XLR Cable length
 

In the A1 manual, there is a note stating that the maximal length of XLR cables is 3 meters. Does anyone know what is the reason for this limitation?

XLR audio cable lengths of 20 meters and more have never caused me any troubles so far.

It's meaningless. Length of the cables doesn't matter, although it's always a good idea to not use much more length than what you need to avoid lots of coils all over the floor.

I've used a 100m XLR cable with no issues.

Well, it's not really meaningless if the mic input is not balanced. The longer length is not related to the input being XLR but being balanced or not.

Is the A1 mic input balanced?

Correct me if I'm wrong, but isn't all XLR connections balanced (hence the need for three or more pins)? I can't say I've ever heard of an unbalanced XLR connection (obviously you can use XLR cable for an unbalanced signal if you use adapters). So I'm presuming the A1 has balanced connections?

Related Post: http://dvinfo.net/conf/showthread.php?t=32070

What you can't have is 48v phantom power on unbalanced interface, but you can have unbalanced XLRs.

Particularly Canon had a mic interface (the MA100) that they sold for the XL1 or XL2 that had XLR unbalanced connectors, if I am not wrong.

To me that would sound as the only explanation for the A1 manual requirement. But of course this is only a guess... that should checked :)

The A1 has balanced audio connections as does the XL1 and XL2.

Then that's good for the A1.

The XL1/XL2 had only unbalanced inputs. That only changed on the H1, AFAIK.

Is there signal attenuation with length? Do they sell inline amps for XLR cables?

Success using a long cable does not imply that it was the optimal solution. In the particular application it just might not have made a difference.

The whole point of balanced lines is long line length -- there is no other advantage. The XL1 uses balanced inputs, as does the XL2 -- I don't know why anyone would report otherwise.

You wouldn't gain anything by inline amplifying a balanced line that you won't gain by boosting gain at the recorded -- I have worked in industrial/studio settings where the client made a balanced feed from a common mic available to all shooters, and the cable run was easily in the scores of meters, if not over a hundred. I lack the engineering smarts to do a calculation on just how far you could run a signal, but 'three meters' as a limitation is a mystery.

Balanced cabling works even if mixed with unbalanced, in that a device with an unbalanced input (say a mic mini phone jack) can be connected to an XLR to mini jack device like the venerable Studio 1 Pro we all used back in the day of the VX1000 -- you could then use XLR cabling to get the mic signal to the adapter, and three feet of mini jack to get the signal to the camcorder, with no loss.

GB

Yes, there is some signal attenuation on long distances, but it's usually taken care of by good preamps. Sometimes you put the mic preamps closer to the mics and use line levels from then on.

Long cables are usually a problem on unbalanced lines. The inputs also need to be low impedance and well designed. I wouldn't use more than 20 meters for a mic line, and that will take away some of the higher-frequencies.

Noise is another major problem when signal levels are low. Balanced lines null most noises, if they are well designed. Particularly if using transformers.

No, only starting in the XL2 they began using balanced mic inputs. The XL1 did not.

Just to confirm on that:

http://www.usa.canon.com/consumer/co...7&modelid=8274

http://www.usa.canon.com/consumer/co...5&modelid=7471

But I think I was wrong that the MA100 or MA200 had unbalanced inputs. They just didn't have phantom power.

I can only assume you to mean because the XL1 without the XLR adapter had no XLR inputs were the inputs unbalanced -- when you added the required XLR adapter (either the MA-100 or the MA-200) then you had balanced XLR inputs on a Canon XL1 ... otherwise, you had no XLR inputs on an XL1.

Is that what you mean?

GB