Recommendation for Unbalanced to Balanced Line Level Converter

[TomCarlos]

MEF members....

Perhaps someone can recommend an Unbalanced to Balanced Line Level Converter, two channels.

I have a cheapo Mixer that has 1/4" Unbalanced outputs. I have a power amp that has Balanced inputs. I tried using two cheapo passive direct boxes but that didn't cut it. So I am looking for a device that has two 1/4" inputs, volume level not needed (might be nice to have), and two XLR outputs (TRS might be ok). And this would have to be a powered device. I have the feeling that passive transformers just don't work.

Anything come to mind?

Thanks!!

[x-pro]

so it makes it difficult to connect the amplifier directly to the unbalanced input?

[TomCarlos]

so it makes it difficult to connect the amplifier directly to the unbalanced input?

If I was to try that (again), would the 1/4" plug be a TRS or mono plug (where you need a mono plug on one end of the cable and XLR at the other hoping to use the correct pins)?

[Mick Bailey]

The unbalanced 1/4" output will be a regular mono socket. TRS would usually for a balanced 1/4" output. There are plenty of wiring diagrams depending on whether you're using single-core + screen , or two-core + screen.

A downside of connecting equipment directly is the possibility of ground loop hum. A transformer isolates the signal and removes this possibility. Passive transformer setups can work pretty well, but you have to watch the impedance matching to avoid losses. Even the tiny transformers work fine - one of my main test leads uses one for testing powered PA speakers etc from a portable CD player (unbalanced to balanced) and the signal is loud, clear and undistorted off the player's line-out socket. Tim Boscorelli published some scope shots of frequency responses of miniature transformers in the Stompbox Cookbook - some surprising results.

[nosaj]

Like this?
https://www.shure.com/en-US/products...f?variant=A85F
nosaj

[TomCarlos]

Like this?
https://www.shure.com/en-US/products...f?variant=A85F
nosaj

Thanks. I have a couple Line Matching Transformers and I will test those. I take it they work the same as a cheapo Direct Box. Like Mick said, you have to watch the impedance matching.