living sounds

Adapting S/PDIF input to accommodate AES/EBU
« on: December 15, 2018, 09:10:07 PM »
My DAC uses the attached input schematic for S/PDIF signals. What would be the correct resistor value(s) for AES/EBU signals? Thanks!


abbey road d enfer

Re: Adapting S/PDIF input to accommodate AES/EBU
« Reply #1 on: December 16, 2018, 10:46:45 AM »
My DAC uses the attached input schematic for S/PDIF signals. What would be the correct resistor value(s) for AES/EBU signals?
https://www.rane.com/note149.html
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

living sounds

Re: Adapting S/PDIF input to accommodate AES/EBU
« Reply #2 on: December 21, 2018, 06:41:50 PM »
Thanks, does this mean I cannot simply change resistor values here but have to add a voltage divider?

john12ax7

Re: Adapting S/PDIF input to accommodate AES/EBU
« Reply #3 on: December 21, 2018, 08:11:19 PM »
Do you know the ratio of the transformer? Probably around a 1:2 to match the impedance and also increase the spdif level.

So a pad would probably be necessary when using aes  level signals, as you wouldn't want a step up for them.

living sounds

Re: Adapting S/PDIF input to accommodate AES/EBU
« Reply #4 on: December 21, 2018, 08:57:56 PM »
Do you know the ratio of the transformer? Probably around a 1:2 to match the impedance and also increase the spdif level.

So a pad would probably be necessary when using aes  level signals, as you wouldn't want a step up for them.

I'm pretty sure the one I've got is a 1:1 transformer, since I took it out of an old converter's AES/EBU circuit. And I think the circuit drawing of my current converter calls for a 1:1 transformer as well.

I tried both professional and consumer level from the AES output (RME cards allow you to change this) and both work with the converter's input. But I'd rather have the correct circuit for AES/EBU. I was hoping to get away with using a different resistor for the 330R one.

john12ax7

Re: Adapting S/PDIF input to accommodate AES/EBU
« Reply #5 on: December 21, 2018, 09:45:16 PM »
My guess was 1:2 based on the 330, as that would give 330/4 or 82.5 load,  which is close to the 75 used in spiff.  What is down stream  impedance after the 330?

If it's really 1:1 transformer than a simple 110 ohm would probably be ok.  Or something a little larger than 110 to account for the down stream load that is in parallel.

living sounds

Re: Adapting S/PDIF input to accommodate AES/EBU
« Reply #6 on: December 23, 2018, 06:04:52 PM »
Thanks! I'll try next week and report back. Merry Christmas!

Whoops

Re: Adapting S/PDIF input to accommodate AES/EBU New
« Reply #7 on: February 07, 2019, 06:42:42 PM »
AES to SPDIF



« Last Edit: February 07, 2019, 06:47:13 PM by Whoops »


 

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