AES/EBU to SPDIF coax input, how?

[tubenut]

I would like to try and hook my transport up to my DAC using AES/EBU. The Dac only has co ax inputs... No transformer on dac input, just a 75 ohm resistor.
The transport does have a txf coupled AES/EBU output.

Will the attached conversion cct sketch do the trick? I think fig 1 would give me the right impedance to hook onto the co ax input of my DAC without loosing the AES/EBU benefit....

Any advice welcome!

Thanks

[moamps]

One more idea..
(elektor 7/97)

[Algar_emi]

See this very good site: http://www.scientificonversion.com

They provide excellent transfo for this application. I'm planning in using this part myself in my DCA:
SC939-06: Transfo, Pulse 1.2:1:1.2, 0.20mH

[Nisbeth]

http://www.epanorama.net/documents/audio/spdif.html (around the middle of the page)


/U.

[tubenut]

Thanks a lot guys, I guess what I need to do is actually get the part # of the Vitec transformer I have and see what it's turns ratios are, from there I hopefully can pick a suitable circuit.....
This is all to use with my Theta Data Basic II and DS Pro Basic II.
I have a transformer on a reclock board from them that I am not using at the moment. Once I make up my mind between AES?EBU and co ax I will implement the output reclock board as required. It is configured for co ax as standard.
I could not see prices on Scientific Conversion site, does anyone know what these things cost? Only problem is that the bank transfer will possibly cost more then the TX. Using the Vitec will be first choice.....

Guillaume

[tubenut]

This technical note from Rane is probably the most informative and I think it has given me the information I need....

http://www.rane.com/note149.html#foot

[Jocko Homo]

I don't like any of the Scientific Conversions transformers. Not familiar with the other one, but try to find out the leakage inductance and/or interwinding capacitance.

As for your sketches.............worry about making the input look like 110 ohms, or whatever impedance that you cable has. Then play games with resistors..............

Jocko

[tubenut]

I am not likely to use my original idea at all. The Rane note gives me the info needed to do this properly. Worst case I may just buyt the Neutrik transformer they mention. At least they have an agent here in SA. I guess we have the sun and beautiful wildlife, but it really s#cks that we can not just get some of these sexy components you guys buy of the shelf.... Paypal does not even accept South African registered credit cards.....

Later

[gmarsh]

Originally posted by Jocko Homo
I don't like any of the Scientific Conversions transformers. Not familiar with the other one, but try to find out the leakage inductance and/or interwinding capacitance.

Jocko,

what do you suggest? I'm redesigning an older board with a SC936 on it. Deciding between SC937, Pulse 65812 and Mini Circuits ADT1. Any other ideas/suggestions? it's for AES/EBU.

[Jocko Homo]

Mouser sells a cheap Chinese knock-off of a Schott transformer that I used to use. It is ok............has minor flaws, but is cheap, and easy to get.

Digi-key now sells something that may be Schott, built under a different name. More expensive..........seems to measure as good as the Shotts.

Of course.......if you do use a transformer..........get ready to make a Zobel. Using one without a network makes for rotten sound.

Another reason that I refuse to use SC is that they do not publish leakage inductance. You need that in order to design the network.

Jocko