Re: [Elecraft] K3S Microphone Cable

[Jim Brown]

The only environmental issues that could affect audio are 1) magnetic 
fields developed by faults in the power wiring in your home or leakage 
flux from big power transformers; 2) a variable-speed motor controller 
very nearby; 3) difference in potential between interconnected equipment 
that creates leakage currents on cable shields.


Cable shields have NO effect on magnetic coupling at audio frequencies. 
Twisting, however, is VERY resistant to magnetic coupling. #2 is by 
magnetic coupling if the source is nearby. The cure for #3 is BONDING.


Magnetic coupling also occurs in loops that are part of the signal path, 
like cable shields in unbalanced circuits. Coupling is proportional to 
the area of the loop, so keeping bonding conductors as short as possible 
helps.  Also, by virtue of the difference in the resistance of cable 
shields and bonding conductors, a beefy #10 or #12 bonding conductor 
will carry far more of any induced current than cable shields that are 
typically #18 - #22 gauge.


73, Jim K9YC

 On 1/17/2018 4:35 AM, Clay Autery wrote:
Frankly...  the electromagnetic environment in my home vicinity 
prrsently is like trying to manage airspace in a war zone during a 
major offensuve.




Sent from my Verizon, Samsung Galaxy smartphone

 Original message 
From: Garry VE7PNQ <ve7...@telus.net>
Date: 1/16/18 22:09 (GMT-06:00)
To: j...@audiosystemsgroup.com, elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3S Microphone Cable

Back in my broadcast years I worked at the low budget end of the 
industry where we did what ever it took to get on the air at the 
lowest cost possible. In  small market stations where Radio Shack was 
our primary local parts supplier we abused unbalanced lines to the 
extreme as long as the cable length was not too long and the nearest 
transmitter was not too close. Low cost mixers had 3 pin connectors 
but with two pins grounded to accommodate a broad range of low cost 
mics, cables and adaptors.


Later in life when I had more money, the cost of mixers, differential 
amps etc was lower and the distance to high powered amateur radio 
transmitters was inches rather than miles, I adopted a more rigid 
adherence to broadcast standard low impedance cables even over 
relatively short cable lengths of a few inches or feet. As good as the 
noise rejection of new pre-amplifiers are, I still find separation of 
shield grounding and the minus side of a mic input important with 
modern radios. This has become more important in the era of huge 
numbers RFI sources such as digital radios, local residential RFI from 
IOT, LED lamps, cheap switching power supplies, thermostats and people 
still using compact fluorescent lights.


OK honest truth, how many of us only have one radio operating at a 
time? How often do you need your HF rig to reject RFI from your 
VHF/UHF transmitter, computer accessories or switching power supplies 
in our energy saving appliances.


I may be showing my age but physics doesn't change. Shielding external 
noise before it reaches the input to the pre-amplifier is still an 
effective strategy. I still use balanced lines when ever I can.


Garry
VE7PNQ





-Original Message-
From: elecraft-boun...@mailman.qth.net 
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown

Sent: Tuesday, January 16, 2018 9:49 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3S Microphone Cable

The nature of the shield matters a lot. Back in 1994, Neil Muncy, 
ex-W3WJE (SK), published the landmark AES paper in which he exposed 
both The Pin One Problem and Shield Current Induced Noise (SCIN). The 
Pin One Problem is the (now) well known equipment design defect, 
whereby the cable shield fails to contact the shielding enclosure, 
first going to the circuit board, where shield current is coupled to 
the circuitry. SCIN is a defect in the construction of "rack cable" 
having a foil/drain shield, whereby the drain wire is twisted at the 
same rate as the signal pair and is much closer (along the cable) to 
one signal conductor than the other. This causes shield current to 
induce a differential voltage on the signal pair.


Neil did his work on how these mechanisms coupled at audio 
frequencies, but in multiple bar conversations when we met at 
conventions, he said that both were also very strong causes of RFI, 
and that Pin One was the dominant cause. In 2003, I did research that 
confirmed this. Audio old-timers may recall that in the late '80s and 
early '90s, Mackie mixers were almost certain to pick up AM broadcast 
stations that were on the high end of the band. My work on 
susceptibility of equipment showed that they suffered both from Pin 
One Problems AND that the bandwidth of their audio circuitry extended 
past 1 MHz!  In attempting to use one of these mixers to test 
condenser mics for RFI from FM and TV broadcast, I found that these 
mixers themselves strongly detected RF from TV channel 2, and were 
th

Re: [Elecraft] K3S Microphone Cable

[Clay Autery]

Frankly...  the electromagnetic environment in my home vicinity prrsently is 
like trying to manage airspace in a war zone during a major offensuve.


Sent from my Verizon, Samsung Galaxy smartphone
 Original message From: Garry VE7PNQ <ve7...@telus.net> Date: 
1/16/18  22:09  (GMT-06:00) To: j...@audiosystemsgroup.com, 
elecraft@mailman.qth.net Subject: Re: [Elecraft] K3S Microphone Cable 
Back in my broadcast years I worked at the low budget end of the industry where 
we did what ever it took to get on the air at the lowest cost possible. In  
small market stations where Radio Shack was our primary local parts supplier we 
abused unbalanced lines to the extreme as long as the cable length was not too 
long and the nearest transmitter was not too close. Low cost mixers had 3 pin 
connectors but with two pins grounded to accommodate a broad range of low cost 
mics, cables and adaptors. 

Later in life when I had more money, the cost of mixers, differential amps etc 
was lower and the distance to high powered amateur radio transmitters was 
inches rather than miles, I adopted a more rigid adherence to broadcast 
standard low impedance cables even over relatively short cable lengths of a few 
inches or feet. As good as the noise rejection of new pre-amplifiers are, I 
still find separation of shield grounding and the minus side of a mic input 
important with modern radios. This has become more important in the era of huge 
numbers RFI sources such as digital radios, local residential RFI from IOT, LED 
lamps, cheap switching power supplies, thermostats and people still using 
compact fluorescent lights. 

OK honest truth, how many of us only have one radio operating at a time? How 
often do you need your HF rig to reject RFI from your VHF/UHF transmitter, 
computer accessories or switching power supplies in our energy saving 
appliances.

I may be showing my age but physics doesn't change. Shielding external noise 
before it reaches the input to the pre-amplifier is still an effective 
strategy. I still use balanced lines when ever I can.

Garry
VE7PNQ





-Original Message-
From: elecraft-boun...@mailman.qth.net 
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown
Sent: Tuesday, January 16, 2018 9:49 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3S Microphone Cable

The nature of the shield matters a lot. Back in 1994, Neil Muncy, ex-W3WJE 
(SK), published the landmark AES paper in which he exposed both The Pin One 
Problem and Shield Current Induced Noise (SCIN). The Pin One Problem is the 
(now) well known equipment design defect, whereby the cable shield fails to 
contact the shielding enclosure, first going to the circuit board, where shield 
current is coupled to the circuitry. SCIN is a defect in the construction of 
"rack cable" having a foil/drain shield, whereby the drain wire is twisted at 
the same rate as the signal pair and is much closer (along the cable) to one 
signal conductor than the other. This causes shield current to induce a 
differential voltage on the signal pair.

Neil did his work on how these mechanisms coupled at audio frequencies, but in 
multiple bar conversations when we met at conventions, he said that both were 
also very strong causes of RFI, and that Pin One was the dominant cause. In 
2003, I did research that confirmed this. Audio old-timers may recall that in 
the late '80s and early '90s, Mackie mixers were almost certain to pick up AM 
broadcast stations that were on the high end of the band. My work on 
susceptibility of equipment showed that they suffered both from Pin One 
Problems AND that the bandwidth of their audio circuitry extended past 1 MHz!  
In attempting to use one of these mixers to test condenser mics for RFI from FM 
and TV broadcast, I found that these mixers themselves strongly detected RF 
from TV channel 2, and were thus unusable!

I also tested the RF rejection of quad cables, including Canare, and found that 
they were inferior in that regard to a good braid-shielded cable like Belden 
8412. Gotham Audio cable (an EU cable then imported by the Neumann distributor) 
also performed quite well.

All of that work was published as AES papers. You can buy them for $10 each at 
aes.org, or you can download them without the AES logo from my website for 
free. :)  k9yc.com/publish.htm  Scroll down to find the AES papers.

As to the Heil cable -- I've never seen it, don't know its construction. 
As Don notes, additional conductors can be useful for control functions.

73, Jim K9YC

On 1/16/2018 8:59 AM, Don Wilhelm wrote:
> The Heilwire is IMHO the best wire for ham applications because it 
> contains additional conductors for PTT as well as a shielded twisted 
> pair and is soft and flexible.


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Re: [Elecraft] K3S Microphone Cable

[Jim Brown]

Hi Garry,

As a genuine OF (born 1941) who still keeps trying to learn something 
new every day, I strongly suggest that you study the material on my 
website about The Pin One Problem. I own thousands of feet of high 
quality pro mic cables and about 40 pro mics. Yes, physics doesn't 
change, but some of what we have learned about it over the years is 
simply wrong.


If all of the gear in a station is properly bonded, everything in your 
home is properly bonded, including power, and all of that is properly 
bonded to your station, and if the input gains and output levels are 
reasonably well set, and if all cable shields are bonded to the chassis 
at the point of entry, and if all power for station equipment comes from 
outlets that either share the same green wire back to the panel or from 
outlets that have their green wires bonded together, there is no need 
for anything fancy in the way of cable, nor is there any need for 
balanced wiring.


There are two tutorials on power, grounding, and bonding on my website. 
One, written for installers and contractors for large and small  audio 
and video systems, was commissioned. You'll find it listed as a "white 
paper for the real world." The other is in the form of slides for a talk 
that I've been invited to give at ham events and to ham clubs on power, 
grounding, bonding, and audio interfacing for hams. k9yc.com/publish.htm


If I were in the position of defining standards for consumer audio and 
ham radio back in the '60s and '70s when the transformation began 
between hollow state and solid state gear, I would certainly have gone 
for balanced interfaces (i.e., shielded twisted pair). But that didn't 
happen, and we're stuck with unbalanced interfaces. The simple, solid 
engineering outlined in those slides is an inexpensive and dependable 
solution.


73, Jim K9YC

On 1/16/2018 8:09 PM, Garry VE7PNQ wrote:

As good as the noise rejection of new pre-amplifiers are, I still find 
separation of shield grounding and the minus side of a mic input important with 
modern radios.



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Re: [Elecraft] K3S Microphone Cable

[Garry VE7PNQ]

Back in my broadcast years I worked at the low budget end of the industry where 
we did what ever it took to get on the air at the lowest cost possible. In  
small market stations where Radio Shack was our primary local parts supplier we 
abused unbalanced lines to the extreme as long as the cable length was not too 
long and the nearest transmitter was not too close. Low cost mixers had 3 pin 
connectors but with two pins grounded to accommodate a broad range of low cost 
mics, cables and adaptors. 

Later in life when I had more money, the cost of mixers, differential amps etc 
was lower and the distance to high powered amateur radio transmitters was 
inches rather than miles, I adopted a more rigid adherence to broadcast 
standard low impedance cables even over relatively short cable lengths of a few 
inches or feet. As good as the noise rejection of new pre-amplifiers are, I 
still find separation of shield grounding and the minus side of a mic input 
important with modern radios. This has become more important in the era of huge 
numbers RFI sources such as digital radios, local residential RFI from IOT, LED 
lamps, cheap switching power supplies, thermostats and people still using 
compact fluorescent lights. 

OK honest truth, how many of us only have one radio operating at a time? How 
often do you need your HF rig to reject RFI from your VHF/UHF transmitter, 
computer accessories or switching power supplies in our energy saving 
appliances.

I may be showing my age but physics doesn't change. Shielding external noise 
before it reaches the input to the pre-amplifier is still an effective 
strategy. I still use balanced lines when ever I can.

Garry
VE7PNQ





-Original Message-
From: elecraft-boun...@mailman.qth.net 
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown
Sent: Tuesday, January 16, 2018 9:49 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3S Microphone Cable

The nature of the shield matters a lot. Back in 1994, Neil Muncy, ex-W3WJE 
(SK), published the landmark AES paper in which he exposed both The Pin One 
Problem and Shield Current Induced Noise (SCIN). The Pin One Problem is the 
(now) well known equipment design defect, whereby the cable shield fails to 
contact the shielding enclosure, first going to the circuit board, where shield 
current is coupled to the circuitry. SCIN is a defect in the construction of 
"rack cable" having a foil/drain shield, whereby the drain wire is twisted at 
the same rate as the signal pair and is much closer (along the cable) to one 
signal conductor than the other. This causes shield current to induce a 
differential voltage on the signal pair.

Neil did his work on how these mechanisms coupled at audio frequencies, but in 
multiple bar conversations when we met at conventions, he said that both were 
also very strong causes of RFI, and that Pin One was the dominant cause. In 
2003, I did research that confirmed this. Audio old-timers may recall that in 
the late '80s and early '90s, Mackie mixers were almost certain to pick up AM 
broadcast stations that were on the high end of the band. My work on 
susceptibility of equipment showed that they suffered both from Pin One 
Problems AND that the bandwidth of their audio circuitry extended past 1 MHz!  
In attempting to use one of these mixers to test condenser mics for RFI from FM 
and TV broadcast, I found that these mixers themselves strongly detected RF 
from TV channel 2, and were thus unusable!

I also tested the RF rejection of quad cables, including Canare, and found that 
they were inferior in that regard to a good braid-shielded cable like Belden 
8412. Gotham Audio cable (an EU cable then imported by the Neumann distributor) 
also performed quite well.

All of that work was published as AES papers. You can buy them for $10 each at 
aes.org, or you can download them without the AES logo from my website for 
free. :)  k9yc.com/publish.htm  Scroll down to find the AES papers.

As to the Heil cable -- I've never seen it, don't know its construction. 
As Don notes, additional conductors can be useful for control functions.

73, Jim K9YC

On 1/16/2018 8:59 AM, Don Wilhelm wrote:
> The Heilwire is IMHO the best wire for ham applications because it 
> contains additional conductors for PTT as well as a shielded twisted 
> pair and is soft and flexible.


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Re: [Elecraft] K3S Microphone Cable

[Nr4c]

Call HRI in Woodbridge. My source!


Sent from my iPhone
...nr4c. bill


> On Jan 16, 2018, at 10:08 AM, "j...@kk9a.com"  wrote:
> 
> I saw the Heil connectors and Heil wire when I first started my search. I
> was not interest in the wire. I did have an interest in the Foster
> connectors but could not find them in stock anywhere.
> 
> 73,
> John KK9A
> 
> 
> Bill Wrote:
> 
> Heil has the best Foster connector. Sold in pairs. Not sure if price but
> very reasonable.
> 
> Sent from my iPhone
> ...nr4c. bill
> 
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Re: [Elecraft] K3S Microphone Cable

[Jim Brown]

Hi Bob,

Shield coverage does not matter!  Study the SCIN paper -- what matters 
is the UNIFORMITY of the shield. In the world of pro audio, we learned 
long ago that twisting is at least as important as shielding, both at 
audio and RF frequencies. From the earliest days of telephony, telco 
cables ran on the same poles as power. In those days, power was 
relatively free of AF noise components. The only noise rejection 
employed was that the telco pairs were crossed over every few poles. 
This was sufficient because of the long wavelength of 60 Hz and the low 
harmonics associated with running motors.


At an RFI workshop I taught in 2005 with other members of the AES 
Standards Committee WG on RFI, I demonstrated the use of one pair of a 
CAT5 cable carrying mic audio from a pro condenser mic to the audio 
mixer with both conductors of another pair connecting the Pin 1s. That 
connection provided a bond for the mic shielding and a path for phantom 
power needed to power the mic. I injected RF along the cable using a 
Nextel phone and a TH-F6A Kenwood talkie, moving both along the cable, 
and keying the talkie on-off continuously to generate AM. Another of the 
same mic type was connected to the same mixer via Belden 8412. The mics 
had some RFI susceptibility at VHF and UHF. The two cables were equally 
good at rejecting the RFI.  In his workshops, Neil Muncy demonstrated 
the value of twisting by running a very long chain of mic cables around 
the facility where he was presenting it, then moving a tape demagnetizer 
along the line. The only hum heard was where the twist was interrupted 
at mated XL connectors.


Someone asked about cross-references to the cable types tested. The 
foil/drain cables included everything I could get my hands on at the 
time. The braid-shielded cables included a variety of what was in my 
working stash, a few samples that Belden provided, and a nice selection 
from Gepco. Based on my work, Gepco later produced a miniature 
braid-shielded twisted pair with no drain wire (comparable in size to 
standard rack cable and mic snake pairs). The braid/foil pair came from 
a member of the SynAudCon pro audio community working in Brazil. Based 
on Neil's work, he got a local cable company to build it for him.


In general, all you need to know is to avoid foil/drain cables, if the 
cable is shielded, it should have a braid shield with no drain wire, and 
that a twisted pair cable with a drain wire is worse than no shield at all.


73, Jim K9YC

On 1/16/2018 10:40 AM, Bob McGraw K4TAX wrote:

The braid shield type is necessary where flexibility is required however, just 
as in coax, not all braid is the same.  Some provides 85% shield (poor) while 
others approach near 100% shielding (good).   There is a difference in price, 
usually for this reason.



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Re: [Elecraft] K3S Microphone Cable

[Clay Autery]

Star Quad is >95% coverage according to the spec sheet.


Sent from my Verizon, Samsung Galaxy smartphone
 Original message From: Bob McGraw K4TAX <rmcg...@blomand.net> 
Date: 1/16/18  12:40  (GMT-06:00) To: Clay Autery <k...@montac.com> Cc: 
j...@audiosystemsgroup.com, elecraft@mailman.qth.net Subject: Re: [Elecraft] 
K3S Microphone Cable 
I've used some star quad cable in certain pro audio applications. 

The braid shield type is necessary where flexibility is required however, just 
as in coax, not all braid is the same.  Some provides 85% shield (poor) while 
others approach near 100% shielding (good).   There is a difference in price, 
usually for this reason. 

Bob, K4TAX


Sent from my iPhone

> On Jan 16, 2018, at 12:11 PM, Clay Autery <k...@montac.com> wrote:
> 
> Canare Star Quad does have a braided shield... 
> Never did any head to head testing, but I've used it for both balanced and 
> unbalanced runs, and it's always performed flawlessly for me.
> Ease of handling, flexibility, and durability gets high marks from me too.
> Granted, I am probably a bit biased due to my heavy use of Canare materials 
> in my ouw whole house project and several other distribution setups.  Love 
> their F and BNC connectors and tools, too.
> 
> 
> Sent from my Verizon, Samsung Galaxy smartphone
>  Original message From: Jim Brown 
> <j...@audiosystemsgroup.com> Date: 1/16/18  11:48  (GMT-06:00) To: 
> elecraft@mailman.qth.net Subject: Re: [Elecraft] K3S Microphone Cable 
> The nature of the shield matters a lot. Back in 1994, Neil Muncy, 
> ex-W3WJE (SK), published the landmark AES paper in which he exposed both 
> The Pin One Problem and Shield Current Induced Noise (SCIN). The Pin One 
> Problem is the (now) well known equipment design defect, whereby the 
> cable shield fails to contact the shielding enclosure, first going to 
> the circuit board, where shield current is coupled to the circuitry.  
> SCIN is a defect in the construction of "rack cable" having a foil/drain 
> shield, whereby the drain wire is twisted at the same rate as the signal 
> pair and is much closer (along the cable) to one signal conductor than 
> the other. This causes shield current to induce a differential voltage 
> on the signal pair.
> 
> Neil did his work on how these mechanisms coupled at audio frequencies, 
> but in multiple bar conversations when we met at conventions, he said 
> that both were also very strong causes of RFI, and that Pin One was the 
> dominant cause. In 2003, I did research that confirmed this. Audio 
> old-timers may recall that in the late '80s and early '90s, Mackie 
> mixers were almost certain to pick up AM broadcast stations that were on 
> the high end of the band. My work on susceptibility of equipment showed 
> that they suffered both from Pin One Problems AND that the bandwidth of 
> their audio circuitry extended past 1 MHz!  In attempting to use one of 
> these mixers to test condenser mics for RFI from FM and TV broadcast, I 
> found that these mixers themselves strongly detected RF from TV channel 
> 2, and were thus unusable!
> 
> I also tested the RF rejection of quad cables, including Canare, and 
> found that they were inferior in that regard to a good braid-shielded 
> cable like Belden 8412. Gotham Audio cable (an EU cable then imported by 
> the Neumann distributor) also performed quite well.
> 
> All of that work was published as AES papers. You can buy them for $10 
> each at aes.org, or you can download them without the AES logo from my 
> website for free. :)  k9yc.com/publish.htm  Scroll down to find the AES 
> papers.
> 
> As to the Heil cable -- I've never seen it, don't know its construction. 
> As Don notes, additional conductors can be useful for control functions.
> 
> 73, Jim K9YC
> __
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> This list hosted by: http://www.qsl.net
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> Message delivered to rmcg...@blomand.net


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Re: [Elecraft] K3S Microphone Cable

[Mark Goldberg]

On Tue, Jan 16, 2018 at 10:48 AM, Jim Brown 
wrote:

> The nature of the shield matters a lot. Back in 1994, Neil Muncy, ex-W3WJE
> (SK), published the landmark AES paper in which he exposed both The Pin One
> Problem and Shield Current Induced Noise (SCIN). The Pin One Problem is
>


> I also tested the RF rejection of quad cables, including Canare, and found
> that they were inferior in that regard to a good braid-shielded cable like
> Belden 8412. Gotham Audio cable (an EU cable then imported by the Neumann
> distributor) also performed quite well.
>
> All of that work was published as AES papers.
>

I looked at your paper "Common-Mode to Differential-Mode Conversion in
Shielded Twisted-Pair Cables (Shield-Current-Induced Noise)" The cables are
not identified by name. Is there a cross reference you can provide?

I try to use double shielded cables or hardline in my RF installations. I
have seen leakage on the order of -40 dB on crappy cables.

I did use a knockoff Star Quad cable for my microphones but have no data to
substantiate using it. Reading your info, it may not be the best choice. I
had to add a braid from the mixer chassis to the microphone mounting for a
good ground to eliminate my RFI problems. Connecting the braid to the shock
mount inner ring did not work. The Metal shock mount inner ring was not
connected to the metal microphone body! It looked connected, but must have
a painted plastic part or non conductive paint.

Thanks for all the info,

Mark
W7MLG
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Re: [Elecraft] K3S Microphone Cable

[Bob McGraw K4TAX]

I've used some star quad cable in certain pro audio applications. 

The braid shield type is necessary where flexibility is required however, just 
as in coax, not all braid is the same.  Some provides 85% shield (poor) while 
others approach near 100% shielding (good).   There is a difference in price, 
usually for this reason. 

Bob, K4TAX


Sent from my iPhone

> On Jan 16, 2018, at 12:11 PM, Clay Autery <k...@montac.com> wrote:
> 
> Canare Star Quad does have a braided shield... 
> Never did any head to head testing, but I've used it for both balanced and 
> unbalanced runs, and it's always performed flawlessly for me.
> Ease of handling, flexibility, and durability gets high marks from me too.
> Granted, I am probably a bit biased due to my heavy use of Canare materials 
> in my ouw whole house project and several other distribution setups.  Love 
> their F and BNC connectors and tools, too.
> 
> 
> Sent from my Verizon, Samsung Galaxy smartphone
>  Original message From: Jim Brown 
> <j...@audiosystemsgroup.com> Date: 1/16/18  11:48  (GMT-06:00) To: 
> elecraft@mailman.qth.net Subject: Re: [Elecraft] K3S Microphone Cable 
> The nature of the shield matters a lot. Back in 1994, Neil Muncy, 
> ex-W3WJE (SK), published the landmark AES paper in which he exposed both 
> The Pin One Problem and Shield Current Induced Noise (SCIN). The Pin One 
> Problem is the (now) well known equipment design defect, whereby the 
> cable shield fails to contact the shielding enclosure, first going to 
> the circuit board, where shield current is coupled to the circuitry.  
> SCIN is a defect in the construction of "rack cable" having a foil/drain 
> shield, whereby the drain wire is twisted at the same rate as the signal 
> pair and is much closer (along the cable) to one signal conductor than 
> the other. This causes shield current to induce a differential voltage 
> on the signal pair.
> 
> Neil did his work on how these mechanisms coupled at audio frequencies, 
> but in multiple bar conversations when we met at conventions, he said 
> that both were also very strong causes of RFI, and that Pin One was the 
> dominant cause. In 2003, I did research that confirmed this. Audio 
> old-timers may recall that in the late '80s and early '90s, Mackie 
> mixers were almost certain to pick up AM broadcast stations that were on 
> the high end of the band. My work on susceptibility of equipment showed 
> that they suffered both from Pin One Problems AND that the bandwidth of 
> their audio circuitry extended past 1 MHz!  In attempting to use one of 
> these mixers to test condenser mics for RFI from FM and TV broadcast, I 
> found that these mixers themselves strongly detected RF from TV channel 
> 2, and were thus unusable!
> 
> I also tested the RF rejection of quad cables, including Canare, and 
> found that they were inferior in that regard to a good braid-shielded 
> cable like Belden 8412. Gotham Audio cable (an EU cable then imported by 
> the Neumann distributor) also performed quite well.
> 
> All of that work was published as AES papers. You can buy them for $10 
> each at aes.org, or you can download them without the AES logo from my 
> website for free. :)  k9yc.com/publish.htm  Scroll down to find the AES 
> papers.
> 
> As to the Heil cable -- I've never seen it, don't know its construction. 
> As Don notes, additional conductors can be useful for control functions.
> 
> 73, Jim K9YC
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Re: [Elecraft] K3S Microphone Cable

[Russ]

Jim:

Still on topic any tying into a query the other day on the Reflector

You are are the RFI mitigation guru - I am very impressed with the wealth of 
test data (especially on ferrite characteristics) that you have amassed. I have 
this cheap little Rolls MX28 mixer that I am using for SO2R monitoring.  I 
brute force added about a pound of RG-8 size #31 beads to the AF and power 
inputs (it worked) but I want to fine tune the scheme.  I have planned (using 
your data) to make chokes by wrapping the beads with 6 turns of RG-174 (used 
for audio) and grounding the "output" where it enters the mixer and leaving the 
input floating for CMRR.  The mixer's impedance is 10K (resistive - no xfmr) 
bridging.

Thanks, Russ KD4JO

-Original Message-
From: elecraft-boun...@mailman.qth.net 
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Jim Brown
Sent: Tuesday, January 16, 2018 12:49 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3S Microphone Cable

The nature of the shield matters a lot. Back in 1994, Neil Muncy, ex-W3WJE 
(SK), published the landmark AES paper in which he exposed both The Pin One 
Problem and Shield Current Induced Noise (SCIN). The Pin One Problem is the 
(now) well known equipment design defect, whereby the cable shield fails to 
contact the shielding enclosure, first going to the circuit board, where shield 
current is coupled to the circuitry. SCIN is a defect in the construction of 
"rack cable" having a foil/drain shield, whereby the drain wire is twisted at 
the same rate as the signal pair and is much closer (along the cable) to one 
signal conductor than the other. This causes shield current to induce a 
differential voltage on the signal pair.

Neil did his work on how these mechanisms coupled at audio frequencies, but in 
multiple bar conversations when we met at conventions, he said that both were 
also very strong causes of RFI, and that Pin One was the dominant cause. In 
2003, I did research that confirmed this. Audio old-timers may recall that in 
the late '80s and early '90s, Mackie mixers were almost certain to pick up AM 
broadcast stations that were on the high end of the band. My work on 
susceptibility of equipment showed that they suffered both from Pin One 
Problems AND that the bandwidth of their audio circuitry extended past 1 MHz!  
In attempting to use one of these mixers to test condenser mics for RFI from FM 
and TV broadcast, I found that these mixers themselves strongly detected RF 
from TV channel 2, and were thus unusable!

I also tested the RF rejection of quad cables, including Canare, and found that 
they were inferior in that regard to a good braid-shielded cable like Belden 
8412. Gotham Audio cable (an EU cable then imported by the Neumann distributor) 
also performed quite well.

All of that work was published as AES papers. You can buy them for $10 each at 
aes.org, or you can download them without the AES logo from my website for 
free. :)  k9yc.com/publish.htm  Scroll down to find the AES papers.

As to the Heil cable -- I've never seen it, don't know its construction. 
As Don notes, additional conductors can be useful for control functions.

73, Jim K9YC

On 1/16/2018 8:59 AM, Don Wilhelm wrote:
> The Heilwire is IMHO the best wire for ham applications because it 
> contains additional conductors for PTT as well as a shielded twisted 
> pair and is soft and flexible.


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Re: [Elecraft] K3S Microphone Cable

[Clay Autery]

Canare Star Quad does have a braided shield... 
Never did any head to head testing, but I've used it for both balanced and 
unbalanced runs, and it's always performed flawlessly for me.
Ease of handling, flexibility, and durability gets high marks from me too.
Granted, I am probably a bit biased due to my heavy use of Canare materials in 
my ouw whole house project and several other distribution setups.  Love their F 
and BNC connectors and tools, too.


Sent from my Verizon, Samsung Galaxy smartphone
 Original message From: Jim Brown <j...@audiosystemsgroup.com> 
Date: 1/16/18  11:48  (GMT-06:00) To: elecraft@mailman.qth.net Subject: Re: 
[Elecraft] K3S Microphone Cable 
The nature of the shield matters a lot. Back in 1994, Neil Muncy, 
ex-W3WJE (SK), published the landmark AES paper in which he exposed both 
The Pin One Problem and Shield Current Induced Noise (SCIN). The Pin One 
Problem is the (now) well known equipment design defect, whereby the 
cable shield fails to contact the shielding enclosure, first going to 
the circuit board, where shield current is coupled to the circuitry.  
SCIN is a defect in the construction of "rack cable" having a foil/drain 
shield, whereby the drain wire is twisted at the same rate as the signal 
pair and is much closer (along the cable) to one signal conductor than 
the other. This causes shield current to induce a differential voltage 
on the signal pair.

Neil did his work on how these mechanisms coupled at audio frequencies, 
but in multiple bar conversations when we met at conventions, he said 
that both were also very strong causes of RFI, and that Pin One was the 
dominant cause. In 2003, I did research that confirmed this. Audio 
old-timers may recall that in the late '80s and early '90s, Mackie 
mixers were almost certain to pick up AM broadcast stations that were on 
the high end of the band. My work on susceptibility of equipment showed 
that they suffered both from Pin One Problems AND that the bandwidth of 
their audio circuitry extended past 1 MHz!  In attempting to use one of 
these mixers to test condenser mics for RFI from FM and TV broadcast, I 
found that these mixers themselves strongly detected RF from TV channel 
2, and were thus unusable!

I also tested the RF rejection of quad cables, including Canare, and 
found that they were inferior in that regard to a good braid-shielded 
cable like Belden 8412. Gotham Audio cable (an EU cable then imported by 
the Neumann distributor) also performed quite well.

All of that work was published as AES papers. You can buy them for $10 
each at aes.org, or you can download them without the AES logo from my 
website for free. :)  k9yc.com/publish.htm  Scroll down to find the AES 
papers.

As to the Heil cable -- I've never seen it, don't know its construction. 
As Don notes, additional conductors can be useful for control functions.

73, Jim K9YC
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Re: [Elecraft] K3S Microphone Cable

[Jim Brown]

The nature of the shield matters a lot. Back in 1994, Neil Muncy, 
ex-W3WJE (SK), published the landmark AES paper in which he exposed both 
The Pin One Problem and Shield Current Induced Noise (SCIN). The Pin One 
Problem is the (now) well known equipment design defect, whereby the 
cable shield fails to contact the shielding enclosure, first going to 
the circuit board, where shield current is coupled to the circuitry.  
SCIN is a defect in the construction of "rack cable" having a foil/drain 
shield, whereby the drain wire is twisted at the same rate as the signal 
pair and is much closer (along the cable) to one signal conductor than 
the other. This causes shield current to induce a differential voltage 
on the signal pair.


Neil did his work on how these mechanisms coupled at audio frequencies, 
but in multiple bar conversations when we met at conventions, he said 
that both were also very strong causes of RFI, and that Pin One was the 
dominant cause. In 2003, I did research that confirmed this. Audio 
old-timers may recall that in the late '80s and early '90s, Mackie 
mixers were almost certain to pick up AM broadcast stations that were on 
the high end of the band. My work on susceptibility of equipment showed 
that they suffered both from Pin One Problems AND that the bandwidth of 
their audio circuitry extended past 1 MHz!  In attempting to use one of 
these mixers to test condenser mics for RFI from FM and TV broadcast, I 
found that these mixers themselves strongly detected RF from TV channel 
2, and were thus unusable!


I also tested the RF rejection of quad cables, including Canare, and 
found that they were inferior in that regard to a good braid-shielded 
cable like Belden 8412. Gotham Audio cable (an EU cable then imported by 
the Neumann distributor) also performed quite well.


All of that work was published as AES papers. You can buy them for $10 
each at aes.org, or you can download them without the AES logo from my 
website for free. :)  k9yc.com/publish.htm  Scroll down to find the AES 
papers.


As to the Heil cable -- I've never seen it, don't know its construction. 
As Don notes, additional conductors can be useful for control functions.


73, Jim K9YC

On 1/16/2018 8:59 AM, Don Wilhelm wrote:
The Heilwire is IMHO the best wire for ham applications because it 
contains additional conductors for PTT as well as a shielded twisted 
pair and is soft and flexible. 



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Re: [Elecraft] K3S Microphone Cable

[Don Wilhelm]

John,

I agree that the Heil 8 pin connectors are the best.
The Heilwire is IMHO the best wire for ham applications because it 
contains additional conductors for PTT as well as a shielded twisted 
pair and is soft and flexible.


73,
Don W3FPR

On 1/16/2018 10:08 AM, j...@kk9a.com wrote:

I saw the Heil connectors and Heil wire when I first started my search. I
was not interest in the wire. I did have an interest in the Foster
connectors but could not find them in stock anywhere.

73,
John KK9A


Bill Wrote:

Heil has the best Foster connector. Sold in pairs. Not sure if price but
very reasonable.


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Re: [Elecraft] K3S Microphone Cable

[Nr4c]

Heil has the best Foster connector. Sold in pairs. Not sure if price but very 
reasonable. 

Sent from my iPhone
...nr4c. bill


> On Jan 16, 2018, at 8:10 AM, Bob McGraw K4TAX  wrote:
> 
> For a reason Clay stated and that is not using the shield as a current 
> carrying conductor in audio, I use a 3 wire shielded cable for all my mike 
> applications, ham radio and professional.   There are several good brands, 
> Alpha, Belden, and others.  Also Heil has some cable which is suitable  where 
> audio and PTT circuits are required.
> 
> A single conductor shielded cable is not suggested.   As to where to find and 
> buy a good Foster connector, I haven't found a good source. As to other 
> connectors such as the XLR series, I find Neutrik  to be the preferred brand 
> or Amphenol as a 2nd choice.
> 
> 73
> 
> Bob, K4TAX
> 
> 
>> On 1/15/2018 10:16 PM, Clay Autery wrote:
>> In my experience, the best microphone cable stock currently existing is 
>> Canare Star Quad cable.
>> I'm on my phone, so don't want tp peck out a complete answer here and now.
>> Star Quad cable has 2 twisted pairs and a shield and is nice and flexible 
>> broadcast quality cable stock.  Has great endurance.
>> I use it for my microphone, key, and any other cables I can.  There are at 
>> least 2 sizes now  Get the largest wire gauge available.  Consider 
>> putting some on your shelf for future use too.
>> I use a condenser mic so my wiring may be different, but I would never use 
>> the shield as a signal wire if I wasn't forced to  Use the twisted pairs 
>> to your advantage.
>> Can't help on the multi-pin connectors, as I don't use it at all.  But find 
>> and use the best ones tou can find.
>> 73, ClayKY5G
>> 
>> 
>> Sent from my Verizon, Samsung Galaxy smartphone
>>  Original message From: j...@kk9a.com Date: 1/15/18  19:46  
>> (GMT-06:00) To: 'Elecraft Reflector'  Subject: 
>> [Elecraft] K3S Microphone Cable
>> I am remaking my SO2R control box cables and I need to purchase quality
>> microphone cable however I am not sure what to get. I am using an electret
>> microphone. I assumed that I would need a cable with a single conductor and
>> a shield but most mic cables that I see have two conductors. Belden has a
>> single conductor
>> http://www.awcwire.com/mfg/belden/product/belden-high-impedance-microphone-c
>> able  but it's a high impendence cable and the Belden multi conductor cables
>> are all low impendence. Does that matter? What gauge wire should I use for a
>> 5ft

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Re: [Elecraft] K3S Microphone Cable

[Bob McGraw K4TAX]

For a reason Clay stated and that is not using the shield as a current 
carrying conductor in audio, I use a 3 wire shielded cable for all my 
mike applications, ham radio and professional.   There are several good 
brands, Alpha, Belden, and others.  Also Heil has some cable which is 
suitable  where audio and PTT circuits are required.


A single conductor shielded cable is not suggested.   As to where to 
find and buy a good Foster connector, I haven't found a good source. As 
to other connectors such as the XLR series, I find Neutrik  to be the 
preferred brand or Amphenol as a 2nd choice.


73

Bob, K4TAX


On 1/15/2018 10:16 PM, Clay Autery wrote:

In my experience, the best microphone cable stock currently existing is Canare 
Star Quad cable.
I'm on my phone, so don't want tp peck out a complete answer here and now.
Star Quad cable has 2 twisted pairs and a shield and is nice and flexible 
broadcast quality cable stock.  Has great endurance.
I use it for my microphone, key, and any other cables I can.  There are at 
least 2 sizes now  Get the largest wire gauge available.  Consider putting 
some on your shelf for future use too.
I use a condenser mic so my wiring may be different, but I would never use the 
shield as a signal wire if I wasn't forced to  Use the twisted pairs to 
your advantage.
Can't help on the multi-pin connectors, as I don't use it at all.  But find and 
use the best ones tou can find.
73, ClayKY5G


Sent from my Verizon, Samsung Galaxy smartphone
 Original message From: j...@kk9a.com Date: 1/15/18  19:46  
(GMT-06:00) To: 'Elecraft Reflector'  Subject: 
[Elecraft] K3S Microphone Cable
I am remaking my SO2R control box cables and I need to purchase quality
microphone cable however I am not sure what to get. I am using an electret
microphone. I assumed that I would need a cable with a single conductor and
a shield but most mic cables that I see have two conductors. Belden has a
single conductor
http://www.awcwire.com/mfg/belden/product/belden-high-impedance-microphone-c
able  but it's a high impendence cable and the Belden multi conductor cables
are all low impendence. Does that matter? What gauge wire should I use for a
5ft cable?  I would appreciate any suggested cable models or feedback. I am
also having a difficult time locating brand name quality 8-pin Foster mic
plugs (I prefer using the front jacks).

73,

John KK9A

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Re: [Elecraft] K3S Microphone Cable

[Don Wilhelm]

John,

For microphone wire and 8 pin plugs, check out Universal Radio 
https://www.universal-radio.com
I have used the ultra flexible Heilwire (universal Radio #2645) and find 
it quite suitable with its shielded twisted pair, and they have 8 pin 
plugs their p/n #2112 that are quite satisfactory.


73,
Don W3FPR

On 1/15/2018 8:46 PM, j...@kk9a.com wrote:

I am remaking my SO2R control box cables and I need to purchase quality
microphone cable however I am not sure what to get. I am using an electret
microphone. I assumed that I would need a cable with a single conductor and
a shield but most mic cables that I see have two conductors. Belden has a
single conductor

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Re: [Elecraft] K3S Microphone Cable

[Clay Autery]

In my experience, the best microphone cable stock currently existing is Canare 
Star Quad cable.
I'm on my phone, so don't want tp peck out a complete answer here and now.
Star Quad cable has 2 twisted pairs and a shield and is nice and flexible 
broadcast quality cable stock.  Has great endurance.
I use it for my microphone, key, and any other cables I can.  There are at 
least 2 sizes now  Get the largest wire gauge available.  Consider putting 
some on your shelf for future use too.
I use a condenser mic so my wiring may be different, but I would never use the 
shield as a signal wire if I wasn't forced to  Use the twisted pairs to 
your advantage.
Can't help on the multi-pin connectors, as I don't use it at all.  But find and 
use the best ones tou can find.
73, ClayKY5G


Sent from my Verizon, Samsung Galaxy smartphone
 Original message From: j...@kk9a.com Date: 1/15/18  19:46  
(GMT-06:00) To: 'Elecraft Reflector'  Subject: 
[Elecraft] K3S Microphone Cable 
I am remaking my SO2R control box cables and I need to purchase quality
microphone cable however I am not sure what to get. I am using an electret
microphone. I assumed that I would need a cable with a single conductor and
a shield but most mic cables that I see have two conductors. Belden has a
single conductor
http://www.awcwire.com/mfg/belden/product/belden-high-impedance-microphone-c
able  but it's a high impendence cable and the Belden multi conductor cables
are all low impendence. Does that matter? What gauge wire should I use for a
5ft cable?  I would appreciate any suggested cable models or feedback. I am
also having a difficult time locating brand name quality 8-pin Foster mic
plugs (I prefer using the front jacks).

73,

John KK9A  

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Re: [Elecraft] K3S Microphone Cable

[Jim Brown]

On 1/15/2018 5:46 PM, j...@kk9a.com wrote:

I assumed that I would need a cable with a single conductor and
a shield but most mic cables that I see have two conductors. Belden has a
single conductor
http://www.awcwire.com/mfg/belden/product/belden-high-impedance-microphone-c
able  but it's a high impendence cable and the Belden multi conductor cables
are all low impendence.


This is a VERY old (and very outdated) of mic cables, mics, and their 
impedance.  The more important description for the cable is single 
conductor shielded or twisted pair shielded. In the old days, mics that 
used a single shielded conductor WERE high Z mics, and worked into high 
Z input circuits. Think guitar amps. Most modern mics are either 
electret condenser mics or dynamic mics, the vast majority are low 
impedance (150-250 ohms), and are designed to work into a load at least 
5x their own output Z. Good engineering practice is for audio input Z to 
be at least 10x the Z of the source.


Audio cables are NOT transmission lines, they are FAR, FAR, FAR too short.

Virtually NO practical cables have an Zo greater than about 110 ohms. 
Shielded twisted pair cables designed for digital audio are nominally 
110 ohms. Shielded twisted pair designed for analog audio have Zo in the 
range of 70 ohms.  Zo matters ONLY for digital audio, which has 
broadband components.



Does that matter?

No.


What gauge wire should I use for a 5ft cable?


Cable gauge matters only for physical strength. Audio cables are 
typically #24 - #26.


Many years ago, I found a partial spool of miniature Belden coax at a 
ham flea market. I use it for unbalanced (single conductor plus shield) 
audio patch cables. It's small enough to fit into virtually any 
connector you're likely to want to use and more robust than most 
alternatives.


There's nothing wrong with using shielded twisted pair for unbalanced 
mics. Simply tie one conductor to the shield at both ends.


73, Jim K9YC

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Re: [Elecraft] K3S Microphone Cable

[Mark Bayern]

Belden has many variations for mic cable.

is a quick list I found. We used something like Belden 8428 for
broadcast radio work.

Mark AD5SS

On Mon, Jan 15, 2018 at 7:46 PM,   wrote:
> I am remaking my SO2R control box cables and I need to purchase quality
> microphone cable however I am not sure what to get. I am using an electret
> microphone. I assumed that I would need a cable with a single conductor and
> a shield but most mic cables that I see have two conductors. Belden has a
> single conductor
> http://www.awcwire.com/mfg/belden/product/belden-high-impedance-microphone-c
> able  but it's a high impendence cable and the Belden multi conductor cables
> are all low impendence. Does that matter? What gauge wire should I use for a
> 5ft cable?  I would appreciate any suggested cable models or feedback. I am
> also having a difficult time locating brand name quality 8-pin Foster mic
> plugs (I prefer using the front jacks).
>
> 73,
>
> John KK9A
>
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