STP-1 Dual Variable Attenuator
The audio attenuator shall be an RDL STP-1. The unit shall provide two independent audio attenuators each configured for connection and operation in a balanced or unbalanced audio circuit. Each attenuator pad shall be electrically isolated from the other.   Attenuation shall be adjustable using a multi-turn trimmer of no fewer than 15 turns.

The unit shall be passive and shall not include reactive components in the audio path capable of altering frequency response.  Each attenuator pad shall be electrically configured as an “H” pad when connected in a balanced audio circuit, and shall be electrically configured as a “T” pad when connected in an unbalanced audio circuit.

Each attenuator connected in a high-impedance balanced or unbalanced line shall be capable of attenuation from 1 dB to 85 dB. Each attenuator connected in a low impedance balanced line shall be capable of attenuation from 5 dB to 35 dB. 

The unit shall be constructed in an electrically non-conductive, thermally conductive enclosure. Internal circuitry shall be protected from moisture and vibration using a thermally conductive compound that permanently secures the circuitry within the enclosure.

The face of the unit shall provide graphical labels identifying wiring connections and operating controls. Controls shall be oriented toward the front edge of the unit.

Connection to external wiring shall be provided using a fixed terminal block on the edge of the unit. The terminal block shall accept wiring gauges from 14 to 22 and shall include a positive electrically conductive mechanism to prevent wire abrasion by the terminal screws.

The unit shall measure 3” (7.6 cm) x 1.6” (4 cm) x 0.7” (1.7 cm) and be compatible with all RDL STICK-ON mounting accessories. The unit shall be supplied with a two part re-closable polypropylene fastener system equipped with a rubber adhesive that bonds to low surface energy materials.

The unit shall be passive requiring no power supply. The unit shall be engineered, assembled and tested in the U.S.A. and be specified for continuous duty in professional installed systems. The unit shall be specified for operation in an ambient temperature between -20 and 60 degrees C. The unit shall comply with relevant EMC requirements and shall bear the CE marking.

The unit shall be an RDL STP-1.