ar-t;348183 Wrote: > BTW......XLR connectors........they -really- are 110 ohms. But, like he > said..........they don't stay that way. (Hint: look at how far apart > the pins are, and how long they are. Look at a BNC. See why now?)
It looks like I can't agree with a lot you write tonight so sorry but no, I don't see it. Are you referring to the difference in size? The BNC is a UHF coax connector with just one pin while the XLR3 is a LF connector with 3 pins. The size of the connector doesn't influence the impedance at all but is matched to the cable to be used for it. Thick coax with less loss doesn't fit a BNC but does fit a big N-type connector while both have the same impedance. Sturdiness is another reason for bigger connectors. If you would move the pins closer (or further apart) you would change the impedance of the connector but it wont fit the female pins anymore so that won't happen I think. Do you mean it changes impedance because of contact corrosion or wear? Or aging of the dielectric insulation? This is true but it's valid for all connectors and all coax cables. That's why they have a limited life-span. Coax with foam dielectric is famous for it's good spec's but also for it's short lifespan. Please let me know if this is what you mean with the connector changing it's impedance. XLR3 is not a problem for AES because I think (correct me if I'm wrong here) the max. frequency is the sampling rate (biphase mark code modulation) which would make that 192 kHz, which is still LF. BNC 75 Ohm is good from DC to 2 GHz (50 Ohm version up to 4 GHz) but mostly only needed for 250 MHz and up but gets a lot more use because it's a convenient and cheap connector. Even the cheapest of the cheap F-type TV connector that uses the coax center-conductor as the pin for the male connector (!) has a good 75 Ohm impedance up to a couple of GHz. RCA is so messed up because it was used for everything from DC feed to UHF and you never know what you get. But one could design and manufacture a good quality 75 Ohm version! So I conclude that for home-use S/PDIF, BNC connectors are great and I would consider replacing RCA's with BNC. But if I had AES with XLR3 I would be happy too; it's probably even better. I've never seen AES with RCA but I read that it is in use and I would be not so happy with that. I would definitely --not-- settle for any adapters (like RCA->BNC) because they are an extra source of echo's. cheers, Nick. -- DeVerm ------------------------------------------------------------------------ DeVerm's Profile: http://forums.slimdevices.com/member.php?userid=18104 View this thread: http://forums.slimdevices.com/showthread.php?t=52817 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
