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Balanced Cable for Unbalanced Connection
Old 16th February 2015
  #1
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Seditionary's Avatar
 

Balanced Cable for Unbalanced Connection

Hi!

I've read a bunch about this -- I know the standard method of using a balanced cable for an unbalanced connection is to solder cold to the shield and use hot for the connection. Obviously, this is one method for going from a balanced to unbalanced signal w/o a transformer...

However! What I am trying to do here is a different scenario. I am connecting unbalanced to unbalanced throughout a system... but using balanced cable to do it! Why? Well -- I have some Mogami unbalanced cable I coud use -- but it is pretty thick cable (won't fit in this system!) I also have some balanced Mogami 8 pair cable -- when you strip off the outside sheathing... the individual balanced strands are perfect size (small) for interconnecting in this system!

Now -- I read that you can use 4 core, for example, to make a better connection (2 core to hot, 2 core to cold), which made me consider...

Could I solder the two cores together for the HOT and use the shield for shield (GROUND).

I'm sure it doesn't really matter... as the run is short, probably won't hear much difference... but going from unbalanced to unbalanced within a system using a balanced cable -- any thoughts on this? Any sound benefit using both cores of the cable to HOT and shield to shield vs using one core and shield together and just one core for HOT?

From taking a bit of physics... seems like having the two cores together would provide an added benefit on the HOT side as there would be less resistance as there will be more core cable carrying the signal?

Thanks!
Old 17th February 2015
  #2
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Richard Crowley's Avatar
Unless you are driving big speakers, the amount of "power" going through an audio cable is negligible. So doubling up on wires/conductors doesn't really buy you much.
Now you could simply connect all the inner wires together (2 or 4 or whatever), and that would work perfectly fine.

However, it is somewhat more common to connect the cables as if they were "balanced", with the "hot" side on one wire, and ground on the other.
It won't make any real difference to the signal, but it allows for the easy option to put a balanced connector on the cable at some later date.
It also allows the option of "telescoping ground" should you discover that you need it for a problem solution.
Old 17th February 2015
  #3
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Seditionary's Avatar
 

As always -- thanks for your insight, Richard. Could you explain telescoping ground? Sounds interesting.

To be more specific -- I'm attempting a mod (same one as with those switches you helped me with on the other thread. I'm trying to wire around an input card on a tape machine. When the input card is not engaged, I can hear the signal faintly still with a ground hum... When wiring directly to the pot (bypassing the input card) the signal is very loud (hot). I could put a series resistor in to lower the volume... But then I'd be getting more hum, as I'd have to open the pot up more. With the pot turned down, there is very little hum. I've tried a variety of ground scenarios... None of which get rid of this slight hum, so I'm interested in your telescoping ground ideas!

Quote:
Originally Posted by Richard Crowley View Post
Unless you are driving big speakers, the amount of "power" going through an audio cable is negligible. So doubling up on wires/conductors doesn't really buy you much.
Now you could simply connect all the inner wires together (2 or 4 or whatever), and that would work perfectly fine.

However, it is somewhat more common to connect the cables as if they were "balanced", with the "hot" side on one wire, and ground on the other.
It won't make any real difference to the signal, but it allows for the easy option to put a balanced connector on the cable at some later date.
It also allows the option of "telescoping ground" should you discover that you need it for a problem solution.
Old 17th February 2015
  #4
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Hi
From your original question, if your system is only UNbalanced then you should have 1 wire as 'hot' and join screen and 'cold' wires together at both ends. This is to reduce the resistance of the GROUND. This is important because the GROUNDS need to be tightly connected to reduce hum as it is largely a 'brute force' connection. In some respects using cable that only has a small amount of copper for the SCREEN is a bad idea as it really should be as low a resistance as possible. Of course it depends on exactly what you are connecting so the effects will be different depending on conditions.
Using a single core for 'hot' also reduces the capacitance to ground slightly, but not much.
Telescoping ground is a 'technique' for balanced signals and is a 'sop' for badly designed gear that does not have correct ground management.
Matt S
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