So SPDIF has a 75 ohm characterisc impedance, and RCA's don't do 75 ohms.
You can buy (or be given) 75 ohm BNC's.
With a proper 75 ohm BNC, there is no reflection, and basically no signal degradation through the connector, as opposed to a RCA, where you will get both. There are plenty of pics floating around here and other audio websites where you can see the signal degradation when it passes through something other than 75 ohms.
Since this is diyaudio, I think people can change a RCA to a BNC.
So I guess I don't understand why people would use RCA's for SPDIF?
I will admit I never listened, to see if I could hear a difference between RCA and BNC for SPDIF, I am not even using SPDIF at this time. But if I was, since I know RCA is not optimal, why use it?
Randy
You can buy (or be given) 75 ohm BNC's.
With a proper 75 ohm BNC, there is no reflection, and basically no signal degradation through the connector, as opposed to a RCA, where you will get both. There are plenty of pics floating around here and other audio websites where you can see the signal degradation when it passes through something other than 75 ohms.
Since this is diyaudio, I think people can change a RCA to a BNC.
So I guess I don't understand why people would use RCA's for SPDIF?
I will admit I never listened, to see if I could hear a difference between RCA and BNC for SPDIF, I am not even using SPDIF at this time. But if I was, since I know RCA is not optimal, why use it?
Randy
If I built some digital stuff I would use BNC. If bought stuff has RCA I would leave it in place. Changing to BNC could make things worse unless the DIYer is used to making VHF connections - most are not.
A very knowledgeable person wrote, about 44/48 S/PDIF:
First off, while SPDIF cables carry digital signals, the digital signals are not sharp edged square waves because consumer SPDIF outputs are generally fed though a low pass filter to minimize EMI so that the equipment can pass FCC Part 15 rules. Typical bandpass runs from 8 to about 20 Mhz.
First off, while SPDIF cables carry digital signals, the digital signals are not sharp edged square waves because consumer SPDIF outputs are generally fed though a low pass filter to minimize EMI so that the equipment can pass FCC Part 15 rules. Typical bandpass runs from 8 to about 20 Mhz.
You may need a bit more than that.
Sample rate x 2 (stereo) x bit length x harmonics (say, 5 bare minimum).
For 48kHz, 16 bit, this gives 7.68MHz - which is very much a low estimate. You would want a better square wave, and there is a little metadata to add too. 15-20MHz might be better. 96kHz will double it. Anything above 30MHz is VHF.
Sample rate x 2 (stereo) x bit length x harmonics (say, 5 bare minimum).
For 48kHz, 16 bit, this gives 7.68MHz - which is very much a low estimate. You would want a better square wave, and there is a little metadata to add too. 15-20MHz might be better. 96kHz will double it. Anything above 30MHz is VHF.
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