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Post by mrholmes on Sept 22, 2020 5:51:50 GMT -6
My new RME AD-DA is not supporting the Cinch out for the SPDIF signal. Two questions come up.
1. Is the XLR pin configuration similar to the audio signal except that we have just two lines.
2. Does it matter that I only have 75 Ohm cable instead of 110 Ohms at a length of 16 feet.
Cheers
A.
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Post by svart on Sept 22, 2020 6:03:01 GMT -6
My new RME AD-DA is not supporting the Cinch out for the SPDIF signal. Two questions come up.
1. Is the XLR pin configuration similar to the audio signal except that we have just two lines.
2. Does it matter that I only have 75 Ohm cable instead of 110 Ohms at a length of 16 feet.
Cheers
A.
1. What's a cinch connector? 2. AES XLR is the same pinout as a regular audio XLR. 3. Not really. Modern Spdif/AES receivers are the same chips these days so they're set up for detecting signals beyond a threshold. Amplitude differences from slightly different resistances shouldn't matter. I just wouldn't make the cable any longer and you should be ok. |
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Post by mrholmes on Sept 22, 2020 6:32:51 GMT -6
My new RME AD-DA is not supporting the Cinch out for the SPDIF signal. Two questions come up.
1. Is the XLR pin configuration similar to the audio signal except that we have just two lines.
2. Does it matter that I only have 75 Ohm cable instead of 110 Ohms at a length of 16 feet.
Cheers
A.
1. What's a cinch connector? 2. AES XLR is the same pinout as a regular audio XLR. 3. Not really. Modern Spdif/AES receivers are the same chips these days so they're set up for detecting signals beyond a threshold. Amplitude differences from slightly different resistances shouldn't matter. I just wouldn't make the cable any longer and you should be ok.
Cinch is the EU Term I think...
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Post by svart on Sept 22, 2020 7:12:45 GMT -6
1. What's a cinch connector? 2. AES XLR is the same pinout as a regular audio XLR. 3. Not really. Modern Spdif/AES receivers are the same chips these days so they're set up for detecting signals beyond a threshold. Amplitude differences from slightly different resistances shouldn't matter. I just wouldn't make the cable any longer and you should be ok.
Cinch is the EU Term I think...
Ah ok. We call those RCA connectors here. |
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Post by mrholmes on Sept 22, 2020 7:47:23 GMT -6
svart I wonder if the 110 ohm thing is a true value market delivers diffrent cabels 0.22 or 0.38 and they all say its 110 Ohms something cant be right with this?
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ericn
Temp
Balance Engineer
Posts: 14,934 
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Post by ericn on Sept 22, 2020 8:53:43 GMT -6
Cinch is the EU Term I think...
Ah ok. We call those RCA connectors here. We call them Crap |
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Post by svart on Sept 22, 2020 9:27:01 GMT -6
svart I wonder if the 110 ohm thing is a true value market delivers diffrent cabels 0.22 or 0.38 and they all say its 110 Ohms something cant be right with this? Cables have no inherent impedance of their own. They're just verified to have a certain amount of loss at that impedance. A lot of times the cable is exactly the same, just tested at both impedances. |
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Post by mrholmes on Sept 22, 2020 11:41:00 GMT -6
Ah ok. We call those RCA connectors here. We call them Crap I know, but the receiver unit is having one for space reasons... |
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Post by mrholmes on Sept 22, 2020 15:50:34 GMT -6
svartTotally crazy the AES EBU makes sample rate trouble when the main unit is connected via Fire Wire. Connecting via USB everything runs perfect. Anything wrong with using USB2 for AUDIO?
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Post by johneppstein on Sept 22, 2020 16:22:49 GMT -6
1. What's a cinch connector? 2. AES XLR is the same pinout as a regular audio XLR. 3. Not really. Modern Spdif/AES receivers are the same chips these days so they're set up for detecting signals beyond a threshold. Amplitude differences from slightly different resistances shouldn't matter. I just wouldn't make the cable any longer and you should be ok.
Cinch is the EU Term I think...
those are RCA phono connectors. Cinch connectors are something quite different and not like to be encountered at your level.
EDIT: Googling I see that RCA connectors are sometimes called "cinch" in Europe, which is a misapplication of the term. A REAL Cinch connector, also called "Cinch-Jones" is a (usually) rectangular multipin connector usually encountered in various types of obsolete/vintage equipment. It is available in varions numbers of pins, which are flat metal. AFAIK Cinch connectors are usually polarized.
The Cinch company is currently a subsidiary of ITT and, as far as I can tell, now primarily makes various RF connectors, mostly BNCs (Bayonet-Nut Connectors).
Cinch connectors have now been superseded in most applications by various smaller types of multipin - D-sub, Amphenol, etc.
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Post by jeremygillespie on Sept 22, 2020 16:50:08 GMT -6
Cinch is the EU Term I think...
those are RCA phono connectors. Cinch connectors are something quite different and not like to be encountered at your level. Yikes man... that’s a weird flex |
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Post by svart on Sept 22, 2020 17:00:43 GMT -6
those are RCA phono connectors. Cinch connectors are something quite different and not like to be encountered at your level. Yikes man... that’s a weird flex I looked it up and they are indeed alternately called cinch connectors in Europe. Cinch is also a brand of connectors. |
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Post by jeremygillespie on Sept 22, 2020 17:14:37 GMT -6
John’s probably taking about a Cinch Jones connector.
No excuse for the taking down to folks though, especially if he’s not going to be specific. Not sure if that was intended or if I’m reading too much into it. Whatever.
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Post by johneppstein on Sept 22, 2020 17:19:19 GMT -6
svart I wonder if the 110 ohm thing is a true value market delivers diffrent cabels 0.22 or 0.38 and they all say its 110 Ohms something cant be right with this? Cables have no inherent impedance of their own. They're just verified to have a certain amount of loss at that impedance. A lot of times the cable is exactly the same, just tested at both impedances. Not in HF stuff like video or clocking. If you mix 75 ohm and 95 ohm you can really mess up your timing.
Since impedance is essentially AC resistance, cables definitely DO have impedance, but in audio it usually doesn't matter. In video or any type of digital transmission it definitely does.
for explanations in detail, google "cable impedance"
Back when I had a Video Toaster editing /switching system it DEFINITELY mattered. Not only did all (analog) video cables have to be 75 ohm, they also needed to be the same length or weird things happened to your picture. Same thing running a master clock in an audio system.
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Post by svart on Sept 22, 2020 19:09:24 GMT -6
Cables have no inherent impedance of their own. They're just verified to have a certain amount of loss at that impedance. A lot of times the cable is exactly the same, just tested at both impedances. Not in HF stuff like video or clocking. If you mix 75 ohm and 95 ohm you can really mess up your timing.
Since impedance is essentially AC resistance, cables definitely DO have impedance, but in audio it usually doesn't matter. In video or any type of digital transmission it definitely does.
for explanations in detail, google "cable impedance"
Back when I had a Video Toaster editing /switching system it DEFINITELY mattered. Not only did all (analog) video cables have to be 75 ohm, they also needed to be the same length or weird things happened to your picture. Same thing running a master clock in an audio system.
I'm not sure you've picked up on it in the past but I design electronics that use high speed and high bandwidth transmission lines (cables, traces, antennas, etc). I'm quite well versed in impedance and transmission line theory, been doing it for the last 15 years. And you're dead wrong. Cables do not have an impedance. They simply interact with the impedances they're interfaced with. |
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Post by johneppstein on Sept 22, 2020 23:06:13 GMT -6
Not in HF stuff like video or clocking. If you mix 75 ohm and 95 ohm you can really mess up your timing.
Since impedance is essentially AC resistance, cables definitely DO have impedance, but in audio it usually doesn't matter. In video or any type of digital transmission it definitely does.
for explanations in detail, google "cable impedance"
Back when I had a Video Toaster editing /switching system it DEFINITELY mattered. Not only did all (analog) video cables have to be 75 ohm, they also needed to be the same length or weird things happened to your picture. Same thing running a master clock in an audio system.
I'm not sure you've picked up on it in the past but I design electronics that use high speed and high bandwidth transmission lines (cables, traces, antennas, etc). I'm quite well versed in impedance and transmission line theory, been doing it for the last 15 years. And you're dead wrong. Cables do not have an impedance. They simply interact with the impedances they're interfaced with. OF COURSE they have an impedance. EVERYTHING above absolute zero (temperature) has an impedance. It's basic physics.
If it has resistance it has impedance. The question is whether that impedance matters.
Have you ever set up a video switcher or an editing suite? I have. And when you have you know damn well that cables have impedance and that length matters.
Show me a cable that has zero resistance. Resistance is simply DC impedance. Impedance, being frequency sensitive, is more complex, but it's still the same basic thing. Ask any commercial radio/TV engineer.
And yes, I know you're a designer. Much of the time designers ignore things that are seen as unimportant to the things they work on. I'm not a designer, I'm a tech. Sometimes techs have to deal with stuff that designers dismissed as "unimportant".
If cables had no impedance all transmission would be instantaneous and they're not - which is why it's important in video and digital clocking systems to keep all cables the same length - otherwise you get crap like rolling screens when doing a transition.
Since analog audio is all relatively "low frequency" - below 20kHz - it's unimportant for the most part, although it can sometimes result in "phase smearing" of higher frequencies. Because since impedance is frequency dependant it can throw off the phase of harmonics in an audio signal.
You SHOULD know this, unless you don't often deal with electrically parallel lines between source and load.
When I got my Toaster system back in the early 90s the manual drilled this into you, because if you don't pay attention to it the switcher won't work right.
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