[guzzler]

http://www.mellowparenting.demon.co....r/2702RevA.brd

Enjoy

 

[danko]

thank you, so much!!!

 

[awagner]

Thanks for providing such a great kit Guzzler! Here is a photo of one of my completed kits, all cased up. If you are using USB power, I highly recommend this enclosure; it machined cleanly (two holes), it seems bomb-proof, and it looks good (to me at least). It cost me about $5.

The enclosure is aluminum die-cast with four phillips screws:
BUD CU-123

The stereo 3.5mm chassis jack is an MCM 27-655, I believe.

The grommet is 3/16 x 5/16"

The USB cable is a chopped printer cable, soldered directly into the board.

If you use solid core hookup wire and insulate the board/box with electrical tape, it fits snugly in one direction and is held in place by the wires in the other two directions. (wire = shock absorber)

Don't forget to put the grommet in the hole and thread the cable through the grommet before soldering into the board. I also tied a knot in the cable to provide additional strain relief.

 

[Mod_Evil]

Hi friends. I will make a USB DAC with the PCM2704DB... What the differences of the PCM2704DB to PCM2702? The sound input? The sound quality is better than PCM2704? What drivers I use in PCM2704DB/PCM2702 ?

thanks.

 

[dsavitsk]

Quote:

Originally Posted by awagner The USB cable is ... soldered directly into the board.

Seems like such a simple idea, but it's a really good idea with this kit.

 

[jboehle]

I still have one of the original versions of this kit that I never built up. The board is labeled "BETA-1" on the back. I have a couple of questions:

1) Is there anything wrong with the layout of the BETA-1 boards that would discourage me from building it up?

2) Does anyone have instructions for building up the BETA-1 board (ie. what goes in each labeled hole)? I can't remember if it even originally came with instructions (if it did I lost them).

3) Should I even bother building this kit up, seeing as how it requires AA batts and the later versions of this board and the new version Alf is working on are powered from USB (seems much more convenient)? Should I just wait for Alf's new version to come out?

 

[Nisbeth]

1) No.Other than an optimized power arrangement on the newer version of the board, they are identical.

2) This should get you most of the way:
http://www.mellowparenting.demon.co....er/usbdac.html

3) The kit works fine and it doesn't have to be run on batteries. You might get a little noise, but it shouldn't be too much.


/U.

PS: If you don't want to assemble the kit, I'm pretty sure someone will be willing to take it off your hand.

 

[jboehle]

So to run the BETA-1 board off USB power I make a jumper from one of the R7 pads to the BATT+ pad, right? Is that it or do I need anything in between (reading through this thread, I think someone used a diode to protect the MAX1722?)?

 

[Nisbeth]

It could be my post you've read because I'm using a diode on mine - just in case - but it shouldn't really be necessary

/U.

 

[jboehle]

So is the only extra connection to enable USB powered operation from R7->BATT+? Or are there other jumpers elsewhere?

 

[Nisbeth]

Quote:

Originally Posted by jboehle So is the only extra connection to enable USB powered operation from R7->BATT+?

Yup, that's it

/U.

 

[jboehle]

Finally got around to building my BETA-1 board. The 3.3V and 5V outputs from the regulators measure fine. I think I may have a problem though. I have my meter hooked up to measure the output DC offset before I plug in the USB. I then plug it in, and the DC offset jumps to .25V-.5V and then after 30-60 seconds, settles down to ~1mV on each channel. I am measuring this from OG->OL, and get the same results on OG->OR. Shouldn't the DC offset be 0mV at all times due to the Black Gate output caps? I wonder what I messed up...

 

[jboehle]

Anyone got any ideas on how I should troubleshoot my dac?

 

[guzzler]

Did you get polarised caps, or non-polarised? Could you perhaps give us a couple of pictures as well?

cheers

 

[jboehle]

Mine was one of the original kits put together by Itzbitz in the US. It came with everything needed to build the board (except for a case). I took some pics last night but they're blurry...I'll try to take some better ones tonight. As far as I can see, I haven't bridged any of the pins on the 2702, but then again I don't have a magnifying glass handy so I can't be sure.