Fostex 750 User Manual

Issue 3, May 1997

Model 750 User Guide

Page 26

Studio Technologies, Inc.

 Model 750

Stereo Line Inputs

The Model 750 contains two identical

stereo line input channels. They are

unique, having the ability to support true

stereo sources, as well as single or two-

channel monaural sources that are com-

mon to broadcast environments. The

circuitry was designed for compatibility

with signals that have a nominal level of

+4dBu. However, nominal signal levels of

–10 to +10dBu are perfectly acceptable.

Level Controls
Two level controls are used to set the

amount of input signal that is sent to the

left/right routing buttons, and subse-

quently on to the main and AUX bus

assignment buttons. The inner knob

controls the level of the left channel input

signal; the outer knob controls the right

channel signal. On the front panel, note

the small arrow graphic symbol and the

letter “U,” located at approximately the

“1-o’clock” rotation position. This indi-

cates the approximate setting for the

level controls to give unity gain.

Status LEDs
Two bi-color LEDs serve as signal

present/peak indicators for the left and

right signals. Electrically they monitor the

output of the left and right level controls.

The LEDs light with the color green when

the signals are 18dB or greater below the

Model 750’s nominal internal operating

level. The LEDs light with the red color

when the signals are within 6dB of the

maximum.

Input-to-Output Channel Routing
From the level controls, the signals pass

to two pairs of channel assignment but-

tons. The assignment buttons allow the

input signals to be routed and, if desired,

combined before being sent to the main

and AUX bus assignment buttons. The

four routing buttons provide a unique and

powerful function, allowing the left and

right input signals to be routed in any

manner desired, not simply the “left input

connects to left output” and the “right

input connects to right output” situation

that is found in most audio mixers. This

flexibility is provided specifically for broad-

cast applications where a source signal

Figure 11.  Detail of front panel showing setup

section