know if the tone 2 pro is similar? I'm still hanging out for the pre function firmware update slated for Augist and likely to connect to an amplifier and conrol minor volume with the PC so scenarios with unexpected noises are interesting to me. Has anyone gone rogue and tried the headphone outs for a preamp? I read back a little and saw people suggesting this - but then I've also read on the Khadas forum that the larger of the two headphone jacks lacks "pop-protection-circuit" or something similar, and it can output higher level potentially so perhaps one should watch out for transients from turn on/off etc on that output when connecting it to something sensitive.

 

[Grooved]

New firmware released : https://www.khadas.com/post/tone2-pro-firmware-1-3
with mainly a new line-out volume control added, I will test it later today

" Changelog:

• Added the pre-amp feature (when enabled, line-out volume is controlled by the volume knob)
• Added LED indicator lights for pre-amp (3 green lights)
• Added a feature in which the volume gradually increases from zero on startup
• Fixed an issue in which the DSD format caused the input priority to revert to defaults
• Fixed other minor software issues… "

 

[Grooved]

Did the update with the DFU tool, needed to reboot after that as it re-installs the Windows driver, but everything's working, it allows to control the volume on balanced/unbalanced RCA as expected

 

[TimW]

I saw this update and wondered how the volume is controlled. As you can see in the block diagram, the NJU72315 hardware volume control is only used for the headphone outputs. This preamp output volume control must be done in the ES9038Q2M?

 

[Gouwa]

I saw this update and wondered how the volume is controlled. As you can see in the block diagram, the NJU72315 hardware volume control is only used for the headphone outputs. This preamp output volume control must be done in the ES9038Q2M?
View attachment 148407

Yep, in preamp mode:
1. The NJU72315 hardware volume chips are set to maximum
2. the ESS DAC volume works for both Line out and headphones