Cheap 24/96 DAC, Revision B.

[hifi]

It´s suppose to, the CS4390 can, here´s a link to a dac that uses tranformer coupling anyway it does convert the balanced out, so I get double the signal level:

http://digilander.libero.it/paeng/a_...ll_article.htm


here´s another pic showing only components mounted on top side,


/ Micke

[apassgear]

JWB,

Which is your impresion of the sond provided by this circuit?

How much will you be paying for the board?

[jwb]

I haven't built the revision B board. You'd have to ask someone who has. On the revision A, I paid $30/board. The sound is quite a bit better than the NAD CD player that feeds it. The sound is simply much less harsh. I notice it the most when I really want to turn it up. On the NAD, if I turn the music up very loud, it is difficult to enjoy. But with this DAC I can enjoy it even at very high levels.

The problems with this DAC are:

1) The grounding on the first revision was suboptimal, leading to noise.

2) The CS8420 really should be used in software mode, because hardware mode has a few bugs that can cause it to lock-up.

3) The power regulation could be improved.

With the version posted by hifi above, the grounding problems should be improved. Micke, how big is that board? It looks huge!

[peranders]

Originally posted by jwb
The problems with this DAC are:

1) The grounding on the first revision was suboptimal, leading to noise.

I mentioned somewhere else that groundplanes and separation of digital and analog ground is very important. You see, this IS very important if you want the lowest noise possible. All manufactures recommends very narrow bridge between the analog and digital groundplanes and it's located under the DAC chip.

[hifi]

Hello,

>> JWB The board is about the same size as yours 98x83mm I just moved some stuff around a bit.


>>Peranders, is this the way you would recomend the groundplanes? but then I would not use the isolation properties of the transformers fully...

And this board have the oscillator mounted directly above the CS8420. and also balanced outputs.


/micke

[jwb]

Tut tut peranders; no gloating please. Anyway I have no evidence that the split ground plane improves the situation. My PCM1704 DAC has a single ground plane and is very quiet.

-jwb

[Elso Kwak]

JWB,
Tut, tut, gloating???
My experience is better sound with analog & digital groundplanes separated by a ferrite bead as suggested in some AD datasheet. I have even gone further and replaced the ferrite bead by a ferrite cored 2.2mH inductor at the powersupply. The latter is contrary to AD's suggestion to place the bead at the DAC. The bead at the DAC produced a lot of noise in my loudspeakers.
/Maybe my last post before getting banned.
Hurrah

[mlloyd1]

Why???
What's going on around here?
mlloyd1

Originally posted by Elso Kwak
..../Maybe my last post before getting banned.

[Elso Kwak]

Hi Michael,
Please see:
http://www.diyaudio.com/forums/showt...812#post155812

[peranders]

Originally posted by jwb
Tut tut peranders; no gloating please. Anyway I have no evidence that the split ground plane improves the situation. My PCM1704 DAC has a single ground plane and is very quiet.

Gloat, I had to look in a dictionary, new word for me...

I don't mean gloating. I only wanted to say it really hard to get it right with a high performance DAC. One thing is hearing (noise) an another is to make it quite in RFI/EMI which in Europe is a serious matter.