Lexicon 20 - QUICK REFERENCE GUIDE REV 1 Quick Reference Manual

20/20 AD Quick Reference Guide
UNBAL THRESH UNBAL THRESH
OVL
0
3
6
12
18
24
30
36
42
60
1 2
Getting Started
Input Connections
Balanced Unbalanced
pin Screen Screen and
1 (Shield) Return
pin Positive Positive
2 Polarity Polarity
pin Return Open or
3 Return
ATTEN reduces input level by
6dB. Use sparingly, and only
on balanced input signals.
Level Meters
When the compressor is
OFF, the behavior of the level
meters is determined by set-
tings of 1 dB SCALE and PK
HOLD.
Switches ON
none
4-Channel
1 dB SCALE
Mode
DISPLAY
none
2-Channel
1 dB SCALE
Mode
DISPLAY
Alternate Modes
To activate
the alternate modes...
press and hold
1dB SCALE
ATTEN
ALT MUTE
4 CHAN
~
Repeat to exit the alternate mode.
© 1993
UNBAL THRESH UNBAL THRESH
OVL
1dB SCALE
0
ALT
3
6
PK HOLD 12
18
24
30
M 36 +
ATTEN
C 42 •
MUTE
60
P –
3 4
Make sure the rear panel
BALANCE switches are set
to match the type of input.
(IN = unbalanced; OUT =
balanced) The red UNBAL
light will indicate an error if
there is a mismatch.
Note: Non-linearity of the poten-
tiometer can cause the signal to
become unbalanced when the
level knob is set to 11:30. To
correct this, turn the knob slightly
in either direction until the UN-
BAL light goes out.
Press 1dB SCALE to select
1dB scale on level meters.
Press PK HOLD to cause the
level meters to hold at the
highest level received.
Meters 1 & 2 Meters 3 & 4
Normal Normal
1 dB Scale 1 dB Scale
Gain Reduction Gain Reduction
Normal (Blank)
Normal 1 dB Scale
Normal Gain Reduction
ALT-ATTEN will mute the out-
puts. The level meters will still
work.
...then press one of these.
DISPLAY DITHER
RMT
LINK
ON
VID
DIGITAL COMP/LIMITER
DISPLAY
RMT
6
-18
4 CHAN
4
~ 8
-22
LINK
EMPH
2 10
-26
12
0
ON
-36
M
P
C
VID
GAIN THRESHOLD
EXT SYNC allows you to syn-
chronize to an internally de-
rived sample clock, or to an
external AES or Word Clock
signal in the range of 41-
51kHz.
Note: The Word Clock input is
not transformer-isolated, and re-
quires a ground connection be-
tween the 20/20 AD and the sig-
nal source.
Before switching between Internal and External modes, be
sure to reduce monitor volume, as some D/A converters do
not mute when they lose lock.
When the compressor is ON, pressing DISPLAY will cause gain
reduction (in dB) to be displayed on the right two meters (2-
channel mode) or on all four meters (4-channel mode).
OVL
0
3
6
12
18
24
30
36
42
60
ALT-4 CHAN activates output
of a digital sinewave at the
AES ports.
ALT-DISPLAY activates re-
mote mode/front panel lock-
out. When activated, the 1dB
SCALE and DISPLAY LEDs
flash and front panel controls
are locked into their current
settings.
DITHER WIDE 20BIT
100
mS HF PL DN
-14
48 44.1
-10
FORMAT
10 1S
AES SPDIF
-6
WC AES
0
0 + • –
AES / WC: PRES LOCK
RELEASE
Dither types vary in spectral
distribution of noise:
WIDE produces white noise
HF produces noise whose
amplitude is lower than WIDE
at low frequencies, but higher
at high frequencies.
20 BIT has the same spectrum
as HF, but with lower ampli-
tude. Use this setting when
recording to 20-bit media.
NORMAL 1dB SCALE
- red - OVL
- red - 0
- yellow - -3
- yellow - -6
- green - -12
- green - -18
- green - -24
- green - -30
- green - -36
- green - -42
- green - -60
In 4-channel mode, ALT-LINK
activates a synchronized short
tone burst.
ALT-ON is reserved for future
enhancements.
ALT-DITHER activates psy-
choacoustically optimized
noise shaping. (Disables 4-
channel mode, compression
and mute functions.)
POWER
SAMPLE RATE
20/20 AD
EXT SYNC
20 BIT A/D CONVERTER
GAIN
REDUCTION
OVL 1
0 2
-1 3
-2 4
-3 5
-4 6
-5 7
-6 8
-7 9
-8 10
-9 11
070-09091 Rev 1