[geeks] T-3 Coax as Audio Cable

Sridhar Ayengar ploopster at gmail.com
Fri Oct 5 10:58:38 CDT 2007


Francois Dion wrote:
>> I have two 50-ft lengths of Belden 734A coax cable.
> [...]
>> Too much interference from such a long run of line-level?
> 
> That's not a very long run. 734A coax is not that well suited for this
> imho, not because of transmission or interference/length, but it's big
> and not flexible enough for my taste. But since you already have the
> cable, it's basically free, right? Use it.

Very good!  There aren't going to be many bends in the cable anyway.

> I'm assuming RCA at each end, just use decent rca connectors that hold
> well. Of course it's not like a BNC, but some will tolerate a tug here
> and there.

The cable is already terminated in BNC, so I was just planning on using 
some BNC->RCA adapters.

> If I had to buy cable:
> http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=100-282

That's probably more than what I spent on this coil of 734A.

> I've used low noise microphone cables before to do 50ft rca runs. And
> patch cables. Average price, but work like a champ. It's still a bit
> on the big side, but it is very flexible.

Microphones run at even a lower signal level than line-level, no?  So 
one would expect microphone cable to be by-and-large constructed to a 
higher tolerance.

> Another option is mini coax, if you can find it for less than 35 cents
> a foot. I had a source for some, I dont remember if it was mini rg8,
> mini rg59 or what, but I was paying like 18 cent a foot, so 18$ for a
> 100ft run insulated audio line level than you can actually hide and
> snake around stuff, hard to beat.

I'll keep that in mind for future use.

> All in all, there are plenty of choices for less than $40 for 2x50ft.
> Anything more is really overkill.
> 
> I personally prefer to have a multiamp setup centralised, and run
> speaker wires directly, it is much less messy (and you need 110v
> everywhere etc).

I honestly wouldn't mind doing that.  Wouldn't decent speaker wire be 
more money, though?  I understand that the s/n would be a lot higher 
even with the interference from the cable run, since the signal level is 
so much higher, but is there anyone out there making coaxial cable 
capable of carrying 150W RMS signal?  I also already know about that 
overpriced twisted pair speaker wire out there.

Peace...  Sridhar



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