DIGI balanced AES/EBU -> SPDIF Coax

meta · 26th May 2003, 12:29 PM

Hey...

Does anyone have any info on making the appropriate cable? I understand somekind of resistor network is needed...

Cheers..

Dan

dhaen · 26th May 2003, 02:50 PM

First of all, AES /EBU and SPDIF actually use slightly different data format. But, if you are just going from a source into a DAC, that usually doesn't matter, unless the DAC has a bitrate and error-rate display.

I think what you may be asking is:
How to go from balanced 110 ohm 5 volt to unbalanced 75 ohm 0.5 volt.

The answer is to use a transformer. There are various devices about. Depending on how critical you are, you could spend lots on one from Sowter or Schott, or you could use a data pulse transformer from RS or Farnell.
As for the the level difference, I would forget about it. You'll upset more with attenuators than you'll gain with level accuracy. besides, most reciever chips accept both levels.

Now, who's got a better constuctive suggestion?

meta · 26th May 2003, 03:21 PM

Hey John

The sources are all in the digital domain and will be kept there so I wont be goin into a DAC...

Looking at FIG1 in this Pic:

I can just use a few resistors compared to forking out for a transformer, but I'm just wondering the values of the resistors used in the diagram - is it 2 x 56ohm, 1 x 110ohm and a 220ohm? what are the values in the brackets?

Ta...

Dan

PS: Still aint done that PSU yet, that project is on hold atm... will be done tho!!

dhaen · 26th May 2003, 05:51 PM

If you use only resistors, you depend on the source using a transformer as an output device. This is likely, but not certain. The AES strongly recommends makers to use one, but a few don't.

The voltages in brackets are for alternative signal levels.
Please note my earlier post.

I'm just waiting for the "digital police" to catch up with me..

26th May 2003, 12:29 PM	#1
meta diyAudio Member Join Date: Nov 2002 Location: London	DIGI balanced AES/EBU -> SPDIF Coax Hey... Does anyone have any info on making the appropriate cable? I understand somekind of resistor network is needed... Cheers.. Dan

26th May 2003, 02:50 PM	#2
dhaen diyAudio Moderator Emeritus Join Date: Jun 2002 Location: U.K.	Here goes, First of all, AES /EBU and SPDIF actually use slightly different data format. But, if you are just going from a source into a DAC, that usually doesn't matter, unless the DAC has a bitrate and error-rate display. I think what you may be asking is: How to go from balanced 110 ohm 5 volt to unbalanced 75 ohm 0.5 volt. The answer is to use a transformer. There are various devices about. Depending on how critical you are, you could spend lots on one from Sowter or Schott, or you could use a data pulse transformer from RS or Farnell. As for the the level difference, I would forget about it. You'll upset more with attenuators than you'll gain with level accuracy. besides, most reciever chips accept both levels. Now, who's got a better constuctive suggestion?

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26th May 2003, 03:21 PM	#3
meta diyAudio Member Join Date: Nov 2002 Location: London	Hey John The sources are all in the digital domain and will be kept there so I wont be goin into a DAC... Looking at FIG1 in this Pic: I can just use a few resistors compared to forking out for a transformer, but I'm just wondering the values of the resistors used in the diagram - is it 2 x 56ohm, 1 x 110ohm and a 220ohm? what are the values in the brackets? Ta... Dan PS: Still aint done that PSU yet, that project is on hold atm... will be done tho!!

26th May 2003, 05:51 PM	#4
dhaen diyAudio Moderator Emeritus Join Date: Jun 2002 Location: U.K.	If you use only resistors, you depend on the source using a transformer as an output device. This is likely, but not certain. The AES strongly recommends makers to use one, but a few don't. The voltages in brackets are for alternative signal levels. Please note my earlier post. I'm just waiting for the "digital police" to catch up with me..