Review and Measurements of WesionTEK Khadas Tone Board DAC

[escalibur]

The DFU is for firmware updates only. You'll need to install the demo driver if you ever decide to update the firmware, but can remove it again after.

That’s what I’ve thought. Gladly my board came with the latest fw.

ps. Khadas and Burson FUN are such a good friends.

 

[DarrylG]

Could it be that some unknown head phones have a build in amp on batteries

I assume the Khadas' DAC chip was driving the headphones with output that would normally go to a power amp.

 

[DarrylG]

The text in the shop for the cable does state "Connect your Tone Board's RCA stereo output to a 3.5mm compatible set of speakers or headphones. "

I don't know, maybe they're marketing this thing to people who can't or don't want to swing the extra money for an amplifier, or maybe I'm wrong about that. In any case, it made me curious about how the volume is controlled, and how it the DAC chip sounds on its own. Here's the video. Go to 7:20:

 

[thunderchicken]

I'm having a very weird issue with mine- it's connected to a MacBook Pro and disappears from the sound menu after 30 minutes or so of listening, with output shifting to the MBP's speakers. It'll swing back and forth in rapid succession for a bit, then either work or not until I unplug it for for a minute or so. It's a frustrating glitch. What could be causing it? More importantly, how can I fix it? I'd like to install it permanently in my Scott 299 case, but not if I can't rely on it.

 

[BYRTT]

Hi @thunderchicken suggest try use another USB cable and if that doesn't work try KTB hooked up another computer, if neighter works imagine KTB have some temporary damage ab fabric that should be covered by garuantee, if KTB works on another computer one could imagine some power management settings on that MacBook Pro maybe shut it down to save on power.

 

[thunderchicken]

Thanks, I'll give that a shot and see what happens!

 

[dheepak10]

Got my KTB today - sounds quite clinical and has the typical ESS tonality. Compared to my iFi Nano BL, this one has better separation across the frequency range, which gives it the extra airiness at the highs. But the Burrbrown DAC on the iFi packs some extra warmth around the 60Hz to 90Hz region which makes it sound more musical. There are definitely a lot of tracks where I prefer the extra warmth, but keep coming back to the KTB to experience the clean, well separated sound signature.

Current setup - Laptop > USB connection with DAC > Headamp Gilmore Lite MK2 amp > Sennheiser HD650

 

[dheepak10]

I don't know, maybe they're marketing this thing to people who can't or don't want to swing the extra money for an amplifier, or maybe I'm wrong about that. In any case, it made me curious about how the volume is controlled, and how it the DAC chip sounds on its own. Here's the video. Go to 7:20:

I did try this - the USB driver on Windows has volume control. So I hooked my HD650 directly to the DAC at -18db level with an RCA to 3.5mm female cable and it sounds quite good. In fact, I did not notice any difference without my Headamp GL2 in the chain - that also shows that the amp is so transparent and doesn't color the sound .

 

[OldMold]

I'm having a very weird issue with mine- it's connected to a MacBook Pro and disappears from the sound menu after 30 minutes or so of listening, with output shifting to the MBP's speakers. It'll swing back and forth in rapid succession for a bit, then either work or not until I unplug it for for a minute or so. It's a frustrating glitch. What could be causing it? More importantly, how can I fix it? I'd like to install it permanently in my Scott 299 case, but not if I can't rely on it.

This has been happening to me as well on my new PC build (didn't happen on the old one). It sucks that I have to keep reaching around the back to disconnect and reconnect. I just switched it to a different USB port to see if that changes anything.

 

[Chiv]

I also had issues with it disconnecting/connecting repeatedly. I fixed the issue replacing the usb-c cable with just a basic amazon one. The cool patterned one that came with it was the issue for me it seems!

 

[somebodyelse]

I did try this - the USB driver on Windows has volume control. So I hooked my HD650 directly to the DAC at -18db level with an RCA to 3.5mm female cable and it sounds quite good. In fact, I did not notice any difference without my Headamp GL2 in the chain - that also shows that the amp is so transparent and doesn't color the sound .

The Tone Board has a 100 Ohm series resistor in the output which is fine for driving amplifiers, but too high to drive most headphones without altering the frequency response, including the HD650s. Compare this with the headphone amp reviews and you'll see 10 Ohms is usually considered too high. It's possible you prefer the altered frequency response though. It would also get low marks for output power, and the optput opamps are likely to distort considerably more into such a low load. It really isn't designed to drive headphones.

 

[dheepak10]

How's the tonality of Modi 3 in comparison to the Tone board? I find the tone board to be too clinical with the typical ESS glare which I'm not liking much.

 

[daftcombo]

How's the tonality of the tone board in comparison to the Modi 3? I find the tone board to be too clinical without the typical ESS glare which I'm not liking much.

What do you mean by clinical? Bright? Lacking in mids? Lacking in bass?

 

[dheepak10]

What do you mean by clinical? Bright? Lacking in mids? Lacking in bass?

Neutral, slightly bright - lacking warmth, zero coloration - sometimes feels like listening through a grater (raw sounding)

 

[mahirzukic2]

Neutral, slightly bright - lacking warmth, zero coloration - sometimes feels like listening through a grater (raw sounding)

Isn't that the point of a good DAC? To have zero colorations and to give you the (bit) perfect OUT (analog)? If you don't like the sound it may be due to your headphones?
You may be accustomed to your coloured setup and like it that way.

 

[dheepak10]

Isn't that the point of a good DAC? To have zero colorations and to give you the (bit) perfect OUT (analog)? If you don't like the sound it may be due to your headphones?
You may be accustomed to your coloured setup and like it that way.

Yup That's exactly what I mentioned - it sounds clinical and it is not my preference as I like some warmth. Also, this tends a bit to the bright side.

PS: My original query was the comparison to the tonality of Modi 3 for those who have experienced both.

 

[BYRTT]

Yup That's exactly what I mentioned - it sounds clinical and it is not my preference as I like some warmth. Also, this tends a bit to the bright side.

PS: My original query was the comparison to the tonality of Modi 3 for those who have experienced both.

Your PCB is naked, suggest try a grounded box or pull naked PCB as far away from other equipment on that picture there, also if you have any dificulty with tonality it should be very easy make measurement of output and adjust with some EQ upstream of KTB to whatever your tonality preference is about, also notice KTB is free of using high pass capacitor at output so if you prefer that feature try set a say 2Hz or there about 1st order high pass filter upstream of KTB. BTW here is simulation what @somebodyelse tried to tell about altering frq response (tonality) when out put impedance is high verse low, in below simulation frq response is set flat to 20Hz-20kHz with 2nd order BW stopbands and transducers impedance curve is real measurement for a pair of HD650 loading into some plastic model/copy of real ears, grey curves are with zero output impedance and blue curve show how response/tonality change as we add 100 ohms as output impedance, the higher the load impedance is the less is the change response/tonality so for example a pair of 60 ohm cans will get a huge change in response/tonality compared to below, but also it should be said that there is cans out there with flat impedance that hinder this response/tonality phenomen, but then again remember KTB output is a voltage line level output so it probably can't drive whatever power we wan't it to do.

 

[countbasey]

Do the different firmware drivers have an effect on the sound? I got my KTB from the french website yesterday and put it into my speaker system but only use mac/ipad as source so I'm not sure i can update the drivers. It works in roon if i leave the sample rate native but if i try to upsample to 300+ i get static music sounds. would this also be solved by a firmware update?

I also find the sound very in your face and fatiguing after about an hour compared to my allo dac and ayre codex reviewed on this site. chain is ipad/roon > KTB > w4s stp-se preamp > decware mystery amp > vivid audio 1.5 > room acoustic treatments.

 

[milw50717]

Clinical, cold, fatiguing ... isn't that why we have tubes ?

For my main speaker based setups I use an AKM based DAC with transformer output that I prefer the warmer, fuller sound of compared to the KTB that is for headphone only use. I hate to think how they measure on a purely scientific basis.

There are instructions for upgrading the KTB firmware on a MAC. I have not tried to use them as I have a Windoze desktop. Not sure if it would help with the static on upsampling though.

 

[Kingsley]

I look at the tone board have upgraded the KTB firmware, the new firmware could found from https://forum.khadas.com/t/tone-board-v1-04-firmware/4007