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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





Quote from: 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: 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.



Quote from: 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: 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.   ;)