I am working on a CD940 using a blog page from Lampizator, and was wondering if I could replace the SP/DIF coaxial output connector to a XLR output connector.
Using the RCA output connector, a wire comes from the chip, into an L-Pad with a 270 ohm to the hot pin of the connector, and from there 75 ohm to ground.
Step six on this page
If I read things right, I don't even need to lower the voltage (according to the S/PDIF Wikipedia page. The voltage for AES3 balanced has to be between 2V and 7V peak to peak, so 4V is fine.
Meaning I would only need a 110 ohm resistor to ground.
But that leaves me with wiring the chassis connector.
From what I read I need to connect chip wire to pin 2, and ground to pin 1.
Then, if I have it correct, 110 ohm resistor will be between pin 1 and 2.
Am I making any wrong assumptions here?
Using the RCA output connector, a wire comes from the chip, into an L-Pad with a 270 ohm to the hot pin of the connector, and from there 75 ohm to ground.
Step six on this page
If I read things right, I don't even need to lower the voltage (according to the S/PDIF Wikipedia page. The voltage for AES3 balanced has to be between 2V and 7V peak to peak, so 4V is fine.
Meaning I would only need a 110 ohm resistor to ground.
But that leaves me with wiring the chassis connector.
From what I read I need to connect chip wire to pin 2, and ground to pin 1.
Then, if I have it correct, 110 ohm resistor will be between pin 1 and 2.
Am I making any wrong assumptions here?
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spdif out
You should have a look over there
SPDIFTransfo
PhilipsCD931
The wire noted "masse" should be connected to the drive ground with a 100nF capacitor
You should have a look over there
SPDIFTransfo
PhilipsCD931
The wire noted "masse" should be connected to the drive ground with a 100nF capacitor
I think you mixed up our flags 😉
I don't speak nor read a word of French.
I will look at the schematics to see if I can get any wiser from those tomorrow.
I don't speak nor read a word of French.
I will look at the schematics to see if I can get any wiser from those tomorrow.
Hello,
If you want to carry S/PDIF using an XLR and balanced cable over a short distance (< 10m) then I think you will be fine doing pretty much as you suggest.
As soon as you are planning to carry the signal a moderate distance you have to worry about impedance matching, signal balance, etc. In this case, a balanced driver (26C31) + 56 ohms in each leg driving a 1:1 110 ohm AES transformer should work OK. You then need to start using 110 ohm AES/EBU cable and worrying about driving correctly terminated loads, return loss, EMC etc.
There are some bit stream differences between S/PDIF and AES3- a Consumer/Pro bit (amongst others), but I have never had an issue with wrongly identified bit streams.
Regards, Mark
AudioBox, an FPGA experiment
If you want to carry S/PDIF using an XLR and balanced cable over a short distance (< 10m) then I think you will be fine doing pretty much as you suggest.
As soon as you are planning to carry the signal a moderate distance you have to worry about impedance matching, signal balance, etc. In this case, a balanced driver (26C31) + 56 ohms in each leg driving a 1:1 110 ohm AES transformer should work OK. You then need to start using 110 ohm AES/EBU cable and worrying about driving correctly terminated loads, return loss, EMC etc.
There are some bit stream differences between S/PDIF and AES3- a Consumer/Pro bit (amongst others), but I have never had an issue with wrongly identified bit streams.
Regards, Mark
AudioBox, an FPGA experiment
Mark, it would be a meter to a meter and a half max to hook it up to my Devialets AES/EBU connector.
Nick, it looks to me both articles clash a bit.
The Rane article figure 4 just uses a transformer, while the other article uses diodes, capacitors and an IC to do the same.
Oh wait, I see now the first is just AES3 while the other does AES/EBU.
The second is also quite difficult to read IMO.
They talk about 75r and 10u which I get, but what about the 2,2k and 4,7k.
No mention on what it is.
Nick, it looks to me both articles clash a bit.
The Rane article figure 4 just uses a transformer, while the other article uses diodes, capacitors and an IC to do the same.
Oh wait, I see now the first is just AES3 while the other does AES/EBU.
The second is also quite difficult to read IMO.
They talk about 75r and 10u which I get, but what about the 2,2k and 4,7k.
No mention on what it is.
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