The ProCo TradeTools AV1A Audio-Visual Interface allows the line-level outputs of audio and video playback devices, etc., to be connected to microphone inputs of house or portable P.A. systems for programs in school auditoriums, lecture halls, civic meetings and corporate board rooms. The AV1A provides audio interfacing and isolation with wide response and low distortion.< p>All inputs are parallel and resistively mixed to monaural. 1/4" 3-conductor phone jack, accepts signals from balanced or unbalanced line-level or speaker level sources such as audio and video tape recorders and movie projectors. (Has 16-ohm, 5-watt dummy load, 20 dB attenuator network, and low-pass filter, -3 dB@8 kHz, 6 dB/octave when Spk/Line switch is up Input impedance: approx. 16 ohm). Two RCA phono jacks and one stereo mini jack, for signals from nominal -10 dBV sources such as radio, cassette, computer or DVD outputs. Input impedance: approx. 4 kohm. Line Output: 1/4" (6.3mm) phone jack takes signal after SPKR/LINE and PAD ("up" position = pad "in") switches and provides unbalanced line-level source to feed suitable inputs of tape recorders, CDs, DVDs, sound systems, etc. Recommended load impedance: 100 kohm.. The DBT-1 transformer provides a floating 150-ohm output with a standard 3-pin male XLRtype connector, so connection to most P.A. system mixers or mixer/amplifiers requires only a standard microphone cable. The GND/LFT switch eliminates hum and buzz from AC ground loops between equipment. For further versatility of operation, there is also a 1/4" (6.3mm) unbalanced line-level output.< p>The AV1A's construction and components are top-grade throughout, ensuring trouble-free operation in educational, institutional and A/V rental settings. ProCo's "Uni-box" enclosure is formed of extruded aluminum side channels and 16-gauge steel top, bottom and end plates and is designed to protect it's switches and connectors from accidental damage. The use of steel also provides excellent magnetic shielding for the transformer from EMI/RFI fields. The finish is durable black textured powder coat on the end plates and the side channels are black anodized aluminum. Easily readable control and connector identification graphics are incorporated into a durable Lexan® overlay on the top panel. The uniquely slotted side channels allow for stacking on top or strapping side-to-side of virtually any number of ProCo TradeTools devices using the Uni-box construction.