Mobilux,
AVCC should not be powered from an LDO, IMHO. AVCC_L and AVCC_R should also be powered separately. Please take a careful look at the ESS document at: http://www.esstech.com/files/4514/4095/4306/Application_Note_Component_Selection_and_PCB_Layout.pdf
In addition, we usually use a low noise reference in front of the recommended AVCC opamp buffers.
On the other hand, ideally VCCA, DVCC, and the clock should each be powered from its own dedicated regulator mounted on the same ground plane as the dac chip and located close to the chip. LT1763 works fine IME.
In any case, AVCC is/are the most critical dac pins for good voltage regulation in terms of effects on sound quality, that and a better output stage quality probably are the two best mods. Beyond those things a number of other things can be done too, but doing everything that helps improve sound quality can be a lot of work.
Many of us have decided to move on to AKM dac chips instead of ESS. However, ESS sound can be better with DSD input. Many have used AK4137 for that and found improvement. Tweaking dac I2C registers can also pay off well in terms of improved sound quality.
AVCC should not be powered from an LDO, IMHO. AVCC_L and AVCC_R should also be powered separately. Please take a careful look at the ESS document at: http://www.esstech.com/files/4514/4095/4306/Application_Note_Component_Selection_and_PCB_Layout.pdf
In addition, we usually use a low noise reference in front of the recommended AVCC opamp buffers.
On the other hand, ideally VCCA, DVCC, and the clock should each be powered from its own dedicated regulator mounted on the same ground plane as the dac chip and located close to the chip. LT1763 works fine IME.
In any case, AVCC is/are the most critical dac pins for good voltage regulation in terms of effects on sound quality, that and a better output stage quality probably are the two best mods. Beyond those things a number of other things can be done too, but doing everything that helps improve sound quality can be a lot of work.
Many of us have decided to move on to AKM dac chips instead of ESS. However, ESS sound can be better with DSD input. Many have used AK4137 for that and found improvement. Tweaking dac I2C registers can also pay off well in terms of improved sound quality.
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The ESS document I linked to contains tabular information showing the effects of different opamps used for the circuits ESS recommended in terms resulting of harmonic distortion at the audio outputs.
That said, others have come along since (including me) and shown by various measurements that RF coming out of the dac chip analog outputs can affect downstream electronics.
A problem or issue to some people encountered in the process of trying to improve audio dac performance is that some audible effects are difficult to measure. Even for some things that are relatively easy to measure, there is disagreement by some people about what matters for human listeners and what can be safely ignored.
Like or or don't like it, the way some audio designers deal with such issues is by learning to listen critically and by designing for the most critical listener that they think may end up using or listening to the designer's work.
Resulting designs can sometimes be argued to be overkill, and sometimes argued to be still audibly less than perfect. It depends largely on who is doing the listening and or arguing.
That said, others have come along since (including me) and shown by various measurements that RF coming out of the dac chip analog outputs can affect downstream electronics.
A problem or issue to some people encountered in the process of trying to improve audio dac performance is that some audible effects are difficult to measure. Even for some things that are relatively easy to measure, there is disagreement by some people about what matters for human listeners and what can be safely ignored.
Like or or don't like it, the way some audio designers deal with such issues is by learning to listen critically and by designing for the most critical listener that they think may end up using or listening to the designer's work.
Resulting designs can sometimes be argued to be overkill, and sometimes argued to be still audibly less than perfect. It depends largely on who is doing the listening and or arguing.
As kind of an update on USB to I2S boards, another member was kind enough to privately tell me about configuring Amanero to work with AK4499. In addition, there is private contact information for communicating with Amanero, if ever needed. While I can't share private contact information, no reason I couldn't talk about configuring Amanero for use with AK4499 (including using external clocks and external clean power).
The above having been said, I'm still kind of disappointed that Amanero documentation is not fully self-consistent nor fully self explanatory, and there is apparently no easy way for most people to ask them to fix it nor to ask for help if problems.
None the less, Amanero does happen to operate on the same 22/24MHz clock frequencies as AK4499 does (768kHz PCM being a rare exception for AK4499). That makes simpler in some ways to use Amanero verses I2SoverUSB.
The above having been said, I'm still kind of disappointed that Amanero documentation is not fully self-consistent nor fully self explanatory, and there is apparently no easy way for most people to ask them to fix it nor to ask for help if problems.
None the less, Amanero does happen to operate on the same 22/24MHz clock frequencies as AK4499 does (768kHz PCM being a rare exception for AK4499). That makes simpler in some ways to use Amanero verses I2SoverUSB.
When I had a DAC with an Amanero input, the firmware could not handle native DSD on Linux. There were random times when noise would be added to the output and sometimes would continue even when the music stopped. After few years the firmware improved, but it seems it is still a mixed bag since some users still report issues. You can read all about it here: Amanero card now supporting DSD native * Issue #12 * lintweaker/xmos-native-dsd * GitHub
Wealas, Looks like there is line at Amanero firmware page that reads:
"native DSD512 Linux/Windows firmware_2006be11 Windows Driver Setupuac2 1.1.0.73 (11 Mar 2020)"
Amanero Technologies
Do you know if anyone has tested that Linux version? Any idea if it supports external clocks?
By the way, the ambiguity of that firmware page is one of my complaints about Amaneo. They may know what they are trying to say, but not everything there is self-evident to me at least.
"native DSD512 Linux/Windows firmware_2006be11 Windows Driver Setupuac2 1.1.0.73 (11 Mar 2020)"
Amanero Technologies
Do you know if anyone has tested that Linux version? Any idea if it supports external clocks?
By the way, the ambiguity of that firmware page is one of my complaints about Amaneo. They may know what they are trying to say, but not everything there is self-evident to me at least.
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I'm using firmware firmware2006be11, on Linux, DSD native (and DSD direct in the 4499), external master clock 22/24MHz, (so in 'slave' mode) constantly in dsd256 oversampling, (HQP). Recently tried up to dsd512.
Works without a hitch.
Did not try this latest, 2020 march firmware update.
Though firmware_2006be11 had been present since a while..
Works without a hitch.
Did not try this latest, 2020 march firmware update.
Though firmware_2006be11 had been present since a while..
Listening comparison of the finished product would reveal whether the effort was in vain or not. Where is the evidence of such listening result?
Thank you for letting us know about your good result. We like to read user reports and see pictures of mods here, likely the lurkers do too
May I ask what circuit you are using for the AVCC regulators, do you have schematic you might post?
Typically you could connect a power amp without needing a preamp, maybe 3v peak to peak or so by default, or more could be had by changing some resistors (although there may be some trade-offs in doing that). The dac chip has a pretty good internal volume control too.
Of course, the bad news is that the cheap dac board can make for a good modding project which can be quite extensive and time consuming. Although there are a few people who describe being happy with the default sound, most people in this thread report modding provides considerable improvement in sound quality.
For someone that doesn't want to do a lot of modding work, there are now more options for fairly decent low-ish cost commercial dac and or dac board kits, at least as compared to back when we started modding in this thread.
Please let us know if you have any more questions or if we can do anything to help with whatever you have in mind
Of course, the bad news is that the cheap dac board can make for a good modding project which can be quite extensive and time consuming. Although there are a few people who describe being happy with the default sound, most people in this thread report modding provides considerable improvement in sound quality.
For someone that doesn't want to do a lot of modding work, there are now more options for fairly decent low-ish cost commercial dac and or dac board kits, at least as compared to back when we started modding in this thread.
Please let us know if you have any more questions or if we can do anything to help with whatever you have in mind
They report their perception. Whether it actually made audible improvement or not hasn't been verified.
Typically you could connect a power amp without needing a preamp, maybe 3v peak to peak or so by default, or more could be had by changing some resistors (although there may be some trade-offs in doing that). The dac chip has a pretty good internal volume control too.
Of course, the bad news is that the cheap dac board can make for a good modding project which can be quite extensive and time consuming. Although there are a few people who describe being happy with the default sound, most people in this thread report modding provides considerable improvement in sound quality.
For someone that doesn't want to do a lot of modding work, there are now more options for fairly decent low-ish cost commercial dac and or dac board kits, at least as compared to back when we started modding in this thread.
Please let us know if you have any more questions or if we can do anything to help with whatever you have in mind
Which DAC board do you suggest for a really good project without spend a lot of money? I only need i2s input and toslink.
Thanks
Depends what you consider a lot of money and how much work you want to do in a project. JL Sounds makes some well designed stuff including an A4493 dac board, but it doesn't include SPDIF. Products - I2S over USB Audio
There are various other options too, depends on what might interest you. For SPDIF you might consider adding an AK4137 board with SPDIF input from Ebay or Aliexpress. Patching all the boards together, adding power supplies, maybe a case, could make up the scope of a project. Modding one of the dacs here can be a project too, up to you.
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That one wouldn't be acceptable to me. I think in this day and age is is reasonable to expect to be able to play DSD256 and maybe DSD512, if for no other reason than to explore how good it can sound with high quality conversion. IME, its the best way to accomplish CD playback. Sounds better than direct 16/44 PCM playback, sometimes far better. Depends a lot on the conversion algorithms used.
That being the case I would rather stick with newer and higher end dac chips (AKM and ESS seem to be the main choices). Unfortunately, as dac chips become more sophisticated it takes more sophisticated circuitry around them to get the full benefits. That's life in the world of dacs
Note: All the foregoing is IMHO only!
For modding the ES9038Q2M board of this thread, there is some info covering a output stage mod that can be downloaded from: Dropbox - Output Stage Instructions.zip - Simplify your life
There is also a schematic of a prospective AVCC power supply attached to post #3003 of this thread.
An output stage schematic with some alternate parts values, but the same multi-feedback differently summing topology was posted and is supposed to be of a Topping D30. I could post that schematic if you want.
There is an ESS document on their downloads page that discussed layout and other considerations I tried hard to comply with for my modded dac. The document also recommend the types of output stage and AVCC circuits we used here. It can be found at: http://www.esstech.com/files/4514/4095/4306/Application_Note_Component_Selection_and_PCB_Layout.pdf
In addition to those things, other possible mods to the dac board include a clock upgrade (typically to a Crystek 575 type 100MHz clock), and separate voltage regulators for DVCC, VCCA, and the clock (I used 3 each of LT1763 mounted on the back of the dac board - the ground plane side).
In addition to mods to the board itself, some people opt to add an AK4137 board for upsampling and or for hardware conversion to DSD. There are a number of such boards available on Ebay and or Aliexpress. Some have SPDIF inputs and some have I2S inputs only.
One thing we never did with AK4137 was to try a reclocker on its output. That would be implemented with a D-flip flop of the I2S signal before they come into the dac board, and it would be clocked by a divided version of the dac clock.
A divided version of the dac clock can also be used to clock AK4137 if desired, say, at 25MHz, although its not necessary it might help with sound quality. Recently, I found that the Chinese AK4137 boards can benefit from a dedicated low-noise LDO voltage regulator just for the AK4137 chip and the A/B I2S selector switch that feeds the AK4137 inputs (I mounted a low noise LDO on the back ground plane side of an AK4137 board and used it to power the sensitive chips - recommended mod).
Just remembered one last mod of the dac board itself, and that is to take over the I2C bus between the MCU and the dac chip. An Arduino or other MCU can be used to take control of the dac chip and reprogram it for improved sound quality (mostly by reducing DPLL bandwidth). Although ESS data sheets normally require an NDA, ESS seems to have quietly allowed the Khadas Tone Board folks to post one in their support documents. You might try Google or take a look around the Khadas downloads area.
By the time you are done, you can potentially have a very nice ES9038Q2M dac, but as you can see from the above a lot of work could be involved to get there (most people seem to mod until they have had enough of it or are satisfied with the sound quality they have and stop there).
One other last comment, recently Allo talked about a new ES9038Q2M dac board they are coming out with. It doesn't support SPDIF, but the interesting thing is they found was that sound quality could be improved by additional filtering in the output stage between the I/V outputs and the differential summing op amp inputs. Might be an interesting thing to take a look at if someone wanted to contribute more to the accumulated thread knowledge.
There is also a schematic of a prospective AVCC power supply attached to post #3003 of this thread.
An output stage schematic with some alternate parts values, but the same multi-feedback differently summing topology was posted and is supposed to be of a Topping D30. I could post that schematic if you want.
There is an ESS document on their downloads page that discussed layout and other considerations I tried hard to comply with for my modded dac. The document also recommend the types of output stage and AVCC circuits we used here. It can be found at: http://www.esstech.com/files/4514/4095/4306/Application_Note_Component_Selection_and_PCB_Layout.pdf
In addition to those things, other possible mods to the dac board include a clock upgrade (typically to a Crystek 575 type 100MHz clock), and separate voltage regulators for DVCC, VCCA, and the clock (I used 3 each of LT1763 mounted on the back of the dac board - the ground plane side).
In addition to mods to the board itself, some people opt to add an AK4137 board for upsampling and or for hardware conversion to DSD. There are a number of such boards available on Ebay and or Aliexpress. Some have SPDIF inputs and some have I2S inputs only.
One thing we never did with AK4137 was to try a reclocker on its output. That would be implemented with a D-flip flop of the I2S signal before they come into the dac board, and it would be clocked by a divided version of the dac clock.
A divided version of the dac clock can also be used to clock AK4137 if desired, say, at 25MHz, although its not necessary it might help with sound quality. Recently, I found that the Chinese AK4137 boards can benefit from a dedicated low-noise LDO voltage regulator just for the AK4137 chip and the A/B I2S selector switch that feeds the AK4137 inputs (I mounted a low noise LDO on the back ground plane side of an AK4137 board and used it to power the sensitive chips - recommended mod).
Just remembered one last mod of the dac board itself, and that is to take over the I2C bus between the MCU and the dac chip. An Arduino or other MCU can be used to take control of the dac chip and reprogram it for improved sound quality (mostly by reducing DPLL bandwidth). Although ESS data sheets normally require an NDA, ESS seems to have quietly allowed the Khadas Tone Board folks to post one in their support documents. You might try Google or take a look around the Khadas downloads area.
By the time you are done, you can potentially have a very nice ES9038Q2M dac, but as you can see from the above a lot of work could be involved to get there (most people seem to mod until they have had enough of it or are satisfied with the sound quality they have and stop there).
One other last comment, recently Allo talked about a new ES9038Q2M dac board they are coming out with. It doesn't support SPDIF, but the interesting thing is they found was that sound quality could be improved by additional filtering in the output stage between the I/V outputs and the differential summing op amp inputs. Might be an interesting thing to take a look at if someone wanted to contribute more to the accumulated thread knowledge.
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