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ES9038Q2M Board
ES9038Q2M Board
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Old 11th July 2018, 08:59 PM   #1861
eziitis is offline eziitis
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Dear Ian, the matter is a little more complicated in fact. So, could you please pay a little respect to the people reading this thread and familiarize yourself with these DACs?
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Old 11th July 2018, 09:04 PM   #1862
Ian Greenhalgh is offline Ian Greenhalgh  United Kingdom
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I haven't failed to show respect and I'm doing my best to learn. Try to remember a time when you were not so well informed on the subject and how you had to learn.

I was being told 'do it this way' and all I was doing was resisting making the decision to go that way until I had learned why that was the best way, if you find this disrespectful then we will simply have to agree to disagree.

My approach is to be thorough in exploring different options before finalising a design decision, which is how I was taught to approach a problem, if this upsets some people then they should be less easily upset, quite frankly.

Last edited by Ian Greenhalgh; 11th July 2018 at 09:17 PM.
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Old 11th July 2018, 09:39 PM   #1863
Markw4 is online now Markw4  United States
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Quote:
Originally Posted by eziitis View Post
Dear Ian...
No point wasting effort. Maybe best just to add to the ignore list. There seems to be more going on here than than we fully understand, so probably best to be patient and not give it much attention in the meantime.

Also, no reason to stop everything else we might be talking about. Is anybody still waiting for parts or actively modding these DACs, or are we kind of getting to a point where people mostly have gotten out of the thread whatever there is to get one of these Chinese DACs into tiptop shape?

There is only one thing I am still actively interested in investigating more that could be applicable to ES9038Q2M and that is outboard interpolation filtering. Problem is it takes a Sharc chip to do it, and the software development system for Sharc chips is not free. If one buys a Sharc development board then it comes with, I think, a 3-month 1-seat software development system license. Personally, I don't know enough yet about what I might want to do to consider starting the clock ticking. I did get a little ADAU1452 to play around with since the software for that doesn't expire. But, it is no where near fast enough for outboard interpolation filtering. Still pretty early in the learning curve for it too, so it may be awhile before much more to say on that.

Other than that though, if others are interested in doing more with Q2M such as master mode I2S, with ASRC on or off, I would be happy to help with software and advice, but not much curiosity about it at this point myself.

Last edited by Markw4; 11th July 2018 at 10:01 PM.
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Old 11th July 2018, 09:45 PM   #1864
Ian Greenhalgh is offline Ian Greenhalgh  United Kingdom
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Quote:
Originally Posted by Markw4 View Post
No point wasting effort. Maybe best just to add to the ignore list. There seems to be more going on here than than we fully understand, so probably best to be patient and not give it much attention in the meantime.
Have I really done something so bad that this guy's ego has been bruised so badly that not only does he not want to help me, but he now seems to want to try to stop anyone else from helping me either?
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Old 11th July 2018, 10:32 PM   #1865
Markw4 is online now Markw4  United States
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Ian, even though you are on my ignore list I can still read your posts if I choose to. Just so you know, I was not trying to prevent to you from getting help. I was trying to suggest to eziitis to not let you aggravate him if he does in fact find you aggravating. As far as you getting help, I'm sure if you ask for help somebody will step up to help you.
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Old 12th July 2018, 12:25 AM   #1866
Ian Greenhalgh is offline Ian Greenhalgh  United Kingdom
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Fair enough, I apologise for the misunderstanding.
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Old 12th July 2018, 12:55 AM   #1867
Ian Greenhalgh is offline Ian Greenhalgh  United Kingdom
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Here is a discussion on DACs, in particular the I/V stages that includes John Siau, the VP of Benchmark Systems and which I found rather informative:

DAC IV stages
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Old 12th July 2018, 01:56 AM   #1868
abraxalito is offline abraxalito  United Kingdom
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Interesting link, thanks.

One thing which caught my eye there and which looks to differ from ESS's own recommended circuits is this, written by John Siau :

One complication is that high-frequency switching noise is always present on the current outputs of sigma-delta converters. This high-frequency noise must be bypassed with rather large NPO or COG capacitors before entering the I-V converter.

Mark have you looked at the internal circuits of your DAC3 to notice the large NP0 cap right next to the DAC chip? Could this be a part of the reason why DAC3 has sounded better than your designs based on ESS's recommendations?


<afterthought> Do you have a link to Bruno's thinking about what people can hear you've referred to in your post directly under this one?
Oh and a useful link pertaining to ESS DAC common-mode noise (referred to by Mr Siau) : Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project
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Last edited by abraxalito; 12th July 2018 at 02:21 AM.
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Old 12th July 2018, 02:00 AM   #1869
Markw4 is online now Markw4  United States
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John Siau designs some of the best DACs in the world, but IMHO he is wrong about some aspects of human aural perception. Not really his fault, I guess. Not his area of expertise. Let's get him and Jakob2 together, would probably be a good idea. I would like to be in on that conversation as well. Be nice to get that resolved. Bruno Putzeys who also knows how to design a DAC seems to have rather different views about what people can and can't hear as compared to Mr Siau. I would probably come out more on the same side as Bruno on that.
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Old 12th July 2018, 02:32 AM   #1870
Ian Greenhalgh is offline Ian Greenhalgh  United Kingdom
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Another thing John Siau said is this:

Quote:
Analog output stages include:

1) I-V conversion
2) Low-pass filters
3) Gain stage
4) Output buffers
Now, my understanding is that the ES9038 has an output current of 60mA, whereas a 'traditional' DAC chip is around 2.5mA.

To get the output of a traditional DAC upto a suitable line level, you would have to amplify it by a factor of about 20, which would be at least 50mA.

However, the ES9038's output is already above 50mA, so does this mean when designing the analogue stage for the ES9038 we can omit the gain stage altogether?

That would mean the analogue stage for an ES9038 would be:

1) I-V conversion
2) Low-pass filters
3) Output buffers
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