User`s manual
6
2.2 Voltage Controlled Amplifier (VCA)
2.3 Inputs
2.3.1 Take it easy: Balanced Inputs
3. CONTROLS
Pic.1: Front panel layout of the ACL 2
The ACL2 presents with right and left channels. Each channel is equipped with the same control elements: 2 push-button
switches, 7 rotary controls and 15 LED's.
3.1 Expander/Gate Section
Pic.2: Controls of Expander/Gate section
1
2
EXP / GATE
THRESHOLD
dBu
CLOSE
OFF
+10
-70 0
-50 -15
-30
-30
1. Threshold Control
This control adjusts the threshold level for the Expander/Gate Section in the range of OFF to +10dBu. Signals
below this level cause expansion.
2. Close LED
This LED illuminates when expansion occurs.
But if you sing into your microphone more gently in a soft passage, the level of the signal generated by your
voice will get much closer to the floor noise level and such floor noise will become disturbing. In order to kill
this problem expander and noise-gate are used. An expander is the opposite of a compressor: attenuating
the signal when the amplitude drops they can limit the floor noise.
Now, we do not need dramatic expansion of a signal across the range, This would generate a resulting dy-
namic range of over 150dB. For this reason the amplitude control will be applied only to those audio signals
which are below a set threshold. Those audio signals above the set threshold will not be affected. Noise-
gate can be regarded as a simple expander. But the expander will attenuate the audio signal continuously
below the set threshold while the noise-gate will simply dramatically cut-off the audio signal completely.
The VCA is the soul of the ACL2 and it is one of the best components available today in his category thanks to
its excellent performances in terms of distortion, linearity, noise and temperature stability.
To make your life easy and clean we have provided ACL2 with electronically balanced inputs. Even if you
operate at high signal levels, hum and noise will be reduce automatically. There is also a servo-function that
will automatically adjust the internal level when unbalanced connectors are detected. The correction range
of 6dB will avoid differences in level in between input and output signal.
AUTO
EXP / GATEEXP / GATE
COMPRESSOR / LIMITER
ENHANCER
COMPRESSOR/
LIMITER/GATE
ACL2
POWER
OFF
ON
R
LTO
THRESHOLD THRESHOLD
ATTACK
RELEASE
AUTO
OUTPUT
PROCESS
CH1 IN
AUTO
RATIO
AUTO
THRESHOLD
OUTPUT
PROCESS
AUTO
RATIO
THRESHOLD
CH2 IN
IN/OUT
COMPRESSOR / LIMITER
ENHANCER
ATTACK
RELEASE
AUTO
CLOSE
3
5
6
4
OFF
1
2
30 27 24 21 18
15
12 9 6
4
2
1
IN/OUT
CLOSE
dBu N:1
2.5
5
8
LIM
2
1.5
1
ms
50
100
150
200
10
1
0.1
sec
0.5
1
2
4
0.3
0.1
50m
30 27 24 21 18
15
12 9 6
4
2
1
3
6
4
OFF
1
2
5
-30
0
OFF
-50
-70
+10
-15
dBu
-10
+10
-40
-20
-30
+20
0
dB
0
+14
-20
-6
-14
+20
+6
dBu
0
OFF
-30
-50
-70
+10
-15
dBu
N:1
ms sec
2.5
5
8
LIM
2
1.5
1
50
100
150
200
10
1
0.1
0.5
1
2
4
0.3
0.1
50m
-10
+10
-40
-20
-30
+20
0
dB
0
-6
-14
-20
+20
+14
+6