DIYHiFi.org

peufeu has suggested that we could use some modules and settle on standard pinouts.
That's a great idea.
Here's my contribution, a reclock module.
It is intended to be used with 90º angle ribbon/jumper connectors. So, the board stays vertical.
These connectors are bought at 10cm lengths (don't make me count the pins) and can be cut to size. Female connectors can be cut too.
I only have the straight ones, have to look around for angled...

The PSU is based on what Guido Tent recommends for his XO clock (diy version):

http://www.tentlabs.com/Products/Compon ... index.html

I'm using 6V to feed the 74HC74s, though.
L1, L2 and L3 are ferrite beads.
I also included an option for SMD, because I bought 100 on ebay, cheap.
From NIC Components, code NCB1210C800TR040F.
Datasheet:
http://www.niccomp.com/Catalog/ncb.pdf

On each signal there's the option of non-inverted or inverted output (BCK and WS), just by the flip of a resistor.
On the DATA there's both outputs. Just use non-inverted, inverted or both.

I made this today. Didn't make a schematic. I think it's not needed. I named the components with their values.
This is done on single layer, so that everybody can easily make one. I avoided jumper wires as much as possible.
This is just a printscreen, preliminary. In the end I will post high resolution PDF.
Comments welcome. But have in mind that I may not have the time to make many changes.
And what about the pinout?

I don't think I'll use a reclock module (I think I'll put reclocking on the main board coz it's the same for all DACs).

I'd have used double sided and SMD ;) (with double sided you can use straight connectors as in the included photo, the board thickness corresponds to the connector spacing). In this case half the pins end up on the ground plane, signal pins are on the other side.

See image : I removed the ground loops above and below (ground rings make nice antennas)

Also :

You don't need resistors on the inputs
You could have used the resistors as wire links, and made them vertical to get an uninterrupted ground plane
Also replace the trace below the chips to set the Reset pin by a link to clear the path from decoupling cap to ground pin.

see image

Have fun !

This is something I've done for me, to put inside CDPs, not necessarily stand alone dacs.
I've been doing this on veroboard for my CDPs, I'm tired of that.



Good idea!
But I think I'll keep this single sided...
I have some single row connectors!

Btw it just came to my mind, while I was in the bathroom (!) that to eventually use the differential output on the data, I would need another 74HC74.
This is for the case of dual differential dacs, so I need data left and data right. Duh...

These are small values, no problem. I don't like to drive several devices in parallel directly.



Yes, I agree.



I really thought about that when I was doing it, and you are absolutely right. But then it would make me have to use sockets, which also put the chips's pins at more distance from the decoupling caps.
Thinking about it again, I think you are right, a solid groundplane is better.



Thanks for the input, I will update soon.

I managed to fit another 74HC74 and make the board a few milimeters smaller than before.
It measures ~ 10x4cm, and it now uses a single row connector, vertically mounted with the board. It solders to the holes/tracks. Alternatively, wires can be used, that's why I kept the holes.
Very sexy.

Your PCB software probably has several resistor models with various lengths (more or less spacing between the pads). I suggest you try "longer" resistors in some places, to simplify layout (and get more ground plane)

I does, but they get larger. Like the 3.3R resistor on the PSU.
About the groundplane, I've just had an idea.
It is a challenge to make this as single layer, it would be much easier to make it dual layer. BUT single layer is easier to etch at home, and even cheap to order.
Sooo... the idea is to use split groundplanes (in several parts, probably 5), returning all the currents to a central point, the grount pins in the center of the board.

And so it goes like this (btw there is a resistor with slightly longer leads and the same body):

Easier to see without silkscreen.

Revision.

Hi Carlos

You should go back to a integral ground plane! ..or to a double layer with top layer full copper (a big step forward)!

You've create big loops in the supply returns and some jumps between planes in the signals returns ...=EMI + RFI , you're in the HF world!
Check the layout considering the full flow of currents.
Place a gnd pin between signal pins in the connector to ensure a proper return path.

A double sided board with SMDs should be half the size of a single sided board with through-hole components... so in the end, I wonder which one is really more expensive.

The nice thing about the Net is that you don't need to bother with ordering PCBs from a fab, just post it on diy audio, wait a few weeks and then you will be able to order it from some swedish site

That's right, but if you post a through-hole single sided board you won't attract them.