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...We hope (BNC is) the connection of choice...for anyone using...an outboard DAC. BNC connectors have a true 75 Ohms impedance, and will not create reflections that corrupt the integrity of digital signal transmission...
"...doesn't think much of the AES3 digital-on-balanced-cables standard, which he believes is the result of an engineering compromise in the early days of digital intended to allow European broadcasters to save money by using their installed base of balanced analog microphone cables as digital-audio cables..."
"simply wrong for digital audio, in all mechanical respects"
...The result is reflections-echoes of the signal travel back and forth, corrupting the real signal resulting in jitter and ringing near the signal edges which are the transitions between 0 and 1. The longer the cable and the higher the sampling rate, the worse the problem."
"[...]BNC connectors have a true 75 Ohms impedance, and will not create reflections that corrupt the integrity of digital signal transmission..."
I'd love to have an Oscilloscope. Don't know how to use one or what all I could do with it but still, I'd like to own one There's a 2245a on CL in my area now for $150.00. Looks kinda rough from the front. Owner say's it's 4ch but he only has two leads.
Wow, those are amazing differences in the images. Thanks very much.So do you agree with Schram 100%? That speaks badly of the industry in general, and especially manufacturers still including XLR and RCA digital connectors.
And here's a quick demo of what can happen to digital signals when encountering impedance mismatches.....................Now instead of this rather controlled setup, let's imagine some generic microphone cable with RCA connectors at the ends.... each of a different impedance and all varying with frequency .
A terminator is one thing and a connector is another! Get out your Ohm-meter and measure the terminator, it will read it's listed value. Measure a connector and it will read near infinity. For a rather low frequency circuit like S/PDIF the connector is not a factor. For short interconnects like 1 or 2 meters the co-ax is not a factor either.
RCA's and XLR's are not 75 ohm, so they will create reflections and degrade the signal.
And it's a good thing the XLR connector impedance isn't 75 ohm, as the specified impedance for an AES/EBU connection is 110 ohm.
You can get 75 ohm rca connectors, but BNC is the way to go if you can.
Examples?Guys smarter than me say that the RCA's that claim to be 75 ohm are not really 75 ohm, and some of them have the instruments to really measure it.Randy
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