GodDAC - 192/24 USB DAC

[woodturner-fran]

I'll take one from you....

please let me know when you need $$

Fran

 

[fireworks]

Hello BizonGod,

This is a very interesting project ! I actually wanted to do something similar but it seems that you did most of the work already 🙂
Is this project open source, i.e. are the schematics and PCB layout openly available ?
Another question is about the analog input / output: do you use op. amps. before the ADC / after the DAC ? If so, which op. amps. ?
How many layers has the PCB ?

I'd like to buy one of the assembled boards from you but please do not solder on the op. amps. since I might want to use some others. Can you deliver a board like that ? I mean, can you send the board and the op. amps. in the same packet but the op. amps. not soldered on the board ?

 

[BizonGod]

Of course, no problem, You will get one without opAmps 😉
Do I have to solder other components of LPF around DAC/ADC?
Resistors and caps are 0603 size, tantalum decoupling caps are
A size, of course there are no ceramic/tantalum/electrolytic caps in
audio path.

For all 8 pcs I ordered 24 pcs of OPA2134 and 8 pcs MC33078
for dual opAmp (each device needs 4 pcs) and 6 pcs of LME49710 of
single opAmp (each device needs 2 pcs).

PCB is four layer mainly due to BGA package of CPU, also ground and power
planes are separated into analog and digital parts. Of course PCB is gold plated 😉

I have plans to make it open source (code, schematics, gerber files for PCB),
but I need confirmation from programmers that they will take part in software.

Code project web page started :
http://code.google.com/p/goddac/
Soon I will place there all usefull examples to mix up 😉

 

[Rodeodave]

Hi BizonGod,

I'm very much interested! Your project sounds very like it's an incredible tool. Do the USB and audio circuitry share grounds of can an isolation transformer (for digital stream) be used?

 

[BizonGod]

That would be hard to realize. I2S MCLK is high as 24.576MHz, so it would be not easy
to transport. According DAC/ADC datasheet grounds are separated and connected just in
one place (by small ferrite).

 

[Rodeodave]

Okay, that's too fast for a transformer. But still, I'd be interested in one of the DACs.

 

[BizonGod]

Ok, so all non-free DACs are booked.

Any one interested in free one (2pcs)?
Just programming skills are required..
Maby Your friends are interested?

 

[gene_klein]

Is one of them for sale.
I don't want to be a programmer under pressure but just for fun.
But all code written will be shared of course.

What should be the exact pricing for a module ?

 

[BizonGod]

Do You have any programming experience?

 

[BizonGod]

I just added few interesting documents and examples, to dowload go:

http://code.google.com/p/goddac/

 

[woodturner-fran]

What about power supplies for the board? Would there be an easy way to use, for example battery power?

Sorry, I haven't any programming knowledge....

Fran

 

[BizonGod]

Board is powered by USB. OpAms by DCDC converter with CLC filter including
tantalum caps and large FC series electrolytic one. Every one chip on board is
well decoupled (each power pin of analog part has own 100n + 10uF or 47uF).
Of course, you can bypass DCDC and take power for analog part from external power
supply (-+10V, +5V)

 

[BizonGod]

Today opAmps arrived (except LME49710 - will be in week or 2)
Soon I will solder them, and make new photo.

 

[carpenter]

Interesting thread. BizonGod, you may find Nelson Pass' discrete DIY I/V converter valuable. The information is located in "Articles" which you can locate in the bar at the top of the page.

 

[Noiseisgood]

I am following this project with interest, I think its great!

Please keep the updates posted, very interesting reading Bizongod😎

 

[Hacker]

I have plans to make it open source (code, schematics, gerber files for PCB),
but I need confirmation from programmers that they will take part in software.

Code project web page started :
goddac - Project Hosting on Google Code
Soon I will place there all usefull examples to mix up 😉

Hi,

I just came across your project while researching async USB audio. Very interesting.

I'm a long-time C and x86 asm programmer and reverse-engineer, almost exclusively in the security field (binary analysis, stack/heap overflows, shellcode development etc) although recently I've been working on some ARM reverse engineering projects on the iPad, particularly in the field of bypassing/disabling certain security mechanisms. I can't really say much more about that due to NDA issues.

Anyway, I'm game for getting involved in this project. Let me know what you need and I'll let you know if I can help. It sounds like a lot of fun 🙂

Cheers,
Carl

 

[Sostenuto]

Any updates on the project? I'd love to see the schematics.