How to DIY Digital Coaxial cable for DAC

Wharfedale Speakers

cha_indian

Active Member
Joined
Dec 14, 2007
Messages
429
Points
28
Location
Hyderabad/Chennai, India
I am looking to build a coaxial cable for my DAC and I am looking for cable suggestions ... From what i read on the net, coaxial cable is easy to build.

I got RCA jacks and looking for a 75 Ohm impedance cable..... Can we use the cable used in cable TV ??
 

spirovious

Well-Known Member
Joined
Apr 10, 2008
Messages
12,415
Points
113
Location
Mumbai
I have made coax from spk cable(both regular & OFC 16awg)
OFC sounds better than regular as they sound little bright.
As thickness is increased,higher freq try to dominate Lower.
 

cha_indian

Active Member
Joined
Dec 14, 2007
Messages
429
Points
28
Location
Hyderabad/Chennai, India
Hi Cranky,

Thanks for the reply... Any other suggestions apart from cable tv ka cable ??

I am planning to visit the Chetan cabletronics shop in Hyderabad and looking for any specific model of Coaxial that is more suitable for Audio
 

cmsajith

Well-Known Member
Joined
Feb 19, 2008
Messages
1,590
Points
63
Location
Cochin - Bangalore
Ask them for regular solid inner core coax 75 ohm (TV) cable. Anything else is an unknown quantity.

So what you mean to say is that a normal 75ohm TV cable is more than enough for subwoofer and digital coaxial cable, no need to spend much on that?
 

cmsajith

Well-Known Member
Joined
Feb 19, 2008
Messages
1,590
Points
63
Location
Cochin - Bangalore
Yup. But there's more to it than meets the eye.

The trick is the connectors, not the cable. Regular RCAs are usually 50 ohm and no amount of trickery will solve that. The only 'certified' 75 ohm connectors I know of are the Canare RCAs.

FWIW, I have two digital coax cables, one is a 3m run using regular microphone patch cable with Neutrik RCAs on the end, connecting the onboard soundcard of one of my PCs to an AVR for a gaming surround system. The second is a slightly better cable for a PC-DAC connection in my main music PC, built with 75ohm coax, but 50 ohm RCAs from Amphenol. The second cable performs slightly better, but I know there is some more potential for improvement. I had bought a ton of the cable and some connectors to experiment with optimal cable length, but have not found the time to get down to it.

Basically because of the impedance mismatch between conductor and connector (and input terminal) there is a reflection of the transmitted signal at the junction where the mismatch occurs. Longer cables alleviate this somewhat in case they are not properly designed in the first place (though it's a band-aid). Someday soon I'll have more concrete first-hand evidence of this and a report on whether all this is actually audible or not, which is the big Q. In the meantime, I suggest not worrying about it.

Subwoofer cable is analog. Totally different ball of wax. TV coax is *not* recommended for analog applications as the impedance is too high, and the capacitance will kill most of the sound, and can damage audio preamplifiers.

Thanks. For a subwoofer cable which is the best for economic DIY and which parameter we need to check for the connectors?
 

kaushik

Well-Known Member
Joined
Mar 3, 2008
Messages
2,525
Points
113
Location
Bangalore
cha_indian ,

If you want silver RCA cable , grab silver wire from Alberts Audio Store , ebay ... bid to grab at a pretty low price.


Blue jeans cable is one good RCA pair for less(ready made).
I made co-axial Guitar cable with chetna cable , very well shielded .Some people say co-axials are not that good for
analog interconnects. Check the result.
 
Last edited:

cha_indian

Active Member
Joined
Dec 14, 2007
Messages
429
Points
28
Location
Hyderabad/Chennai, India
Hey Kaushik, thanks for your recommendation.

I already got my interconnects and speaker cables made of silver made by Valab. I am looking to build my own Coaxial cable for my DAC which i am building.
 

kaushik

Well-Known Member
Joined
Mar 3, 2008
Messages
2,525
Points
113
Location
Bangalore
Top