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Gear / Technical Help => Cables => Topic started by: tedyun on August 17, 2010, 12:22:00 PM

Title: BNC > RCA cable
Post by: tedyun on August 17, 2010, 12:22:00 PM
I tried to make a digital cable to go out of an AD2K+ to a PMD-661. I am using a 75 ohm cable (Mogami 2964). I thought this should be brain-dead simple, ie., solder the conductor to the tips of the connectors and the sleeve to the shield. When I connect the cable, I get a "digital-in error." When I use my RCA > RCA cable with a BNC adapter, the connection is fine, so I'm sure it's my handiwork.

I made sure there are no loose connections, and no shorts.

Is there something obvious I'm overlooking?
Title: Re: BNC > RCA cable
Post by: tgakidis on August 17, 2010, 12:27:52 PM
BNC connectors exist in 50 and 75 ohm versions.  Looks like you might have a 50 ohm

http://en.wikipedia.org/wiki/BNC_connector
Title: Re: BNC > RCA cable
Post by: tedyun on August 17, 2010, 12:38:42 PM
I thought that might have been it, but it looks like it's a 75 ohm BNC:

http://www.redco.com/shopexd.asp?id=686&bc=no

This is the RCA connector:

http://www.redco.com/shopexd.asp?id=299&bc=no

and this is the cable:

http://www.redco.com/shopexd.asp?id=511&bc=no





BNC connectors exist in 50 and 75 ohm versions.  Looks like you might have a 50 ohm

http://en.wikipedia.org/wiki/BNC_connector
Title: Re: BNC > RCA cable
Post by: notlance on August 17, 2010, 02:47:21 PM
"I made sure there are no loose connections, and no shorts."

How did you make sure?  Did you use an Ohm meter to check your work?  I do not intend to doubt your abilities, but working with coax it's easy to get a stray shield wire that shorts the cable.  I do it all the time!
Title: Re: BNC > RCA cable
Post by: tedyun on August 17, 2010, 04:15:33 PM
I can check again. The shield wire is definitely not touching the cable.



"I made sure there are no loose connections, and no shorts."

How did you make sure?  Did you use an Ohm meter to check your work?  I do not intend to doubt your abilities, but working with coax it's easy to get a stray shield wire that shorts the cable.  I do it all the time!
Title: Re: BNC > RCA cable
Post by: spyder9 on August 17, 2010, 06:56:17 PM

http://www.bluejeanscable.com/store/digital-audio/index.htm

I just bought the Belden 1694A, 6 feet RCA/BNC for $23.00 shipped.  Might save you the time and aggravation.   ;)