Max VDI cable length

[Indianrock2020]

I have two 25-foot VDI cables from Amazon, but was thinking of getting a longer one (  50 ft ) for the rare times I want to wander off the stage out into the room to see how I'm doing in the band mix at rehearsal.   I only run VDI and use the JTV/Helix functionality so never use a 1/4 inch cable and wireless isn't an option.   How long can such cables be before you lose signal quality.?

I guess the question is whether the VDI cable is only carrying digital signals --- so JTV converts analog to digital on the way to the Helix and vice versa

https://btpa.com/98-030-004-XXX.html

[cruisinon2]

A digital signal either gets where it's going, or it doesn't.....

[Indianrock2020]

Thanks Cruisinon

[silverhead]

7 hours ago, Indianrock2020 said:

....

I guess the question is whether the VDI cable is only carrying digital signals --- so JTV converts analog to digital on the way to the Helix and vice versa
....

 

That's my understanding - only digital info carried on the VDI cable so no loss of quality like an analog cable. Like cruisinon2 says, it either works or it doesn't.

[Indianrock2020]

Three comments on this from over on Facebook:

 

The power isn't converted to digital.. I think you can power web cameras and such over Cat-5 for a good long length.

 

 25 feet is the documented limit. Although it’s the same cable as Ethernet it is not a network protocol. They use 4 pair of wire, one for variax, one for mags, one for power, one for control messages

 ^what Ron said. Using twisted pair cable and RJ45 connectors does not automatically mean it’s a computer network protocol. Many non-LAN compatible devices use Cat5/5e/6 cabling and RJ45 connections. (For example, cue monitor systems.)

 In the IT world 300’ before any loss, even with POE

[jerseyboy]

 

There’s 2 schools of thought regarding if JTV Magnetic pickup signal runs analog or digitized over the VDI cable.  

 

I suspect VDI carries analog magnetic pickup signal much like a regular guitar cable.  

 

From a practical matter, all else being equal, I notice a slight change in volume/tone of the magnetic pickups when using VDI as opposed to the 1/4” phono audio output.   Audio output that works with no power to the Variax circuitry.  

 

Some folks believe magnetic pickup signal is digitized and sent along the VDI as data and unpacked at the POD/HELIX end.  

 

I’m not convinced about that and of course the good folks who do know aren’t saying.  Maybe someone can O-Scope VDI to settle the matter once and for all?

 

Perhaps simpler, I suppose a 50-100’ cable would certainly demonstrate if it’s Hi-Z audio or not by noticeably weakening the magnetic audio output of a long VDI cable run?  

 

Even still, DC power will have it’s wire length limits and these Variax circuits pull some current (mA).  Depending on the wire gauge, 50’ might be too much DC voltage drop for Variax?  There again, probably wouldn’t hurt anything to try it and see how the DC behaves and/or if the magnetic pickup audio level/tone noticeably degrades over a longer CAT 5 wire run?  

 

[Indianrock2020]

I'm just going to try the 25 footer I've been using over the last year.  It will get me 10 ft out in front of the stage anyway -- good enough to see if the sound techs are toasting my tones.

[jerseyboy]

[psarkissian]

Read Steve Lampen's books on this subject before messing with cables, he's at Belden Cable.