Aes/ebu and bnc why so rare?

[mordante]

I was just wondering. Why do so few (budget) DACs have an aes/ebu input? And why do so many devices have rca style outputs instead of bnc?

 

Aes/ebu is arguably the best digital connection for audio there is. But it is relative rare. I don't get it. For digital bnc is superior to rca but hardly used for home audio. I don't get it.

[Kal Rubinson]

I was just wondering. Why do so few (budget) DACs have an aes/ebu input? And why do so many devices have rca style outputs instead of bnc?

 

Aes/ebu is arguably the best digital connection for audio there is. But it is relative rare. I don't get it. For digital bnc is superior to rca but hardly used for home audio. I don't get it.

Nothing new. The same observations were made in the analog days.

[gmgraves]

I was just wondering. Why do so few (budget) DACs have an aes/ebu input? And why do so many devices have rca style outputs instead of bnc?

 

Aes/ebu is arguably the best digital connection for audio there is. But it is relative rare. I don't get it. For digital bnc is superior to rca but hardly used for home audio. I don't get it.

 

BNC connectors are more expensive, are designed for VHF/UHF frequencies and are considered overkill for audio, even digital audio. Remember, the lowly RCA connector was designed originally to couple the IF frequency of a VHF TV tuner to the IF amplifier strip of an RCA Victor model 630 TV of 1946.

 

As for AES/EBU, it's just one of those things. Like why VHS over Beta, or why Windows over Mac, or blu-ray over HD-DVD? There really is no concrete reason for any of it.

[sandyk]

BNC connectors are more expensive, are designed for VHF/UHF frequencies and are considered overkill for audio, even digital audio.

 

Cost is a major factor, but very few RCA connectors come remotely close to a 75 ohm impedance, so many upgrade specialists change them to 75 ohm BNC. Of course if you only use something like a<$100 BluRay player then it's not worth the trouble,

[Audio_ELF]

I was just wondering. Why do so few (budget) DACs have an aes/ebu input? And why do so many devices have rca style outputs instead of bnc?

 

Aes/ebu is arguably the best digital connection for audio there is. But it is relative rare. I don't get it. For digital bnc is superior to rca but hardly used for home audio. I don't get it.

There is an argument that BNC is actually superior to AES/EBU unless you are running a long distance / studio environment. A lot of the design decisions for AES/EBU were actually down to convenience / ease of use (i.e. in many studios the same Mic cables will be used for AES/EBU as for analogue connections). Gordon from Wavelength has written posts on the technical failings of AES/EBU before.

 

As for BNC vs RCA Phono ... the main reason for RCA being used is the availability of interconnects and convenience for the end user rather than any technical reasons. Also RCA will save a few pence.

[mordante]

BNC connectors are more expensive, are designed for VHF/UHF frequencies and are considered overkill for audio, even digital audio. Remember, the lowly RCA connector was designed originally to couple the IF frequency of a VHF TV tuner to the IF amplifier strip of an RCA Victor model 630 TV of 1946.

 

As for AES/EBU, it's just one of those things. Like why VHS over Beta, or why Windows over Mac, or blu-ray over HD-DVD? There really is no concrete reason for any of it.

 

I talked about this with a engineer a while back. According to him RCA connectors are seldom truly 75 Ohm while BNC is always 75 Ohm.

 

AES/ebu and BNC are standards within the pro-audio, just like XLR. Pro Audio is I think more budget minded so I have a hard time believing that BNC is more expensive.

[gmgraves]

I talked about this with a engineer a while back. According to him RCA connectors are seldom truly 75 Ohm while BNC is always 75 Ohm.

 

AES/ebu and BNC are standards within the pro-audio, just like XLR. Pro Audio is I think more budget minded so I have a hard time believing that BNC is more expensive.

 

RCA connectors are more universal. They are designed to connect a relatively low source impedance to a relatively high destination impedance (which describes most audio applications). BNC otoh, is designed to connect 75 ohm sources to 75 ohm destinations, where that impedance coupling is crucial, but it's just a connector and it doesn't have to. I.E. BNC will work just fine for audio.

 

Btw, BNC and XLR are not generally interchangeable. BNC is unbalanced, and XLR is balanced, so they are used for two entirely different purposes.

[mordante]

RCA connectors are more universal. They are designed to connect a relatively low source impedance to a relatively high destination impedance (which describes most audio applications). BNC otoh, is designed to connect 75 ohm sources to 75 ohm destinations, where that impedance coupling is crucial, but it's just a connector and it doesn't have to. I.E. BNC will work just fine for audio.

 

Btw, BNC and XLR are not generally interchangeable. BNC is unbalanced, and XLR is balanced, so they are used for two entirely different purposes.

 

I might be mistaken but it seems you are mixing up some things.

 

RCA is designed for analog applications where impedance is indeed an issue. BNC is a for digital connections like you said 75 Ohm.

 

XLR again is analogue while AES/ebu 110 Ohm is digital.

[gmgraves]

There is an argument that BNC is actually superior to AES/EBU unless you are running a long distance / studio environment.

 

Since BNC is merely a mechanical connector, and AES/EBU is a digital audio interface protocol, that is totally independent of the connectors used (AES/EBU can even be transmitted over optical) I really don't get your point. Were you perhaps trying to say something else?

[gmgraves]

I might be mistaken but it seems you are mixing up some things.

 

RCA is designed for analog applications where impedance is indeed an issue. BNC is a for digital connections like you said 75 Ohm.

 

XLR again is analogue while AES/ebu 110 Ohm is digital.

 

No, I'm not mixing anything up. And BTW, all three connectors were designed well before there was much digital anything. For instance, Tektronix was using BNC connectors on their oscilloscopes in the early 1950's.

[Audio_ELF]

Since BNC is merely a mechanical connector, and AES/EBU is a digital audio interface protocol, that is totally independent of the connectors used (AES/EBU can even be transmitted over optical) I really don't get your point. Were you perhaps trying to say something else?

You're correct (I was using some shorthand) ... I should have said ...

There is an argument that

using SPDIF over

BNC is actually superior to AES/EBU

over balanced XLR

unless you are running a long distance / studio environment.

 

As I recall ... AES/EBU should correctly be referred to these days as AES3 which is spec'd to run over balanced 110ohm XLR though there is also a version which runs over Cat5. This is in contrast to AES3id which is run over co-ax via BNC and is very closely related to SPDIF which can run over co-ax using either RCA or BNC connectors - or even over optical when it is typically known as TOSLink. AFAIK AES does not have a version which runs over optical - standards based digital optical links are either SPDIF/TOSLink or ADAT (which is multi-channel).

[Audio_ELF]

I talked about this with a engineer a while back. According to him RCA connectors are seldom truly 75 Ohm while BNC is always 75 Ohm.

Well they are 75ohm ... unless they are 50ohm connectors!

 

AES/ebu and BNC are standards within the pro-audio, just like XLR. Pro Audio is I think more budget minded so I have a hard time believing that BNC is more expensive.

XLR for AES3 is as much down to the available cables in a pro-environment as them being "better". (At least according to Gordon from Wavelength). Go into any pro-audio environment (studio or live performance) and there will be a surfeit of microphone cables around. Equally if the pro-audio environment does anything video related, there will be a number of 75ohm BNC terminated cables around. There will be very little RCA terminated cabling in either environment.

 

Pro-audio is budget conscious, but they are much more into what is quick and convenient to use.

[sandyk]

BNC Connectors.

 

 

[gmgraves]

You're correct (I was using some shorthand) ... I should have said ...

There is an argument that

using SPDIF over

BNC is actually superior to AES/EBU

over balanced XLR

unless you are running a long distance / studio environment.

 

As I recall ... AES/EBU should correctly be referred to these days as AES3 which is spec'd to run over balanced 110ohm XLR though there is also a version which runs over Cat5. This is in contrast to AES3id which is run over co-ax via BNC and is very closely related to SPDIF which can run over co-ax using either RCA or BNC connectors - or even over optical when it is typically known as TOSLink. AFAIK AES does not have a version which runs over optical - standards based digital optical links are either SPDIF/TOSLink or ADAT (which is multi-channel).

 

 

OK, that makes more sense.

 

BTW, TOSLINk is a consumer optical connection and you are right, typically AES/EBU is not transferred over TOSLINK, but can be transmitted over glass Fiber Channel (FC) compliant to IEC 61754-13.

[gmgraves]

Well they are 75ohm ... unless they are 50ohm connectors!

 

 

XLR for AES3 is as much down to the available cables in a pro-environment as them being "better". (At least according to Gordon from Wavelength). Go into any pro-audio environment (studio or live performance) and there will be a surfeit of microphone cables around. Equally if the pro-audio environment does anything video related, there will be a number of 75ohm BNC terminated cables around. There will be very little RCA terminated cabling in either environment.

 

Pro-audio is budget conscious, but they are much more into what is quick and convenient to use.

 

The main reason why RCA connectors aren't used in the pro world is because they're basically unreliable when used in an environment where connections must be made/broken multiple times. RCA's were designed, originally, to made one time - when the TV was manufactured. Those old analog TV tuners were subject to wearing out (usually the switch drum would become intermittent) and thus occasionally had to be replaced. So, perhaps the IF connection was made/broken twice in it's life. The lowly RCA became ubiquitous for audio because the tinned connectors could be easily soldered and they were very cheap; just pennies each. In the early days of hi-fi, people had to "roll their own" interconnects. You couldn't buy them already made. a hank of RG-59U coax and a couple of RCAs and a soldering iron, and you were in business. Unfortunately, the resultant "home made" interconnects weren't very reliable, especially if you swapped equipment often. BNCs OTOH, are not soldered but rather crimped and they were more substantially made and therefore more expensive. The crimping tool wasn't cheap, and required some skill to make the connection correctly. BNC is much more reliable and much more positive than the RCA. It has always puzzled me why an audio connector would be designed in such a way that it made the hot connection BEFORE it made the ground! How many speakers have been blown because the ground connection came loose or the audiophile forgot to turn-off his power amp before swapping out components up the line!

 

RCA's came rather late to Europe. If you look at say, a British Quad preamp or a Danish B&O component from the 1960's, you will find that all the interconnects are of the German DIN type. I had a friend who had a Quad Preamp, and a Quad Power amp (and the Quad model 57 ESL speakers) and in order to connect a Sherwood tuner, an AR turntable and a TEAC tape deck to his system, he had to make-up DIN to RCA adaptors.

[Audio_ELF]

It has always puzzled me why an audio connector would be designed in such a way that it made the hot connection BEFORE it made the ground! How many speakers have been blown because the ground connection came loose or the audiophile forgot to turn-off his power amp before swapping out components up the line!

Of course jack (TR and TRS, etc) are even worse as there is a potential for shorting live to ground as you remove the connector ... especially when its used as a speaker connector. Can be quite impressive when you find a jack plug welded half way out the socket!

 

RCA's came rather late to Europe. If you look at say, a British Quad preamp or a Danish B&O component from the 1960's, you will find that all the interconnects are of the German DIN type. I had a friend who had a Quad Preamp, and a Quad Power amp (and the Quad model 57 ESL speakers) and in order to connect a Sherwood tuner, an AR turntable and a TEAC tape deck to his system, he had to make-up DIN to RCA adaptors.

DIN connectors have the advantage of a single ground connection rather than separate L/R ground too ... Naim are still using them for that reason.

[pl_svn]

further question: S/PDIF "official specs" are indeed limited to 192KHz or it just only depends on manufacturer implementation?

[gmgraves]

further question: S/PDIF "official specs" are indeed limited to 192KHz or it just only depends on manufacturer implementation?

 

Since some DACs will do 24/384 via SPDIF, I'd have to say that 192 KHz is not the limit of the spec. But I do suspect that SPDIF via TOSLINK is bandwidth limited to 192 KHz (and with some implementations TOSLINK is limited to 96 KHz) I'm not sure what the limit really is via coax.

[sandyk]

IIRC, John Swenson is using a fast Video amplifier I.C. in the coax SPDIF output of one of his designs.

Given that some of these I.C.s have a bandwidth of 200MHZ, it seems likely that proper implementation could push the limits even further.

[17629v2]

"DIN connectors have the advantage of a single ground connection rather than separate L/R ground too ... Naim are still using them for that reason."

 

I don't know if Naim is a good example. I think some of the stuff they do is intended to make it harder for customers to buy from other brands. I've put their din cables next to other brands and did some listening with a few people, and we all felt that the Naim cables came in last place for SQ. Its entirely possible that some people get better results than we did, but I can only go but what I heard.

[Audio_ELF]

"DIN connectors have the advantage of a single ground connection rather than separate L/R ground too ... Naim are still using them for that reason."

 

I don't know if Naim is a good example. I think some of the stuff they do is intended to make it harder for customers to buy from other brands. I've put their din cables next to other brands and did some listening with a few people, and we all felt that the Naim cables came in last place for SQ. Its entirely possible that some people get better results than we did, but I can only go but what I heard.

You are mixing up two different things (IMO) - the quality of the cables and the connection method.

 

Put it this way - if you run a Naim system using all DIN connectors, you will (almost) never come across ground loops.

 

As for "some of the stuff they do is intended to make it harder for customers to buy from other brands" ... I've been thinking on this in relation to other companies recently ... and I say you have to look at it from the other point of view. They make is so that their own components, devices work best together. If you have to do a bit of harder work to get them to work with other devices so be it. But nothing they do actively prevents their components working outside a Naim system - they have even added standard connectors to all their current components though connecting by the DIN is always recommended (and I've never found anyone preferring high end RCA over high end DIN).

[gmgraves]

Eloise Wrote:

Put it this way - if you run a Naim system using all DIN connectors, you will (almost) never come across ground loops.

 

Ground loops are pretty rare anyway. I wouldn't think that's much an incentive to go to a non-standard system. Naim's stuff is very good quality, there's no question of that in my estimation - none whatsoever. But the DIN connectors are enough to completely quell my interest.

[sandyk]

But the DIN connectors are enough to completely quell my interest.

 

Likewise, although these days you can get lockable types that don't fall out .

[17629v2]

"(and I've never found anyone preferring high end RCA over high end DIN)"

 

That's exactly what we found in my first post. I was considering a Naim CD player, so I brought in one of my current players for comparison (Arcam 33). I wasn't sure what the dealer had in his store, but it was a long drive so I brought some AQ cables with me, just in case. To make a long story short, the dealer tried my AQ cables on his Naim gear that had both rca and din connectors, an was so impressed with them, he immediately picked the line up for his store.

 

For the rest of it, I know Naim insists you use only their preamps with Naim amps. Also, if you have ever tried their power supplies, you know they make a huge difference. But for me, the difference was just too big. I couldn't help but think they did a poor job on the internal power supplies, so that when customers hear the upgraded PS, it becomes a mandatory purchase.

 

My last statement about the PS's is just speculation on my part. I want to make that clear because I have no evidence to suggest otherwise. For me, the difference seems much bigger than average, and I'm also biased because of the cable and preamp issues I mention.

 

"Put it this way - if you run a Naim system using all DIN connectors, you will (almost) never come across ground loops."

 

You should never have ground loops no matter what gear you use.

[Panelhead]

I have build many components using the Deltron locking DIN connectors. The one I used were three pin to allow balanced connectors. So there were still two ground connections.

Always thought these are higher quality than the non-locking type. The Deltron DIN plugs and jacks are non-magnetic. And low mass.