|
|
Post by brucew268 on Nov 23, 2021 11:53:50 GMT
I find some issues around SPDIF cables a bit curious (non-optical).
Some refer to a specific construction needing to be used for 75ohm and mention coax, yet there are several out there which appear not to be coax and yet advertise as 75ohm.
RCA does not have the right distances between conductors to maintain 75ohm, yet so many digital components use it rather than BNC.
Some say the distance of signal through an RCA plug is so short that it won’t likely affect the 75ohm characteristic of the signal.
Some have said that a BNC cable using BNC>RCA adapters would be better than an RCA terminated cable.
One ebayer claims to use re-terminated Nordost cable with a completely, non-coax construction and claims 75ohm (unspecified model equivalence). So not sure what to make of that. Can’t find any forum discussing user experience of his SPDIF cables. www.ebay.co.uk/itm/133932398682
Of course, Tony shows measurements that seem to indicate that reflections are rarely an issue.
OTOH: I recall that when Sommovigo came out with the D60 that was precisely 75ohm and 1.3M or longer (anti-reflection) people seemed to report that the SQ was significantly higher than others who did not. Whether that was hype or real, and whether it was due to the impedance, the length, the pure silver solid core conductors, or the use of air and Teflon in the dielectric… do we really know?
But what about coax vs other constructions, BNC, etc, etc? |
|
optical
Moderator
BIG STAR
Be Excellent To Eachother
Posts: 1,624 
|
Post by optical on Nov 23, 2021 12:05:28 GMT
Not surprised to see I am now banned in advance from these kind of threads . . . .
Haha
Really interesting discussion anyway, as you point out I was under the impression that it was the distance between the conductors which governs the cables ability to maintain 75ohm at both ends . . . Not seen the BNC-RCA adapter point raised before but to me that seems counter-intuitive to getting the 75ohm standard.
I'm sure those more in the know will be along shortly to confirm/deny this.
|
|
|
|
Post by brucew268 on Nov 23, 2021 12:12:36 GMT
Not surprised to see I am now banned in advance from these kind of threads . . . . Haha We know you're such a troublemaker! Sorry, nothing personal... what's in a name?  |
|
|
|
Post by macca on Nov 23, 2021 12:24:51 GMT
my understanding is the cable would need to be very long before the impedance became an issue - like hundreds of feet.
|
|
|
|
Post by antonio on Nov 23, 2021 12:33:48 GMT
Not surprised to see I am now banned in advance from these kind of threads . . . . Haha We know you're such a troublemaker! Sorry, nothing personal.  He's not a trouble maker Bruce, I call it playing Devil's Advocate, and for me, the more of them the better  |
|
|
|
Post by firebottle on Nov 23, 2021 12:34:11 GMT
Not strictly true there Martin for digital transmission, it depends on the frequencies involved. Higher frequency will be affected with shorter lengths if mismatched.
It is true at audio frequencies.
|
|
|
|
Post by firebottle on Nov 23, 2021 12:36:45 GMT
Some have said that a BNC cable using BNC>RCA adapters would be better than an RCA terminated cable.
I have to disagree here. Most adapters are cheap and nasty, so a properly terminated cable is better. There are better quality adapters available that generally have gold plated contacts and PTFE insulators. |
|
|
|
Post by brucew268 on Nov 23, 2021 12:41:50 GMT
my understanding is the cable would need to be very long before the impedance became an issue - like hundreds of feet. "Became an issue," I imagine would need to be characterised more specifically. Before what level of self-induced noise (reflections) and loss would become problematic in its originally intended application? Would that measure have the same level of relevance for the kind of high fidelity music transmission that our sort tend to care about? |
|
|
|
Post by misterc on Nov 23, 2021 12:42:35 GMT
my understanding is the cable would need to be very long before the impedance became an issue - like hundreds of feet. Acutally Martin it be be as short as 12" if the connectors are at different impedances this is where reflections from the signal bouce back and forth along the hitting 'hitting' an impedance discontinuity and there fore more reflections are generated. Co-ax isn't the only cable to have a speficied impedance.
Impedance is just but one aspect of a cable parameters which may or may not be important when selecting a cable for a suitable purpose. Insertion loss, standing wave ratio, dieletric constant, conductivity index to name but a few few.
|
|
|
|
Post by brucew268 on Nov 23, 2021 12:50:29 GMT
Some have said that a BNC cable using BNC>RCA adapters would be better than an RCA terminated cable.
I have to disagree here. Most adapters are cheap and nasty, so a properly terminated cable is better. There are better quality adapters available that generally have gold plated contacts and PTFE insulators. I've noticed that Black Cat Cable and Nordost Tyr cables both tend to sell their cables as BNC's with RCA adapters. Whether they are custom made or they just found a supplier with consistent measurements and flashed gold onto them... who knows?
www.thecableco.com/bnc-to-rca-adapter-single.html
|
|
Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,401
|
Post by Bigman80 on Nov 23, 2021 12:56:20 GMT
|
|
|
|
Post by brucew268 on Nov 23, 2021 12:56:27 GMT
One ebayer claims to use re-terminated Nordost cable with a completely, non-coax construction and claims 75ohm (unspecified model equivalence). So not sure what to make of that. Can’t find any forum discussing user experience of his SPDIF cables. www.ebay.co.uk/itm/133932398682 Impedance is just but one aspect of a cable parameters which may or may not be important when selecting a cable for a suitable purpose. Insertion loss, standing wave ratio, dieletric constant, conductivity index to name but a few few.
Good, so who has defined appropriate range for each... and why do manufacturers never list those measurements? Too complicated and would not make for sexy marketing? What would you predict for the cable products of the ebayer above? |
|
|
|
Post by brucew268 on Nov 23, 2021 12:59:21 GMT
I'm going to give you the honorary "Antonio Finder" award for the hour! |
|
optical
Moderator
BIG STAR
Be Excellent To Eachother
Posts: 1,624
|
Post by optical on Nov 23, 2021 12:59:57 GMT
+1 on the Neotech - best I've tried for both digital and analogue. (Still waiting for my Triple C to be posted!). My, that is one very lovely plug there. |
|
|
|
Post by misterc on Nov 23, 2021 13:20:23 GMT
Good, so who has defined appropriate range for each... and why do manufacturers never list those measurements? Too complicated and would not make for sexy marketing? What would you predict for the cable products of the ebayer above? Bruce, this is audio  ask 80% of EE's outside of RF and they is no difference at all for signal transfer what so ever reguardless of wht you think you hear just to give you a hint of what they really feel check out this out.
Remember the vast majoirty of EE's are strickly if you can't meaure it then it doesn't exsist, and the other side are hard core audiofools who can a pin drop at the bottom a volcanic casum 2000 feet down during an eruption 
The REAL truth is nearer the middle ground imho, never been a fan of BNC<>RCA cables never kaerd any satisfactory results from that configure just marginaly better than using adapters lol
Here the guy's real dig deeper into Tarun's musing (I find him quite funny and patronising at the same time) but a he's a good watch even if politely barking mad!
Round the Mulberry bush
The real question that should be posoded and Macca will use both boots here, what REALLY DOES PARAMETER wise (make that difference that quaitifies an audiable difference) is it something we have not yes discovered ?, is it a combination of circumstances (various cable traits that in a state of combination make that difference) we are all totally deluded and should be commited to listen to James Blunt for Eternity ona Naim or Linn system!!!!!!!!!!!!!!!!!!!!!!!!!!!
Who's knows?
But then I should be at the head of the que for the JB listening room then!
|
|
|
|
Post by brucew268 on Nov 23, 2021 13:28:24 GMT
Bruce, this is audio ask 80% of EE's outside of RF and they is no difference at all for signal transfer what so ever reguardless of wht you think you hear just to give you a hint of what they really feel check out this out. Remember the vast majoirty of EE's are strickly if you can't meaure it then it doesn't exsist, and the other side are hard core audiofools who can a pin drop at the bottom a volcanic casum 2000 feet down during an eruption The REAL truth is nearer the middle ground imho, never been a fan of BNC<>RCA cables never kaerd any satisfactory results from that configure just marginaly better than using adapters lol
Here the guy's real dig deeper into Tarun's musing (I find him quite funny and patronising at the same time) but a he's a good watch even if politely barking mad! Round the Mulberry bushYeah, been present for those arguments/slatings for 30 years. I usually "leave the room" after a minute or two. |
|
|
|
Post by brucew268 on Nov 23, 2021 13:35:46 GMT
+1 on the Neotech - best I've tried for both digital and analogue. (Still waiting for my Triple C to be posted!). My, that is one very lovely plug there. Need a serviette for that drool?!
|
|
optical
Moderator
BIG STAR
Be Excellent To Eachother
Posts: 1,624
|
Post by optical on Nov 23, 2021 13:45:53 GMT
|
|
|
|
Post by misterc on Nov 23, 2021 13:49:26 GMT
My observations have been over the years silver maybe the best conductor in terms of electrical properties but to my ears has never produced the most desriable sounds.
Two years ago pre covid I conducted an expeeriment with six of our beta test clinets, made two indentical sets of grounding leads ups one with some silly cost 7N's ultra pure Japanese silver conductors hemiectially sealed and vac packed deliverd via two guys that make me look like a 18 month study case for belimia!
We even kept 500 gramms for smelting so we could plated the conductors with 8 micron's of the matching material.
sent them out to all of the cleints and asked for detailed commentry on whay they felt about the cables, the were indentical lengths , had matching triple dielectrics and shilding.
No of them felt the silver cable produced any benefits over the other conductor material, sound wise you could tell pretty much straight way BUT they had to work out for themselves what they felt and why.
That expriment cost myself personally five figures to conduct bit it worth every penny for the research and results. It just re affirmed my thoughts on this subject and surprised a lot of other people.
One last comment on the silver cable thang, pure silver conductors are NOT bright or forward in any way, they are open and smooth another audiomyth states they are bright and forward, maybe with cheap and nasty silver plated multi stranded tow rope (qed et al) but in no way with high quality pure silver cabling imho.
|
|
|
|
Post by antonio on Nov 23, 2021 15:00:28 GMT
+1 on the Neotech - best I've tried for both digital and analogue. (Still waiting for my Triple C to be posted!). My, that is one very lovely plug there. Need a serviette for that drool?!
Bruce, you may as well buy this, which uses Oyaide's silver BNC connectors, probably the best you can get www.ebay.co.uk/itm/353662924966?epid=14015171299&_trkparms=ispr%3D1&hash=item5257f3f8a6Optical, those two MPS cables are both exceptionally well priced in my opinion. |
|
|
|
Post by macca on Nov 23, 2021 16:36:37 GMT
Not strictly true there Martin for digital transmission, it depends on the frequencies involved. Higher frequency will be affected with shorter lengths if mismatched. It is true at audio frequencies. I'm talking about impedance over very long runs and how that relates to the impedance of the connector, and hence why it doesn't matter that the connector is not 75 ohm unless the cable is very long. I'm aware of transmission line reflection and the need for a cable to be 1.5 metres minimum, although I have seen it stated that this is not an issue with modern DACs, I forget why exactly. Still, I use a 1.5 metre cable just for peace of mind and since it isn't expensive, why not? |
|
|
|
Post by brucew268 on Nov 23, 2021 18:25:17 GMT
That's a much better price than available from UK sellers and almost as cheap as doing it DIY with the Aeco BNC's. Not that I'm ready to go Oyaide.
Separately: I’ve noticed how coax which by nature is shielded is still SO sensitive to dressing. Interesting what these two mfrs say about their shielding. Whether they could actually make it fairly insensitive to dressing seems logically possible but unlikely... this IS marketing material!
Kimber D60 - "Dual layer pure silver shielding with 100% coverage is circumferentially bonded to the connector shell for absolute immunity to noise."
Black Cat Silverstar - "Mk. II now includes a secondary silver-plated copper shield, addition of RFI rejection material, and an overall braided jacket from multifilament nylon."
|
|
|
|
Post by mrian on Dec 14, 2021 18:50:35 GMT
Best solution i found was 1.5m belden component leads with canare rca. Used to be cheap because everyone dumped them when they moved to hdmi. But still offer great value when they come up. Not bad as interconnects too if you buy a triway component cable
|
|
|
|
Post by brian2957 on Dec 14, 2021 20:50:19 GMT
|
|
Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,401
|
Post by Bigman80 on Dec 14, 2021 22:08:11 GMT
That MPS stuff is very respectable. |
|
|
|
Post by brian2957 on Dec 14, 2021 22:15:09 GMT
Yup, agreed Oli. TBH I wasn't that keen on this cable when used as interconnects but I've been really surprised at how good the MPS cable sounds when used as a digital cable. I will have a good listen over the next few days.
To be fair, it is sold as a digital cable.
|
|
Bigman80
Grandmaster
The HiFi Bear/Audioaddicts/Bigbottle Owner
Posts: 16,401
|
Post by Bigman80 on Dec 14, 2021 22:22:01 GMT
Yup, agreed Oli. TBH I wasn't that keen on this cable when used as interconnects but I've been really surprised at how good the MPS cable sounds when used as a digital cable. I will have a good listen over the next few days. To be fair, it is sold as a digital cable. Yes, like you I wasn't keen as an interconnect either. For the money it's excellent for digital transfer duties. |
|
|
|
Post by mrian on Dec 15, 2021 6:52:32 GMT
Belden 1694a can be bought for under £3/m, the large component retailers sell it or 2m delivered for under £10 via ebay auction
|
|
|
|
Post by brucew268 on Dec 15, 2021 10:27:17 GMT
Belden 1694a can be bought for under £3/m, the large component retailers sell it or 2m delivered for under £10 via ebay auction Yes, I've been using the Canare/Bleden combination and is pretty decent but I am looking for a bit more performance than it's delivering. |
|
|
|
Post by mrian on Dec 15, 2021 13:37:26 GMT
No point in starting another cable debate, but with spdif i suspect the quality of the terminals and termination will have a far bigger impact on the wave form than changes between different types of 75 ohm cable.
You might see improvements if you removed all the connectors and hard wire the spdif cable.
|
|
ask 80% of EE's outside of RF and they is no difference at all for signal transfer what so ever reguardless of wht you think you hear just to give you a hint of what they really feel check out this out.
