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What does this warning mean - dBx compressor hookup?

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What does this warning mean - dBx compressor hookup?

Postby DC-Choppah » Thu Sep 05, 2019 2:55 am

I am re-running all the cables in the project studio.

We use a rackmount dBx 1046 quad compressor.
https://dbxpro.com/en/products/1046

From the manual it says:



Connecting the 1046 to your system

Make audio connections via XLR, 1/4" TRS, or 1/4" TS plugs. Both types of connectors for the inputs and outputs can be used for balanced or unbalanced connections.

The use of more than one connector at a time for the input/output pair could unbalance balanced lines, cause phase cancellations, short a conductor to ground, or cause damage to other equipment connected to the 1046.

Apply power to the 1046 Connect the AC power cord to the AC power receptacle on the back of the unit. Route the AC powercord to a convenient power outlet away from audio lines. The unit may be turned on and off via the rear panel power switch or from a master equipment power switch.



What does that part in bold mean?

I was about to plug channels 1 and 2 in using balanced cables while channels 3 and 4 using unbalanced cables. But wait! She's gonna blow!!!!



BTW the input to channel 1 and 2 come from the main analog mix and the output goes to my main Adam monitors. The job of the 1046 is to limit in case the DAW freaks out and generates a full scale ear piercing sound.

Channels 3 and 4 are similar but are a cue mix and drive floor monitors through a power amp around the studio, and also sends the signal to headphones distribution. Again the 1046 is to limit in case of an ear splitting glitch from the DAW. Yes it happens!
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Re: What does this warning mean - dBx compressor hookup?

Postby innerchord » Thu Sep 05, 2019 7:00 am

It's simply telling you not connect both TRS and XLR connectors at the same time in case of issues. For example, don't have an XLR connected, and try to plug in a TRS to the same input or output. Nothing more sinister than that.
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Re: What does this warning mean - dBx compressor hookup?

Postby Wonks » Thu Sep 05, 2019 7:00 am

It just means that you only plug in one input cable and one output cable per channel. Doesn't matter that 2 channels use balanced connectors and 2 are unbalanced. Just don't have both an XLR and a jack going into an input (and the same for an output).

I'm sure you are only using one cable in and one cable out per channel, so you'll be fine.

It's not designed as a splitter box, so there's no isolation between the XLR and jack connections on each input and output.
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Re: What does this warning mean - dBx compressor hookup?

Postby Hugh Robjohns » Thu Sep 05, 2019 9:17 am

+1 to what that lot up there ^ have said. :-)

The XLR and TRS connector pair provided for each input and output is wired in parallel, so (in general) you should only use one physical connector, and not try and use them as an input mixer/combiner or output splitter (although the latter is technically possible if you know what you're doing).

The warning concerns the potential for damage if trying to combine two input signals, or if connecting both balanced and unbalanced sources/destinations whereby the unbalanced connection will inherently unbalanced the balanced one and potentially cause damage there too...

So it's not so much a dire warning, as the application of common sense, and it isn't an issue in normal applications. Just use the appropriate connector type to suit your wiring and requirements, and only use one of the two connectors provided for each input and output. :-D

H
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Re: What does this warning mean - dBx compressor hookup?

Postby DC-Choppah » Fri Sep 06, 2019 12:52 am

Thank you guys!

When offered an XLR and TRS type plug option for a single connection, only use one at a time. Got it!
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