ES9038Q2M Board

This is a link to a board which is an example of what I thought of:

That one would probably do. It depends on what the back of the board looks like, which they don't show. Probably okay though.

Probably both can be done on separate boards avoiding too much delicate surgery on the basic board.

Actually, that's not a good idea. The AVCC supply and output stage should be on the same ground plane as the dac chip. The output stage mod project I linked to yesterday describes how to extend the dac board ground plane. The AVCC mod can go more or less underneath the dac chip, on the ground plane side. The easy fix used by Victor just puts a lot of electrolytic caps in parallel with the existing AVCC filter caps where they extend through mounting holes to the back side of the board (aka: the solder side, back side, and ground plane side in this case). A more complicated opamp AVCC supply is detailed in some forum posts I could probably find and link to.


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.

The board we found the be the best quality looks like it has changed a bit, and is also no longer as easily found. This is appears to be the latest version: ES9038Q2M DSD DAC Decoder Board +TFT Screen+Remote Control+Coder Switch+Cables | eBay

The one you found looks okay from what I can see of it. Probably fine.
 
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The above setup worked for about 3 months...Any suggestion on how I can safely reset the board and DAC to factory default?

Don't see any way to reset the hardware in the picture. If you already checked all the wiring and power cycled everything, is there anything else you did or did't do? Does it get HDMI from a TV or from a PC? Could anything have changed at the source? Otherwise, if you want to troubleshoot signal flow in the hardware you would need a suitable oscilloscope.
 
Thanks Mark for good advice!

Ground plane: No doubt about significance of a very good ground plane. I noticed the other guys doing this and will try myself to be as good.

Choice of board: The one board per your link is fine with me and I would take this unless there is another one with better documentation or history of good results on this Forum.

Would you have names of DIYers on this subject having reasonable documents about this board such as circuit diagrams, block diagrams, pinout of headers, terminals and solder joints?

There are guys named MrSlim, PJN, Kaytata and others using a board they name V1.07 which looks close to the one you recommended, on which there are a few recommendations about PS's and output boards. Can I use the same circuits for "your" board as well?

I need to do lots more of searching, reading and harvesting ideas of others on this thread.
 
Thanks Mark for good advice!

Happy to be of assistance!

Can I use the same circuits for "your" board as well?

Absolutely, that's why they are shared in the thread. We try to help each other.

I need to do lots more of searching, reading and harvesting ideas of others on this thread.

I have posted a list of what I consider to possibly some of the more interesting posts in this thread. Posts near the beginning may tend to offer ideas that evolved further over the course of the thread, so later posts should probably be more heavily weighted. I will attach a version of the list below.
 

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Here is my take on the cheap Chinese boards. If you want to dabble replacing components to get the diy experience and get a better sounding dac, have at it. Just keep your budget in mind. You can easily spent hundreds of dollars to end up with a cobbled together ok dac. You could also build a dac with decent modular components and a good psu for a little .more that can sound much better. There are also a lot of complete well regarded and tested dacs in the $250 and below price range. This gets you a nice case, good functionality, ok psu and decent performance for what you could easily spend on something cobbled together on a piece of plywood. That said diy is fun.
 
PJN, Thanks for the words of wisdom. I agree with you.

IME there is no free lunch, and no good* and cheap dac. Others disagree and think all modern dacs have no audible defects.

Most people seem satisfied with a dac somewhere between the extremes of opinion. Folks in this thread seem to enjoy making improvements themselves, that is, until they get tired of modding dacs and stop. The dac is declared done, and interest moves elsewhere.

I will say this: if stuck at home its better to find something interesting to work on than just sit around. Humans need a sense of meaning and purpose. Often one's job is an important part of that. Hobbies can help in a fun way too.


* 'good' to me means a very high level of sound quality; exceptional.
 
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Others disagree and think all modern dacs have no audible defects.
If you think contemporary DACs sound different, just present the evidence. You haven't so far. All you've presented are claims and opinion.

I think those people have never experienced a really bad DAC. :D

Mark your posts never fail to interest me. Thanks for your contributions!
Has he ever shown you a proof that DAC mods or high price DACs sound audibly superior to un-mod or cheap DACs?
 
The following is what fellow forum member Jakob2 said about guys like our troll (and I think he probably nailed it):
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IME this kind of obsession is often to find in people who converted themselves from "golden-ear" to "non-golden-ear" , usually by doing some kind of "blind tests" without knowledge about propper sensory testing.

So they decide having erred all the time when perceiving differences between electronic audio devices (including cables and other stuff) under the premise that the measured numbers are below the known hearing thresholds.

The next step in the reasoning seems to be that they did not just have fooled themselves (when believing these differences exist) but were misled by a world wide conspiracy of manufacturers, reviewers and sales men. This way it is obviously easier to accept the former illusion. "It wasn't my fault, I was tricked into it...."

In this state of belief it is (IMO) apparently extremely difficult to accept informations that provide evidence contrary to the new belief, as it would mean to accept that he might have triple-fooled himself during the conversion process.
 
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Thank you Mark for nailing. I was on my way to pm the poster of 5551 in order to not pollute here but his pm service was not activated. Another sign - sigh - of one way communication about nothingness.
Let us hope this thread may focus again on those who are on topic, by sharing their diy and listening adventures. I am about to take a next step, a separate AVCC opamp supply.
 
...I am about to take a next step, a separate AVCC opamp supply.

Should be interesting. Some of my thoughts about opamp AVCC have evolved since my last ES9038Q2M modding project. In particular, I find AKM's approach with AK4499 to be very interesting. I did a quick try with an opamp supply for it much like the opamp supplies we used for ESS dacs.

In general what I found subjectively is opamp supplies for dac switched resistor networks need low impedance power supplies for the opamp in order to get best bass response.

Also, I didn't measure as I probably should have (not enough time to play around when I briefly tried it for AK4499), but it sounds like there may be some frequency peaking in the opamp AVCC supply depending on choice of output cap. My thinking at this point is that it should probably be the smallest standard electrolytic that guarantees stability (which is 10uf for most of the opamps we use). The big electrolytic caps should be reserved for the opamp power pin bypass or local energy storage near the opamps.

Also, probably best to ground the negative power pin of the AVCC opamps since that is essentially the reference pin for opamps without dedicated ground pins. Otherwise, the reference for the opamps is only as good as the negative power supply rail. Seemed to sound better grounded, is the short conclusion. (Of course, that runs the opamp sorta close to negative saturation of the output. However, 3.3v should far enough away to keep it linear. Most opamps can come within a couple of volts of the rails, and some can go closer. Don't recall offhand how close AD797 can go.)

Best opamp for AVCC is probably AD797, however they are not compatible with the power rails we usually found sounded best when using OPA1612 or LME49720 output stage opamps. The latter sounded best with a mix of electrolytics and film caps on the power rails (for ES9038Q2M only, not for, say, my brief experiment with AK4499). AD797 on the other hand can go unstable with film caps on its power rails or if on shared power rails with the output stage opamps (if they are using films).

As a result, probably better to use only one kind of opamp, or have two sets of rails for opamps, one that allows film caps and one that doesn't.
 
The following is what fellow forum member Jakob2 said about guys like our troll (and I think he probably nailed it):
-----------------------------------------------------------------------------------------------------------------------------------------------

IME this kind of obsession is often to find in people who converted themselves from "golden-ear" to "non-golden-ear" , usually by doing some kind of "blind tests" without knowledge about propper sensory testing.

So they decide having erred all the time when perceiving differences between electronic audio devices (including cables and other stuff) under the premise that the measured numbers are below the known hearing thresholds.

The next step in the reasoning seems to be that they did not just have fooled themselves (when believing these differences exist) but were misled by a world wide conspiracy of manufacturers, reviewers and sales men. This way it is obviously easier to accept the former illusion. "It wasn't my fault, I was tricked into it...."

In this state of belief it is (IMO) apparently extremely difficult to accept informations that provide evidence contrary to the new belief, as it would mean to accept that he might have triple-fooled himself during the conversion process.

Quoting Jakob is the blind leading the blind!