My first DAC!

MWP · 12th September 2003, 11:36 AM

Hi guys...

I had to show off my first DAC project success.

In the chain of parts: PCM2902 -> DIR1703 -> PCM1730 -> OPA627BPs.

The PCM2902 is doing a good job of interfacing with the PC... looks like it doesnt do any resampling, much better than a cheap SPDIF out soundcard.

All ive got it to compare to is my Turtlebeach SantaCruz soundcard, so i cant really say how it sounds as yet.

A few photos of the PCB finished and working:
http://www.overclockers.com.au/~mwp/pics/dac

The schematic:
http://www.overclockers.com.au/~mwp/...WP-USB-DAC.pdf

Yay!

kiwi_abroad · 13th September 2003, 12:04 AM

Good looking work.
Did you design and etch the board yourself, if so, How did you do the image transfer?
Also, how did solder the SMD chip? What pitch are they?

Adrian.

MWP · 13th September 2003, 02:14 AM

Quote:

Did you design and etch the board yourself, if so, How did you do the image transfer?

Yeh, i designed & made the board here at home.
The transfer was done onto the presensitised double sided board (kinsten brand) using bubble jet printer transparency sheets and a bubble jet pronter (Canon S400).
One sheet for each side, both sides exposed seperatly under a fluro for 16mins.

Sounds low-tech i know, but it works brilliantly... there are lots of 14mil tracks on that board for the surface mount ICs.
Ive also made lots of other boards this way.

Nice and cheap too.

Quote:

Also, how did solder the SMD chip? What pitch are they?

Soldered by hand by first tinning the pads on the PCB very lightly, then placing the IC and quickly running a clean soldering iron tip accross the leads.
With the help of good flux, it works every time.

The pads on the ICs are 14mil wide with a 11mil gap.

demeter · 16th September 2003, 07:13 PM

Could you give to project PCB in any normal format??? (pdf, tiff, bmp)
(((Thank you!)))

MWP · 17th September 2003, 04:40 AM

Ok, im building a web page for it here:

http://www.overclockers.com.au/~mwp/dac3/

Should be finished shortly, with schematic, top, bottom and overlay pdf's.

analog_sa · 17th September 2003, 08:41 AM

And how does it sound compared to the Santa Cruz? Did you also compare it to the PCM2902 alone?

demeter · 17th September 2003, 06:13 PM

please name IC11,IC12 ???Best Regards

MWP · 18th September 2003, 02:50 AM

Quote:

And how does it sound compared to the Santa Cruz? Did you also compare it to the PCM2902 alone?

Its hard to compare them since i really dont listen to music that makes picking up details easily possible.
Also, my speakers are not the best... they get upgraded next.

But i can say that the DAC is a lot quieter than the SantaCruz (no PC induced noise), and sounds much much clearer.
The mid-lows are much more defined.

I didnt compare the PCM1730s output to the PCM2902's since i didnt put any way of getting the PCM2902s signal off the board.

Quote:

Please name IC11,IC12 ???Best Regards

Ooops, thats an old schematic... ill put up a new one.
IC11 = REG103-5
IC12 = 78LM33

The new schematic:
http://www.overclockers.com.au/~mwp/...p-dac3-sch.pdf

Matttcattt · 18th September 2003, 06:49 AM

If you didnt get my E-mail, may i use your schematic and PDB layouts make a copy of your DAC?

MWP · 18th September 2003, 11:21 AM

Quote:

Originally posted by Matttcattt
If you didnt get my E-mail, may i use your schematic and PDB layouts make a copy of your DAC?

I didnt...
And, yeh, thats fine.
All the info (beisdes parts list) is on page:
http://www.overclockers.com.au/~mwp/dac3/

12th September 2003, 11:36 AM	#1
MWP diyAudio Member Join Date: Oct 2002 Location: Adelaide, South Australia	My first DAC! Hi guys... I had to show off my first DAC project success. In the chain of parts: PCM2902 -> DIR1703 -> PCM1730 -> OPA627BPs. The PCM2902 is doing a good job of interfacing with the PC... looks like it doesnt do any resampling, much better than a cheap SPDIF out soundcard. All ive got it to compare to is my Turtlebeach SantaCruz soundcard, so i cant really say how it sounds as yet. A few photos of the PCB finished and working: http://www.overclockers.com.au/~mwp/pics/dac The schematic: http://www.overclockers.com.au/~mwp/...WP-USB-DAC.pdf Yay!

16th September 2003, 07:13 PM	#4
demeter diyAudio Member Join Date: Aug 2002 Location: Czech Republik	usb DAC Could you give to project PCB in any normal format??? (pdf, tiff, bmp) (((Thank you!)))

17th September 2003, 06:13 PM	#7
demeter diyAudio Member Join Date: Aug 2002 Location: Czech Republik	please name IC11,IC12 ???Best Regards __________________ nunu@seznam.cz

18th September 2003, 06:49 AM	#9
Matttcattt diyAudio Member Join Date: Feb 2003 Location: Bristol	If you didnt get my E-mail, may i use your schematic and PDB layouts make a copy of your DAC? __________________ If it aint broke, don't fix it. If it is broke, fix it. If you can't fix it, take it apart and see how it "worked".

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13th September 2003, 12:04 AM	#2
kiwi_abroad diyAudio Member Join Date: Sep 2001 Location: Wellington, New Zealand	Good looking work. Did you design and etch the board yourself, if so, How did you do the image transfer? Also, how did solder the SMD chip? What pitch are they? Adrian.

17th September 2003, 04:40 AM	#5
MWP diyAudio Member Join Date: Oct 2002 Location: Adelaide, South Australia	Ok, im building a web page for it here: http://www.overclockers.com.au/~mwp/dac3/ Should be finished shortly, with schematic, top, bottom and overlay pdf's.

17th September 2003, 08:41 AM	#6
analog_sa diyAudio Member Join Date: Aug 2002 Location: Sofia	And how does it sound compared to the Santa Cruz? Did you also compare it to the PCM2902 alone?

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