Our latest custom projects was done in cooperation with the chief technician, Dennis Maximova of the Showbox located here in Seattle/WA . Dennis was looking for some sort of audio disrtobution for the PA set up, that is more than a plain old resistor split and flexible enough to insert additional mixing consoles, without breaking down his house setup up every time a band brings in their own mixing console. Nearly all splitting/distribution snakes currently available, suffer the same problem, signal loss due to resistive coupling/decoupling of two or more signal paths. Aside the biggest problem with multiple audio connections, ground loops, and HF interference.

Main objective was to come up with a solution so the house set up, a Gamble front of house and a Midas monitor console can be fixed installed, with one auxiliary audio path so any additional mixing console can be insert. Several outlines were made to come up with the best solution and a user friendly price tag. After calculating every setup, from simple buffers, active line drivers, etc. we settled on a transformer split. One direct line to front of house plus two galvanic decoupled channels, one for monitor the other one as auxiliary.

Due to the hard conditions in live situations, a solid aluminum enclosure was chosen, cut out of 4'x 8' solid 8mm plates, all openings for connectors and holes were machined and than welded together. Dennis ordered a custom faceplate made by Whirlwind to house all 54 male and female Whirlwind XLR connectors for the auxiliary output. Front of house and monitor are connected through Ramtech RAMX025 connectors. Before final assembly they housing was black anodized. 25' for monitor and 250' for front of house, Flexalloy 54 pair wire bridges the distance stage/monitor/front of house.

All 54 decoupling transformer are screwed to the back of the front plate. Audio connections are soldered via a hardpaper plate with press in stand offs on the top of each x-former. The basic design of the x-former is a EI625 two chamber square nickel core, each primary is split in half, both sides are wound out of phase and than electrical connected in phase. This keeps the stray field as small as possible so that there is no cross talk between channels and external hum srayfields are rejected. The x-formers layout was chosen that all windings have the same DC resistance and a short impedance of 600 Ohms, so that every signal, from mic level to line level can be split of with minimal loss of signal. The bandwidth of all three channels is 20 to 20 @+12dB (+0/-0.5dB) at any load from 600 to 10kHz. The perfect set up for live recording. Phantom power can be applied via front of house or build in "Power One" 48V/3A supply.

All connections are made through 16AWG silver plated teflon wire, in old fashion style AC and audio ground are pulled separate to two big brass ground plates with a single termination for every reference point. Via three main ground switches, AC and Audio can be lifted, a scenario that is only needed in the most difficult set-ups.

Even with the x-former set-up the finished snake is able to withstand direct magnetic strayfield of 100mG and is immune of HF interference caused mostly by dimmers in show light equipment.

The whole project took from design to final asambly about 4 month, were mechanical design, all assembly, metal and wiring was done by Dennis, electrical layout and design, manufacturing of x-formers, and final testing by us. With a price tag of about $14k, it is not a cheap solution, but it takes care of all possible live set ups and problems. For more information please conntact Dennis Maximova <dennymax@erthlink.net> or Oliver Archut <oliver@Tab-Funkenwerk.com>