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PCM2706 USB DAC - Page 2

post #16 of 50
Thread Starter 

I saved all the links you gave me and will sure read about this later today as I have uni soon. Maybe I have the opportunity to print the schematics in a glossy type of paper (as I read it should work). I just am a bit anxious to start creating this : ) If that paper doesn't work, I will sure try to options you said.


And I will keep the thread updated as the progress goes! It's my first DIY, even though I study electrical engineering.

post #17 of 50
Thread Starter 

Sorry for the double post.


I tried to buy the double sided copper clad today but the there was none. Found some online but the shipment is absurd so I'll buy it from ebay. This one seems safe:


Will also buy the headphone socket that wakibaki linked.


Not everything is bad news. I managed to get the schematics printed by laser on a glossy paper. Even the employee knew what I wanted this for and said it would work. I really hope so.


Here are the components and everything else:


post #18 of 50


Looks like a good start!

post #19 of 50
Thread Starter 

I intend to have the PCB by next week as I ordered it today and comes from UK, so shouldn't really take too long. I still need to get the hydrochloric acid and the hydrogen peroxide for the etching.

post #20 of 50
Thread Starter 

Finally the copper clad PCB arrived, yay! Still need to get the hydrochloric acid, thought. But will try to print the circuit today then I'll post some picture. Hope you're sitll following this :p

post #21 of 50


If I remember correctly, you can erase the toner off the board with  isopropyl alcohol.

That way, if it doesn't turn out well, you can just erase it and try again.


Good luck!

post #22 of 50
Thread Starter 

Yep, I have so isopropyl alchol and will need to use as it didn't turn out so well. This is how it went:



As you can see, some parts of the circuit are missing. There are still some paper there, I know but I as will need to redo everything I didn't take much time taking it all away. I guess next time I need to heat it more time? I did it over 15 minutes though, I thought it would be enough... :( At least I still have the other side, may try it out later today and if it doesn't work, I'll need to go to Staples and print another one.


PS: I ordered some anti-etching marker but it will only arrive in a couple of weeks and as it is too much to do I'll just prefer to do it all over again.


PS1: I also found it a bit challenging to old the paper in place while print it on the board. I had put some tape holding both but it soon went away with the heat.

Edited by scanferr - 9/25/13 at 8:20am
post #23 of 50

The problems you have encountered are some of the reasons I switched to doing photo etching...


Fred_Fred is a real expert at the transfer method.

I'll PM him and see if he will contribute his expertise.


Here is an example of the results you can get with photo etching.


This was for a PCM2704

post #24 of 50
Thread Starter 

I just finished another one a couple of minutes ago and this one went better. There's still a bit of paper on the circuit and I can't seem to get it out, lol. Here it is:



I would like to do the photo etching but I need the UV light and aren't those a bit expensive? Also, I searched for the components that you have on your thread and I can't seem to find some of them.

post #25 of 50


That looks like a much better result.


I just use a cheap florescent light to expose my boards.

Takes about twelve minutes or so. 

post #26 of 50

Hi guys having fun :-)


Just a few points


firstly etch with Ammonium Persulphate or Ferric Chloride


the paper that is stuck to the board I remove it with a scouring pad, those green plastic ones, gentle scrubbing and it will all come off


when you have done the etching remove the toner using acetone


it looks like you are 90% there but it is not as accurate as photo etching




post #27 of 50
Thread Starter 

Thank you :)


I read the thread you linked on the 1st page but as I reckon, you need to have a special florescent light, right? One that emits UV? Can you say how you built yours?


Sorry for disturbing :)

post #28 of 50

The light was just a cheap (made in China) light meant to mount under the cupboards in your kitchen.


I think it cost me $15 at Walmart.

You can probably find something similar at a discount store in your country.

All florescent lights emit lots of UV.


Hey, I found a picture of it...


As you can see in my other pictures, I just built a wooden frame for it

to keep it a fixed distance above the work surface and so I would not have to

look right at the light while it was on.

Edited by Avro_Arrow - 9/25/13 at 3:41pm
post #29 of 50

Understandably you are a bit impatient.


Your results are improving visibly though.


I use multiple UV LEDs, they are cheap, but need to be arranged carefully to get even coverage. In the past I used small UV striplights with equal success. At work I had a proprietary double-sided lightbox with a timer.


UV tech is more expensive because you have to buy resist-coated PCB, you need transparency to print on, you need a lightbox. It's easier, however, to develop the skills required for UV than the toner-transfer method in terms of the achievable resolution. UV PCB printing is used extensively in industry, and it's common to have a development tank with side-by-side developers for photo-resist and etching.


Keep at it, you're getting there.



post #30 of 50
Thread Starter 

Thank you both. You really have been of great help.


It happens that I have one of those lights that you showed, Avro. Maybe a bit too small, will post it here tomorrow. I will definitely get a resist-coated PCB and the developer solution. Don't know where to get the solution but I'll search for it around here. Will get the circuit printed on a transparency by tomorrow. As I read on your thread, it can be printed on inkjet, right?

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