Item is new in original box. I listed it as a "10" instead of new because of the rough condition of the box due to storage/shelf life. It has been in a dry storage location since new.
Used to reduce AC noise and improving the noise floor.
Please do your own research and be safe when using this. There are situations that will cause problems such as not being able to plug lighting into these units.
I have used several of these in production studios I've built over the years and they have always performed incredibly well.
IT-1220 Balanced Power Isolation Transformer
The IT-1220 ($1,599), designed for the most critical, ultralow-noise installations, is the ultimate power device. The unit supplies 20 amps of balanced AC power to a recording studio, video or film production facility, broadcast station, etc. Its purpose is to reduce hum and buzz caused both by ground currents from power supply filtering and by radiation from supply cables into sensitive signal sources like guitar pickups and microphones. The box not only reduces the noise floor but it also improves dynamic range and sonic clarity. The box is built around a specially-wound and shielded toroidal isolation transformer with a center-tapped secondary transformer and can be installed in minutes without the need for an electrician.
The IT-1220 includes an accurate, self-checking AC voltmeter that not only measures normal voltages, but also flashes eye-catching special pattern alerts for off-scale but not extreme conditions (80V – 90V or 130V – 140V). The Extreme Voltage Shutdown circuit causes a protective shutdown if the unit is exposed to dangerous voltages and Furman Sound's exclusive "Soft Start" circuit prevents the large inrush surge currents and spikes that would otherwise occur at turn-on and turn-off with such a large transformer.
North America uses a three-wire distribution scheme in which 120V branch circuits have a hot wire and a neutral wire, with the neutral tied to a third wire connected for safety to an earth ground. The third wire does not carry any current unless there is a short circuit. This unbalanced scheme can cause hum in audio circuits. With a center-tapped isolation transformer (as is the case with the IT-1220), the AC power feeding a studio can be balanced at its source. The current-carrying wires then are no longer "hot" (120V) and "neutral" (0V), but two 60V lines of opposite polarity (referenced to the safety ground connected to the center tap), whose difference is 120V. This type of power, when run around a room, does not induce hum into nearby audio wiring, because the two conductors induce equal and opposite voltages that cancel each other out. In addition, ground currents are all but eliminated by the same common-mode cancellation effect. The IT-1220 typically provides a 16 dB improvement in back ground noise floor in system wide installations.