WPA Module Racks have WPA internal power supplies fitted with toroidal transformers for zero added hum & buzz. Other racking outfits use off-the-shelf internal power supplies that don’t have toroidal transformers and thus often impart some hum in the outputs.
Virtually any console module or other audio module can be racked up for use in the studio or in the field. Here are a few samples of gear that has been racked up at World Pro Audio.
Most racks are built so that the modules can be extracted for service, making removal of the entire rack unnecessary. Quality parts and neat internal wiring round out the design so that service of the rack itself will be a rare occurance.