Rear Panel Features, Microphone Input | Altec Lansing 1662A instruction

Operating Manual -1662A Mic/Line Mixer

6. REAR PANEL FEATURES

6.1 Microphone Input

The 1662A microphone input is an active balanced type with a nominal impedance of 1200 ohms. Its noise performance is best with a 200 ohm microphone. The mic input connector is a 3-pin Euroblock with the shield on (G), the

(+)in-phase connection on (+), and the (-) out- of-phase connection on (-). If the input is unbalanced, or single ended (meaning there is only one signal wire with a shield) connect the signal wire to (+), and connect the shield to both (-) and (G).

+ - G

Euroblock + - G

Connector

System

6.2 Input Pad

The input pad is a 20dB attenuation switch for extremely loud microphone or line level inputs. It should normally be left in the "out" position for best signal to noise ratio, but can be used when the input is being clipped with the gain and level control at minimum.

6.3 Channel TRS Insert

A 1/4" stereo phone jack insert point allows a device such as a remote level controller, graphic equalizer, noise gate, compressor/limiter, or direct out recording device to be used with one or more input channels.

The 1662A TRS (tip-ring-sleeve) insert jacks use the tip for output and ring for the returning input. These signals will be unbalanced, so cable length should be at a minimum to maintain low noise.

To use the TRS insert as a Direct Line Output (pre EQ) for recording individual channels, make a special cable with tip and ring connected at the 1662A end and a tip-sleeve mono plug at the other end. Connecting tip and ring at the mixer insert jack is necessary for uninterrupted signal within the mixer when using direct line outputs.

Tip

Ring

Sleeve (Ground)

Stereo Phone Plug

6.4 Sum Inputs

The RCA sum inputs on channels five and six are typically used for auxillary audio sources such as a disc or tape player, summing a stereo source into a mono signal for each channel's input. Using the sum inputs does not prevent