Tone board test
Hello,
I've received a tone board (usb xmos + es9038q2m+ with i/v stage all integrated ). I've done a small comparison with my custom board ( avcc mod , 0 15v supply and thd compensation, stock buffer).
As you can see, the noise level is very good , not too bad for a usb device . Thd is higher than expected given it uses the i/v stage, I wonder if the thd compensation is activated. Not shown here, but the tone board has better channel separation.
Hello,
I've received a tone board (usb xmos + es9038q2m+ with i/v stage all integrated ). I've done a small comparison with my custom board ( avcc mod , 0 15v supply and thd compensation, stock buffer).
As you can see, the noise level is very good , not too bad for a usb device . Thd is higher than expected given it uses the i/v stage, I wonder if the thd compensation is activated. Not shown here, but the tone board has better channel separation.
Attachments
@occip: Do you have a link where we can take a look at 'tone board?'
Also, don't know if you have separate left and right AVCC supplies? If so, and channel separation isn't that good, maybe worth trying adding a whole lot of power supply filter capacitance for the AVCC supply and for the voltage output opamp. I have seen channel separation issues before that turned out to be a hint that PSRR wasn't quite as good as I was expecting. I used some big electrolytics and a few 0.1uf and 1uf film caps to remedy the situation I had like that.
Also, don't know if you have separate left and right AVCC supplies? If so, and channel separation isn't that good, maybe worth trying adding a whole lot of power supply filter capacitance for the AVCC supply and for the voltage output opamp. I have seen channel separation issues before that turned out to be a hint that PSRR wasn't quite as good as I was expecting. I used some big electrolytics and a few 0.1uf and 1uf film caps to remedy the situation I had like that.
here is :
Tone Board: Hi-Res Audio Board Designed for Music Fanatic.
schematics are on the docs page :
regarding my avcc supply i'm using one aop plus 1 1500uf on each channel (-86db channel separation)
I've added 6800uf but the 50 hz peak is still visible, maybe a good buck converter will help to remove the peak (and move it at higher frequency
)Khadas Tone Board USB HiFi Sound Card Hi-Res Audio XMOS DAC 384KHz Stereo Audio | eBay
The description has this to be a 4 layer board as well. One needs still to get a VIM. So it looks like for $200, you're in with an XMOS with a SiTime Crystal.
The design looks to be a lean mean get the job done with a cost constraint on the designers. On paper they appear to have done what I commented on recently. The value engineered the design.
So we just need for someone to assess its performance relative to the cost and does it qualify as a poor man's decent DAC.
The description has this to be a 4 layer board as well. One needs still to get a VIM. So it looks like for $200, you're in with an XMOS with a SiTime Crystal.
The design looks to be a lean mean get the job done with a cost constraint on the designers. On paper they appear to have done what I commented on recently. The value engineered the design.
So we just need for someone to assess its performance relative to the cost and does it qualify as a poor man's decent DAC.
It looks like I am mistaken BIG TIME there is no need for a VIM.
Khadas Tone Board User Manual | Khadas Docs
For $99 you're into a USB class 2 DAC using the XMOS U208 coupled with a SiTime crystal. Whoa. I purchased the XMOS with SiTime for about $40 alone. Is this real? Sounds like what I need for video.
The noise is possibly a USB noise issue. I wonder if one can patch in a clean 5V into a USB cable and not use the 5V from say the laptop.
Khadas Tone Board User Manual | Khadas Docs
For $99 you're into a USB class 2 DAC using the XMOS U208 coupled with a SiTime crystal. Whoa. I purchased the XMOS with SiTime for about $40 alone. Is this real? Sounds like what I need for video.
The noise is possibly a USB noise issue. I wonder if one can patch in a clean 5V into a USB cable and not use the 5V from say the laptop.
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Depending on how the Tone Board is intended to be used, one might need to know how to program the XMOS chip and the DAC chip over I2C bus. But, it might make a much better starting point than one of the Chinese boards. Clock is one of the new MEMs, but don't know how it is for phase noise down at 10Hz and 1Hz.
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That's what I thought at first but the instructions clearly indicate. Read the instructions. Install Driver into Windows. Plug in USB cables at both ends. Connect to your amplifier. Voila!
I elected to get one of those newer mems on my XMOS board I recently received. Well, I don't have one of the normal crystals to compare but it kills the 4392 SRC. None of that high end distortion that the 4392 imparts, the soundstage and depth is the same and the clarity/distortion to my ears has improved. In my system the SPDIF delivery whether optical or coax was so bad that the SRC initially patched it up a bit but jitter still dominated....and there's another very interesting side to that as well as regards the analogue stage but I will not conclude until I put in a decent Crystek crystal.
Ok, reality check time. I just ordered a crystek crystal a couple days ago. That was $30 by itself. Xmos board was $40. Total of $70 for upgrades to any board and that does not include the DAC board yet, op amps etc.
For $99, even it worked slightly better than the stock 9038Q2M Chinese board and judging by the measurements it likely will, then this looks to be a gamechanger but understand it is likely not upgrade friendly because of the integration.
Here's how you look at it from my perspective. For the budget user, are they likely to own a high end transport with a low jitter SPDIF? NO. If not, how can we deliver the bits to the DAC the best for a given cost for a budget user....Use asynchronous USB. thus XMOS. An Amanero USB board is close to the cost of the tone board!
Remember we have to sell this and put bread on the table. OK, what else do we need to do. Put in some separate power supplies for AVCC L and AVCC R and one for the clock etc. We can put in 5 separate power supplies. OK boss. How much money left? Well, we still need to put in the DAC. OK boss, Now what is the minimum we need for the IV section. three op amps. All dual. OK Boss. What's left? Oh yeah that crystal thingy. What is the best bang for buck and still not exceed our budget. That mems thing. OK. What else. We need good grounds and short paths So we will need a 4 layer board. Any room for that. Lemme check. I think we can do it.,,,if we have to survive, what can we sell it for ? I think under a $100 and it comes with a type C cable.
I never thought I'd see this thing so quick for so little. I really wonder how it sounds. They say auditioning was part of the design process. This is going to be interesting. Real interesting....not from a DIY perspective because it dampens the hobby.
I elected to get one of those newer mems on my XMOS board I recently received. Well, I don't have one of the normal crystals to compare but it kills the 4392 SRC. None of that high end distortion that the 4392 imparts, the soundstage and depth is the same and the clarity/distortion to my ears has improved. In my system the SPDIF delivery whether optical or coax was so bad that the SRC initially patched it up a bit but jitter still dominated....and there's another very interesting side to that as well as regards the analogue stage but I will not conclude until I put in a decent Crystek crystal.
Ok, reality check time. I just ordered a crystek crystal a couple days ago. That was $30 by itself. Xmos board was $40. Total of $70 for upgrades to any board and that does not include the DAC board yet, op amps etc.
For $99, even it worked slightly better than the stock 9038Q2M Chinese board and judging by the measurements it likely will, then this looks to be a gamechanger but understand it is likely not upgrade friendly because of the integration.
Here's how you look at it from my perspective. For the budget user, are they likely to own a high end transport with a low jitter SPDIF? NO. If not, how can we deliver the bits to the DAC the best for a given cost for a budget user....Use asynchronous USB. thus XMOS. An Amanero USB board is close to the cost of the tone board!
Remember we have to sell this and put bread on the table. OK, what else do we need to do. Put in some separate power supplies for AVCC L and AVCC R and one for the clock etc. We can put in 5 separate power supplies. OK boss. How much money left? Well, we still need to put in the DAC. OK boss, Now what is the minimum we need for the IV section. three op amps. All dual. OK Boss. What's left? Oh yeah that crystal thingy. What is the best bang for buck and still not exceed our budget. That mems thing. OK. What else. We need good grounds and short paths So we will need a 4 layer board. Any room for that. Lemme check. I think we can do it.,,,if we have to survive, what can we sell it for ? I think under a $100 and it comes with a type C cable.
I never thought I'd see this thing so quick for so little. I really wonder how it sounds. They say auditioning was part of the design process. This is going to be interesting. Real interesting....not from a DIY perspective because it dampens the hobby.
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Okay, how do you select the reconstruction filter you want through the Windows driver? Do the settings appear in the Windows sound control panel? How do you set the DPLL bandwidth? Distortion compensation? At the moment, I am still feeling kind of skeptical, but maybe some very basic music playing functionality could exist. What if you wanted to use an AK4137 with it? More questions than answers at the moment. But, it looks like there might be some info on their website if someone does want to do more...
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Oh, sure. That could be. But it is more money in that case isn't it?
Doesn't matter though in a way. My interest would be more towards its utility as a platform to mod, assuming it could benefit from some mods.
http://www.xmos.com/download/private/USB-Audio-2.0-Driver-for-Windows---Overview(3.34.0).pdf
Khadas gives you the Thesycon driver.
Khadas gives you the Thesycon driver.
I suspect someone using and buying a tone board might not be a potential customers of an AK4137. To be honest, I had ordered more parts etc to test but after installing the XMOS, the path to the end shortened dramatically. I will put in a better Crystek and a SuperReg for the Analog. After that, I will box it all up and just enjoy the music. Anything better than what I have now, will be like a dog lying over and getting stroked. Paralyzed in elation.
YouTube
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According to this Introduction to the XMOS USB Audio 2.0 Reference Design - YouTube , you might be able to get your cake and eat it too. I've wondered why one needs so many mips. Well this It’s not just about the MIPS! might explain it all as well.
DSP, control of I2C is also possible. Then one can determine the THD+N compensation and play with that as well. Put in some in room DSP as well.
Time to put away the solder irons and start coding I guess.
I think hardware mod will be difficult on the tone board smd components are so tiny, es9038q2m i2c is not available directly.
Software mods will be easier if you want to take some risk of bricking the board for example :
Manage mixer and hardware volume ( not done today ! ) but possible according to xmos Datasheet
Modify es9038q2m filter on the fly ( I don't know how to do it through usb audio maybe adding an additionnal hid usb endpoint).
Manual switching between spdif input and usb data
DSP filter
As bonus the noise plot of the tone board connected to my laptop versus my es9038q2m modded board. Not too bad ( but not completly realistic given the soundcard i use (asus xonar).
Software mods will be easier if you want to take some risk of bricking the board for example :
Manage mixer and hardware volume ( not done today ! ) but possible according to xmos Datasheet
Modify es9038q2m filter on the fly ( I don't know how to do it through usb audio maybe adding an additionnal hid usb endpoint).
Manual switching between spdif input and usb data
DSP filter
As bonus the noise plot of the tone board connected to my laptop versus my es9038q2m modded board. Not too bad ( but not completly realistic given the soundcard i use (asus xonar).
Attachments
For the Khadas Tone Board - I wonder if you could use a Raspberry Pi or Arduino, instead of their VIM, for tickling various XMOS/ES9038 bits? I only skimmed over their info, but, at least superficially, it seems surprisingly well documented (at least compared to the standard cheap stuff). Putting it on my "want to buy" list!
"Both editions designed with the remaining IO include JTAG to the GPIO header, make it an ideal platform for XMOS developers."
JTAG has you covered for recovery from bricking
According to docs, RPI is also covered as well.
Someone sat back and thought this device through it appears.
JTAG has you covered for recovery from bricking
According to docs, RPI is also covered as well.
Someone sat back and thought this device through it appears.
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