72 ft AES cable vs. analog XLRs cables

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JayNYC

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72 ft AES cable vs. analog XLRs cables
« on: 1 Mar 2014, 06:02 pm »
From my PC, I have a firewire audio interface with an AES output.  I can place my BDA-1 either by the PC or with my stereo preamp on the other side of the room.

What's better....
a) Run a 72 ft AES digital cable from the firewire audio interface to the BDA-1
or
b) Run a 72 ft. pair of analog XLRs from the BDA-1

Any insights greatly appeciated.

HsvHeelFan

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Re: 72 ft AES cable vs. analog XLRs cables
« Reply #1 on: 1 Mar 2014, 07:19 pm »
From some internet sleuthing, Firewire cable is limited to 4.5 metes (approximately 15 feet).  However, you can daisy chain up to 16 cables provided you add repeaters between the cables.

Have you considered a dedicated pc near the audio system and either controlling it via a mobile device or via remote desktop?

HsvHeelFan

JayNYC

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Re: 72 ft AES cable vs. analog XLRs cables
« Reply #2 on: 1 Mar 2014, 07:42 pm »
I cannot move the Firewire audio interface as I am using the inputs on it for mics and MIDI near the PC.

I appreciate the idea/strategy of moving the Firewire interface instead.

werd

Re: 72 ft AES cable vs. analog XLRs cables
« Reply #3 on: 1 Mar 2014, 07:54 pm »
Put the dac by the computer and run long Xlr into the preamp ... always. Its a noise reducition tactic.

JayNYC

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Re: 72 ft AES cable vs. analog XLRs cables
« Reply #4 on: 1 Mar 2014, 08:48 pm »
Put the dac by the computer and run long Xlr into the preamp ... always. Its a noise reducition tactic.

Ok, so running 72 ft analog XLRs is better than a 72 ft AES run even with Upsampling active on the BDA-1

werd

Re: 72 ft AES cable vs. analog XLRs cables
« Reply #5 on: 1 Mar 2014, 09:03 pm »
Ok, so running 72 ft analog XLRs is better than a 72 ft AES run even with Upsampling active on the BDA-1

I would say the drive capability of the Xlr is better than the the 72 AES (but it may not be). If it's the same  or better keep the dac closer to the source. Your 2 concerns are noise and drive capability.

If you were using rca at that length your soundstage would lose its stiff ness. Bass would be soft with more noise. I am not sure how long Xlr is good till but I would say it's at least a 100 feet for sound staging in Xlr and probably using AES too. If that's the case then noise is really your only concern.

JayNYC

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Re: 72 ft AES cable vs. analog XLRs cables
« Reply #6 on: 1 Mar 2014, 09:21 pm »
oh, I was thinking Jitter was the primary concern.

*Scotty*

Re: 72 ft AES cable vs. analog XLRs cables
« Reply #7 on: 1 Mar 2014, 10:27 pm »
If the AES/EBU cable is transformer coupled at both ends and the cable and its connectors have a matching characteristic impedance you will have a transmission line condition and you shouldn't have too big a problem with a 72ft. run.
Scotty

werd

Re: 72 ft AES cable vs. analog XLRs cables
« Reply #8 on: 1 Mar 2014, 11:02 pm »
oh, I was thinking Jitter was the primary concern.

The dac wants to be near the source for jitter. Which is probably the most important reason to keep it close. There is less noise since the dac isn't plugged-in anywhere near amplification.

JayNYC

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Re: 72 ft AES cable vs. analog XLRs cables
« Reply #9 on: 22 Mar 2014, 06:08 pm »
Ok... revisiting this thread please.

I did a comparison of 72 ft AES vs. analog XLRs and the stereo analog XLRs run sounds better.  I guess jitter is a real issue.  So I am pleased.

However... a new problem has emerged.  As a result of connecting the stereo XLRs to my preamp, I am now hearing a hum (buzzing sound) in my center and surround channels.  To confirm I am not crazy, I unplugged the XLRs from the BDA-1.  Hum gone.

Is my BDA-1 defective, or is this behavior by design?  For comparison, I tried an RME Babyface via XLRs as well.  There was still some hum, but much less.

« Last Edit: 23 Mar 2014, 10:05 pm by JayNYC »

bjski

Re: 72 ft AES cable vs. analog XLRs cables
« Reply #10 on: 22 Mar 2014, 06:20 pm »
Ok... revisiting this thread please.

I did a comparison of 72 ft AES vs. analog XLRs and the stereo analog XLRs run sounds better.  I guess jitter is a real issue.  So I am pleased.

However... a new problem has emerged.  As a result of connecting the stereo XLRs to my preamp, I am now hearing a hum (buzzing sound) in my center and surround channels.  To confirm I am not crazy, I unplugged the XLRs from the BDA-1.  Hum gone.  Here's what's really weird:  If I unplug the BDA-1 from power, but leave the XLRs in, I still hear the hum.  To repeat, even when the BDA-1 is off and unplugged from power, if I leave the analog XLR outputs connected, I hear hum in my center and surround channels.



Is my BDA-1 defective, or is this behavior by design?

I had a similar thought with my BDA-1. I bought a BDA-2 problem solved.