ES9023 / WM8804 S/PDIF DAC Group Buy

[jean-paul]

Edge connectors ? Brand ? Type ?

[Ryssen]

Jean Paul or other did you try this DAC with the J-G Filter buffer?
Did it sound any better or ?

[hochopeper]

The J-G Filter Buffer GB boards are still with WK for soldering matched jfets, to my understanding the only people who have heard it are Joachim, Patrick and a couple who posted in the ES9022 thread and had made their own boards.

Joachim and Patrick have decided that it is good enough to spend XEN Audio's time producing boards and providing matched jfets, IMO that's usually a sign that it is worthwhile.

[korben69]

Hi

I've ordered a JG buffer too, but inductors won't be available before Christmas...
See EUVL post here about this : Fastron Inductor Group Buy for JG Filter Buffer
So we have enough time to close the GB and deliver Subbu's DAC V3

[Ryssen]

Well,I´m on the waitinglist for the buffer,we will se if there will be enough for a GB..

[ByronInLawrence]

Greetings,
My Subbu DAC didn’t work right after I built it. I didn’t mess with it for a while because as I was busy with other stuff. I got back to it last night. I measured the voltages which korben69 posted. Thank you korben69 for that post! It was very helpful.


I found the voltage at pin 1 of U4 was ~3V (though it bounced around), and the output voltage (pin 5) was about 0. So I replaced it and measured the same voltages.


Then I figured that a low voltage at pin1 of U4 could be caused by low resistance across C16 or C17 to ground, or by a high resistance across L1. First, I replaced both caps and got the same measurement. Then I replaced L1. This time I measured 5V at pin 1 of U4, but I found that both L1 and U4 got super hot, so I turned off the power supply. So I’m guessing that L1 and maybe U4 were fried, but that was a symptom of something else wrong. They would probably fry again if I continued to apply voltage.
L2 was not hot, and voltages at all pins of U3, U5 and U6 were consistent with korben69’s post.


So now I’m thinking a short across C16, C17, C18, C19, C8, U4 or Q2 could cause too much current through L1 and U4. But I just replaced C16, C17,* C8 and U4. Does anyone have any suggestions? Or should I just keep removing things until L1 and U4 don’t heat up anymore, then start replacing things, measuring and feeling as I go?
Also, I’m a little concerned that my C19, C22, C26 & C29 don’t look like the pictures in the data sheet, or in Skouliki’s, Skylab’s, or Tome’s photos. They may match Gary B’s photo. Ignore C8 in my photo. It was taken before I replaced it with the correct cap.

[grufti]

C32 is the wrong way around, but that does not explain your problem.

Your soldering on both U3 and U4 looks a bit suspicious to me in your picture. Try to look at that with magnification and/or a more closeup picture.

[syklab]

Looks like there are solder bridge on U3 and U4. Check voltage on the input pin for both U3/4, check it again at the point before the inductor, both places should give you close to 5V, if ok then check the output pin on U3/4.

[jean-paul]

Resolder the chips with good 60/40 solder as the connections are substandard. You probably have a short between pins. C32 is soldered in the wrong way around.

I would start with cleaning the PCB and check the situation around the XO with a magnifying glass. What resistance do you measure over C8 ?

[ByronInLawrence]

The problem was Q2, which is powered by U4. Though U4 may also have been a problem. A line of solder from at least one corner had climbed all the way up Q2 to the metal top. I replaced Q2 instead of just cleaning it up. I also cleaned up U3 and U4 with some wick. They look much better, and reversed C32. I'm listening to it right now, and I haven't even put C8 or C19 back yet. Sounds great as-is. I can't wait until I put it in a case and give it a better power supply. I'm currently using a Velleman kit.

Thank you everyone for your help. The second one, and V3 should go much more easily.