Highly Shielded Audio Cable
 

Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


Thanks!

Highly Shielded Audio Cable
 

In article ,
"Ralph D." wrote:

Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.

Look for a cable TV-coax (RG-6, maybe) that has a continuous foil shield.

Isaac

Highly Shielded Audio Cable
 

In article , Ralph D.
writes

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

Off-the-wall suggestion: run them through a length of copper pipe or
through that flexible metal conduit used in electrical installations?

You'd probably want to earth (ground) just one end to be sure a ground
current didn't flow, causing interference.

--
(\_/)
(='.'=)
(")_(")

Highly Shielded Audio Cable
 

"Ralph Dope"

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly
shielded to connect my audio source to a transmitter across a room. This
cable passes many sources of interference, so the shielding is critical.


** I have a sense of "deja vu" about this question ?

Is the signal stereo or mono ?

A 20 foot long 3.5mm two core cable is not gonna be easy to find at all let
alone with different qualities.

BTW:

Do you REALLY have a problem or are you just imagining one ?

How about some details ?

The solution may NOT be what you have guessed it to be.



..... Phil

Highly Shielded Audio Cable
 

On 03/09/2014 08:30 PM, Ralph D. wrote:
Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


Thanks!



What type of input does the transmitter have? Balanced +6dB? Unbalanced
50 Ohms? If it's Balanced, use transformers at the send end, or a
balanced line driver (aka Direct Box) of some kind (2 for stereo).
Ground only the receive end of your shields. Use as much "send" as you
can get away with; this will reduce noise at the xmtr input.

Highly Shielded Audio Cable
 

On 3/9/14 23:49 , isw wrote:
In article ,
"Ralph D." wrote:

Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.

Look for a cable TV-coax (RG-6, maybe) that has a continuous foil shield.

Isaac




For this application, you'd want a cable with at least a 95% braid shield.

A more effective solution would be to convert the audio to a balanced
line at one end, and then back to unbalanced at the other. Better CMRR.
Shielded twisted pair, here, will get the job done.

Highly Shielded Audio Cable
 

On Mon, 10 Mar 2014 08:24:12 -0700, D. Peter Maus
wrote:

...snip...
For this application, you'd want a cable with at least a 95% braid
shield.

A more effective solution would be to convert the audio to a balanced
line at one end, and then back to unbalanced at the other. Better CMRR.
Shielded twisted pair, here, will get the job done.




might look into high quality cabling like Belden 1800F
John Woodgate in UK and I worked together to extensively analyze that
cabling and exploring 'weaknesses', have LTspice models and he has a lot
of application data.

Highly Shielded Audio Cable
 

In sci.electronics.repair Ralph D. wrote:
Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly shielded
to connect my audio source to a transmitter across a room. This cable passes
many sources of interference, so the shielding is critical.

get some electrical conduit.

Highly Shielded Audio Cable
 

The Lady from Philadelphia suggests...

Have you tried using an inexpensive cable //simply to see what happens//,
rather than assuming you //need// a highly shielded cable?

If it doesn't work, you could encase the cable in braiding, grounding the
braiding at the reception end?

Highly Shielded Audio Cable
 

On Sun, 9 Mar 2014, Ralph D. wrote:

Hi,

I need a cable (ideally about 20ft), stereo 3.5mm male/male, highly
shielded to connect my audio source to a transmitter across a room. This
cable passes many sources of interference, so the shielding is critical.

Just use coax. Even something small like RG174 likely has better
shielding than many audio cables.

Of course, if there is a real issue here, little stereo plugs end up
leaving an unshielded area for the RF to get in. Changing to something
else would complete the shield. I know I'd use BNC connectors for audio
connectors if that pile of 200 male connectors I found on the sidewalk
had included 200 female BNC connectors as well.

Make sure the output feeding the coax is low impedance, that's not for
feeding the coax, but a high impedance would make it easier for the RF to
be picked up. And terminate at the transmitter end, so that point sees
relatively low impedance.

Make sure the usual low value bypass capacitors are at the input to that
transmitter, so even if there is RF pickup, it is bypassed to ground and
won't be rectified by the input stage. Get some ferrite beads (the tiny
ones, and put them on the lead between the input jack of the trnasmitter
and the first stage, or the traditional method would be an RF choke of
suitable value.

Look in any radio handbook and there should be a section on RF
interference, which would describe how to keep RF out of the first stage
of an audio amplifier.

Michael






I would prefer to get it from Amazon so as to get it quick with Prime
(incredibly narrow window of free-time during a currently very busy
schedule) but would be OK with ordering from one of the Ham sites if
turnaround time is very good. I could not get a good search parameter on
Amazon that didn't turn up thousands of hits that I just don't have time to
sift through right now.

Any good cable with known good isolation would be good. I have ferrite
chokes I can use, but would prefer a cable of suitable quality that did not
need them (current cable is getting interference even with them as this is
not just run-of-the-mill 60cycle stuff).

Any good suggestions would be appreciated.


Thanks!