PCM2903 sound card - Page 1
Forum section: electronics / projects

author: bennet321
author_rank: Newbie
timestamp: March 02, 2016, 05:57:16 am
content: Just wanted to show off my PCM2903 sound card project. Circuit board layout was done by me, the design of the circuit is pretty much from the datasheet. It was going to have an optical input, but as you can see from the photos that did not work out. Also it sounds pretty good for what it is. Even though this is far from perfect as far as design goes I am quite happy with it as I get use out of it everyday.

author: Wor3d
author_rank: Contributor
timestamp: March 02, 2016, 06:33:26 am
content: Wow, that's cool!Can you give us some specs? I know, there's the datasheet, but I want to hear from the creator, what he actually implemented, and what's he proud onSent from my Orange Rono using Tapatalk

author: bennet321
author_rank: Newbie
timestamp: March 02, 2016, 07:19:49 am
content: The only measurement I really made when I made this was of the power and that was under 100ma@ 12v(I think it was around 70ma). As for features the PCM2903 is multi purpose usb audio decoder. It can decode PCM audio streams over usb, optical or coaxial and it can be also used as a kind of bridge to extract the PCM stream from usb to feed into a higher end dac. I basically implemented the usb and optical. One feature I did not implement is that the ic also support external buttons for volume control and mute if I remember correctly. I think what I am most proud of with it is the fact that it work great(at least the usb does) and I get use out of it everyday. I'm also quite happy with how the home etched board turned out, it was the first one i did that was smd.

author: Wor3d
author_rank: Contributor
timestamp: March 02, 2016, 09:09:24 am
content: Looks really nice for home-etched work! What do you use for etching? Because I am too afraid to etch such thin traces with ironing toner and using Ferrite Chloride.Sent from my Orange Rono using Tapatalk

author: bennet321
author_rank: Newbie
timestamp: March 02, 2016, 09:15:55 am
content: Amonium persulfate

author: Wor3d
author_rank: Contributor
timestamp: March 02, 2016, 09:18:29 am
content: So, what is trace width precision with that? ^_^Sent from my Orange Rono using Tapatalk

author: bennet321
author_rank: Newbie
timestamp: March 02, 2016, 09:45:47 am
content: In my opinion it has not got so much to do with the etchant as it does with whatever resist you are using on the pcb, whether that be a proper photo resist or printer toner. Lowest spacing I have gone is 0.5mm and as for track width i have gotten 0.25. On the data sheet of the presensetized pcb's I use it say's you can get down as low as 0.1mm, but I personally I don't think that's really possible.

author: Wor3d
author_rank: Contributor
timestamp: March 02, 2016, 10:32:10 am
content: What is achievable in your opinion with classic magazine paper and proper laser printer? And, whats the ironing temp/time for applying toner on copper for such clutch widths? Sorry, bit off topic, but I cannot find any reliable dataSent from my Orange Rono using Tapatalk

author: bennet321
author_rank: Newbie
timestamp: March 02, 2016, 10:44:11 am
content: I can't really say I have never used the toner transfer method myself.

author: Wor3d
author_rank: Contributor
timestamp: March 02, 2016, 10:50:56 am
content: So, how do you use Amonium Persulfate then? It's not just standart etcher like Ferrite Chloride?Sent from my Orange Rono using Tapatalk

author: Fred27
author_rank: Unknown
timestamp: March 02, 2016, 11:19:16 am
content: You can't find any data on toner transfer? I'd say that got to be a subject that's been done to death. Everyone thinks they just discovered it and thst the world needs yet another YouTube video or Instructable on how they do toner transfer. That and using "nice and safe" HCl/H2O2 instead of nasty FeCl3.My opinion: Go with presensitised boards and Ferric Chloride unless you really need to save a few pennies and are only doing through hole Arduino shields. Dynamask 5000 dry film solder mask is good stuff too.

author: Wor3d
author_rank: Contributor
timestamp: March 02, 2016, 12:00:51 pm
content: Yeah it is, and I have done it myself couple of times, but few things are varying (max/min transfer temperature, or max reliable width of trace)