[Sorry to be so slow responding, been kinda busy lately with the "day job"...]
I have been on a similar quest for awhile now. I have some longish cable runs in my
studio and it would be nice to balance them out with a box that had 8-16 unbalanced
signals in and balanced outputs. I thought I had found "just the thing" in the MAM
DI-16. It is a passive 1U rack mount box that has 16 inputs and 16 outputs. It was
very difficult to figure out if it was balanced or not from the information on the
web so I got my hands on one and opened it up. As expected, it is just 16 small
transformers connected between 16 sets of TRS jacks. Unfortunately, the
transformers only operate on the "tip" signal and don't do anything for the "ring"
signal. So, it doesn't truly balance the signals on the way out but it will get rid
of ground loops by decoupling the input and output and that may be just enough in
many situations. I see from the tiny circuit boards, that it would be possible to
add a second transformer to handle the "ring" signal and truly balance the output.
Perhaps that's a project for later...
It doesn't seem like building such a box would be too difficult of a DIY project.
You just have to find the right audio transformers. There are many commercial
single/dual channel direct boxes out there with a wide range in cost. You might
check the sweetwater web site for a few models.
Eric
---
pow333@... wrote:
> Does anyone have plans for a small bi-directional direct box. I'm
> building a modular system to do processing with, mostly, and I'm really
> scared of unwanted noise (I hate it, clients hate it, we all hate it,
> if I want noise I'll patch it in, or hire a cabbie to sit outside the
> studio and chat with his dispatcher). I'm sure we all have the problem
> of coming out of our patchbays and into filters, envelope followers,
> whatever and then returning our output back to our mixer. There has got
> to be a simple fix for this. All I've seen is a DL connectorized piece
> of glorious overkill by Purple Audio (the 1176 cloners). I'm imagining
> something much simpler. Terminate one end at a patch row, the other a
> bank of jacks, 6-8 of them, unbalanced goes in or out at the synth,
> patchrows are balanced, maybe 2U wide. How have y'all addressed this
> problem?
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