something to do the "balancing" operation and output unbalanced signal

gloves

New member
Yo! I'm a programmer but I need to figure out some audio stuff for work, any advice would be amazing! I don't like asking things unless I've done my fair share of work too, so here goes:

I'm replacing a lecture-recording box (this one - link to wiring documentation) with a different lecture recording box (this one). The old box accepts a 5-bare-wire balanced input (ground, and then 2 wires for left-channel and 2 wires for right-channel). The new box only accepts a simple stereo 3.5mm jack input.

I just read an article about how balanced wires work and it seems really cool and clever. My question is: can I buy a small box that will accept balanced bare-wire inputs (that are probably running a hundred feet or something), do the balancing-magic, and output an unbalanced 3.5mm signal (that will only travel a few inches, so it shouldn't pick up too much noise along the way) ?

I could just tape-over the inverted signals and be left with 3 wires, and then use one of these 3-wire to 3.5mm thingies, but then I get all the noise from the 100-foot wire, and I want to do this right for my customer.

Any suggestions would be amazing, thanks again! <3
 
Thinking about this a little more, I could probably buy an audio interface that accepts 2 balanced inputs, and buy some bare-wire-to-LXR adapters, and then take the mixed line-output of that. Is that the best option?

interface.PNG
 
Hi,
There are devices out there that will let you run a balanced signal over distance, properly terminate it, and feed unbalanced to something at the other end.
Something like this, I think, would do that job. I'm sure there are others.

In a situation with bare wires, yes, the adapter you showed would work fine.
T-R-S are UB left, UB right and ground respectively.

The box I linked has RCA out so you'd just use a twin RCA to 3.5mm pre-made cable. They're common and cheap.
 
Your second post came in as I was typing.
An audio interface is probably overkill and you'd have to make sure that the chosen interface allows for standalone operation.
A lot of them don't. My presonus and motu ones do. Something to investigate.

Still...There are probably smaller/cheaper/more useful solutions.
If you're going the road of a biggish device like that maybe a small mixer would be more useful with its additional inputs, faders, mute, solo etc?
 
Awesome, thank you! Something like the little box you linked to, or a small mixer like you suggested, sounds perfect. I'll try to find something along those lines!
 
Howdy Gloves.
If you have a balanced line running a hundred feet or more (is it screened?) the likelihood is it will pickup a shedload of noise, hum but more importantly RF energy. The devices* so far mentioned are essentially for BALANCING an output. Yes, they WILL work to UBalance a line but they are not ideal and will do little to stop RF crap.

What is needed are INPUT 'de-balancing' transformers. These are wound to a much higher impedance, often called '10k-10k traffs, and incorporate an interwinding electrostatic screen which chops RF dead.

Lookup 'Jensen Transformers' (if in US) for the devices and, since you seem to be a chap that likes to 'read and get it right' seek out the technical from Jensen's Bill Whitlock.

The other transformers do work but if you want THE best solution and this is a 'once done, forget it' installation the extra cost of the right components makes sense?

*To get technical they are 'low impedance, bifiliar wound line output transformers' Often dubbed '600-600 Ohm traffs.
 
What you can do is run a simple microphone preamp. the cheapo interface boxes would work for you and you could use the headphone amp out to record with and be able to set gain structure.
 
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