line out signal wire question - diyAudio
Go Back   Home > Forums > General Interest > Everything Else
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 23rd November 2006, 08:19 PM   #1
diyAudio Member
Join Date: Jun 2002
Location: Denver, CO
Default line out signal wire question

Any suggestions on the type and size of wire for line out from a computer headphone output to tube preamp, tube power amp, etc?

I am finishing out a basement and want to place stereo jacks on the wall with signal cable to the preamp running through the walls.

Suppose there could be a lower high frequency roll off due to wiring impedance, no?

  Reply With Quote
Old 23rd November 2006, 10:05 PM   #2
lineup is offline lineup  Sweden
diyAudio Member
lineup's Avatar
Join Date: Dec 2005
Location: the north
I use rather normal stereo cable.

It is a black pair about 2 meter length.

There are at least 3 groups of quality.
~1.5-2.0 mm. Very thin and badly shielded,
Type often attached in cheap stereo gears packages.

2.5-4 mm.(1/10inch-) Shielded of a better quality.
This is what I use for my 3.5 mm stereo jacks connections.
For good normal hifi applications.

5-8 mm. Very thick and a bit more expensive hifi cable.
This is most often used together with RCA Phono plugs.
It is difficult to mount smaller 3.5 mm stereo plugs onto such thick cable.

Best solution is maybe to use a very short
ready made 3.5mm stereo .. to 2 RCA Female sockets.
This is what I use from my Computer to my stereo inputs.
It is less than 20cm(8 inch) long.

From these two Female RCA to my stereo two Female RCA inputs,
I can use any quality of stereo RCA cables, with RCA plugs in both ends.

The influence of a cable is in proportion to the length.
If using very short 'normal quality' cable + a much longer high quality cable,
As my RCA cables are 150cm (1.5m) and the other only 20cm
the overall performance will be like the better longer one.

See picture here:
Click the image to open in full size.
3.5mm Stereo Plug to Two Phono Sockets Information:
Nickel-plated connectors
Fully screened cable
Durable PVC jacket
Cable strain relief
20cm (approx) cable length
Link to product at
Maplin: 3.5mm Stereo Plug to Two Phono Sockets

  Reply With Quote
Old 23rd November 2006, 10:49 PM   #3
moamps is offline moamps  Croatia
diyAudio Member
Join Date: Oct 2002
Location: Croatia
I'd like to point out two potential issues with the type of installation in Rick's post. Firstly, connecting the computer and the piece of audio equipment separately to power outlets in different parts of the house may give rise to ground loop problems. Secondly, if the connecting cable is too long and unbalanced, there is a danger of inducing various noises, regardless of whether the cable is shielded or not. In such cases, the best solution IME would be using audio transformers to get the balanced signal with separate grounds between the PC and the audio eqipment. These transformers are connected directly to the PC output and the signal is brought to the audio equipment via balanced cables.

  Reply With Quote
Old 23rd November 2006, 10:55 PM   #4
diyAudio Moderator
pinkmouse's Avatar
Join Date: Apr 2002
Location: Rotherham, England
I second balanced signal runs.
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 24th November 2006, 12:08 AM   #5
dangus is offline dangus  Canada
diyAudio Member
Join Date: May 2004
Location: Vancouver Island
I'll vote for S/PDIF... you'll get cleaner sound out of the 'puter if you use a separate DAC. Regular CAT-5 twisted-pair may be good enough, or else cable TV coax should work since it's the correct impedance. There must be some deals out there on used DACs, or there's the Behringer SRC-2496 for around $130. You can spend more than that on a pair of audio transformers without trying too hard.
  Reply With Quote
Old 24th November 2006, 02:20 AM   #6
lineup is offline lineup  Sweden
diyAudio Member
lineup's Avatar
Join Date: Dec 2005
Location: the north
hi again

I don't know how long cables you will need.
-> But first thing is to try keep them as SHORT as possible.

Going into balanced is probably the most perfectionist approach.
But if you do not want to try that road
which will require more than only cables,
-> you should use very good quality unbalanced RCA cables.

At least if length is like 5 meter or more.
At audio outputs/inputs you may have to consider some counter measures against capacitive loading.
Typical unbalanced, even of very good quality, can have 200pF per meter.

Done in the best way, I don't think you will have be too afraid using long cables.
Performing artists on stage and public sound systems
can have several 10's of meters cables for signals.
Even if many of these are balanced,
I would guess many times they also using unbalanced high quality.
At least for line level signal outputs.

But first thing is to figure out the shortest possible way
to fit your cables in your house.

I say you can make an unbalanced cable test first.
Using same length, but not put them into walls, yet.

My opinion is there is a good chance it will work well.
If not, there are people here that can help you design a balanced alternative.
If you would need such assistance.

  Reply With Quote
Old 24th November 2006, 01:51 PM   #7
diyAudio Member
Join Date: Jun 2002
Location: Denver, CO
Default great info and good discussion

Thank you! Very useful info!

  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
45' sub signal wire run causing problems chubby chaser Subwoofers 9 31st March 2008 05:24 AM
What kind of signal wire do you use in your DIY DAC or CDP? MGH Digital Source 54 22nd April 2006 11:10 AM
How do I turn an high current signal into a line level signal?? sardonx Tubes / Valves 8 27th August 2005 11:16 AM
signal wire yuval Tubes / Valves 4 21st October 2002 02:26 PM

New To Site? Need Help?

All times are GMT. The time now is 11:57 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2