Technical notes, Model 770 – Studio Technologies 770 User Manual

Page 38

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Issue 1, October 1997

Model 770 User Guide

Page 38

Studio Technologies, Inc.

Model 770

5. Adjust the AUX master level control so

that the meter displays 0 VU. The AUX

bus is now set for unity gain.

6. The procedure has now been com-

pleted. Return the 1kHz to main and

AUX button to the off (out) position.

Signal Present/Peak LEDs
Bi-color status LEDs are provided on the

mixer section’s mic/line input sections.

Under normal operating conditions the

LEDs should light only with the color

green. Signal peaks may cause an occa-

sional red flash, but sustained lighting of

the peak indicator means that audio per-

formance is being compromised. Adjust

the level controls so that you aren’t “in the

red” except on rare occasions.

Limiter/Compressor
While the Model 770 was designed to

provide lots of signal “headroom,” most

applications, especially broadcast, won’t

benefit from it. In fact, wide dynamic

range, in many cases, will simply tax the

transmission chain and lead to signal

degradation. Our feeling is that leaving the

limiter/compressor in the on state is your

best bet. If you can’t think of a good rea-

son why extended dynamic range on the

mixer section’s main audio bus is desired,

leave the limiter/compressor active!
Don’t misunderstand our position: Ex-

tended dynamic range is great for music

recordings. We love listening to terrific

classical, jazz, and, when available, pop

recordings. But for most applications

served by the Model 770 dynamic range

is not really a factor.

Talent Amplifiers
Both the Model 32 and Model 33 Talent

Amplifiers utilize a ¼-inch 2-conductor

phone jack for their audio output. On the

Model 32, either IFB audio or the channel

2 audio source, if configured, can be

selected as the audio source. On the

Model 33, either or both audio signals

can be selected. The level control(s)

should be adjusted for the desired level.

Note that even when the level control(s)

are set to the fully counterclockwise posi-

tion, the audio output will not be fully “off.”

This ensures that personnel will never

(hopefully!) miss an important cue be-

cause a level control was accidentally

turned “off.”

Technical Notes

¼-Inch Plugs and EIA RS-453
An incompatibility problem lurks between

some ¼-inch 2-conductor and 3-conduc-

tor phone plugs and the jacks found on

professional audio equipment. While all

the plugs seem to “look” the same, some

do not comply with the industry standard,

called EIA RS-453. This standard defines

the physical dimensions, including the

shape of the plug’s tip. It seems that some

plug manufacturers don’t bother to make

the tip comply with the standard.
Why is this relevant to you? Because the

phone jacks used on the Model 770 do

comply with the standard, and they expect

to be mated with plugs that do, too.

Should a connection seem “flaky,” sound

noisy, or make intermittent contact, the

most likely problem is a nonstandard

phone plug. Replace the plug if this is

the case.
You should find that all plugs from

Switchcraft or Neutrik will work correctly,

specifically Switchcraft No. 297 or Neutrik

NP3C. In our experience, headphones are

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