Mr White's "Opus", designing a simple balanced DAC

[Russ White]

Originally posted by awpagan

Russ
any updates on your project?

allan

Getting prototype PCBs made next week after the holiday. Just had to finish off some other projects first. This one is up next.

There will definitely be a USB to I2S converter too. Will probably get that made at the same time. I may contact a few of you to see if you are interested in beta testing the DAC and/or USB PCBs.

The DAC board on its own should be able to go directly into a 10-100K load with no problem (most preamps) , but it would not be filtered at all. I have a third line stage module based on the THS4131 which I will use to filter the output a bit. Balanced input and output.

I will post circuit details here soon. Along with pics of the layout for those who are interested.

One question to anyone who knows, can anyone shoot me a link to a good small input trafo to use for SPDIF that is easy to obtain in the U.S.? I am thinking of including one, but I need to find a good simple example of an SPDIF input circuit using a trafo and identify the trafo I could use.

Cheers!
Russ

[pinkmouse]

Originally posted by Russ White
One question to anyone who knows, can anyone shoot me a link to a good small input trafo to use for SPDIF that is easy to obtain in the U.S.? I am thinking of including one, but I need to find a good simple example of an SPDIF input circuit using a trafo and identify the trafo I could use.

What, this kind of thing?

[Russ White]

Originally posted by pinkmouse


What, this kind of thing?

Now thats a solution I could live with.
Reading it over. Thanks!

[awpagan]

Originally posted by Russ White



Getting prototype PCBs made next week after the holiday. Just had to finish off some other projects first. This one is up next.

There will definitely be a USB to I2S converter too. Will probably get that made at the same time. I may contact a few of you to see if you are interested in beta testing the DAC and/or USB PCBs.

The DAC board on its own should be able to go directly into a 10-100K load with no problem (most preamps) , but it would not be filtered at all. I have a third line stage module based on the THS4131 which I will use to filter the output a bit. Balanced input and output.

I will post circuit details here soon. Along with pics of the layout for those who are interested.

One question to anyone who knows, can anyone shoot me a link to a good small input trafo to use for SPDIF that is easy to obtain in the U.S.? I am thinking of including one, but I need to find a good simple example of an SPDIF input circuit using a trafo and identify the trafo I could use.

Cheers!
Russ

I have ordered the eval pcb with some dac's to try.
the reason i like the voltage out is so i can try something like this
Marantz CD63 & CD67 mods list
post 1924


allan
ps also would like to try the software version

[Russ White]

I looked at the site Craig pointed to:

http://www.scientificonversion.com

And found the SC979-03 which seems to be a good fit. I will call them Tuesday to see what the price is and if I can even get them. But they seem small enough.

Thanks Craig.

Cheers!
Russ

[pinkmouse]

Sowter seem to do one as well, the 8285. They use a strange frames system on their site, so you can't link to the specs directly, but if you go to sowter.co.uk it's under pro audio.

[hayenc]

Digi-Key also carries some transformers from Newava. Have a couple but have not tested them. 470-1006-ND, 407-1007-ND.

Have to admit that Canare piece looks intriguing if we find a good supplier.

[chris719]

That canare transformer is not the right transformer, not even close. It is an impedance matching transformer.

[pinkmouse]

What are we looking for then?

[chris719]

A 1:1 75 ohm pulse transformer, the Newava parts digikey carries will do fine, also the SC parts. If you use the search you can find quite a few threads on them.