Author Topic: Not Digital... but need some help with dbx 900 racks  (Read 578 times)

Offline MisterKeeks

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Not Digital... but need some help with dbx 900 racks
« on: July 10, 2016, 03:35:49 PM »
I have 2 Dbx 900 racks that I would like to test out. There are 5 902 de-essers, 8 903 compressors, and 4 904 noise gates.

I don't have much (any) pro Audio knowledge, however, I do have functioning computer knowledge, and I was wondering if this plan would work. Basically, I would like to run signal through the inputs of each module and see if there is an output. To test these, I was wondering if I could use a 3.5mm audio jack to xlr male adapter, and plug that into a cable that converts XLR female into +, -, and ground connections. Would that work as an input for this?

Next, I would need to find an output. I was thinking doing the reverse, and converting the Dbx's +, -, and ground connections to female XLR, and then to 3.5mm using a male XLR to 3.5mm jack. Would this work for an output?

One question I have is grounding. The inputs and outputs share grounds. Would I connect the ground on both the input and the output to the common ground, or would I leave one unattached?

Anyway, thanks for your help on these stupid questions.

Offline GaryN

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Re: Not Digital... but need some help with dbx 900 racks
« Reply #1 on: July 11, 2016, 05:39:00 PM »
What you're suggesting will work, sorta kinda…
First: Why the XLRs? If they're just for reach, OK I guess BUT if it was me or any other engineer, we'd just attach the 3.5 mini-phones to a length of shielded cable. If you're just trying to avoid soldering, it would be better to just find a decent length mini-phone cable and cut it in half.

Second: The modules inputs should have the – and ground tied together - leave the ground disconnected on the outputs.

Third: The 900 modules were intended for use with a large-scale recording console and are designed to operate at much higher nominal signal levels than the (computer connected I assume) levels you're going to use. They'll work, but you'll be cranking the inputs up and the outputs down to try to match them to your equipment. You'll need a level / impedance matching module (such as an Ebtech LLS-8 ) in between to actually use them without excessive noise (hiss/hum) and distortion in the long run.