Studio Technologies Model 742A Audio Mixer

The Model 742A is targeted for use by operators with numerous audio sources that need to be quickly and reliably adjusted and routed to create one or two independent audio mixes. In these days of operators having too many tasks to handle, and too little time to do them, the Model 742A is a refreshing combination of performance and simplicity. Using their experience in mobile broadcast applications, the engineers at Studio Technologies were able to design the Model 742A to include all the crucial features required to meet the needs of fast-paced news-gathering operations, while still providing the operator with an easy-to-use product.

The hallmarks of the Model 742A are application flexibility, simplicity in use, audio quality, and long-term reliability. For powering, the unit can be directly connected to an AC mains source. A true "universal input" design that's intended for worldwide use, the input voltage can range from 100 to 240 volts, 50/60 Hz. A source of 10 to 18 volts DC can also be connected to power the Model 742A. If both AC and DC sources are connected, the AC source will power the unit while the DC source will serve as a backup. In this way a battery can be connected, ready to serve in a standby capacity.

A carefully selected feature set ensures that the Model 742A will be a "team player" when it is integrated into an audio system. A number of internal configuration "jumpers" allow the unit's performance to be tailored to the needs of specific installations. And while there's flexibility on the inside, the operator is presented with an easy-to-use set of front-panel controls and indicators—the operator typically never has to access the back panel to operate the unit. In this way the goal of delivering successful on-air and production audio, day-after-day, can best be achieved. The Model 742A's audio quality is "pro" throughout. The components were carefully selected to deliver low-noise, low-distortion performance.

Long-term reliability was also part of the Model 742A's design criteria. To that end the unit's enclosure is made of lightweight yet rugged aluminum with a steel front panel for overall rigidity which adds to rack-mounting stability. On the inside, a conservative circuit design combines state-of-the-art integrated circuits for sonic quality with numerous filtering and protection components for long-term reliability.

Mic/Line Inputs

Four input channels are provided for connection to microphone or line-level signals. The electronically balanced circuitry is "ruggedized" for reliable operation under tough operating conditions. The low-noise, low-distortion, high-headroom audio performance is what's expected of sophisticated "pro audio" equipment. Features provided for each input channel include an input sensitivity button, rotary level control, signal level status LED, and output bus assignment switch. To support condenser microphones, the four mic/line inputs can be individually configured to supply 48 volt phantom power. Four DIP switches, accessible on the back panel, allow individual channel phantom power on/off control.

For ease of use, each input's rotary level control sets the gain of the input circuit as well as the level being sent to the selected main output bus (or buses). For convenience the input sensitivity button, as with the other Model 742A operator controls, is located on the front panel. For operator assistance, a dual-color level status LED provides signal present and peak level indication.

Associated with each mic/line input channel is a 3-position output bus assignment switch. This allows each input to be assigned to bus 1, bus 2, or both, quickly creating two fully independent audio "feeds." Bus assignment switches, rather than the more-typical "pan pots," were specifically selected for the Model 742A's design. This allows a more positive assignment of an input source to the desired output bus (or buses), minimizing the chance of unwanted "leakage." Pan pots are fine in an audio mixer destined for use in stereo music situations, but are inferior when used for two-bus applications.

Line Inputs

Four input channels are provided for connection to line-level signals. Features provided for each line input channel include a rotary level control, level status LED, and output bus assignment switch. The rotary level control is used to set the amount of input signal that is sent to the selected main output bus (or buses). The dual-color level status LED provides signal present and peak level indication. A 3-position switch allows the input signal to be assigned to the desired output bus (or buses).

For further information please view the attached Datasheet.