I just finished making a pair of BNC quad shield cables and I was wondering if there were many people out there rocking with BNC and Quad Shield Coax for Line Level applications?
Benefits of BNC over RCA:
#1 They are certianly a lot cheaper than most high end RCA cables and have a much more rugged connection than RCA having the center conductor protected.
#2 There is also a great deal less variation in quality compared to RCA which has been remade ad-infinitum to the point that no one can standardize properly.
#3 BNC connects the shield first before the tip, another benefit.
#4 BNC to RCA adaptors and vice versa are widely available and cheap.
#5 Higher bandwidth, lower ingress of noise.
#6 At frequencies below 10 MHz the impedance mismatch between a 50 ohm connector or cable and a 75 ohm one has negligible effects. (http://en.wikipedia.org/wiki/BNC_connector#Compatibility)
#7 A beautiful pure copper 18 AWG center conductor with 4 shields, 2 braided and 2 foil.
#8 Much lower impedance connection vs RCA = lower noise floor.
These cables are going inbetween my DAC and my soon-to-arrive KT88 SE kit amplifier, They measure on my multimeter as 000.3 ohms (or 000.0 ohms, unregisterable) for 3 meters of coax or shield. without any inter conductor short, I'm old hat at terminating quad shield to F connectors so this was a cinch.
The novel book inside of the box is Condorman.
Benefits of BNC over RCA:
#1 They are certianly a lot cheaper than most high end RCA cables and have a much more rugged connection than RCA having the center conductor protected.
#2 There is also a great deal less variation in quality compared to RCA which has been remade ad-infinitum to the point that no one can standardize properly.
#3 BNC connects the shield first before the tip, another benefit.
#4 BNC to RCA adaptors and vice versa are widely available and cheap.
#5 Higher bandwidth, lower ingress of noise.
#6 At frequencies below 10 MHz the impedance mismatch between a 50 ohm connector or cable and a 75 ohm one has negligible effects. (http://en.wikipedia.org/wiki/BNC_connector#Compatibility)
#7 A beautiful pure copper 18 AWG center conductor with 4 shields, 2 braided and 2 foil.
#8 Much lower impedance connection vs RCA = lower noise floor.
These cables are going inbetween my DAC and my soon-to-arrive KT88 SE kit amplifier, They measure on my multimeter as 000.3 ohms (or 000.0 ohms, unregisterable) for 3 meters of coax or shield. without any inter conductor short, I'm old hat at terminating quad shield to F connectors so this was a cinch.
The novel book inside of the box is Condorman.
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Probably not so many. If you are doing this in order to optimise perceived sound quality i see some issues. Unless you forgo using rca-terminated equipment you will be forced to use either horrible or very expensive conversion kits. And there goes your "low-impedance".
Not all of us are convinced in the sonic superiority of screened cable for line level use. And especially if the screen is used to carry signal.
Not too sure about the superiority of friction connection to between the screen and the connector either. Even less sure about the outer connector metal composition.
If you hate RCAs, why don't you go for XLRs? Much better for audio methinks.
I'm not using BNC for any perceived sound quality improvements, I'm doing it because I think its finally time to put RCA out to pasture on my equipment and I need a replacement for unbalanced inputs and outputs on all of my devices.
I hate XLR too, but it has its place, I have a desk mike here that is XLR, but drilling a small bnc hole is much easier than a big xlr socket, less metal cut out.
I can make really small projects and use bnc whereas xlr wouldnt fit, even if the coax moves the amplifier or preamp off the table, at least its getting a big bit of 18 awg copper to it that is heavily shielded.
quad shield when bought from the right place is high quality and cheap and very very easy for me to terminate, aswell as being able to find it in almost any hardware store so if in an emergency i need to replace a cable i can.
I'm not sure how well xlr will stand up to shielding against radio transmissions, If i ever want to get into ham radio then I don't want my precious audio equipment being damaged by a coax transmission line that has an RF leak, or my tube amplifier amplifying at RF frequencies and taking out one of my tweeters, at least with coax I can reduce the chance of this occuring at the most sensitive and susceptible areas of a circuit.
I listen into shortwave, what happens when that xlr cable which is carrying digital from my heavily RFI shielded computer is layed down near-to my shortwave radio antenna coax?
I hate XLR too, but it has its place, I have a desk mike here that is XLR, but drilling a small bnc hole is much easier than a big xlr socket, less metal cut out.
I can make really small projects and use bnc whereas xlr wouldnt fit, even if the coax moves the amplifier or preamp off the table, at least its getting a big bit of 18 awg copper to it that is heavily shielded.
quad shield when bought from the right place is high quality and cheap and very very easy for me to terminate, aswell as being able to find it in almost any hardware store so if in an emergency i need to replace a cable i can.
I'm not sure how well xlr will stand up to shielding against radio transmissions, If i ever want to get into ham radio then I don't want my precious audio equipment being damaged by a coax transmission line that has an RF leak, or my tube amplifier amplifying at RF frequencies and taking out one of my tweeters, at least with coax I can reduce the chance of this occuring at the most sensitive and susceptible areas of a circuit.
I listen into shortwave, what happens when that xlr cable which is carrying digital from my heavily RFI shielded computer is layed down near-to my shortwave radio antenna coax?
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it would handle it better than your BNC, provided you arew actually using balanced gear that is. because it has CMRR as well as having a completely separate shield. with RCA and BNC when used in its place, shield and ground are the same thing, what point is your quad shield when its directly connected to your signal ground?
an interesting viewpoint, though I have no balanced equipment and I don't know of anyone else who does either, not in the home anyway, good luck finding well shielded cable for xlr too.
I don't believe in using heatshrink unless its necessary, like for example in very high voltage circuits, one tube of heatshrink might be $2 and for low voltages I've found that a simple layer of duct tape does just as good and enables me to rip it up and do a repair and reuse the tape again or simply put new tape down, and duct tape is much cheaper in the long run to simply have the duct tape handy.
For making test leads for example though I would use heatshrink.
I also forget to put the heatshrink on the wire first far more often than I remember to do it before I start stripping. haha. I'm too eager I guess.
This thread is also about replacing RCA with something thats slightly more modern for unbalanced equipment.
I've also had rca center conductors snap off before, its rare but it can happen.
The only downside I can see so far with going with bnc is that its not colour coded.
the most common setup is to connect pin 1 to the signal ground which is the wrong way to do it according to this website: Sound System Interconnection
so whats the best method? with bnc it connects the signal ground to the same chassis ground, and if you have problems with this then its fairly easy to find a washer and put it behind the bnc socket to shield it from the chassis inorder to float the shielding.
with bnc this is a lot easier, strip the coax, put the coax in, crimp it, done.
I don't believe in using heatshrink unless its necessary, like for example in very high voltage circuits, one tube of heatshrink might be $2 and for low voltages I've found that a simple layer of duct tape does just as good and enables me to rip it up and do a repair and reuse the tape again or simply put new tape down, and duct tape is much cheaper in the long run to simply have the duct tape handy.
For making test leads for example though I would use heatshrink.
I also forget to put the heatshrink on the wire first far more often than I remember to do it before I start stripping. haha. I'm too eager I guess.
This thread is also about replacing RCA with something thats slightly more modern for unbalanced equipment.
I've also had rca center conductors snap off before, its rare but it can happen.
The only downside I can see so far with going with bnc is that its not colour coded.
the most common setup is to connect pin 1 to the signal ground which is the wrong way to do it according to this website: Sound System Interconnection
so whats the best method? with bnc it connects the signal ground to the same chassis ground, and if you have problems with this then its fairly easy to find a washer and put it behind the bnc socket to shield it from the chassis inorder to float the shielding.
with bnc this is a lot easier, strip the coax, put the coax in, crimp it, done.
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ah yes, there are those too if it becomes necessary.
a few good responses from this thread, didn't see it when I searched: www.diyaudio.com/forums/analog-line-level/195235-using-digital-interconnect-analog-interconnect.html
a few good responses from this thread, didn't see it when I searched: www.diyaudio.com/forums/analog-line-level/195235-using-digital-interconnect-analog-interconnect.html
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I use BNC on Mcintosh tubes and quad shielded for antenna feeds to OTA digital TV converter boxes to TVs and been very pleased with its 480i up converted, so recently made 15 ft component video cables with it in an attempt to improve PQ and couldn't believe the difference on DVD, and especially 1080i BD, Vs shorter 9 ft consumer 'high def' cables from 2002. I know I'm in a very high electronic noise area, but had no clue it affected consumer interconnects this much.
Obviously, they need a lot of room to route them compared to consumer cables, but as time permits I'll be converting all my interconnects with it.
Note that this is through a 65" RPTV viewed at THX reference distance, so smaller screens and/or further away the difference will diminish to zero for most folks at around three screen width's distance, so not a worthwhile tweak for everyone.
Hopefully it will improve audio at least as much, but it will be awhile before I have time/$$$ to rebuild my audio system.
GM
Obviously, they need a lot of room to route them compared to consumer cables, but as time permits I'll be converting all my interconnects with it.
Note that this is through a 65" RPTV viewed at THX reference distance, so smaller screens and/or further away the difference will diminish to zero for most folks at around three screen width's distance, so not a worthwhile tweak for everyone.
Hopefully it will improve audio at least as much, but it will be awhile before I have time/$$$ to rebuild my audio system.
GM
We seem to have co-mingled several thoughts into one thread:
a] Without a doubt a BNC connector is a mechanically better connector than a RCA connector. But retro-fitting is a lot of work and you have limited what you can interface to.
b] While the impedance mismatch between a BNC 50 ohm connector or cable and a BNC 75 ohm connector or cable for analog audio is negligible, a few legacy connecter have mechanical size differences.
c] The pin 1 problem.
For balanced analog XLR interconnects, the pin 1 is the chassis/shield not the ground.
For un-balanced analog (co-ax) interconnects the shield is first the chassis/shield then the signal ground.
d] Quad Shield RG-6 Co-ax
Rg-6 co-ax comes in many styles, one manufacture has about 50 different part numbers. Some of the design factors are weather, fire safety, flexibility & ruggedness and frequency range.
Quad Shield RG-6 Co-ax is designed for the very high frequencies of cable and satellite TV signals. It is poorly suited for either analog or signals. A much better choice for analog audio is a low frequency cable with a very heavy braided shield.
a] Without a doubt a BNC connector is a mechanically better connector than a RCA connector. But retro-fitting is a lot of work and you have limited what you can interface to.
b] While the impedance mismatch between a BNC 50 ohm connector or cable and a BNC 75 ohm connector or cable for analog audio is negligible, a few legacy connecter have mechanical size differences.
c] The pin 1 problem.
For balanced analog XLR interconnects, the pin 1 is the chassis/shield not the ground.
For un-balanced analog (co-ax) interconnects the shield is first the chassis/shield then the signal ground.
d] Quad Shield RG-6 Co-ax
Rg-6 co-ax comes in many styles, one manufacture has about 50 different part numbers. Some of the design factors are weather, fire safety, flexibility & ruggedness and frequency range.
Quad Shield RG-6 Co-ax is designed for the very high frequencies of cable and satellite TV signals. It is poorly suited for either analog or signals. A much better choice for analog audio is a low frequency cable with a very heavy braided shield.
I also slightly disagree on point A, the plugs were quite easy for me to terminate and crimp onto RG-6 Quad, easier infact than soldering or terminating an rca connector!! and as for the difficulty of mounting bnc connectors to a chassis or retrofitting them to an existing transport well if people find that difficult then I dont think that a slight improvement of audio quality is our main concern if people on diyaudio.com cant do that or find it difficult.
agree on point b, interesting with point c, thank you for sharing.
i disagree completely on point d, but i dont discount that there are many types, mainly because I have made RCA cables with RG-59 and have had excellent results over all other forms of audio interconnect that I have tried. I havent yet tried bnc or rg-6 quad for audio yet but I expect to get the same result, an improvement over what I currently have which is commercial rca cables which I've paid way too much for even at $15 a pair.
What is this low frequency cable that you speak of?
I know your not supposed to but i have noticed a much stronger and transparent signal when I was using rg-59, I guess this says more about the current poor quality of commercially made rca cables than about rg-59 or rg-6 then?
But I am by no means an expert, but you mention that a heavy braid is best for analog audio yet the rg-6 quad that I have indeed has two very heavy braids in it.
Maybe I can get you a part number tomorrow, I'm typing this from bed at the moment.
agree on point b, interesting with point c, thank you for sharing.
i disagree completely on point d, but i dont discount that there are many types, mainly because I have made RCA cables with RG-59 and have had excellent results over all other forms of audio interconnect that I have tried. I havent yet tried bnc or rg-6 quad for audio yet but I expect to get the same result, an improvement over what I currently have which is commercial rca cables which I've paid way too much for even at $15 a pair.
What is this low frequency cable that you speak of?
I know your not supposed to but i have noticed a much stronger and transparent signal when I was using rg-59, I guess this says more about the current poor quality of commercially made rca cables than about rg-59 or rg-6 then?
But I am by no means an expert, but you mention that a heavy braid is best for analog audio yet the rg-6 quad that I have indeed has two very heavy braids in it.
Maybe I can get you a part number tomorrow, I'm typing this from bed at the moment.
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We may be thinking of different Quad Shield co-ax cables. The type I'm thinking of has a copper coated center conductor and a foil shield with a few strands of a braided shield.
This page touches on some good cables from Belden and Canare:
http://www.bluejeanscable.com/store/subwoofer/index.htm
This page touches on some good cables from Belden and Canare:
http://www.bluejeanscable.com/store/subwoofer/index.htm
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I experienced the exact same thing about 11 years ago when I used BNC instead of rca to copy uncompressed analog composite satellite feed from an Indonesian wildfeed satellite frequency onto Betamax, which had SO-259 sockets, I was blown away, it was almost perfect.
As I am building a new amp I am installing both BNC and RCA inputs on mine. Great to hear that someone else has caught the bnc bug too.
yep, you really notice every single little detail when you enlarge a picture huh.
[/QUOTE]Hopefully it will improve audio at least as much [/QUOTE]
I'm hoping so too!! I'm also hoping that bnc will get the recognition that it deserves.
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Indeed, the quad shield that I have is a solid copper center conductor with one insulator, one foil shield, one thick braid, second foil shield, second thinner braid, and then a black insulation layer.
that to me is and always has been proper quad shield. when I cut the center conductor with my pair of pliers it is not steel inside it is copper all the way through and it feels like it has the softness of copper, and not steel.
if it only has one braid and one foil then it is NOT quad shield, quad = 4 shields.
Its okay in my book if the braid isn't copper, frankly I would be hard pressed to find a copper braided coax nowdays with the price of copper being so high, Not even sure if it would make a difference at high frequencies let alone Audio frequencies,
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Hmm, not really, I was referring to the cable choice. I only use BNC when available. For sure, I doubt McIntosh used it early on just to be different and I assume they quit as a cost cutting measure along with other manufacturers.
WRT RCA connectors, there's nothing intrinsically wrong with them based on UL/CSA testing, just that they must be coated with a proper electrolytic lubricant/paste to ensure good conductivity over time. Unfortunately, a quick search didn't turn up any consumer available product I'd be comfortable recommending.
GM
I don't really see the need for RG6 in audio. Seems like a pain in the butt to use.
I've happily used Canare flexible video cable with BNC for audio. 75 ohm video coaxial Cable(L-3C2VS)
There is a thinner version, too. I'm sure that Belden makes something just as nice, and just as well shielded.
Canare guitar cable is also great for interconnects. Very tight shield and a carbon sleeve. Instrument Cable(GS-6) Works as a speaker cable, too! I've only used it with RCA or banana plugs, don't know if a BNC would fit.
For HD-SDI video (uncompressed HD) we use a Belden RG6 (1694A) especially made for that signal. It does make a difference. But for audio, >1Mhz? I don't see the need. It's stiff and hard to work with. But when you want to run uncompressed HD video over 100 meters, it's the way to go.
I've happily used Canare flexible video cable with BNC for audio. 75 ohm video coaxial Cable(L-3C2VS)
There is a thinner version, too. I'm sure that Belden makes something just as nice, and just as well shielded.
Canare guitar cable is also great for interconnects. Very tight shield and a carbon sleeve. Instrument Cable(GS-6) Works as a speaker cable, too! I've only used it with RCA or banana plugs, don't know if a BNC would fit.
For HD-SDI video (uncompressed HD) we use a Belden RG6 (1694A) especially made for that signal. It does make a difference. But for audio, >1Mhz? I don't see the need. It's stiff and hard to work with. But when you want to run uncompressed HD video over 100 meters, it's the way to go.
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