I understood timH has added a voltage divider in the op amp feedback loop when using 2.5V reference in order to get 3.3V regulated.
If you do the level matching, you have to make sure they are matched within 0.1db otherwise it's a waste of time. Besides, there is aural memory fade that needs to be compensated for which is only good for a few seconds. If you don't want to deal with all these, just measure the output signal before and after.Hi. I was using the standard ltc6655 at 3.3v. At the moment the LN version is only available at 2.5v hence the resistors. Opamps are OPA1612. I’ll have a go at 2.5v and see how it sounds. I tend to have two volumes I use - wife around and wife not around (wife is younger than me and has better hearing) Currently my wife is shirking from home so max volume limited. I could go quiet and very quiet I suppose
I understood it to be the plan. I only suggest careful listening before and after, if possible.
Hello All,
I am putting together a streamer using this DAC. Looking at the data sheet it states 4 separate requirements for power, 3 on the block diagram. looking at the board it has 7 points that feed off the main 3.3v from the VR. what i am wanting to know from this 9038Q experienced forum is how many would benefit from a feed from their own isolated supply?
board 3.3v supply:
1. clock management chip
2. separate clock on board
3. DVCC (core)
4. AVCC_L (DAC PS)
5. VCCA (pin 12)
6. VCCA (pin27)
7. AVCC_R (DAC PS)
Can clock management and clock be on separate supplies, providing they share the same GND?
Is VCCA internally connected across pins 12 + 27 (measures 4.5 Ohm on board)
AVCC_L + AVCC_R must be the same supply?
Thanks
I am putting together a streamer using this DAC. Looking at the data sheet it states 4 separate requirements for power, 3 on the block diagram. looking at the board it has 7 points that feed off the main 3.3v from the VR. what i am wanting to know from this 9038Q experienced forum is how many would benefit from a feed from their own isolated supply?
board 3.3v supply:
1. clock management chip
2. separate clock on board
3. DVCC (core)
4. AVCC_L (DAC PS)
5. VCCA (pin 12)
6. VCCA (pin27)
7. AVCC_R (DAC PS)
Can clock management and clock be on separate supplies, providing they share the same GND?
Is VCCA internally connected across pins 12 + 27 (measures 4.5 Ohm on board)
AVCC_L + AVCC_R must be the same supply?
Thanks
Hi,
I'll try to get to your list of questions in a bit. In the meantime, it is highly recommended to take a detailed look at the following ESS document on their downloads page: http://www.esstech.com/files/4514/4095/4306/Application_Note_Component_Selection_and_PCB_Layout.pdf
Also, an output stage project package can be found at: Dropbox - Output Stage Instructions.zip - Simplify your life
Mark.
Okay, back again. You are right that power supplies matter a lot, but they are not the only things that matter a lot. Clock upgrade, MCU replacement, output stage upgrade, AK4137 upsampling/DSD conversion, etc. Almost everything audibly benefits from improvements. Doing it all involves a an extended journey, but can result in a very good dac. May not end up being the cheapest and easiest way to a good dac if one only wants to do a bit of work and is expecting big improvements from that.
Back to the the 'clock management chip,' there isn't one. The chip you may be thinking of is probably the MCU that controls the dac chip registers. It should be on its own (cheap) voltage regulator to keep digital noise from getting into the sensitive dac circuitry. Eventually, the MCU should be replaced with an Arduino or possibly your RPi, which can result in much better sound quality from the dac due to the ability it gives to optimize dac register settings.
For best results the clock should be on its own low noise LDO mounted on the backside ground plane of the dac board. First though, the existing clock is junk. Most people notice an eventual improvement in sound quality from replacing it with a Crystek 575. However, some people find it hard to notice a lot of change from that mod until enough of the other problems with the dac board have been fixed, then the clock upgrade sound quality improvement becomes clear. That's my take on it, maybe others will chime in with their own experiences. Because of the tight work involved, its one the mods I like to get out of the way early on.
A low noise LDO like for the clock, on the back of the board. I used LT1763 for those things. VCCA gets one too. Both VCCA pins should be connected directly to the VCCA voltage regulator.
Each AVCC pin (L, R) requires its own very special voltage regulator. There is some discussion about using an opamp regulator for that in the ESS document I linked to in my last post (including AVCC supply layout in relation to the dac chip). People often get lazy and are sure a low noise LDO will work great for AVCC...well, it doesn't work that way. Everyone prefers the sound of the ESS recommeded opamp circuit once they hear it. You see, AVCC is input to the switched resistor network that connects to the analog outputs of the dac chip. The resistor network has ZERO PSRR meaning whatever the voltage regulator used sounds like, you will hear it in the analog outputs. Most if not all low noise RF LDOs have poor linearity, despite their super low noise and wide bandwidth. They just don't sound good for AVCC. (Similar thing with the Reference voltage for AKM's AK4499 switched resistor dac chip.)
Another thing about the MCU: the dac chip is programmed over I2C bus. There are posts describing how to take over control of the bus and configure the dac registers using an Arduino. One of the most important register changes is the DPLL Bandwidth setting. It should be set to the lowest stable value possible, and what will be possible depends on incoming jitter on the I2S bus pins. Somewhere in the thread there is a driver link and instructions for setting DPLL Bandwidth via RPi. Maybe we can help you find that if any interest.
The last bit of info I will offer is that the dac chip sounds its best with high sample rate DSD. The upsampling and conversion of PCM to DSD can be done in a PC or in hardware. Many people have found some sound quality improvement using low-cost Chinese AK4137 ASRC/DSD conversion boards. The cheapest one I know of is for RPi. We could talk about modding those boards a bit too. The AK4137 can benefit from cleaner power just like the dac chip can, as it turns out
You are quite welcome, of course!
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Thanks Mark,
Lots of valuable information, thanks for going to the time and effort to put this together, much appreciated.
I have had a good look at the ESS document, I will implement as much of this as I can.
For the output stage project, this will need to be in the next ESS project/addition. (Rightly or wrongly, mainly wrongly, I know) I am committed to valves on the output stage on this one. Next one will be back to opamps for further exploration.
before the DAC I have an RPI running max2play, standard XMOX USB to I2S.
The clock upgrade was planned the clock you mentioned I wasn't aware of.
MCU on my board is a STM8S003F3 first data sheet I found said clock management at the top! I will look into replacing this, ideally with the already present RPI. Also finally explains what the additional Arduinos I kept seeing in DACs are doing.
The DAC board I have has a single LT1963 for everything. My plan was to cut the traces, use the LT1963 for one supply (or none) and have a load of TL431 for everything else.
New plan:
Cut all exiting 3.3v traces
Isolate LT1963 or use for MCU, until replaced with RPI
X1 LDO 3.3 on back of board ground plane for clock
X1 LDO 3.3 for DVCC
X1 LDO 3.3 for both VCCA pins
ESS recommended 3.3 opamp circuit for each AVCC_ (L, R)
Xmos USB I2S board to get LDO treatment Rpi standard supply
Thanks again,
Lots of valuable information, thanks for going to the time and effort to put this together, much appreciated.
I have had a good look at the ESS document, I will implement as much of this as I can.
For the output stage project, this will need to be in the next ESS project/addition. (Rightly or wrongly, mainly wrongly, I know) I am committed to valves on the output stage on this one. Next one will be back to opamps for further exploration.
before the DAC I have an RPI running max2play, standard XMOX USB to I2S.
The clock upgrade was planned the clock you mentioned I wasn't aware of.
MCU on my board is a STM8S003F3 first data sheet I found said clock management at the top! I will look into replacing this, ideally with the already present RPI. Also finally explains what the additional Arduinos I kept seeing in DACs are doing.
The DAC board I have has a single LT1963 for everything. My plan was to cut the traces, use the LT1963 for one supply (or none) and have a load of TL431 for everything else.
New plan:
Cut all exiting 3.3v traces
Isolate LT1963 or use for MCU, until replaced with RPI
X1 LDO 3.3 on back of board ground plane for clock
X1 LDO 3.3 for DVCC
X1 LDO 3.3 for both VCCA pins
ESS recommended 3.3 opamp circuit for each AVCC_ (L, R)
Xmos USB I2S board to get LDO treatment Rpi standard supply
Thanks again,
One more thought regarding the above, if setting dac I2C registers from RPI, probably best to use an isolator chip to prevent ground loops and or ground coupled noise from RPi. Searching for I2C isolator I.C. should turn up some good candidates, or maybe we could recommend something here. You would need to supply 3.3v on the dac side for the isolator chip, RPi would power the other side.
Also, good to get familiar with programming the dac before permanently losing the MCU. Unlike other ESS dac chips, ES9038Q2M is by default in a non-operational state. Some register configuration is necessary to get it to play at all.
Because ESS info is under NDA, we can't get specific about register programming here in the forum. PM you want discuss various alternatives. A $10 ebay logic analyzer works fine at I2C frequencies.
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Hi all!
this is my first post on the DAC-subject and wonder, if you can give me some guidance. I need to buy/build a usable DAC for pimping up the sound of a digital radio above junk level. As I thought about the ES9038 I noticed the following board:
ES9038 Q2M DAC DSD Decoder Support IIS DSD 384KHz Coaxial Fiber DOP | eBay
… and have a few Questions:
* while the price seems miraculous I wonder if such chinese sources are even worth considering. Is this a safe source?
* Is there some documentation coming with the board? Circuit diagram? Board layout? How to wire/connect?
* What are the 2 or 3 most worthwhile changes of the componentry to boost the Sound?
* Capacitors? Power supply? Op amps? Others?
* Or should I rather simply buy this one:
Hifime S2 USB and SPDIF DAC (Sabre ES9038q2m) – Hifime Audio
Thanks for any good advice
this is my first post on the DAC-subject and wonder, if you can give me some guidance. I need to buy/build a usable DAC for pimping up the sound of a digital radio above junk level. As I thought about the ES9038 I noticed the following board:
ES9038 Q2M DAC DSD Decoder Support IIS DSD 384KHz Coaxial Fiber DOP | eBay
… and have a few Questions:
* while the price seems miraculous I wonder if such chinese sources are even worth considering. Is this a safe source?
* Is there some documentation coming with the board? Circuit diagram? Board layout? How to wire/connect?
* What are the 2 or 3 most worthwhile changes of the componentry to boost the Sound?
* Capacitors? Power supply? Op amps? Others?
* Or should I rather simply buy this one:
Hifime S2 USB and SPDIF DAC (Sabre ES9038q2m) – Hifime Audio
Thanks for any good advice
Not sure what you mean by 'safe source.' People generally seem to receive what they order, if that's the concern.
You didn't provide a link to the board you mentioned, so not sure which version it is. Please post a webpage link so we can take a look at it.
Cheap Chinese dacs are usually designed to keep manufacturing costs to a minimum. The reason we use the particular dac board we do in this thread is because the layout lends itself well to modifications.
The two biggest things that can be done to improve sound quality are probably (1) improve the AVCC power supplies, and (2) to add a proper 3-opamp output stage. There are cheap ways to do that and higher quality ways.
See above.
That one is cheap junk, IMHO it will never sound very good (at least to my listening preferences). Depends what sound quality you find good enough though. People seem to have different opinions on that.
On the other hand, modding one of the boards as we do in this thread is at least doable and a lot of potential is there, however it can be a long and involved undertaking. How long and involved depends how much work one is willing to do and what kind of sound quality one is seeking. The first two mods I mentioned above probably make the most difference, but they are the most complicated too (at least in a hardware sense).
A somewhat somewhat simpler approach that measures pretty well, but reportedly doesn't sound as good as the full blown AVCC and output stage mods I recommend was posted by another member, Victor. I could post his AVCC mod and output stage design if that would be of interest. Still need to know which board you are looking at first.
You're welcome, for whatever it is we may have to offer in this thread. Don't know if it will be helpful to you or not.
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Just recalled another thing that may be of interest to you. The component values in the output stage mod I linked to previously may not be optimal. They were starting values we decided to use. Since that time, someone provided an output stage schematic for Topping D30 which is essentially the same standard 3-opamp topology good for ESS dacs but with possibly more optimized ES9038Q2M component values. I have that schematic around here somewhere if you would like me to look for it. Ultimately, fully optimum component values will probably depend on layout and possibly other undefined factors. Possibly most optimal to tweak them after building a physical layout while looking at ESS 'Hump' distortion. Maybe
Thanks for Response Markw4!
Answering your Questions as follows:
Not sure what you mean by 'safe source.'
Yes, that's about my concerne.
You didn't provide a link to the board you mentioned, so not sure which version it is. Please post a webpage link so we can take a look at it.
This is a link to a board which is an example of what I thought of:
https://www.ebay.de/i/383079481434?...MIxLvsvbif6QIVxY4YCh3megaeEAQYBCABEgLcjvD_BwE
I am NOT sticking to any specific one and sure will listen to your recommendations as long as it is in line with my goals (which are flexible as well).
The two biggest things that can be done to improve sound quality are probably (1) improve the AVCC power supplies, and (2) to add a proper 3-opamp output stage. There are cheap ways to do that and higher quality ways.
Sounds like a doable task for a beginner on this specific subject. Probably both can be done on separate boards avoiding too much delicate surgery on the basic board.
Hifime S2 USB and SPDIF DAC (Sabre ES9038q2m) – Hifime Audio
That one is cheap junk, IMHO it will never sound very good (at least to my listening preferences). Depends what sound quality you find good enough though. People seem to have different opinions on that.
Helpful comment! There were positive comments about the S2 USB sound in test reports which surprises at a price around $90,-.
On the other hand, modding one of the boards as we do in this thread is at least doable and a lot of potential is there, however it can be a long and involved undertaking. How long and involved depends how much work one is willing to do and what kind of sound quality one is seeking. The first two mods I mentioned above probably make the most difference, but they are the most complicated too (at least in a hardware sense).
A somewhat somewhat simpler approach that measures pretty well, but reportedly doesn't sound as good as the full blown AVCC and output stage mods I recommend was posted by another member, Victor. I could post his AVCC mod and output stage design if that would be of interest. Still need to know which board you are looking at first.
I was going through 50 pages of this thread but am still not sure about the board you would recommend. I looked at some photographs of other people on this thread which look quite similar to the one in structure and complexity to the one I was considering.
Am open for everything not blowing my budget before even starting with the modding. Only feature which is a must is an optical Input.
Answering your Questions as follows:
Not sure what you mean by 'safe source.'
Yes, that's about my concerne.
You didn't provide a link to the board you mentioned, so not sure which version it is. Please post a webpage link so we can take a look at it.
This is a link to a board which is an example of what I thought of:
https://www.ebay.de/i/383079481434?...MIxLvsvbif6QIVxY4YCh3megaeEAQYBCABEgLcjvD_BwE
I am NOT sticking to any specific one and sure will listen to your recommendations as long as it is in line with my goals (which are flexible as well).
The two biggest things that can be done to improve sound quality are probably (1) improve the AVCC power supplies, and (2) to add a proper 3-opamp output stage. There are cheap ways to do that and higher quality ways.
Sounds like a doable task for a beginner on this specific subject. Probably both can be done on separate boards avoiding too much delicate surgery on the basic board.
Hifime S2 USB and SPDIF DAC (Sabre ES9038q2m) – Hifime Audio
That one is cheap junk, IMHO it will never sound very good (at least to my listening preferences). Depends what sound quality you find good enough though. People seem to have different opinions on that.
Helpful comment! There were positive comments about the S2 USB sound in test reports which surprises at a price around $90,-.
On the other hand, modding one of the boards as we do in this thread is at least doable and a lot of potential is there, however it can be a long and involved undertaking. How long and involved depends how much work one is willing to do and what kind of sound quality one is seeking. The first two mods I mentioned above probably make the most difference, but they are the most complicated too (at least in a hardware sense).
A somewhat somewhat simpler approach that measures pretty well, but reportedly doesn't sound as good as the full blown AVCC and output stage mods I recommend was posted by another member, Victor. I could post his AVCC mod and output stage design if that would be of interest. Still need to know which board you are looking at first.
I was going through 50 pages of this thread but am still not sure about the board you would recommend. I looked at some photographs of other people on this thread which look quite similar to the one in structure and complexity to the one I was considering.
Am open for everything not blowing my budget before even starting with the modding. Only feature which is a must is an optical Input.
In the past year, I added an Amazon Firestick 4K for internet/streaming input. My Sony UBP-X800 can play SACD. I have 2 DSD source and a DSD capable DAC, but no link between the HDMI only source and the DAC. My search led me to a HDMI/MHL Dual-Mode Audio Extraction I2S/DSD board on e/bay.
The board can use external 5V source or the HDMI power. I soldered a 5-pin header to the DAC board and connect the 2 board with 5 Arduino jumper cables. It is done. No programming, no jumper change.
I got a 3-in, 1-out HDMI switch for the Blu-Ray Sony, Firestick and Cable TV box. The DAC uses HDMI input and on DSD mode all the time. I love the DAC before and love the DSD mode even so much more. A cheap solution to good sound.
The above setup worked for about 3 months. The DAC has no input or output in the DSD mode suddenly. I am not sure whether the problem is in the audio extraction board or the DAC. The optical and co-axial link from audio extraction board to the DAC function normally. I am scratching my head. Any suggestion on how I can safely reset the board and DAC to factory default?
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