From the UREI provided manual:
\"The Universal Audio Model 565 Filter Set introduces to the recording studio and motion picture sound department an effective tool for \"saving\" problem tracks, and for creating innovative special effects.
Replacing obsolete, difficult-to-use \"dip filters\", the Model 565 employs modern active filter circuits, for a fresh approach to sound signal processing. As a point of interest, the 565 circuitry was designed with the use of a computer. This technique, called COMPUTER AIDED DESIGN, allows solution of the complex formulas and simultaneous equations which could not otherwise be efficiently solved.
The Universal Audio 565 contains FOUR separate, continuously tunable filters, which may be cascaded to provide: A. Low Cutoff filter, tunable from 20 Hz to 200 Hz; B. Two band REJECT (dip) filters, each of which may optionally be switched to become a band PASS filter; tunable from 20 Hz to 20kHz C. A High Cutoff filter, tunable from 2 kHz to 20 kHz.
The 565 is completely self-contained (with power supply) and is designed for no-loss insertion in program circuits.\"
In addition to what the manual said, this item is the 565T model, which has an output transformer, allowing for connection to 600-ohm loads. This model also has extended range on the high and low pass filters; 20-220 Hz high pass and 2-22 kHz.
Other features include a global bypass and TRS input/output on the front panel in addition to the fork terminal inputs on the back.

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