Making Cables - Balanced vs Unbalanced

[robin watson]

not quite. but I will say there is no such thing as a B/W or Color composite video cable.
A cable doesn't care what kind of signal is passed through it. For example, a TRS connector/cable can be used for balanced signals....and it can be used for a stereo signal (unbalanced). Heck you can send an unbalanced signal down a TRS cable. The type of connector or cable used does NOT make a signal balanced. It's the gear on the ends of the cable that does

Don't tell me, you eat oatmeal with skimmed milk at 7:45 every morning, even Sundays. If I'm using balanced equipment, I'd like to use a 'balanced' cable, thanks. It's a lot easier to say, and saves a hell of a lot of time. Giving me an XLR cable doesn't mean it isn't unbalanced configured, hence the term (recognized the world over), don't knock it.

God, this is petty - I'm beginning to feel unbalanced myself! (^:

 

[robin watson]

Foil shields perform better. As I recall, braided shield's only offer 95% coverage. The flip side is that foil shields are less durable and will eventually crack if flexed often.

If you are making microphone/instrument cables, use the braided shield as it is more durable.

For line level connections that will not get moved around much, use foil shield as they will reject RFI much better.

ALWAYS wire the shield to ground! Some foil shield cable comes with a "drain" that will accomplish this. I forgot the science of it, but not having the shield going to a ground leads to problems.

Agreed, and ideally, a cable with both braid and foil.

 

[bennychico11]

Don't tell me, you eat oatmeal with skimmed milk at 7:45 every morning, even Sundays. If I'm using balanced equipment, I'd like to use a 'balanced' cable, thanks. It's a lot easier to say, and saves a hell of a lot of time. Giving me an XLR cable doesn't mean it isn't unbalanced configured, hence the term (recognized the world over), don't knock it.

God, this is petty - I'm beginning to feel unbalanced myself! (^:

I'm just trying to say there IS a difference. And with people new to the world of recording (which is a lot of people who read this site) I think it would be important for them to KNOW there is a difference.

And I don't think saying TRS or XLR is that much harder...in fact it's easier. It also denotes the connector type. We'll just have to assume that the cable has been properly wired to pass on a balanced signal

 

[SonicAlbert]

Foil shields are good for permanent installs, like the back of racks. I also find foil cables much easier and faster to solder thanks to the drain wire and not having to mess with the braid. But for heavily used cables like mic cables, braid is better because it is more flexible and long lasting. Foil will break down under heavy use and offer *less* coverage over time.

 

[Ford Van]

Foil shields perform better. As I recall, braided shield's only offer 95% coverage. The flip side is that foil shields are less durable and will eventually crack if flexed often.

If you are making microphone/instrument cables, use the braided shield as it is more durable.

For line level connections that will not get moved around much, use foil shield as they will reject RFI much better.

ALWAYS wire the shield to ground! Some foil shield cable comes with a "drain" that will accomplish this. I forgot the science of it, but not having the shield going to a ground leads to problems.

Foil shields are good for permanent installs, like the back of racks. I also find foil cables much easier and faster to solder thanks to the drain wire and not having to mess with the braid. But for heavily used cables like mic cables, braid is better because it is more flexible and long lasting. Foil will break down under heavy use and offer *less* coverage over time.

Is there an echo in here?

 

[bennychico11]

Is there an echo in here?

i think the biggest issues besides breakdown with the foil cable is that it has an aluminum backing. Which has a higher transfer impedance (a worse conductor than copper...for lower freq.)

 

[boingoman]

You can duplicate what's going on with the opamp style outputs by using a center-tapped transformer and grounding the center tap. You then have two out of phase signals referenced to ground, just like an opamp differential output.

-Keith

Yeah, but why would you? That would compromise the benefits of using the transformer.

 

[Testing123]

Yeah, but why would you? That would compromise the benefits of using the transformer.

Sometimes grounding the center tap on an output transformer can be useful to reduce common-mode noise. Otherwise the winding and the differential line it is driving are floating with respect to ground and more susceptable to picking it up.

If there is a transformer on the other end of the line you might not care, but if there is a transformerless input circuit on the other end you might.

-Keith

 

[SonicAlbert]

Is there an echo in here?

Yeah, I guess I missed that part of your post.

 

[MCI2424]

Perhaps my termonology was incorrect but that is what I ment "signal". I've done my research on the actual process of creating balanced and unbalanced signals and how to wire each accoringly.

My main question was "why" would/should I use a unbalanced signal?

Almost all equipment affordable here uses unbalanced signals AFTER the balanced inputs. If you have both balanced and unbalanced inputs or unbalanced inputs only, you skip one amplifier stage. For the total throughput of 1 component, using unbalanced ins/outs skips 2 amplifier stages.

There are components that are balanced throughout the whole signal chain, but they cost quite a bit.

The bad thing is that if your cables are too long you will get some unwanted noise from many sources using the unbalanced approach.

 

[MCI2424]

Foil shields perform better. As I recall, braided shield's only offer 95% coverage. The flip side is that foil shields are less durable and will eventually crack if flexed often.

If you are making microphone/instrument cables, use the braided shield as it is more durable.

For line level connections that will not get moved around much, use foil shield as they will reject RFI much better.

ALWAYS wire the shield to ground! Some foil shield cable comes with a "drain" that will accomplish this. I forgot the science of it, but not having the shield going to a ground leads to problems.

One note: The shielding acts as a faraday cage and only really works when the shield is a non-current carrying node. This means that the shield should only be grounded at one end and the right end is the place where you are getting your common ground. Many times it is the rack. Soldering both ends of the shield to ground can cause the shield to conduct current (if you have different ground potentials) and then you can have a serious noise problem.