ES9038Q2M Production

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Allo Katana dac that I am a reviewer for uses Sparkos opamps for the entire output stage. So far, in listening tests by modded dac sounds as good or better than the Katana dac. Pretty soon Katana 1.2 should be out, and I should have a new output stage finished with more filtering. My impression so far is that for a fully modded dac there is no clear advantage to using discrete opamps.
 
Allo Katana dac that I am a reviewer for uses Sparkos opamps for the entire output stage. So far, in listening tests by modded dac sounds as good or better than the Katana dac. Pretty soon Katana 1.2 should be out, and I should have a new output stage finished with more filtering. My impression so far is that for a fully modded dac there is no clear advantage to using discrete opamps.

So imagine the Sparkos OpAmp on your new output stage !!!:hphones:
 
So imagine the Sparkos OpAmp on your new output stage !!!:hphones:

I thought I did: "My impression so far is that for a fully modded dac there is no clear advantage to using discrete opamps."
Sparkos are discrete opamps, not integrated opamps like I use. In any case, the new output stage needs three opamps. That would be a lot of money that might be better spent on other mods.
 
Yep. With a good dac there is a lot in the way of little details to discover on CDs one never knew existed before. And all music sounds so much better, even genres that may not otherwise be one's favorite. :)

Say, what headphone amp are using?


Totally agree :yes::yes:

My Headphone amp:

WA6 (2nd gen) Headphone Amplifier — Woo Audio

Mine is the first generation with 7N7 / 5AU4G and the Sennheiser HD650

Serge
 
I like your headphones. Sorry to hear about the HPA, though. You paid a lot for cool tube looks and extruded aluminum transformer cover looks. Eye candy, we used to call it. Wonder how much you could sell it for?

If you want to hear the rest of the missing sound on CDs you should mod an LME49600 HPA, as I keep encouraging people to try. It's only $32 for the Chinese kit, and a little modding to make it good enough to be just the right fit to a well modded dac.

Sorry, if I said bad news. Don't mean to make you feel bad, just feel I have to tell you what I believe to be the truth. In the long run we will be better off that way, I hope.
 
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There is no problem Mark.

I tried several headphones amp a few years ago and also the LME49600
I have always been disappointed .
That's why I decided to move on to something more serious, more expensive :confused: but i prefer now what i hear with the WA6.

If I had more money I would definitely buy a high end model at WooAudio.

Serge
 
When you say "the LME49600" that can mean a lot of different things. All the way from $32 to more than $1,000 for a HPA based on that chip. They vary drastically in performance. A good one is very clean and pure, not clinical or anything else bad. The only problem with a good one is it will let you hear very clearly if there is any problem with your dac. There are other headphone amps that function more like bandaids to hide dac problems by covering them up with even more distortion, but a little bit nicer distortion. I tend to put ones that use tubes and or transformers into that nicer distortion bandaid classification.

That's why I try to keep explaining to people that some things that may seem to make a dac sound better lead to false ends. They are what one might call a relative optimal solution, but not global optimal, if that means anything. The first can be a dead end trap because there is no way to keep getting better in that direction. Getting out of the trap requires backing up to worse sound, changing direction there, then moving forward in a new direction without a trap.

I almost got caught too, on this dac project. If I didn't have the DAC-3 here, there were one or two times when I most likely would have gone off in the wrong direction. By working through the labyrinth myself first, now I am trying to show others the path I found through there. It works. I know because I keep getting closer to DAC-3, and so far my dac has not been beaten by Katana, either it has been a tie, or my dac comes out better (although that might change pretty soon :)). And both of them, mine and Katana are getting pretty good. Closer and closer DAC-3, which as I have pointed out is on the Stereophile recommended equipment list, measures as state of the art, and is widely used by audiophiles and professionally. In other words, it is a good target to aim for. Only thing I use tube and transformers for at the moment is electric guitars.

OTOH, the 5U4 rectifier that HPA has is what they used to power a whole TV set back in the days of tubes. More for looks even if some tube rectifier mojo was wanted for a HPA. Way too big for a little HPA. I have to admit though it is a nice looking HPA for tube art. But, as a rectifier it is even too big for my Marshall 17watt-circuit-based guitar amp.
 
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Hi

This document is about a PCB for the LTC6655 .
I kept the original output stage ( one DUAL OpAmp ) so there are not the Vref outputs for the Mark Output stage .
I have not yet tested the PCB .

I advise to change the capacitors of the output stage ( one DUAL OpAmp ) ;)

Serge
 

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Hello Serge
regarding the capacitors on the Avcc regulators, you are using 100uf, is there a reason to use this particular value or any value can be used , or maybe bigger is better?

If using LT304x type regulators for AVCC, bigger output capacitors than recommended in the data sheet can worsen transient response. The problems with LT304x regulators for AVCC include issues as described in this post: https://www.diyaudio.com/forums/power-supplies/311453-tried-chinese-lt3042-board-4.html#post5561404

With careful load layout and design, transient response should be able to be quite good. And LF noise can be improved a lot using a suggested application circuit from one of the LT304x data sheets that shows an LTC6655 used to provide the reference voltage. (See diagram below.) This might actually make for an excellent AVCC supply for ES9038PRO.

Otherwise, if not using LTC665, then LT304x Cset capacitor should be increased to 22uf as described in the data sheet. If that makes start up time too slow, then the fast start up option circuit can be implemented, also as described in the data sheet. Pictures of one being modified for that can be seen here: http://www.diyaudio.com/forums/digital-line-level/314935-es9038q2m-board-154.html#post5468329
 

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    LT3045_with LTC6655reference.jpg
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HI Mark thanks for your reply.
i have seen the link with the problems with the LT3042 regulators, and i tried building the avcc supply with the transistor you sugested 2 times , but for some reason i did not get 3.3V at the output, so decided to use the lt3042 regulators in the end, as i want to move on with another project. myabe i will return to this dac after i finish an amp i want to start building now, and make the correct the avcc supply then along with the output stage.
but still even when using the lt3042 regulators the results are very audible for the better.
 
i have seen the link with the problems with the LT3042 regulators, and i tried building the avcc supply with the transistor you sugested 2 times , but for some reason i did not get 3.3V at the output,

Hi Paul,
I am a little confused. We use opamps, not transistors for the recommended Q2M AVCC supply.

No matter though, if you try to build such a thing again, please keep us informed in the thread or by PM. If we see you putting something together the wrong way maybe we can help get it fixed very quickly. If it does't work as expected when you are done, we can also help you troubleshoot and fix it very quickly then too. There is only a problem for you if you work in secret and don't allow any help, and then it doesn't work. Then you have a problem, right? We want don't want any problems to keep you from being successful with your dac mods, so please do keep in touch and let us assist you when and where we can.
 
Hi

It's not another thread bout the ES9038Q2M .
There is a very popular thread about it :
ES9038Q2M Board - diyAudio

You can find many informations and details ....perhaps too many for the beginners or without realy experience .:eek:

I started a document for those who would like to embark on the adventure:p.

It's not a document for the "pro" :rolleyes:

All comments will be appreciate .:D

If you find errors .....tell me ;)




Serge

Great document! This will be very handy when I start my project. I know this a labor of love, but are you trying to managing any version control of this document? IOW, how many additional mods, or tweaks to existing mods are there past your page 14 of the PDF that are detailed in Mark's thread, and how would the user know? :) Just asking.
 
Great document! This will be very handy when I start my project. I know this a labor of love, but are you trying to managing any version control of this document? IOW, how many additional mods, or tweaks to existing mods are there past your page 14 of the PDF that are detailed in Mark's thread, and how would the user know? :) Just asking.

Hi Serge,
I just did your AVCC Mod with these regulators.
It was really easy and produces great results on my system.
Thank you for making it so clear and it is a noticeable improvement in SQ for me.

For Digital 3.3v, What capa value are you using for decoupling?
Next big thing I'll do will be the clock replacement.

Then, if everything is going well, I'll go for Mark mods.
 
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