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ES9038Q2M Board
ES9038Q2M Board
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Old Today, 12:24 AM   #3011
Markw4 is offline Markw4  United States
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Join Date: Jul 2016
Location: California
Serge's thread is over here: ES9038Q2M Production

You can buy SMD practice soldering kits on ebay, amazon, aliexpress, etc. They mostly don't come with much directions, but if you search for youtube videos there are some good ones.

The new v1.07 boards are available with a display and can work with an optical remote control. However, they cost more with a display and it doesn't help all that much considering the price. If you know you don't want a display there are still 1.06 boards around. We just recommend the green boards over the blue ones which are more cheaply made and are not available with displays. The good thing about having a display, is that it makes it easier to hack into the dac control registers without having to do tricky soldering. Just a quirk of the firmware that makes them that way.

However, I suspect your old board could probably work okay. If you could post pics of the top and bottom in good focus so we can take a look, we could probably give you a better opinion on that.

Also, what type of soldering iron do you have? I used a more or less standard Weller solder station for a long time with a few different tips on hand. If you have a picture or model number that would help understand what type of work it would be okay for.

Last edited by Markw4; Today at 12:30 AM.
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Old Today, 09:08 AM   #3012
dv187736 is offline dv187736
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Join Date: Oct 2015
Quote:
Originally Posted by Markw4 View Post
Serge's thread is over here: ES9038Q2M Production

However, I suspect your old board could probably work okay. If you could post pics of the top and bottom in good focus so we can take a look, we could probably give you a better opinion on that.

Also, what type of soldering iron do you have? I used a more or less standard Weller solder station for a long time with a few different tips on hand. If you have a picture or model number that would help understand what type of work it would be okay for.
Mark,
Photos of the DAC. Embarrassing you will see how bad my soldering skill is.. ha ha.
The RCA jacks on the board are bit flimsy so I have a separate set on the plastic chassis.
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Old Today, 12:46 PM   #3013
androa76 is offline androa76  Slovenia
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Join Date: Mar 2007
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Noise from dac is quite small. Despite 2 stage filtering there is another filter at output. Output load 220R/6,8n is not good for lme49720... of course for my experiences.
Try to filter as much as possible noise before enter the opamp but not load dac too much. This gives me best result at last designs.
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Old Today, 03:10 PM   #3014
Markw4 is offline Markw4  United States
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Quote:
Originally Posted by dv187736 View Post
Mark,
Photos of the DAC.
The dac board looks like it has the right stuff on it to sound good modded.

In case in helps at all, I wrote some info about soldering before:
ES9038Q2M Board
ES9038Q2M Board

Cleaning the tip just before heating each joint helps. Use a brass brillo pad type cleaner, such as the one made by Hakko. There are cheap refills available for that type of cleaner, too.
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Old Today, 03:18 PM   #3015
Markw4 is offline Markw4  United States
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Join Date: Jul 2016
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Quote:
Originally Posted by androa76 View Post
Output load 220R/6,8n is not good...
While I understand the possible concern, I thought about it a lot too. Thing is about a lot of the earlier filtering is that it depends on opamp gain which is falling off as frequency rises, thus the filtering becomes less effective at very high frequencies. In addition, at this point I am not seeing or hearing a problem. Sound quality is better than ever, for one thing. The RF noise is small enough at that point the current flowing into that last filter cap is so small the opamp is hardly loaded. However, a final real pole just before leaving the dac board seems to be best for power amps, at least for mine.
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Old Today, 04:40 PM   #3016
Markw4 is offline Markw4  United States
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Join Date: Jul 2016
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Quote:
Originally Posted by terry22 View Post
Will you publish a complete BOM soon?
thanx
Hi terry22,
Haven't heard from you for awhile. Don't know if I scared you off with LT1763 modding or not? If so, no reason to give up. I'm sure something can be worked out for beginners that will be satisfactory.
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Old Today, 05:03 PM   #3017
Markw4 is offline Markw4  United States
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Join Date: Jul 2016
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Although I said I was planning to get started on it later, I have started looking into Spartan 6 possibilities. The Chinese Spartan 6 board I have is actually has a little bit more stuff in it than the one in DAC-3. However, DAC-3 has the faster 'speed grade 3' rating. The one I have is 'speed grade 2' and runs on a 50MHz clock.

It turns out there is a freeware version of the old Xilinx Spartan 6 development system software, that is mostly obsolete compared to the newer payware development systems. It also turns out that Spartan 6 is now the bottom on of the line for currently active Xilinx chips.

Xilinx makes some really powerful higher grade chips, and has fancy development software making efficient FIR filter development easy. However, not going to happen because of the high entry cost.

Getting back to reality, Spartan 6 is really designed to be a natively 16-bit part, with 18-bit adders to allow for a little overflow. It can be run at double precision by chaining internal processing units together, at some performance cost of course.

My impression at this point is that it might be possible to make a better 8x oversampling interpolation filter for the dac with a Spartan 6, but maybe only for lower sample rates, say up to 192kHz or so, and most likely using a higher speed grade part than what I have right now.

I have quite it bit more to learn about using the things and designing filters to run on them, but I'm just taking it a little at a time and mulling it over as I go.
---------------

In other news, I did do as I said and drew up a pencil sketch layout of a SMD output stage. It's not legible enough for me to post at this point, but it works with three 8-pin Surfboards of this type: https://www.capitaladvanced.com/pdf%...s/9081idsa.pdf
I expect I will probably build one pretty soon to show how it might be done. Since I will have it then, may as well put it to good use by using it to update my 1st modded dac. May I ask if anyone is waiting for the SMD output stage to be completed before starting on dac modding? If I am holding anyone up, I will try to prioritized getting it done sooner rather than later.
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Old Today, 05:21 PM   #3018
nori1000 is online now nori1000  Austria
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Join Date: Dec 2015
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Quote:
Originally Posted by dv187736 View Post
Mark,
I have not done any Smd soldering before, but yes perhaps it is time to try my hands on this. Iíll search for Sergeís pdf on the clock and understand what improvements are to be expected and how to install a new clock.

I read an article reviewing a recently released version 1.07 of this board. Apparently it is a much improved version. But I couldnít find it in eBay. Was thinking to reapply the mods including the new clock suggested.
Buy Products Online from China Wholesalers at Aliexpress.com
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