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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
Posted to rec.radio.shortwave,sci.electronics.repair
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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! |
#2
Posted to rec.radio.shortwave,sci.electronics.repair
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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 |
#3
Posted to rec.radio.shortwave,sci.electronics.repair
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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. -- (\_/) (='.'=) (")_(") |
#4
Posted to rec.radio.shortwave,sci.electronics.repair
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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 |
#5
Posted to rec.radio.shortwave,sci.electronics.repair
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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. |
#6
Posted to rec.radio.shortwave,sci.electronics.repair
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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. |
#7
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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. |
#8
Posted to rec.radio.shortwave,sci.electronics.repair
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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. |
#9
Posted to rec.radio.shortwave,sci.electronics.repair
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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? |
#10
Posted to rec.radio.shortwave,sci.electronics.repair
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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! |
#11
Posted to rec.radio.shortwave,sci.electronics.repair
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Highly Shielded Audio Cable
On 3/10/2014 7:11 AM, Phil Allison wrote:
"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 Hack a long HDMI cable. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net |
#12
Posted to rec.radio.shortwave,sci.electronics.repair
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Highly Shielded Audio Cable
On 03/10/2014 09:56 AM, Cydrome Leader wrote:
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. There should not be a lot of RF in the radio room, compared to near the antennas. Do all the other stations use EMT for audio? It really isn't necessary. You can probably use unshielded twisted pair if you know what you're doing. The Phone Company doesn't use shielded cable for baseband audio. |
#13
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Highly Shielded Audio Cable
On Sunday, March 9, 2014 11:30:08 PM UTC-4, 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). Hmm, What kind of interference are you seeing? (can you turn things off and make it go away?) To get rid of electro-static pick-up (display screeens flourescent lights...) get a cable with both braid and a almuinized mylar sheild. (Driving the cable with a low impedance source should help too.) 60 Hz, magnetic interference is darn hard to shield against (In my limited experience.) Your best bet there is to keep a good distance between transfomeres and the cable. George H. Any good suggestions would be appreciated. Thanks! |
#14
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Highly Shielded Audio Cable
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#15
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Highly Shielded Audio Cable
On Tue, 11 Mar 2014 20:02:49 -0700, Michael Black wrote:
...snip... That's the question most of us missed. I could have sworn he said "rf interference", but when I looked back after posting, realized he hadn't indicated any specific bit of interference. ...snip.... I assumed stuff like nearby motor drivers, or worse, from those new solid state ballasts. The cheap ones can get VERY energetic. and coupling magnetic into audio is not an easy item to stop. People are so used to 'shielding' with electrostatic shields and lowering the impedance to reduce high impedance interference, that they are completely caught off guard when confronted with low impedance noise sources, like magnetic field. May have noticed that lowering the impedance makes little difference. Sometimes, high impedance noise gets 'converted' somewhere to a low impedance source which is really mindboggling, since you recognize the noise and expect it to be coming from high impedance. Best way,...balanced pair, shielded. And I MEAN balanced over the WHOLE spectrum! DC to GHz, 10GHz if you can do it. That includes termination circuitry, Tx/Rx, and high quality cabling with very symmetrical conductor placement and spacings within that cable. That is, if you're goal is 120 dBV, or better 140dBV, down noise floors you had better pay attention to everything. |
#16
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Highly Shielded Audio Cable
On 03/12/2014 07:58 AM, RobertMacy wrote:
On Tue, 11 Mar 2014 20:02:49 -0700, Michael Black wrote: ...snip... That's the question most of us missed. I could have sworn he said "rf interference", but when I looked back after posting, realized he hadn't indicated any specific bit of interference. ...snip.... I assumed stuff like nearby motor drivers, or worse, from those new solid state ballasts. The cheap ones can get VERY energetic. and coupling magnetic into audio is not an easy item to stop. People are so used to 'shielding' with electrostatic shields and lowering the impedance to reduce high impedance interference, that they are completely caught off guard when confronted with low impedance noise sources, like magnetic field. May have noticed that lowering the impedance makes little difference. Sometimes, high impedance noise gets 'converted' somewhere to a low impedance source which is really mindboggling, since you recognize the noise and expect it to be coming from high impedance. Best way,...balanced pair, shielded. And I MEAN balanced over the WHOLE spectrum! DC to GHz, 10GHz if you can do it. That includes termination circuitry, Tx/Rx, and high quality cabling with very symmetrical conductor placement and spacings within that cable. That is, if you're goal is 120 dBV, or better 140dBV, down noise floors you had better pay attention to everything. These are pretty darn close to what you need, as long as they are true balanced. This will put a face on it, any way. http://www.markertek.com/CATV-Headen...ver-CAT5.xhtml |
#17
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Highly Shielded Audio Cable
"RobertMacy" wrote in message newsp.xcl6jxtm2cx0wh@ajm...
Best way,...balanced pair, shielded. And I MEAN balanced over the WHOLE spectrum! DC to GHz, 10GHz if you can do it. That includes termination circuitry, Tx/Rx, and high quality cabling with very symmetrical conductor placement and spacings within that cable. That is, if you're goal is 120 dBV, or better 140dBV, down noise floors you had better pay attention to everything. It's unfortunate that the OP seems limited to 3.5mm connections. There are AR cables (Master Series) that have a separate shield, grounded at the receiving end, with identical wires (not the shield) carrying the signal. There is also a ferrite choke. I use these in my system. http://www.amazon.com/Acoustic-Resea...+master+series They used to be fairly cheap, but have gotten pricey again. (Of course, the price is still rather lower than "audiophile" cables with the same features.) |
#18
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Highly Shielded Audio Cable
On 03/12/2014 07:58 AM, RobertMacy wrote:
On Tue, 11 Mar 2014 20:02:49 -0700, Michael Black wrote: ...snip... That's the question most of us missed. I could have sworn he said "rf interference", but when I looked back after posting, realized he hadn't indicated any specific bit of interference. ...snip.... I assumed stuff like nearby motor drivers, or worse, from those new solid state ballasts. The cheap ones can get VERY energetic. and coupling magnetic into audio is not an easy item to stop. People are so used to 'shielding' with electrostatic shields and lowering the impedance to reduce high impedance interference, that they are completely caught off guard when confronted with low impedance noise sources, like magnetic field. May have noticed that lowering the impedance makes little difference. Sometimes, high impedance noise gets 'converted' somewhere to a low impedance source which is really mindboggling, since you recognize the noise and expect it to be coming from high impedance. Best way,...balanced pair, shielded. And I MEAN balanced over the WHOLE spectrum! DC to GHz, 10GHz if you can do it. That includes termination circuitry, Tx/Rx, and high quality cabling with very symmetrical conductor placement and spacings within that cable. That is, if you're goal is 120 dBV, or better 140dBV, down noise floors you had better pay attention to everything. http://muxlab.com/wp-content/uploads...i-Fi_Balun.pdf |
#19
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Highly Shielded Audio Cable
On 03/12/2014 08:10 AM, William Sommerwerck wrote:
"RobertMacy" wrote in message newsp.xcl6jxtm2cx0wh@ajm... Best way,...balanced pair, shielded. And I MEAN balanced over the WHOLE spectrum! DC to GHz, 10GHz if you can do it. That includes termination circuitry, Tx/Rx, and high quality cabling with very symmetrical conductor placement and spacings within that cable. That is, if you're goal is 120 dBV, or better 140dBV, down noise floors you had better pay attention to everything. It's unfortunate that the OP seems limited to 3.5mm connections. There are AR cables (Master Series) that have a separate shield, grounded at the receiving end, with identical wires (not the shield) carrying the signal. There is also a ferrite choke. I use these in my system. http://www.amazon.com/Acoustic-Resea...+master+series They used to be fairly cheap, but have gotten pricey again. (Of course, the price is still rather lower than "audiophile" cables with the same features.) That is pure audio snake oil. If you are dealing with induced magnetic fields (hum) you need a competent differential input and balanced lines. The copper part of the phone company is not shielded. Even the part that carries high fidelity audio for industry is not shielded. Big clunky interfaces like that are usually very reactive and do affect the sound...badly. Try Hosa brand. Spend the difference on better speakers. |
#20
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Highly Shielded Audio Cable
"dave" wrote in message
news That is pure audio snake oil. My point was that the AR cables had features designed for good shielding. I never directly claimed that they sounded better. Indeed, my experience has been that expensive cables don't sound better than the cheap ones that come "in the box". |
#21
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Highly Shielded Audio Cable
On 03/12/2014 09:31 AM, William Sommerwerck wrote:
"dave" wrote in message news That is pure audio snake oil. My point was that the AR cables had features designed for good shielding. I never directly claimed that they sounded better. Indeed, my experience has been that expensive cables don't sound better than the cheap ones that come "in the box". And I pointed out as someone else did earlier it is not primarily a matter of shielding. |
#22
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Highly Shielded Audio Cable
On 03/12/2014 09:31 AM, William Sommerwerck wrote:
"dave" wrote in message news That is pure audio snake oil. My point was that the AR cables had features designed for good shielding. I never directly claimed that they sounded better. Indeed, my experience has been that expensive cables don't sound better than the cheap ones that come "in the box". I use the DAC in my home theater receiver for all the audio, which comes in via S/Pdif. DTS multichannel audio is as exotic as it gets. Hosa cables are good and cheap. I am just a customer. |
#23
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Highly Shielded Audio Cable
On 03/12/2014 09:31 AM, William Sommerwerck wrote:
"dave" wrote in message news That is pure audio snake oil. My point was that the AR cables had features designed for good shielding. I never directly claimed that they sounded better. Indeed, my experience has been that expensive cables don't sound better than the cheap ones that come "in the box". Here we go. 3.5mm TRS male. http://www.markertek.com/CATV-Headen...c/500030.xhtml |
#24
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Highly Shielded Audio Cable
dave wrote: The Phone Company doesn't use shielded cable for baseband audio. No, but they use twisted pair and they can still pick up a lot of RF. I've seen over 5 volts of RF on phone lines at AM radio stations that were wired with 'station wire' instead of twisted pair. The radio station audio was louder than either party on the line could talk. The fix was to rip out everything, run 25 pair twisted cable to localized terminals and use short runs to the phones. There was still some common mode RF, but at least the lines were usable since it no longer caused the volume limiter to go into continuous conduction. -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge. |
#25
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Highly Shielded Audio Cable
dave wrote: These are pretty darn close to what you need, as long as they are true balanced. This will put a face on it, any way. http://www.markertek.com/CATV-Headen...ver-CAT5.xhtml 75 Ohm unbalanced to 110 Ohm, balanced, twisted pair? The fact that he is using unbalanced audio implies 5K ohm or higher impedance. -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge. |
#26
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Highly Shielded Audio Cable
On Thu, 13 Mar 2014, Michael A. Terrell wrote:
dave wrote: The Phone Company doesn't use shielded cable for baseband audio. No, but they use twisted pair and they can still pick up a lot of RF. I've seen over 5 volts of RF on phone lines at AM radio stations that were wired with 'station wire' instead of twisted pair. The radio station audio was louder than either party on the line could talk. The fix was to rip out everything, run 25 pair twisted cable to localized terminals and use short runs to the phones. There was still some common mode RF, but at least the lines were usable since it no longer caused the volume limiter to go into continuous conduction. Yes, and even in the days of the no real electronics in the phones, there were tips in the books about keeping RF out of the phones. The issue becomes more significant when all the phones are made of electronics, and there's a lot more that can act ad diodes to detect the signals. Michael |
#27
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Highly Shielded Audio Cable
Ralph D. udtrykte præcist:
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. You could go digital/optical with a analog-toslink-analog combo. There is a combination at the bottom of the ad he http://amzn.com/B005F20756 It claims only 18 feet, that could be close enough to your approx 20ft, when there are analog cables in either end. But I haven't seen an 18ft toslink cable... There must transmitters which are more powerful, if you need a longer range. Leif -- Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske beslutning at undlade det. |
#28
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Highly Shielded Audio Cable
"Leif Neland" wrote in message ...
But I haven't seen an 18ft TosLink cable... There are couplers. |
#29
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Highly Shielded Audio Cable
On 03/12/2014 10:20 PM, Michael A. Terrell wrote:
dave wrote: These are pretty darn close to what you need, as long as they are true balanced. This will put a face on it, any way. http://www.markertek.com/CATV-Headen...ver-CAT5.xhtml 75 Ohm unbalanced to 110 Ohm, balanced, twisted pair? The fact that he is using unbalanced audio implies 5K ohm or higher impedance. Baseband Video is always 75 Ohms unbalanced 1VAC p/p. 110 Ohms is a standard for digital audio. The fact the device is a BalUn means the unbalanced audio (and video) is transformed for the balanced transmission line (and back again after). The video will be a couple 10ths low but the first DA it hits will fix that, otherwise most devices will AGC it to where it needs to be. As long as the group delay isn't hideous it'll work for SDTV. There are audio only devices that is the application we need here. PS I'm surprised Ma Bell didn't try to sell you a bunch of 111C coils and active official interface devices. |
#30
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Highly Shielded Audio Cable
On Wed, 12 Mar 2014 23:00:33 -0700, Michael Black wrote:
On Thu, 13 Mar 2014, Michael A. Terrell wrote: dave wrote: The Phone Company doesn't use shielded cable for baseband audio. No, but they use twisted pair and they can still pick up a lot of RF. I've seen over 5 volts of RF on phone lines at AM radio stations that were wired with 'station wire' instead of twisted pair. The radio station audio was louder than either party on the line could talk. The fix was to rip out everything, run 25 pair twisted cable to localized terminals and use short runs to the phones. There was still some common mode RF, but at least the lines were usable since it no longer caused the volume limiter to go into continuous conduction. Yes, and even in the days of the no real electronics in the phones, there were tips in the books about keeping RF out of the phones. The issue becomes more significant when all the phones are made of electronics, and there's a lot more that can act ad diodes to detect the signals. Michael AND! the designers usually violate concept of exactly what 'balanced' line means, then the telephone's own protection system will rectify the AM signals. Most radio stations will supply little pigtails to place between your phone and the line that pretty much drops that RF, for free, as a good neighbor act. In one doctor's office sitting by the relatively low powered 10kW AM towers [Jeff will know where this is, driving south along highway 1 to your left, just south of Santa Cruz] had between 1V/m upwards to 3V/m and in some places concentrated to over 7V/m and the station came in louder than conversations. Now,..extrapolate that to EMP at 20kV to 50kV/m and you can see why nobody wants missiles AND nuclear capability in the same hands. |
#31
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Highly Shielded Audio Cable
On 3/13/2014 8:26 AM, William Sommerwerck wrote:
"Leif Neland" wrote in message ... But I haven't seen an 18ft TosLink cable... There are couplers. Monoprice offers this 25 foot Toslink cable for under $5, as well as longer ones out to 50 foot length. They work beautifully for the applications I have tried, including the connection of an AppleTV audio output to a distant A/V receiver in another room. http://www.monoprice.com/Product?c_i...seq=1&format=2 |
#32
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Highly Shielded Audio Cable
dave wrote: On 03/12/2014 10:20 PM, Michael A. Terrell wrote: dave wrote: These are pretty darn close to what you need, as long as they are true balanced. This will put a face on it, any way. http://www.markertek.com/CATV-Headen...ver-CAT5.xhtml 75 Ohm unbalanced to 110 Ohm, balanced, twisted pair? The fact that he is using unbalanced audio implies 5K ohm or higher impedance. Baseband Video is always 75 Ohms unbalanced 1VAC p/p. Yawn. Actually, it's 1.4 volts, because the sync is .4 volts below the video. 110 Ohms is a standard for digital audio. The fact the device is a BalUn means the unbalanced audio (and video) is transformed for the balanced transmission line (and back again after). The video will be a couple 10ths low but the first DA it hits will fix that, otherwise most devices will AGC it to where it needs to be. As long as the group delay isn't hideous it'll work for SDTV. There are audio only devices that is the application we need here. PS I'm surprised Ma Bell didn't try to sell you a bunch of 111C coils and active official interface devices. 'Ma Bell' didn't own the telephone hardware on that Army base. In fact, they didn't own the White Alice' microwave network that provided the long distance phone service for a large part of Alaska. Test some of those cheap video baluns with audio, then tell us the -3 dB points. You keep forgetting that I built Telemetry & video equipment that you'll never see, and to standards that you can't come close to. Long before digital TV, my video hardware was flat to 40 MHz. That included diversity reception, and video combiners that would provide a solid video signal from multiple fading signals. -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge. |
#33
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Highly Shielded Audio Cable
On Wed, 12 Mar 2014 11:01:01 -0700, dave wrote:
On 03/12/2014 09:31 AM, William Sommerwerck wrote: "dave" wrote in message news That is pure audio snake oil. My point was that the AR cables had features designed for good shielding. I never directly claimed that they sounded better. Indeed, my experience has been that expensive cables don't sound better than the cheap ones that come "in the box". And I pointed out as someone else did earlier it is not primarily a matter of shielding. And i will point out that in OP's case, it is a cabling issue if not exactly a shielding issue, rather than any other issue. ?-) |
#34
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Highly Shielded Audio Cable
On 03/14/2014 04:58 AM, josephkk wrote:
On Wed, 12 Mar 2014 11:01:01 -0700, dave wrote: On 03/12/2014 09:31 AM, William Sommerwerck wrote: "dave" wrote in message news That is pure audio snake oil. My point was that the AR cables had features designed for good shielding. I never directly claimed that they sounded better. Indeed, my experience has been that expensive cables don't sound better than the cheap ones that come "in the box". And I pointed out as someone else did earlier it is not primarily a matter of shielding. And i will point out that in OP's case, it is a cabling issue if not exactly a shielding issue, rather than any other issue. ?-) The shield can make things worse sometimes. |
#35
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Highly Shielded Audio Cable
"dave" wrote in message m... On 03/12/2014 09:31 AM, William Sommerwerck wrote: "dave" wrote in message news That is pure audio snake oil. My point was that the AR cables had features designed for good shielding. I never directly claimed that they sounded better. Indeed, my experience has been that expensive cables don't sound better than the cheap ones that come "in the box". Here we go. 3.5mm TRS male. http://www.markertek.com/CATV-Headen...c/500030.xhtml !!! Cat5 (e & 6 as well) is something I have a *lot* of. Is there any advantage to 5e as opposed to 5 for this application? I'd rather hang on to my 6 & 5e if I could. How about these adapters. I know they may not have the same quality, but for 2 for $15US it might make it worth taking a shot... not much lost if it doesn't work: http://www.amazon.com/3-5mm-To-Audio...gy_misc_text_z |
#36
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Highly Shielded Audio Cable
On 03/16/2014 09:50 AM, Ralph D. wrote:
"dave" wrote in message m... On 03/12/2014 09:31 AM, William Sommerwerck wrote: "dave" wrote in message news That is pure audio snake oil. My point was that the AR cables had features designed for good shielding. I never directly claimed that they sounded better. Indeed, my experience has been that expensive cables don't sound better than the cheap ones that come "in the box". Here we go. 3.5mm TRS male. http://www.markertek.com/CATV-Headen...c/500030.xhtml !!! Cat5 (e & 6 as well) is something I have a *lot* of. Is there any advantage to 5e as opposed to 5 for this application? I'd rather hang on to my 6 & 5e if I could. How about these adapters. I know they may not have the same quality, but for 2 for $15US it might make it worth taking a shot... not much lost if it doesn't work: http://www.amazon.com/3-5mm-To-Audio...gy_misc_text_z They may or not work depending on the quality of the transformers. Look up "CMRR", "differential input" |
#37
Posted to rec.radio.shortwave,sci.electronics.repair
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Highly Shielded Audio Cable
"Ralph D." wrote in message ... 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! Thanks to everyone for their input. I guess the discussion has about worn itself out. After reading what was posted in both groups, I have decided to try this option first, as I have cable on hand and it would be great if it resolved for cheap :-) http://www.amazon.com/Headphone-Jack...5mm+Balun+Cat5 Hopefully I'll have a positive follow-up. Thanks again. |
#38
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Highly Shielded Audio Cable
in my very hard to get this.
http://belajarteknolgi.com Pada Senin, 10 Maret 2014 10:30:08 UTC+7, Ralph D. menulis: 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! |
#39
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Highly Shielded Audio Cable
On Monday, March 10, 2014 8:24:12 AM UTC-7, D. Peter Maus wrote:
On 3/9/14 23:49 , isw wrote: In article , "Ralph D." wrote: 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. 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. Yep, this is the best solution: it takes transformers (or active-circuitry equivalents) though, so it might be a tad hard to implement. The wiring for this kind of thing is widely used for microphones (microphone cable and microphone connectors solves the cable-purchase part of the problem). I'm not sure where to buy, but searching on 'audio balun' seems appropriate. The word 'balun' indicates a balanced-to-unbalanced transformer (and you'll need two). |
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