You're welcome..

Posted by flood2 (A) on March 6, 2016 at 20:25:19

In Reply to: RE: Thanks! I think I found a better link, though.... posted by John Elison on March 6, 2016 at 19:50:26:

I know the ones you mean. I have converted most of my digital equipment to BNC, but a few still need RCA and I also have 75 ohm RCA connectors designed for use with "proper" RF coax like RG59. However, I was generalising; the normal "stranded" coax cable used for interconnects require soldering. The characteristic impedance is more like 50 ohms for those.

TBH, if you run a short length (i.e <1m) the issues about impedance mismatch are not really that big an issue especially with modern interface receivers. The SPDIF spec has an allowable tolerance of nanoseconds of jitter. Of more concern than the transmission line characteristic impedance is the uniformity of the source and load matching impedances as a function of frequency.
"Back in the day" (late 80s, early 90s), it was the source and load impedance mismatches which caused most of the audible differences between DAC/transport. I remember reading an old HiFi Choice reviewing DACs with 3 different transports. Not surprisingly, the results showed that people liked the sound from DACs which matched the transport characteristic for uniformity. Some transports and DACs had large variations in impedance with frequency. A transport that sounded good with one DAC might be less favourably viewed with a different DAC.

These days with superior Interface Receivers and reclocking, this is far less of a problem. For convenience, I use the HDMI output of my Oppo into my NAD M51 - that doesn't suffer from the typically high levels of jitter normally associated with HDMI as the data is reclocked with respect to the 108MHz video clock which forms the reference for the output PWM signal which directly drives the output devices to give an analogue output. These days it is reasonably inexpensive to achieve superior results. I bought a 0.5m HDMI cable rated for 4K video transmission for the equivalent of USD 5 and the results are very close to the AES input reclocked via the Grimm CC1 - If I weren't already using that for my recordings, I would have no real need for it!

Regards Anthony

"Beauty is Truth, Truth Beauty.." Keats

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Follow Ups Full Thread

Topic - AES/EBU digital 110 ohm characteristic impedance - Duster 18:40:57 03/3/16 (19)

RE: AES/EBU digital 110 ohm characteristic impedance - Thorsten 19:38:09 03/9/16 (3)

RE: AES/EBU digital 110 ohm characteristic impedance - noway 06:48:19 03/24/16 (1)

RE: AES/EBU digital 110 ohm characteristic impedance - Thorsten 06:57:23 03/25/16 (0)

RE: AES/EBU digital 110 ohm characteristic impedance - 91derlust 12:57:29 03/21/16 (0)

RE: "...one might think that a rather strict tolerance is required..." - genungo 00:51:05 03/7/16 (0)

What I have been told is... - John Marks 19:05:25 03/3/16 (13)

Let's be careful going forward... - Chris Garrett 22:11:52 03/6/16 (0)

RE: What I have been told is... - PAR 16:26:47 03/4/16 (1)

I agree with many of your points--especially what happens behind the back panels. - John Marks 16:40:26 03/4/16 (0)

RE: What I have been told is... - John Elison 19:40:28 03/3/16 (9)

I am running out the door. - John Marks 13:04:59 03/4/16 (8)

Thanks! I think I found a better link, though.... - John Elison 13:57:07 03/4/16 (7)

RE: Thanks! I think I found a better link, though.... - flood2 18:57:32 03/6/16 (5)

RE: Thanks! I think I found a better link, though.... - John Elison 19:50:26 03/6/16 (4)

You can measure this with a Time Domain Reflectometer - Tony Lauck 10:42:40 03/7/16 (2)

RE: You can measure this with a Time Domain Reflectometer - John Elison 22:18:08 03/7/16 (1)

RE: You can measure this with a Time Domain Reflectometer - flood2 14:59:42 03/8/16 (0)

You're welcome.. - flood2 03/6/1620:25:19 03/6/16 (0)

That's what the math looks like! - John Marks 16:31:35 03/4/16 (0)

Follow Ups

You're welcome.. - flood2 03/6/1620:25:19 03/6/16 (0)

You're welcome..

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