Whirlwind Contractor Splitter Used Backwards?

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Peter Etheredge

Sophomore
Jan 11, 2011
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St. Charles, IL
tnprod.com
I'm not trying to do this (and would never), but I just discovered this at my church and I'm a bit perplexed.

Basically the front of the room is set up so that the band stage can be set up on either side and when the building was built the audio contractor put in a Whirlwind snake system where there is a MASS disconnect on each side of the room and depending on which one you are using you just unplug the snake from the disconnect and plug it into the other side. Makes sense. However to combine the two sides into one XLR per channel into the board they used this:

Whirlwind Contractor Splitter http://whirlwindusa.com/media/uploads/downloads/manuals/misc_box_manuals/spconinfo.pdf

It has the SP8 cards in it which each have 1 input, 2 isolated outputs, and a direct output. What they did is run one side into the input and then the other (the one currently in use) into the direct output. The lines that actually go to the board come out of the iso 1 output. It has phantom power yet if we plug anything that needs it in we still need to turn the phantom on the board on.

This all seems like a bad idea to me and it's always seemed like the gains have to be run awfully hot on the board. Now that I've saw this today I wonder if it could that be part of that? Can this unit be run backwards like this? I don't see why it wasn't just a passive set up seeing as only one side at a time ever will, and ever could, be plugged in to the single console.
 
Re: Whirlwind Contractor Splitter Used Backwards?

Sounds like the wrong tool for the job was used. The installer simply bought an off-the-shelf product (that he may have used in the past), when a simple punch block would have sufficed.

There is nothing wrong with simply multing the two MASS connectors if they are only going to be used for analog audio. If there was AES or DMX on there, there might be problems, but analog will never know the difference. I would double-check that it is connected the way you describe. If the console really is on the ISO output, it can't supply phantom to the mics. Whirlwind has a 48V supply that can supply phantom, but of course it isn't controlled by the console.

Does it actually have transformers installed? Maybe they just jumpered the appropriate terminals, and everything is paralleled on the board already. In that case, it should work fine with no loss from either input to the console, and the console would supply phantom. If the audio level seems low, do some testing with a tone generator to confirm (or disprove) it.

GTD
 
Re: Whirlwind Contractor Splitter Used Backwards?

Geoff,

This is basically confirming my initial thought on this thing.

There are indeed transformers installed however they are not jumpered from what I can tell. There is a Whirlwind phantom supply that is wired in and on at all times, however the phantom on the console still has to be on, at least when the MASS is connected on this side; I think i'll try and see if the phantom works on the other side or if the board needs to be on.

Either way I think it would probably be prudent to get rid of this system and just make a passive connection. Anyone think there's a good reason not to?
 
Re: Whirlwind Contractor Splitter Used Backwards?

Robert Healey said:
Is the split set up in such a way that a transformer isolated recording or monitor split could be added later?
Click to expand...
That was my thought as well, was it originally intended to be two alternate 'input' locations or perhaps instead intended to be an input location and a monitor split? It almost sounds like someone rewired what may have originally been intended for a monitor/recording split to try to make it function differently.

There may have been a reason to disable the splitter's phantom power for some specific inputs but if the FOH console is fed from the transformer isolated outputs then that console's phantom power should have no effect as the transformers shouldn't pass the DC power. The fact that the phantom power of a console that you believe is transformer isolated makes a difference suggests that not everything may actually be wired as you think it is.
 
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