Balanced vs unbalanced connections [Archive] - Audio & Video Forums

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ChrisR
01-07-2005, 05:48 AM
What is the difference between these connections? I am told by two different cable designers that the only real reason to use balanced cables is if you are running the cables for a significant distance. Then the balanced cables have an advantage. IS THIS TRUE?

markw
01-07-2005, 06:08 AM
The only time I need or use balanced cables is when running low level signals for a good distance. The 75' microphonecables in the church use balanced cables. Likewise the 150' run from the mixing console to the bank of amps that pumps out 10,000 watts is balanced.

But. all the gee gaws in the sound room (eq, time delay, recorders, etc.)are interconnected via plain old coaxial cable terminated with RCA connectors or 1/4" phone jacks.

Unless you live in an exteremely RFI rich environment or there's some particular circutry built into your gear, the distances involved in home audio generally don't require balanced cables.

Monstrous Mike
01-07-2005, 09:09 AM
What is the difference between these connections? I am told by two different cable designers that the only real reason to use balanced cables is if you are running the cables for a significant distance. Then the balanced cables have an advantage. IS THIS TRUE?
markw covered it essentially but the situation is really quite complex. The short answer is that most home audio enthusiasts don't need balanced connections. The reason they appear in some higher end home audio components is mostly because some audiophiles demanded them.

In a quick answer to the difference between balanced and unbalanced connections, let's start witht he fact that they both have the goal of rejecting noise from getting into the signal in the cable. An unbalanced connection does this by completely shielding the noise (e.g. coaxial cable). In unbalanced, the shield is also the signal return path. The balanced connection may be shielded or not but the shield is not part of the signal path. The cable consists of the a ground and two signals which are inverted. This means that noise will affect each signal cable equally and can easily be filtered out by circuitry. Thus, balanced connections are better for long runs but there is extra circuitry needed by the connected components.

So in the end, balanced is better for some situations and doesn't matter for others. Home audio falls into the others category unless there is something very particular about the setup.