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Khadas Tone2 Pro Review (DAC & Amp)

gguertin145

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Looking at the directions it looks like the sampling has to be changed when connected to the computer... does that mean if you send it sound of spdif it will be whatever you send it with no sampling? Or does that setting need to be set in the computer first?
 

somebodyelse

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Can this run on just battery for power? If it’s 5v can it run a 2 cell Lopo at 8
We've not seen schematics yet but this seems risky - it might work, but it's not what it was designed for, and it might break it. Use a regulator to bring the battery output down to 5V and all should be good.
 

dsnyder0cnn

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This may be specific to my particular Tone2 Pro, but under v1.0 firmware, it was stuck on the "Min Slow" filter. By this, I mean that using the dial to change filters had no effect. I know many others have said they could hear no difference among filters, and this is likely the reason. :)

Besides filter selection actually working after the MCU and v1.2 XMOS firmware updates, there are other differences. You can get the full details in the link I shared above, but here, we see that frequency response is identical @ 44.1 kHz when using the "Min Slow" filter on the v1.2 DAC:

Frequency Response.png


Noise and distortion is improved going from v1.0 to v1.2:

Distortion v1.0.png

Distortion v1.2.png


Phase has been corrected in v1.2, as we can see by looking at step response:

Step v1.0.png


Step v1.2.png


In case you're curious, here's the frequency response of the seven different filters after installing the new MCU and v1.2 XMOS firmware:

Filters v1.2.png


As far as I can tell, "Linear Fast" looks best, but I've not spent much time listening to see if I can establish a personal preference. Another note, it looks like the original Khadas Tone Board (Tone1) uses Apodizing. Obviously, the higher the sampling rate, the less difference between these filters. Enjoy.

Edit: Here's a link to the REW *.mdat files containing my measurements in case you want to poke around yourself
 
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gguertin145

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I am using the tone2 from the 3rd release plugged into the computer the app shows the sample rate at 44100, how do you change the sample rate I am actually feeding it 352.8? I see in the manual the Yellow dials but i do not see any yellow lights when scrolling on the dac and the sample rate cannot be edited in the app.
 

dsnyder0cnn

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I am using the tone2 from the 3rd release plugged into the computer the app shows the sample rate at 44100, how do you change the sample rate I am actually feeding it 352.8? I see in the manual the Yellow dials but i do not see any yellow lights when scrolling on the dac and the sample rate cannot be edited in the app.

Hmmm, a DAC can't change the sampling rate that you're feeding it. If you want to use a sampling rate of 352.8 kHz, you'll need to find a recording with that sampling rate or upsample using your media player software (eg., Roon, Audirvana, JRiver).
 

Veri

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I am using the tone2 from the 3rd release plugged into the computer the app shows the sample rate at 44100, how do you change the sample rate I am actually feeding it 352.8? I see in the manual the Yellow dials but i do not see any yellow lights when scrolling on the dac and the sample rate cannot be edited in the app.
Sample rate is set at the device connected to the DAC.
 

dsnyder0cnn

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So if I am feeding a higher rate why does it say 44?

We'd like to help, but you're going to need to provide A LOT more detail about what you are trying to do, how you are doing it, and what you are seeing.
 

Veri

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So if I am feeding a higher rate why does it say 44?
If you're on Windows, you must be playing using the default DirectSound output, and Windows will have set the device to 32-bit/44kHz default I suppose.
-you can try an exclusive mode output (for example in foobar2000, WASAPI/ASIO output module needs to be installed). This will disable all effects, including things like equalizerAPO
-you can try setting Windows sample rate higher, but this will just cause windows to resample everything to one rate (not really recommended).
 

dsnyder0cnn

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Hey! What its people setting with Khadas T2P in Roon?

With the old v1.0 firmware, I recommended having Roon resample PCM to 176.4/192 kHz and using DSP to invert phase. With the new MCU and v1.2 XMOS firmware, this is no longer necessary. The settings I’m using should be optimal for most folks.

Screen Shot 2021-04-26 at 11.59.22 AM.png

Screen Shot 2021-04-26 at 11.59.36 AM.png
 

anon2k2

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Finished my MCU & XMOS update tonight. I have a ST-Link USB connector that I can send out to someone for just the cost of shipping. Should be roughly $5 in the US and a week or less for delivery. Shoot me a message if interested.
 

Grooved

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I am using the tone2 from the 3rd release plugged into the computer the app shows the sample rate at 44100, how do you change the sample rate I am actually feeding it 352.8? I see in the manual the Yellow dials but i do not see any yellow lights when scrolling on the dac and the sample rate cannot be edited in the app.

Like said, if you're using the Windows sound (Wasapi without exclusive mode) instead of Wasapi exclusive mode or ASIO, the sampling rate will be the one you set in Windows.
The Dashboard shows the sampling rate of the stream leaving the computer and going to the Tone2 Pro, even if the file has a different one. In exclusive mode or ASIO, it will match the SR of the file as Windows won't change it.
It leads to a specific case if you're using Tidal and play MQA : the sampling rate is the one of the file, so if you play a MQA track said to be 88.2, 96, 176.4, 192,... it will show what is sent to the Tone2 Pro :
- if MQA Core decoder is disabled (in Tidal app setting or in Roon), it will always show 44.1 or 48
or
- if MQA Core decoder is enabled, it will shows 88.2 or 96

Can this run on just battery for power? If it’s 5v can it run a 2 cell Lopo at 8
You can power it from a portable battery like the one used to charge a smartphone, but if you want to build something, you have to use a regulator, in order to get 5V even if your batteries provide more than 5V.
And don't forget that if you're using Lipo batteries, each cell should not go bellow a certain voltage, so you need a security element to stop it or show you that you're near the limit. It was 3V but experience shows that with improve performance, cells need now to be cut higher than that (when used, after a fast voltage decrease, they keep their main voltage longer than before, but when almost empty, they decrease suddenly from a higher voltage than 3V. 3.3V or even 3.5V cut is a safer choice.
 

noel_fs

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Just ordered, Im so hyped


I couldnt really convince myself to buy it from the khadas store, thanks for having it in aliexpress, easy dodge of customs.


Thanks again for making possible an affordable endgame.
 

noel_fs

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god the price of balanced cable is so disgusting but cant really complain when the dac itself outperforms 99% of the market
 

Grooved

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god the price of balanced cable is so disgusting but cant really complain when the dac itself outperforms 99% of the market

If you already have cables and XLR plugs, you can order the special RCA parts only and build the cable yourself like I did (see one of my previous coments), but I admit it's not the easiest soldering job I've done, the RCA is very small and there's not so much place for 3 points.
 

dsnyder0cnn

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god the price of balanced cable is so disgusting but cant really complain when the dac itself outperforms 99% of the market

I don't know…the price seems fair to me. I purchased both lengths with no regrets. I'd rather have a decent quality option than have throwaway low-quality cables included "for free."

I'd love to see balanced XLR catch on and be picked up by companies like Straight Wire, Audioquest, and even component manufacturers. Home theater processors seem like an obvious application since 16 to 28 XLR outputs take up a lot of space compared to balanced RCA. :)
 

noel_fs

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If you already have cables and XLR plugs, you can order the special RCA parts only and build the cable yourself like I did (see one of my previous coments), but I admit it's not the easiest soldering job I've done, the RCA is very small and there's not so much place for 3 points.
oh thats great then, felt a little disgusting to me because it i thought there wasnt an alternative but if they sell the plugs separately its perfect.

All things considered the price of the cables its not even that bad but personally if its something i can make myself i have a hard time justifying to pay for it.
 
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