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Running long interconnects a bad thing?


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#1 of 17 OFFLINE   Legairre

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Posted November 28 2001 - 01:07 PM

My 5 channel amp will be on a special stand underneath my center channel(which sits in front of my RPTV). I will need 5, 14 foot interconnects since my receiver is across the room in the rack. I was planning on using good old 75 ohm coaxial as my interconnects. How bad is it for sound to run the interconnects this long? The up side is my front speaker runs will only be about four feet.

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#2 of 17 OFFLINE   Jaehoon Heo

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Posted November 28 2001 - 01:58 PM

I think that long unbalanced analog connection can be quite susceptible to the noise. In my experiences, some very sharp hum appeared in the audio. However it really depends on the layout of the cables and other signals and/or AC electricity.
Using 75ohm(intrinsic impedance) cable will not help in transmitting audio band signal. To be less susceptible, it need to be well-shielded, and hopefully with very low resistance(not intrinsic impedance).

#3 of 17 OFFLINE   Zbigniew

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Posted November 28 2001 - 02:22 PM

If you re very concerned with audio quality, consider using Rane Balance Buddy http://www.rane.com/bb44x.html; if you look around on Rane site, you will find there that "unbalanced lines should be kept to 10 feet or less...".

I had run in the past unbalanced interconnect signal up to a 75 feet, but my hearing is obviously deteriorating. Well, time to move to balanced runs to my speakers.

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#4 of 17 OFFLINE   Legairre

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Posted November 28 2001 - 02:49 PM

So with long runs is audible noise(hum) the only thing I
need to worry about?

I've seen pictures of high end demos where the amp is on the floor between the speakers but the preamp is about 15 feet away.

Let's say theres no audible noise because of good shielding. Will the music sound the same with long runs and short?

Also aren't sub cables just long interconnects with good shielding? Some people use RG6 quad shield. With a powered sub you have an amplifier, let's say 20 feet away from the preamp, with a very short run from the subs amp to the driver. Long run, but no hum. Wouldn't the same be true of a preamp and amplifier combo?


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#5 of 17 OFFLINE   Wayne A. Pflughaupt

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Posted November 28 2001 - 05:17 PM

Legairre,

It’s not quite the same thing. There is no resolution to be lost on a sub. Any signal loss (i.e., drop in signal level) can be compensated for with the gain control.

Is long as quality cables with good shielding are used, noise will not be an issue. The only concern with long runs is signal loss and a loss of high frequency response. However, it would take a run of 50ft. or more before you would have to worry about any of this. I ran lines from my HT system through the attic to a system in the garage, which I know was more than 100 ft., and there was no problem. There might have been some loss of resolution (can’t tell, since I don’t have a reference system in the garage Posted Image), but there was no noise problem.

Bottom line, Legairre, 15 ft. is not a long cable run. Use good-quality cables (which you should be doing anyway), at least as good as the Radio Shack Gold cables, and you’ll be fine.

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#6 of 17 OFFLINE   Legairre

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Posted November 29 2001 - 02:14 AM

Wayne,
Which one do you think will work out better. RG6 or RS gold interconnects. Both are 75 ohm and shielded. I have a bunch of RG6 laying around from when I installed my sat dish. The RG6 is stiff but that not a problem for me.

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#7 of 17 Guest_John Morris_*

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Posted November 29 2001 - 02:20 AM

Legairre: You might be able to get away with RG6QS depending on how quiet and accurate the rest of your system is. 14 feet is long, but not extremely so. If you have the cable laying around, try it and see. I used to run my interconnects for a music only system 42 feet. I found that the only way I could live with this was by using balanced cables.

#8 of 17 OFFLINE   Legairre

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Posted November 29 2001 - 02:56 AM

Quad shield is what I have lying around. I might as well give it a try.

#9 of 17 OFFLINE   Wayne A. Pflughaupt

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Posted November 29 2001 - 09:50 AM

Legairre,

While RG-6 will work fine, I wouldn’t use it unless you have the skills to properly terminate it. It takes an expensive, professional-grade ratchet-framed crimper to properly install standard F-connectors, and they usually start at $50 (that’s what I paid for my Greenlee). Don’t waste your time or money with a cheap $10 crimper. They don’t work worth a %*&# and really aren’t even worth the $10.

If you can solder, you could solder RG-6 directly to RCA connectors. I’ve had success doing this.

If these options don’t work for you, Legairre, I’d stick with good-quality off-the-shelf RCA cables.

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#10 of 17 OFFLINE   Mark Rich

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Posted November 29 2001 - 10:05 AM

For analog audio I'd go with decent coax cable and not simply some RG6 cable you have lying around! Not all coax cable is created equal. The shielding alone varies between brands and models of cables (double, triple, % coverage, material used etc..). Then there is the insulation ( solid, foamed, Teflon etc..) and center conductor ( tinned copper, solid or stranded bare copper etc...) While I'm sure what you have will probably work how well it sounds will depend on the cables recipe. The fact that its such a long run will make the type of coax cable you use more critical.
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#11 of 17 OFFLINE   Wayne A. Pflughaupt

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Posted November 29 2001 - 04:27 PM

Mark,

I doubt the shielding will be an issue with quad-shield. Any quad shield cable will have a better shield than most audio cable (actually, I’ve “dissected” the RS Gold cables, and the shielding on them is rather poor).

However, the point about the center conductor is well taken. You won’t often find RG-6 with a stranded center conductor (and if would work fine for audio, even if it did), but I have seen RG-6 with a steel center conductor (at least I think that’s what it was—it certainly would not solder). Stuff like that you for sure want to avoid for audio use (heck, probably RF use, too. Posted Image).

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#12 of 17 OFFLINE   Legairre

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Posted November 30 2001 - 02:27 AM

You guys are great. I really appreciate the help. The coax I have lying around from when I installed my DSS is pretty good stuff. DSS is REAL picky about cabling and connections(crimping). It's Beldin quad shield, copper conductor, not sure about the insulation though. My dealer will loan me some Canare interconnects. I'm going to make my interconnects out of the coax and compare that with the Canare. If I can't tell any difference, I'll use the coax. If the Canare stuff sounds better I'll probably just try the RS interconnects and see if they sound better than the coax. I'm not going to start a cable debate, but I just refuse to pay $600.00 or $700.00 for five cables when I could use that money towards a new preamp.

Thanks for the help.

#13 of 17 OFFLINE   Mark Rich

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Posted November 30 2001 - 02:41 AM

Wayne,

Okay I admit it I don't have a lifePosted Image
My conern with the shielding is that some coax uses alum braid as a shield. Dont think its going to sound very good if it does!
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#14 of 17 OFFLINE   Mark Rich

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Posted November 30 2001 - 02:48 AM

Legairre,

You might want to post your cable questions to the cable asylum board. They share their knowledge and opinions freely and have a ton of info for research. Especially good for the DIY projects such as yours.

http://64.154.92.195...cables/bbs.html
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#15 of 17 OFFLINE   Legairre

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Posted November 30 2001 - 05:02 AM

It seems my quest for reasonably priced interconnects might be over. Best Buy has the AR pro series interconnects in a 20ft length for $20.00 a pair (#AP033 I think). I need five so I'm still only looking at $60.00. They should be better then anything I could make.

#16 of 17 OFFLINE   Wayne A. Pflughaupt

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Posted November 30 2001 - 06:21 AM

Quote:
My conern with the shielding is that some coax uses alum braid as a shield
Mark, you nailed it again. Gee, I must have my head in the sand on this one! Posted Image Of course, you don’t want to use coaxial cable with an aluminum shield for audio purposes.

Okay, I’m bending over—-someone give me what I deserve (for those of you with dirty minds, my pants are still up Posted Image ).

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#17 of 17 OFFLINE   Dennis Nicholls

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Posted June 30 2009 - 05:34 AM

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