Tuesday, May 27, 2014

Everything into Anything

 A year or so ago, I realized I had a perfectly good steel box for which I had no actual purpose. Too big to make into a guitar petal, too small for most other purposes. At the time, I also had a bunch of conversion projects: getting -10dBV stuff into +4 stuff and high to low impedance matching stuff and other unbalanced to balanced issues. Even weirder, I had a pair of vintage RCA line-matching transformers with no place to go.

What you see in these pictures is my wife's artistic decoration of my Everything into Anything case. I had something less 60's in mind, but you can not guide art. The other thing you might notice is the 1/4" (TRS or TS), RCA, and 1/8" stereo connectors on one side (for stereo input) and a pair of XLR connectors with a ground lift switch on the opposite side. With a slight amount of loading, you can connect any of the left side unbalanced connectors to any of the other left side connectors to "adapt" connectors. Going through the unbalanced side to the balanced side you pass through some big iron transformers for isolation and signal balancing. The ground lift switch disconnects the balanced side from chassis ground. So far, only one application with which I've used this product has needed the ground lift protection, but most live applications probably would.

The box is heavy. Both the transformers (which fit wall-to-wall in the case) and the steel case add both mass and electromagnetic isolation from 60Hz noise sources. I transferred a crapload of 1/4" 15ips analog tape recordings to digital in a two month period with this rig and none of the typical ground issues that came with old Teac reel-to-reel recorders ended up in the transfers. I used the box for a DI with a 1970's Yamaha DX1 synth in the studio and the combination of the balancing transformers and ground lift gave the quietest signal I've received from that ill-designed semi-analog synth.

Honestly, I'd have liked to include a few other connectors on the box; just for the fun of it. However, there was no room in the inn. The transformers and XLRs take up all of the available space, which actually created additional shielding.

Fun project and useful. Of course, finishing it up a few months before I retired is about par for the course. I could have used this thing most everyday for the last two decades.

Wirebender Audio Rants

Over the dozen years I taught audio engineering at Musictech College and McNally Smith College of Music, I accumulated a lot of material that might be useful to all sorts of budding audio techs and musicians. This site will include comments and questions about professional audio standards, practices, and equipment. I will add occasional product reviews with as many objective and irrational opinions as possible.