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Will XLR connector maintain 75 ohm integrity for S/PDIF?

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Anonymous
March 31, 2005 9:28:51 AM

Archived from groups: rec.audio.pro (More info?)

I have a situation where I need to provide a robust locking jack for
connecting a S/PDIF digital audio output. Can't use BNC because there
will be a parallel control signal (it's for a Meridian digital active
speaker) and I need it to be on a single connector for ease of use. Was
thinking 4- or 5-pin XLR. But I'm concerned the XLR connector won't
maintain the 75 ohm integrity of the S/PDIF signal.

Are my fears warranted? Any suggestions? Thanks.
Anonymous
March 31, 2005 9:47:55 AM

Archived from groups: rec.audio.pro (More info?)

"Roscoe East" wrote ...
>I have a situation where I need to provide a robust locking jack for
> connecting a S/PDIF digital audio output. Can't use BNC because there
> will be a parallel control signal (it's for a Meridian digital active
> speaker) and I need it to be on a single connector for ease of use.
> Was
> thinking 4- or 5-pin XLR. But I'm concerned the XLR connector won't
> maintain the 75 ohm integrity of the S/PDIF signal.

XLR connectors likely will *not* maintain 75-ohm impedance.
OTOH, RCA connectors (very commonly used for S/PDIF)
aren't 75-ohms either (nor are "common" BNCs, for that matter.)

> Are my fears warranted?

Maybe not. Depends on other conditions.

> Any suggestions? Thanks.

Try it. It might work fine depending on your other conditions
(length and type of cable, robustness of sending and receiving
circuitry, etc. etc.)
March 31, 2005 10:12:08 AM

Archived from groups: rec.audio.pro (More info?)

Richard Crowley wrote:
> "Roscoe East" wrote ...
> >I have a situation where I need to provide a robust locking jack for
> > connecting a S/PDIF digital audio output. Can't use BNC because
there
> > will be a parallel control signal (it's for a Meridian digital
active
> > speaker) and I need it to be on a single connector for ease of use.

> > Was
> > thinking 4- or 5-pin XLR. But I'm concerned the XLR connector won't
> > maintain the 75 ohm integrity of the S/PDIF signal.
>
> XLR connectors likely will *not* maintain 75-ohm impedance.
> OTOH, RCA connectors (very commonly used for S/PDIF)
> aren't 75-ohms either (nor are "common" BNCs, for that matter.)
>
> > Are my fears warranted?
>
> Maybe not. Depends on other conditions.
>
> > Any suggestions? Thanks.
>
> Try it. It might work fine depending on your other conditions
> (length and type of cable, robustness of sending and receiving
> circuitry, etc. etc.)

An XLR probably does not look like 75 Ohms but the discontinuity is so
small compared to the wavelengths involved that there should not be any
significant reflections created. The XLR will look like a very small
shunt C or series L.

There are 2 types of BNC's, 50 Ohm and 75 Ohm. If you have 75 Ohm
cable with BNC's attached, they "ought" to be 75 Ohm. But this usually
isn't a problem even at RF up to 1 GHz or so.

It's also important is to maintain the integrity of the shield to
provide EMI protection, both ingress and egress. You may want to
consider wiring the XLR shell as well as one of the pins to the coax
shield ground.

Mark
Related resources
Anonymous
March 31, 2005 2:43:39 PM

Archived from groups: rec.audio.pro (More info?)

Some RCA connectors make an extremely tight fit (like the NF2C-B-2
Neutriks). Why do you think that it would be a problem using the
standard connection instead?

Regards,

Evangelos


%
Evangelos Himonides
IoE, University of London
tel: +44 2076126599
fax: +44 2076126741
"Allas to those who never sing but die with all their music in them..."



Oliver Wendell Holmes
%
Anonymous
March 31, 2005 2:44:10 PM

Archived from groups: rec.audio.pro (More info?)

Roscoe East <roscoeeast@yahoo.com> wrote:
>I have a situation where I need to provide a robust locking jack for
>connecting a S/PDIF digital audio output. Can't use BNC because there
>will be a parallel control signal (it's for a Meridian digital active
>speaker) and I need it to be on a single connector for ease of use. Was
>thinking 4- or 5-pin XLR. But I'm concerned the XLR connector won't
>maintain the 75 ohm integrity of the S/PDIF signal.

Try some of the D-sub connectors with 75 ohm lines in them. The 13W3
is used for video monitors and is very popular. There are smaller ones
available as well, and Newark will carry them.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
March 31, 2005 3:01:26 PM

Archived from groups: rec.audio.pro (More info?)

Thanks for that Scott,
It looks like most of the non-pro gear that I'm using isn't equiped
with BNC cnx and I figured that that's what the speakers actually have
on them (I thought that the Meridians have phono connectors, no?).

By the way, it has been verified that the UL doesn't support NNTP,
again apologies for using Google groups but I've missed RAP and that's
the only way for me to do it behind the firewall.

Best wishes,

Evangelos

%
Evangelos Himonides
IoE, University of London
tel: +44 2076126599
fax: +44 2076126741
"Allas to those who never sing but die with all their music in them..."



Oliver Wendell Holmes
%
Anonymous
March 31, 2005 4:07:56 PM

Archived from groups: rec.audio.pro (More info?)

"Roscoe East" <roscoeeast@yahoo.com> wrote in message
news:1112275731.717891.15960@g14g2000cwa.googlegroups.com

> I have a situation where I need to provide a robust locking jack for
> connecting a S/PDIF digital audio output.

OK, this is an application that requires about 8-15 MHz bandpass,
depending on sample rates.

> Can't use BNC because there will be a parallel control signal (it's
for a Meridian digital active
> speaker) and I need it to be on a single connector for ease of use.

If I was going to guess at the characteristic impedance of an XLR, I'd
probably estimate around 110 ohms - which is the usual impedance of
twisted pair.

Reemmber, XLR is the standard connector for much AES/EBU which shares
more than a few technical attributes with SP/DIF.

> Was thinking 4- or 5-pin XLR. But I'm concerned the XLR connector
> won't maintain the 75 ohm integrity of the S/PDIF signal.

Punching a 75 ohm characteristic impedance 15 MHz signal through a
short slice of 110 ohm transmission line shouldn't cause any problems.

Usual rule of thumb is that it takes about 1/8 of a wavelength of a
mismatched line to cause problems. At 15 MHz The length of the
mismatched line segment in this case is no more than an inch. At 15
MHz it would take more like a foot of mismatched line to cause even
the slightest amount of trouble.

> Are my fears warranted?

No.

>Any suggestions?

Try it, you'll like it, or I'll give you my consulting fee back,
double.

> Thanks.

;-)
Anonymous
March 31, 2005 5:47:30 PM

Archived from groups: rec.audio.pro (More info?)

Evangelos Himonides <himonides@gmail.com> wrote:
>Some RCA connectors make an extremely tight fit (like the NF2C-B-2
>Neutriks). Why do you think that it would be a problem using the
>standard connection instead?

1. The RCA connector isn't 75 ohms, not even close, no way, no how. It
isn't really the standard connector for S-PDIF, but it's a lot cheaper
than the BNC so it appears on most semi-pro gear now. It is not acceptable
for any professional applications.

2. He wants a locking connector.

3. He wants a connector that will have at least two other contacts besides
the 75 ohm coax lead.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
March 31, 2005 7:21:53 PM

Archived from groups: rec.audio.pro (More info?)

In article <1112275731.717891.15960@g14g2000cwa.googlegroups.com> roscoeeast@yahoo.com writes:

> I have a situation where I need to provide a robust locking jack for
> connecting a S/PDIF digital audio output. Can't use BNC because there
> will be a parallel control signal (it's for a Meridian digital active
> speaker) and I need it to be on a single connector for ease of use. Was
> thinking 4- or 5-pin XLR. But I'm concerned the XLR connector won't
> maintain the 75 ohm integrity of the S/PDIF signal.

Give up the ease of use and use two cables and connectors. It's just
good practice. Is it really that big of a burden to mate two
connectors? You can bundle the cables together so you only have to
deal with a single cable, or if you want ot pay enough, you can get a
cable with 75 ohm coax plus other conductors.

If you have complete free choice of connectors, you can get multi-pin
connectors that have 75 ohm coax "pins" as part of the insert. These
are pretty common in the video world, and some computer monitors use
connectors like this.

But there's no reason not to try what you want. If it works well
enough so that you can't tell if there's anything wrong, then go ahead
and do it. But test it well. Generally connector and cable
characteristic impedance (this is not like load impedance) only
becomes significant when the cable length is more than about 20% of
the wavelength of the signal, and at even high sample rates, that's
pretty long.

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
March 31, 2005 10:13:38 PM

Archived from groups: rec.audio.pro (More info?)

I assume you mean mating just at one end!
It's just a bit of convenient multipole hardware to connect Aaaa to Bbbb.
Use anything you like. What a waste of an XLR pair, though. I could do with
those!

"Roscoe East" <roscoeeast@yahoo.com> wrote in message
news:1112275731.717891.15960@g14g2000cwa.googlegroups.com...
>I have a situation where I need to provide a robust locking jack for
> connecting a S/PDIF digital audio output. Can't use BNC because there
> will be a parallel control signal (it's for a Meridian digital active
> speaker) and I need it to be on a single connector for ease of use. Was
> thinking 4- or 5-pin XLR. But I'm concerned the XLR connector won't
> maintain the 75 ohm integrity of the S/PDIF signal.
>
> Are my fears warranted? Any suggestions? Thanks.
>
April 1, 2005 1:11:21 PM

Archived from groups: rec.audio.pro (More info?)

I have looked this mismatch up on the Smith Chart and it looks like it
would create enough reactance on the line to affect the frequency
linearity of the line for hi-fi work. This is because we are concerned
with such low levels of THD in hi-fi.

A 1/4-wavelength stub (electrical 1/4 wave; apply velocity factor of
the line) of 52-ohm coax in a series with the line would create a
75-ohm conjugate match at both ends of the line because the square root
of the product of 115 X 52 is approximately 75. This would avoid any
signal degradation and eliminate attenuation.
Anonymous
April 1, 2005 9:30:25 PM

Archived from groups: rec.audio.pro (More info?)

"Mark" <makolber@yahoo.com> wrote in message
>>
>> Try it. It might work fine depending on your other conditions
>> (length and type of cable, robustness of sending and receiving
>> circuitry, etc. etc.)
>

> An XLR probably does not look like 75 Ohms but the discontinuity is so
> small compared to the wavelengths involved that there should not be any
> significant reflections created. The XLR will look like a very small
> shunt C or series L.

It should be just fine. I tried a bunch of SPDIF transfers over a
coathanger (2 actually) which worked with a 30-something MB song 10 times
without one bit error.

geoff
Anonymous
April 2, 2005 12:39:06 AM

Archived from groups: rec.audio.pro (More info?)

"Bill" <bcrowell@excite.com> wrote in message
news:1112375480.959161.139180@g14g2000cwa.googlegroups.com

> I have looked this mismatch up on the Smith Chart and it looks like
it
> would create enough reactance on the line to affect the frequency
> linearity of the line for hi-fi work.

Te characteristic impedance of audio cable usually grossly mismatched
with its source and termination impedances.

For example, Normal twisted-pair, shielded mic cable has a
characteristic impedance of about 110 ohms. It is commonly driven with
source impedances ranging from 16 ohms to several thousand ohms. It
is commonly terminated with load impedances ranging from 100 ohms to
10,000 ohms or more. Haveing done all of the above, I've concurrently
measured frequency response that was flat within huindreth's of a dB
or less.

> This is because we are
> concerned with such low levels of THD in hi-fi.

Measuring low levels of THD with reasonable accuracy does require
moderately flat frequency response but does not require fractional-dB
precise frequency response.
April 4, 2005 8:52:13 AM

Archived from groups: rec.audio.pro (More info?)

I ran the Smith Chart calculations on the 15-mhz. digital component of
the signal. There's much more reactance at RF than at AF.
Anonymous
April 4, 2005 12:59:41 PM

Archived from groups: rec.audio.pro (More info?)

"Bill" <bcrowell@excite.com> wrote in message
news:1112615533.555803.206790@l41g2000cwc.googlegroups.com

> I ran the Smith Chart calculations on the 15-mhz. digital component
of
> the signal. There's much more reactance at RF than at AF.

Sure, that's obvious. The question at hand is whether or not it will
cause an audible difference. Do you have a Smith Chart that is
calibrated in sones?
Anonymous
April 4, 2005 11:01:30 PM

Archived from groups: rec.audio.pro (More info?)

Evangelos Himonides <himonides@gmail.com> wrote:
>It looks like most of the non-pro gear that I'm using isn't equiped
>with BNC cnx and I figured that that's what the speakers actually have
>on them (I thought that the Meridians have phono connectors, no?).

The Meridian gear I have used actually does use BNC connectors, and they
are one of the few folks out there today who seem to care about that sort
of thing.

>By the way, it has been verified that the UL doesn't support NNTP,
>again apologies for using Google groups but I've missed RAP and that's
>the only way for me to do it behind the firewall.

You need to get yourself a pipex account! Honestly, using NNTP is so
much faster it's not funny. I can't imagine trying to read the huge volume
of this group through google every day. I'd go insane.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 5, 2005 5:29:51 AM

Archived from groups: rec.audio.pro (More info?)

Thanks Scott!
The main problem is not that the Institute here doesn't have a news
server; I have quite a few that I could use from other places that I
maintain accounts with.
The problem is that the tech people downstairs are blocking everything
else besides http (port 119 blocked as well). you cannot even ping in
this damn place.
I used an http tunneling service for a while and it was ok, but my
limited use of it doesn't justify the cost anymore.
But you're right... it's not that friendly.

Many thanks again,

Evangelos
April 5, 2005 8:39:05 AM

Archived from groups: rec.audio.pro (More info?)

No, in decibels. It would cause a 2-db. signal loss [10 log (1.27)] =
approx. 2.

I can hear a 2-db difference. (Isn't the db. defined as the minimum
change in amplitude that the human ear can discern?) When I set the
balance on my preamp so one channel is putting out 33 mv and the other
26 mv (a 2-db. difference), I can really hear it.
Anonymous
April 5, 2005 10:45:40 AM

Archived from groups: rec.audio.pro (More info?)

In article <d2sh0a$9o6$1@panix2.panix.com> kludge@panix.com writes:

> The Meridian gear I have used actually does use BNC connectors, and they
> are one of the few folks out there today who seem to care about that sort
> of thing.

I worked with an engineer once who replaced the RCA jacks on all his
home audio equipment with BNCs - this was back in the days when jacks
were attached to the panel, not part of a cirucit board. Not for
impedance reasons, but for making good solid connections. Also, a BNC
mates the shield before the center conductor so you can make
connections with the system hot without getting blasts of hum.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
April 5, 2005 11:25:26 AM

Archived from groups: rec.audio.pro (More info?)

you can hear a 2 dB difference at 15 MHz?

wow!

or should I say bow wow!

Mark
Anonymous
April 5, 2005 3:25:02 PM

Archived from groups: rec.audio.pro (More info?)

Mark <makolber@yahoo.com> wrote:
>you can hear a 2 dB difference at 15 MHz?
>
>wow!
>
>or should I say bow wow!

With 96 ksamp/sec S-PDIF, a 2 dB difference at 15 Mhz can be the difference
between the system locking up properly and it refusing to work at all.

Hopefully you'd allow enough safety margin that it wouldn't be a problem,
but that's the thing about digital systems.... most folks don't really
know how much safety margin they have left until they don't have any and
all hell breaks loose.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 5, 2005 4:11:50 PM

Archived from groups: rec.audio.pro (More info?)

In article <1112701145.070416.164720@o13g2000cwo.googlegroups.com> bcrowell@excite.com writes:

> No, in decibels. It would cause a 2-db. signal loss [10 log (1.27)] =
> approx. 2.
>
> I can hear a 2-db difference. (Isn't the db. defined as the minimum
> change in amplitude that the human ear can discern?) When I set the
> balance on my preamp so one channel is putting out 33 mv and the other
> 26 mv (a 2-db. difference), I can really hear it.

Does this have anything to do with the original question?

Are you suggesting that a 2 dB drop in the digital level produces a 2
dB drop in the audio level? It doesn't, though it might cause a 100
dB or so drop if the 2 dB drop in digital level brings it below the
threshold of the receiver.

And are you suggesting that a mismatch in the characteristic
impredance of the connectors produces a voltage difference that
follows Ohm's Law? It doesn't, either.

One more strike and you're out.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
April 6, 2005 12:07:37 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:D 2uake$fu0$1@panix2.panix.com...
> Mark <makolber@yahoo.com> wrote:
>>you can hear a 2 dB difference at 15 MHz?
>>
>>wow!
>>
>>or should I say bow wow!
>
> With 96 ksamp/sec S-PDIF, a 2 dB difference at 15 Mhz can be the
> difference
> between the system locking up properly and it refusing to work at all.

I'll have to measure the actual physical characteristics of my coat-hanger
cable one day !

geoff
Anonymous
April 7, 2005 1:55:51 PM

Archived from groups: rec.audio.pro (More info?)

Bill wrote:

> No, in decibels. It would cause a 2-db. signal loss [10 log (1.27)]
=
> approx. 2.

Under what real-world circumstances?

> I can hear a 2-db difference. (Isn't the db. defined as the minimum
> change in amplitude that the human ear can discern?) When I set the
> balance on my preamp so one channel is putting out 33 mv and the
other
> 26 mv (a 2-db. difference), I can really hear it.

The usual threshold for reliable audibility of level changes in the
middle of the audio band is something like 0.5 dB or a little less. At
the extremes, its far more. Please see:

http://www.pcavtech.com/soundcards/techtalk/FR/LevelMat...
Anonymous
April 7, 2005 5:06:21 PM

Archived from groups: rec.audio.pro (More info?)

Aren't XLR connectors usually used with 110 ohm AES, not SPDIF?

Isn't unbalanced SPDIF usually limited to short runs where impedance
doensn't matter much?

If you want to do a long run, shouldn't you convert SPDIF to optical or AES
and use the proper connectors?

Why are we having this discussion?

Julian
Anonymous
April 7, 2005 8:13:53 PM

Archived from groups: rec.audio.pro (More info?)

Julian Adamaitis <nospamJulianPA@Access4Less.net> wrote:
>Aren't XLR connectors usually used with 110 ohm AES, not SPDIF?

Right.

>Isn't unbalanced SPDIF usually limited to short runs where impedance
>doensn't matter much?

No, not at all. Because you can run over 75 ohm coax, it's very common
to use existing video cable plants for S-PDIF systems. I have seen some
extremely long runs.

>If you want to do a long run, shouldn't you convert SPDIF to optical or AES
>and use the proper connectors?

No, the optical stuff over TOSLINK is basically consumer trash and not
much use at all (although there does exist some higher grade optical on
ST connectors). But it's routine to run a couple thousand feet of
S-PDIF with reclocking DAs in many places.

>Why are we having this discussion?

The original poster wanted a connector that would allow him to run both
two power leads and a 75 ohm line on a single plug, and with a connector
that locked. He was considering a 4-pin XLR. That turns out not to be
the best choice. I suggested one of the D-Sub connectors with the
mix of 75 ohm lines and discrete pins.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 7, 2005 8:13:54 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote

>>Isn't unbalanced SPDIF usually limited to short runs where impedance
>>doesn't matter much?
>
> No, not at all. Because you can run over 75 ohm coax, it's very common
> to use existing video cable plants for S-PDIF systems. I have seen some
> extremely long runs.

Where I've seen 75 ohm digital it has usually been with an AES XLR to coax
balun transformer. I guess I also hosed up a lot of BNC to BNC's for
devices that had the audio on a BNC too. I always considered that to be
"unbalanced AES" not SPDIF, but I guess you could call it SPDIF because the
main difference between AES and SPDIF is voltage. I have many times plugged
an AES out into an SPDIF in by using a simple 1:1 resistive voltage divider.
Isn't the 75 ohm BNC stuff higher voltage than "normal" SPDIF on RCA's?

>
>>If you want to do a long run, shouldn't you convert SPDIF to optical or
>>AES
>>and use the proper connectors?
>
> No, the optical stuff over TOSLINK is basically consumer trash and not
> much use at all (although there does exist some higher grade optical on
> ST connectors). But it's routine to run a couple thousand feet of
> S-PDIF with reclocking DAs in many places.

Still, consumer trash will can go a long way. I've seen web sites selling
TOS link cables over 100 feet long.

>
>>Why are we having this discussion?
>
> The original poster wanted a connector that would allow him to run both
> two power leads and a 75 ohm line on a single plug, and with a connector
> that locked. He was considering a 4-pin XLR. That turns out not to be
> the best choice. I suggested one of the D-Sub connectors with the
> mix of 75 ohm lines and discrete pins.

See my previous post on running "Studio Hub", a system designed for running
AES 110 ohm digital and / or balanced analog on cat 5e stp w/ RJ45
connectors: http://www.studiohub.com/

I missed why you think a Dsub is better than an 4 pin XLR? Please repeat.

Julian
Anonymous
April 7, 2005 9:56:15 PM

Archived from groups: rec.audio.pro (More info?)

Julian Adamaitis <nospamJulianPA@Access4Less.net> wrote:
>See my previous post on running "Studio Hub", a system designed for running
>AES 110 ohm digital and / or balanced analog on cat 5e stp w/ RJ45
>connectors: http://www.studiohub.com/
>
>I missed why you think a Dsub is better than an 4 pin XLR? Please repeat.

Because you can buy D-Sub connectors that actually have real 75 ohm
coax pins in them. The 13W3 is an example of this... it has 3 75 ohm
coaxes and 13 discrete pins and it gets used for a lot of video monitor
applications. There are a bunch of variants with a single 75 ohm line
and a varying number of discrete conductors that use the DB-9 and DB-15
shell configurations as well.

Do a google search on "13W3 connector" and you'll probably find a picture.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 7, 2005 10:28:07 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" wrote ...
> Because you can buy D-Sub connectors that actually have real 75 ohm
> coax pins in them. The 13W3 is an example of this... it has 3 75 ohm
> coaxes and 13 discrete pins and it gets used for a lot of video monitor
> applications. There are a bunch of variants with a single 75 ohm line
> and a varying number of discrete conductors that use the DB-9 and DB-15
> shell configurations as well.
>
> Do a google search on "13W3 connector" and you'll probably find a picture.

"5W1" would be ideal with four regular pins, and one coaxial,
all in an "A-size" shell (same size as the 9-pin serial connector,
and 15-pin video connector used by most computers).
Alas: 1) It takes an expensive crimp tool to terminate the coax
pins, and 2) looks like nobody stocks them. Special order only.

And it would appear also that the 13W3 (which is more popular
because the high-end workstation CRTs use it) is no more available
as piece-parts, either.
Anonymous
April 7, 2005 10:36:43 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:D 34a9v$da6$1@panix2.panix.com...
> Julian Adamaitis <nospamJulianPA@Access4Less.net> wrote:
>>I missed why you think a Dsub is better than an 4 pin XLR? Please repeat.
>
> Because you can buy D-Sub connectors that actually have real 75 ohm
> coax pins in them. The 13W3 is an example of this... it has 3 75 ohm
> coaxes and 13 discrete pins and it gets used for a lot of video monitor
> applications. There are a bunch of variants with a single 75 ohm line
> and a varying number of discrete conductors that use the DB-9 and DB-15
> shell configurations as well.

Oh, I see. coax AND TP. But with required special tools and all, wouldn't
it be cheaper and easier to get a cheap SPDIF to AES box and use 110 ohm tp?

Julian
Anonymous
April 8, 2005 1:20:36 PM

Archived from groups: rec.audio.pro (More info?)

Julian Adamaitis <nospamJulianPA@Access4Less.net> wrote:
>"Scott Dorsey" <kludge@panix.com> wrote in message
>news:D 34a9v$da6$1@panix2.panix.com...
>> Julian Adamaitis <nospamJulianPA@Access4Less.net> wrote:
>>>I missed why you think a Dsub is better than an 4 pin XLR? Please repeat.
>>
>> Because you can buy D-Sub connectors that actually have real 75 ohm
>> coax pins in them. The 13W3 is an example of this... it has 3 75 ohm
>> coaxes and 13 discrete pins and it gets used for a lot of video monitor
>> applications. There are a bunch of variants with a single 75 ohm line
>> and a varying number of discrete conductors that use the DB-9 and DB-15
>> shell configurations as well.
>
>Oh, I see. coax AND TP. But with required special tools and all, wouldn't
>it be cheaper and easier to get a cheap SPDIF to AES box and use 110 ohm tp?

Not if you're making a couple hundred boxes. If you're just making one or
two, absolutely. But this was for a production item.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 8, 2005 1:20:37 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote

> Not if you're making a couple hundred boxes. If you're just making one or
> two, absolutely. But this was for a production item.

The beginning of this thread is not showing up on my newsreader. Sorry to
trouble you further, but could please you explain the full scope of the
project?

I just designed a radio station that uses the Telos Axia IP packet audio
routing equipment which uses cat 5e pinouts on RJ45's for analog audio or
digital audio (1 pr), data (2 pr) and optional DC power (1pr). Search Axia
on Google. Its the wave of the future.

Since cat 5 is 110 ohms it has been shown you can get equivalent performance
to typical high end super expensive AES 110 ohm TP cable. Who'd a thunk it?
It's a cool way to go because RJ45 plugs and crimpers are cheap, available
and so is the wire. Plus its fast, which also matters if you are doing a
couple hundred boxes. For 200 boxes, I'd much rather do 400 RJ45's than 400
special crimped DB's.

You obviously can't run cat 5e as far as RG6. I don't know what distances
are involved here. If the distances are prohibited for running the cat 5
AES, It'd still be easier and faster to run a coax and a cat 5 IMO. I'm
pretty sure I can crimp one coax and one regular DB or RJ faster than one
special DB coax combination plug.

Julian
Anonymous
April 8, 2005 1:44:23 PM

Archived from groups: rec.audio.pro (More info?)

In article <d34mn8$q8l$1@news01.intel.com> richard.7.crowley@intel.com writes:

> "5W1" would be ideal with four regular pins, and one coaxial,
> all in an "A-size" shell (same size as the 9-pin serial connector,
> and 15-pin video connector used by most computers).
> Alas: 1) It takes an expensive crimp tool to terminate the coax
> pins, and 2) looks like nobody stocks them. Special order only.

One-offs for anything but simple connectors that can be assembled with
common hand tools are pretty rare. You could probably get one as a
sample for free, but you'd still need the tools. But if you're really
committed to this, you can probably find a custom shop that has the
parts and tools, and can build a cable to your specifications. It
won't be cheap, though.

If this is for your home system, I wouldn't think of it, but if you're
installing something for a paying client, it's all in a day's work.
Get a quote and add it to your bill.


--
I'm really Mike Rivers - (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
April 8, 2005 2:00:32 PM

Archived from groups: rec.audio.pro (More info?)

In article <znr1112957123k@trad>, Mike Rivers <mrivers@d-and-d.com> wrote:
>In article <d34mn8$q8l$1@news01.intel.com> richard.7.crowley@intel.com writes:
>
>> "5W1" would be ideal with four regular pins, and one coaxial,
>> all in an "A-size" shell (same size as the 9-pin serial connector,
>> and 15-pin video connector used by most computers).
>> Alas: 1) It takes an expensive crimp tool to terminate the coax
>> pins, and 2) looks like nobody stocks them. Special order only.
>
>One-offs for anything but simple connectors that can be assembled with
>common hand tools are pretty rare. You could probably get one as a
>sample for free, but you'd still need the tools. But if you're really
>committed to this, you can probably find a custom shop that has the
>parts and tools, and can build a cable to your specifications. It
>won't be cheap, though.

And actually you can solder these things rather than crimping them, but
it won't pass flight qualification if you do. Same with the crimp-on
Bendix connectors, which I solder all the time when i don't have the right
size Bendix tool.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
April 8, 2005 2:53:22 PM

Archived from groups: rec.audio.pro (More info?)

"Scott Dorsey" <kludge@panix.com> wrote in message
news:D 362q0$iag$1@panix2.panix.com...
> In article <znr1112957123k@trad>, Mike Rivers <mrivers@d-and-d.com> wrote:
> >In article <d34mn8$q8l$1@news01.intel.com> richard.7.crowley@intel.com
writes:
> >
> >> "5W1" would be ideal with four regular pins, and one coaxial,
> >> all in an "A-size" shell (same size as the 9-pin serial connector,
> >> and 15-pin video connector used by most computers).
> >> Alas: 1) It takes an expensive crimp tool to terminate the coax
> >> pins, and 2) looks like nobody stocks them. Special order only.
> >
> >One-offs for anything but simple connectors that can be assembled with
> >common hand tools are pretty rare. You could probably get one as a
> >sample for free, but you'd still need the tools. But if you're really
> >committed to this, you can probably find a custom shop that has the
> >parts and tools, and can build a cable to your specifications. It
> >won't be cheap, though.
>
> And actually you can solder these things rather than crimping them, but
> it won't pass flight qualification if you do. Same with the crimp-on
> Bendix connectors, which I solder all the time when i don't have the right
> size Bendix tool.

Some of those single-piece, small coaxial "pins" have only a tiny
hole through the outer shell where the inner pin gets crimped.
No practical way of soldering those things. Even with the thinnest
tip that Weller sells. :-(

Otherwise, indeed most crimp-style fittings can also be soldered
for low-volume. Some may need partial "crimping" with pliers to
reduce the diameter to slip into the shell. In fact, if you don't have
the proper crimp tool, you 'd likely be better off soldering than trying
to crimp with generic pliers, etc.
Anonymous
April 8, 2005 3:19:32 PM

Archived from groups: rec.audio.pro (More info?)

"Richard Crowley" <richard.7.crowley@intel.com> wrote

> Otherwise, indeed most crimp-style fittings can also be soldered
> for low-volume. Some may need partial "crimping" with pliers to
> reduce the diameter to slip into the shell. In fact, if you don't have
> the proper crimp tool, you 'd likely be better off soldering than trying
> to crimp with generic pliers, etc.

I have to agree. I've made a lot of Canare double shield digital video
cables that use precision strippers and crimpers. Gold center pins too. I
am confident these crimpes cables will stand up to the very best, BUT the
system is based on having exactly the right size connectors crimpers,
strippers and connectors. Remove any one of these and you got radio shack
quality.

Julian
!