You could put the cables on a network analyser and compare the results, this has been mentioned in other threads ad-nauseoum and ignored. From results I have seen most competent USB cables (especially these days with USB 3) don't blink at these slower interfaces. In fact from what I've seen over the years in connecting digital systems together with cables is that you really have to work hard at messing things up, any competently designed cable will do the job.
What would concern me more is some of the mods and DIY designs where picking the most aggressive driver with the fastest rise time possible seems to be the fashion and solving such a problem (the JKNY, Hi-face, RF attenuator thread is a good read on how to combine the wrong drive rate, with the wrong solution).
A further thought one eye diagrams is its OK doing them, but you have to read the results correctly, as the previous waveforms shown earlier illustrated, very minor differences were jumped one, yet these differences would not affect the results of the data received in any way. The problem is a lot that don't understand digital transmission look at the waveforms as they would analogue, where a miner difference in the waveform will be noticeable in the analogue output.
Next up is testing digital signals through your mud bath, or come up with some funky vegetable coax interfaces🙂
I am using LMR-195 for my 50 Ohm instrumentation BNC cables and it has one of the best construction qualities I have seen in professional RF cables. So LMR-200-75 should be nice too. http://www.timesmicrowave.com/downloads/products/LMR-200-75.pdf
Its because the thread title asks for "Recommendations For 75 Ohm Digital Wire ". So I provided a link for the 75 Ohm next of kin cable to the one I use and has very nice construction quality and spec.
It is funny how some people still don't seem to grasp these concepts, despite the fact that they have been standard engineering practice since Heaviside's transmission line model from the telegraph lines in 1880..
How about homeopathic transmission cables, that only have an extremely diluted virgin silver core?
Forgot about this:
For 75 ohm trace on a double sided PCB with a contiguous ground plane under the trace, the trace has to be about 1.4mm (about 55 thou/mils, for the dinosaurs🙂)wide.
For 75 ohm trace on a double sided PCB with a contiguous ground plane under the trace, the trace has to be about 1.4mm (about 55 thou/mils, for the dinosaurs🙂)wide.
It's quite simple Julf. I've been tested and I seldom ---{and by seldom I mean I have a 90%+ average}--- mistake copper for silver in my system, which I am intimately familiar with.
I am so sure of my capability that I've publically offered to allow myself and my abilities to be tested by Sy and have Sy publish the results here whether I pass or fail the test. Sy and I have already worked out how the testing will be done. Our only problem is finding a time when Sy can get away from work & family and get to Orlando, Fl. to run the test.
Thetubeguy1954 (Tom Scata)
Chesky Records tested 3 different digital cables on their recording equipment:
https://www.hdtracks.com/index.php?file=catalogdetail&valbum_code=090368006820
Tracks 48, 49, 50 - try them in your system.
Tom wrote that he will arrange test with you, so, please let us know the conditions - what tracks were used for tests, and equipment - source, amp, speakers.
Forum discussion i Danish (but tech talk is somewhat international - try google translate)
Lots of measurements from total 75 ohm match to 100% mismatch
HIFI4ALL Forum: Jitter fra kabel?
Lots of measurements from total 75 ohm match to 100% mismatch
HIFI4ALL Forum: Jitter fra kabel?
F connectors are actually pretty poor. They require solid core wire and leave a bare copper lead as the connector. Their only advantage I see is a pretty constant impedance and being very cheap if you have the correct (expencive) termination equipment.
The BNC is a very good connector, but it is expensive and takes a special crimper to terminate.
The RCA jack was invented for RF! Originally, the braid was soldered around the shell and it maintained a very consistent impedance. (no reflections) This does not hold true for any where the braid is separated and soldered on the side. (99.9% of any I see for sale) I suspect some of the compression type are pretty good, but without a TDR, who knows. They are fine all the way up to microwave. One of their best features was they were really cheap. You can use stranded cable.
When questioning wire, if you buy Belden, there is no question. Quad shield is not necessary. It is a gimmic. A quality 98% braid is fine, or a braid over foil (100%) if you think it is necessary. It is for cable TV. (RG-6) You can't exceed 100% no matter how many additional layers.
When buying made cables, Cablemart, Monoprice and BlueJean are no questions.
Note: I prefer fiber to coax. Any real sonic difference has never been demonstrated to me and fiber does not pass a ground loop. Plastic fiber is limited to about 6 feet, where you can send the PCM down 100' of coax with no problems.
So the measurements show that a "total" mismatch ("infinite" load impedance) causes some reflections, but the effect of even those extreme reflections is not that dramatic. How did it actually affect jitter?
No conclusion yet, and also no jitter measurements. The tech minded don't think the cable impedance is that important - just somewhere near 75 ohm. But, differences can be measured. The tech guys just dont think it's important as long as the transmitter and receiver are 75 ohm and are reasonable well made.
Right - that's what I kind of gathered (I speak/read Swedish, *supposedly* close to Danish 🙂 ), and I agree differences can be measured but wonder if they show up in the end result. They are talking about *extreme* mismatch of impedance.
RCA for RF?
RCA connector - Wikipedia, the free encyclopedia
The open end shots in the link show non-monotonic rising and falling edges, this is bad.
http://pcdandf.com/cms/magazine/192/3554-signal-quality-assessment
I see from numerous sources and audio based sites that the 1.5m SPDIF cable is becoming one of the audiophile myths, such as silver cable sounds brighter than copper!
RCA connector - Wikipedia, the free encyclopedia
The open end shots in the link show non-monotonic rising and falling edges, this is bad.
http://pcdandf.com/cms/magazine/192/3554-signal-quality-assessment
I see from numerous sources and audio based sites that the 1.5m SPDIF cable is becoming one of the audiophile myths, such as silver cable sounds brighter than copper!
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RCA was used for RF on some US domestic and amateur gear, and for undemanding applications you can get away with it. Not ideal. In the UK we tended to use the Belling-Lee, until the chunky (but not very good) PL259 replaced it in the 1970s for amateur gear. BNC is better but it looks more flimsy. Some early PA systems used B-L for microphone connections.
Perhaps we should start a trend for B-L for digital audio - at least it is intended for 75R systems.
Perhaps we should start a trend for B-L for digital audio - at least it is intended for 75R systems.
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