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Audio cable confusion

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Karl H

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I still can't get my head around this.

I never come into the audio thread, so I'm lucky to have stumbled upon the fact that using normal cables will blow the Red audio board (which is super strange), but does this relate to phamtom power only?

I have a 416 that requires Phantom power, so I guess I'd have to use the Red supplied cable to plug this in...

But I also have recently bought an Audio Technica wireless reciever. Which has 2 x mini xlr outputs on it. Now, this obviously isnt phantom power, am I therefore right in assuming I can just plug the audio technica standard cables directly into the Red's mini xlr ports?

Just wanted to check before I go and have to send my camera back.

PS will this audio bug ever be fixed or is it totally hardware related?
 
To save any issues, I would recommend going from the mini-XLR's out to a normal XLR, put a M-F xlr joiner on it and then use the RED XLR to mini-XLR to plug into the camera.

The reason I suggest this, is that it only takes an accidental change to phantom power (say when an AC is fumbling around the audio settings, as they are want to do) with a mic on a non RED cable to ruin the board. Play it safe only use the RED cables to go into the camera.
 
red cables are too expensive. Why can't I just solder the correct resistor to the XLR cables I have? will this work, are there any other modifications to the Red XLR leads I need to know about?
 
I've heard nothing about non Red cables "blowing" the Red. I do know that the signal might not be at the right impedance and so it will come in hot and fuzzy, but I don't think it is going to "blow" the camera.
 
Mike, you should pm Ed Watkins on these boards and get his take. I won't speak for him, but he had to send his RED back because of this exact reason, from what he told me. Ed...around? :-)
 
Kevin Wild said:
Mike, you should pm Ed Watkins on these boards and get his take. I won't speak for him, but he had to send his RED back because of this exact reason, from what he told me. Ed...around? :-)
Click to expand...

That's interesting. Certainly you can duplicate the RED cables with resistors though. Guess that's probably the safest bet.
 
joelnet said:
That's interesting. Certainly you can duplicate the RED cables with resistors though. Guess that's probably the safest bet.
Click to expand...

Actually I've had Audio issues with both my cameras, #509
(which I eventually sold) & #646.

There is a possibility that the audio issue I had on #509 may have been caused by the cables (it was rented out, and thus you never know what people are doing, even when you tell them specifically not to do things).

BUT, I just had to send #646 (my personal DP package) for the exact same audio issue. And I know for a fact it has never had anything but the RED Audio cable on it, and has only ever been used with one of the two battery powered mics I own (no phantom power). RED are being very helpful and trying to establish if it is something to do with my mic / wireless setup that is causing the issues. I hope they can find the cause, I feel afraid to use audio on the camera at the moment in case I inadvertently break it again.

So, it might may, or may not be as simple as the cable used.
 
Ed Watkins said:
I feel afraid to use audio on the camera at the moment in case I inadvertently break it again.

So, it might may, or may not be as simple as the cable used.
Click to expand...

That's good to know but depressing. I just got a phantom power solution going and have started to test audio to get ready for an upcoming shoot. Guess I'll just test the heck out of it and see what happens.

RedRushes really needs to export audio with the video. Exporting Proxies to QT from FCP seems to lose audio right now. Can't wait for the SDK. This stuff is so long overdue.
 
I'm hearing there are chances of blowing audio outputs but no one knows what situations may cause it or why?

As discussed, Red's adapter cables uses a 680Ω resister in series and a 200KΩ in parallel to ground on both signal paths. 200KΩ is hooked to Red side of 680Ω resister.

I hear (that means hearsay) the 200KΩ is used to drain the output capacitor(?) which maintains 48 volts if phantom power is turned on during camera power up. The capacitor(?) will maintain that 48volts even if the phantom is disabled. You need to reboot the camera to remove the 48volt DC level on the audio output, unless you have the Red cable attached, which will drain the charge automatically. I guess the other use of the 200KΩ would be to provide spike protection for the Red audio outputs. Does this 200KΩ also help clean up mike level/phantom power noise I hear about?
The Sound Device pages doesn't recommend using the 200KΩ with there equipment probably because their equipment provides phantom power anyway (and for a host of other audio line/mike world reasons).
Anyway unless you super glue Red's fly leads into the camera, you're going to get people using all sorts of cables in all sorts of ways which you can't control.

So my question(more of a humble plea really!) to Red is:

Can you give us some advice here?
What situations may (potentially) cause audio outputs to blow or why?
Does the 200KΩ provide output protection and must be included with all 3rd party leads?
Dave,
 
Audio cables

Audio cables

Yes its best to use the RED audio cables, and they perform two specific tasks.

a) They pad the line / mic inputs to better match common reference levels.

b) They provide a faster discharge path than the camera itself offers, in the scenario where you have enabled the +48V Phantom Power when there is no external device connected (and hence there will be a charge build up) This aspect therefore is more about protecting the external device than protecting the camera itself..

Bottom line is you don't have to use RED cables at all, but we do recommend them.
 
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