Hi guys, thanks for your comments.
MBA: Volume control: I have no use for it myself, but I'm working on MCU replacement with the original LCD panel, maybe I can present it as Christmas gift... But remember: my MCU needs INT0 pin. Remote control should not be very difficult, but as far as I know now, I've not enough pins on the Nano for RC. But it can be solved by adding an I2C interface to the LCD display, this reduces pins required for display from 6 to 2, thus freeing 4 pins.
terranigma: congratulations! Give the DAC some time to burn in, the sound will open up more, you'll like it
Your solution for TVDD is even more elegant. If you want to upgrade receiver section further, you could separate AVDD of the AK4113 and supply it with a low-noise (super)regulator. This will improve performance of the VCO / PLL. See my post in this thread. Recommended.
kukynas: Thanks for the pic! So version 2 is even easier to mod than my version. I would advice a 47u cap for decoupling, because +5V track has quite some distance from its regulator.
MBA: Volume control: I have no use for it myself, but I'm working on MCU replacement with the original LCD panel, maybe I can present it as Christmas gift... But remember: my MCU needs INT0 pin. Remote control should not be very difficult, but as far as I know now, I've not enough pins on the Nano for RC. But it can be solved by adding an I2C interface to the LCD display, this reduces pins required for display from 6 to 2, thus freeing 4 pins.
terranigma: congratulations! Give the DAC some time to burn in, the sound will open up more, you'll like it
Your solution for TVDD is even more elegant. If you want to upgrade receiver section further, you could separate AVDD of the AK4113 and supply it with a low-noise (super)regulator. This will improve performance of the VCO / PLL. See my post in this thread. Recommended.kukynas: Thanks for the pic! So version 2 is even easier to mod than my version. I would advice a 47u cap for decoupling, because +5V track has quite some distance from its regulator.
Yes, but it can be done. The Amanero outputs 32bit I2S, the AK4399 chips need to be setup to another PCM mode for this. With my MCU, you should be able to experiment with I2S input.
Thanks for input. The dac is running couple days but yet sound is quite satisfying in terms of detail and dynamics in whole range. Powerful bass but silky mids and delicate highs. I appreciate your contribution on this thread. I also expect some good things about your new MCU implementation. I ordered Arduino nano and LCD with i2c circuit. Hope your thoughts on IR and volume control will change in time
No problem otherwise. It would be fun to do such things with your own.ps: I also noticed that dacs were in mute mode when feeding via external i2s. When coax cable plugged, dacs became active but crippling sound.
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Thank you very much guys, that's a very good and easy-to-do mod!
But i noticed a slight too high increase in high frequencies, that can lead to a subtle amount of hiss in certain songs. Maybe lower decoupling capacity could produce a more equilibrate sound? Or should i use a better quality cap (i used a Panasonic FR cap)?
Another question: i am planning to replace the bad XMOS interface using a better XMOS board or a Raspberry Fi directly connected via I2S to the resistors that lead to the 2 DAC chips (using a small multiplexer board to avoid loosing SPDIF and Toslink inputs, all placed inside the chassis to shorten I2S cables).
But are you saying that connecting an USB-to-I2S board directly to the AK4399 chips would lead to a bad sound? What should i do then to avoid this problem?
But i noticed a slight too high increase in high frequencies, that can lead to a subtle amount of hiss in certain songs. Maybe lower decoupling capacity could produce a more equilibrate sound? Or should i use a better quality cap (i used a Panasonic FR cap)?
Another question: i am planning to replace the bad XMOS interface using a better XMOS board or a Raspberry Fi directly connected via I2S to the resistors that lead to the 2 DAC chips (using a small multiplexer board to avoid loosing SPDIF and Toslink inputs, all placed inside the chassis to shorten I2S cables).
But are you saying that connecting an USB-to-I2S board directly to the AK4399 chips would lead to a bad sound? What should i do then to avoid this problem?
No, the bad sound was result of the incompatible format between external i2s adapter and dac chips. For example my amanero configured as 32bit i2s but AK chips were set for 24bit i2s due to onboard spdif receiver compatibility. So, I have to match formats in order to use external adapter. If your i2s adapter is already in 24bit format, it is possibly to use it without any format change.
Lately I figured out that I could switch 24bit i2s mode at Amanero by re-flashing but I soldered those resistors permanently after first unsuccessful attempt. I have to disconnect the resistors at receiver side before new attempt.
See post #525
I was thinking about connecting the output of a multiplexer/I2S switch (think to a TPA OTTO II, for example) to resistors' rheophores, one input to the PCB resistors' holes and one input to the new XMOS board/Raspberry Pi: that would allow theuse of 4113 SPDIF/Toslink outputs too.
But would the signal from that I2S board produce any good sound that way?
Doesn't I2S signal bits depth depend on played file bits depth? Is there a way to convert 32-bit I2S into 24-bit I2S inside the DAC chassis?
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What i want to say, is: what inside this DAC changes AK4399 processed I2S signal format according to I2S input format?
I was thinking this adaptation was automatically performed by the AK4399 chips themselves...
So in software control mode a controller-imposed adaptation is needed, or AK4399 can't adapt to changing I2S signal format?
I was thinking this adaptation was automatically performed by the AK4399 chips themselves...
So in software control mode a controller-imposed adaptation is needed, or AK4399 can't adapt to changing I2S signal format?
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I also found that after the TVDD voltage mod the sound from Weiliang XMOS USB board's input had a large drop in SQ - and in volume too. But SPDIF input had an equally large SQ increase!
Maybe the 3.3V "error" was a trick to improve bad XMOS SQ (i really don't know how that could be achieved)?
Or i missed some particular recommendation when doing the mod?
Maybe the 3.3V "error" was a trick to improve bad XMOS SQ (i really don't know how that could be achieved)?
Or i missed some particular recommendation when doing the mod?
I find that very unlikely. Did you use a capacitor to decouple the TVDD pin? Try to solve the problem by checking decoupling of the XMOS board. I can imagine the TVDD is an extra load to the +5V track.
Regarding I2s: The DAC doesn't switch to the right mode automatically. The AK4113 is only capable of 24 bit I2s mode, the AK4399 can receive 32 bit I2s too. Both need to be setup for 24bit I2s.
I'm using a different data format between AK4113 and AK4399 in my MCU currently, I shall test it with 24bit I2s soon. I don't know what format the original controller is using, if it's using 24bit I2s mode between receiver and DAC, you should be able to feed it 24bit I2s directly.
Thanks NinoSimona. I get the idea now. Just need to translate this to my 4118 board. Still need to measure the TVDD voltage when I get a moment
It's interesting that Weiliang hasn't sought to exploit the potential of these advanced 4399 chips.
You have to set required PCM mode via software. Default is 24bit MSB. Look at the AK4399 datasheet, PCM Mode section (page 19).
I think you're right. Easily the problem is the extra load on the 5V line.
Thank you. That means i couldn't feed 16bit or 32bit I2S?
We should change controller software then and interface it to the new USB to I2S board... seems not an easy task...
I'm going to use a Paul Hynes reg that I have. I'll tie it to a 5V supply line and test it. It is a really good regulator, should be good to go!
Thanks
Do
AK4399 only accepts 24 and 32 bit I2s. 24 bit I2s works fine on my Arduino MCU atm.
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