Tube Tech CL 2A User Manual
1
TUBE-TECH CL 2A
dual compressor
DESCRIPTION.
The TUBE-TECH compressor CL 2A is a dual opto compressor with a gain reduction
element, which have no long-term degradation and almost infini te life. This element are
placed after the input-transformers of the compressors and followed by an all tube-based
amplifier with a gain of -dB to +10 dB.
Thus the signal is not fed through any semiconductor circuitry on its way to the output.
The amplifier is based on two tubes (dual triodes) in push-pull configuration (one ECC 83 as
adifferentialamplifier,andoneECC82astheoutputstage), and an output transformer.
The power supply for the d ifferential amplifiers is stabilised and the heaters of all four tubes
are fed with a stabilised DC voltage.
The two amplifiers (including input and output transformer) and the power supplies are
placed on one PC-board.
Both input and output are balanced and fully floating.
The compressors ar e switched in and out via two relays (click less).
THE SIDECHAIN:
The two side chains are the only part of the compressor that contains semiconductors.
It contains two J-FET quad op-amps, one npn-transistor and one FET-transistor, which
handles the signal for the gain-reduction element.
The compressor contains two time constants circuits:
1. Fixed attack and release times
2. Variable attack and release ti mes
COMPRESSOR INTERCONNECTION:
The sidechain sockets for interconnection of several compressors are located on the rear
panel.
A switch on the front selects which compressors are i nterconnected, and on which bus they
are connected. If you e.g . have 10 compressors in a rack, you can select compressor 1,5,7
and 8 on link 1, and compressor 2,3,6 and 9 on link 2, leaving compressor 4 and 6 in the off
position.
Compressor 1,5 ,7,8 is now interconnected and all four will perform the exact same
compression. This applie s to compressor 2,3,6 and 9 as well. Compressor 4 and 6 are
independent.
(150203)
LYDKRAFT ApS
Mose Allé 20, DK 2610 Rødovre
Denmark
2
The interconnection implies, that the unit that performs the most compression is controlling
the others.
To choose which one you want to control, select the attack/release time, the threshold and
the ratio on that unit, and turn t he threshold fully counter cl ockwise on the remaining
compressors.
It is of course possible to have all the intercon nected compressors cont rol each other
simultaneously.
NB:
Remember to set the ratio- control and the gain-control in the same po sition on
the "slaves". Otherwise the stereo image could be shifted during compression.
The attack/release-control on the slaves will have no effect.
The input/output capability of the sidechain-circuit allows up to
compressors to be linked
ten
together.
They are connected in parallel with a standard 1/4" stereo jack/-jack cord.
(tip: l ink 1, ring: link 2).
The two jack socket on the rear panel is connected in parallel and both are input/output.
CONTROLS:
GAIN:
RATIO:
The
when the unit is compressing. It is placed after the gain-reduction circuit
and therefore has no influence on the threshold setting. The
is continuously variable from off to +10 dB.
The
compressed.
If the ra tio selected is to 1,5:1, and the input signal increases 12 dB, the
output signal is only increased by 8 dB. The
variable from 1,5:1 to 1 0:1.
control is used to "make up" for the gain loss that takes place
gain
control varies the ratio by which the input signal is
ratio
control is continuo usly
ratio
gain
-control
THRESHOLD:
METER:
The threshold is the point where the compressor begins its action. It is
defined as the point where the gain is reduced by 1 dB.
The threshold is continuously variable from off to -20 dBU.
The VU-meter switch has two positions:
1.
Comp.
The VU-meter is reading gain reduction.
Its rest po sition is "0 VU", and the amount of
compression is shown as a decreasing deflection in
dB.
3.
Output
The VU-meter is reading the level at the output
socket.
"0 VU" is equivalent to +4 dBU.
(981214)
LYDKRAFT ApS
Mose Allé 20, DK 2610 Rødovre
Denmark
3
NB:
Leave the meter switch in position
introduce distortion if left in
output
compression
position.
as it might
IN/OUT:
Switches th e compressor in and out of the signal path.
In the out position the entire compressor is bypassed.
ATTACK:
The
attack
an increase in the input signal.
The attack control is continuously variable from 1 to 60 milliseconds.
RELEASE:
The
release
decrease in the input signal.
The release control is continuously variable from 0,06 to 2 seconds.
ATTACK/RELEASE SELECT:
This switch selects how the compressor reacts to a increase (
decrease (
There are two settings of the switch:
1. Fixed.
Attack time: 3mS
Release time: 60 mS
control chooses how fast/slow the compressor respo nds to
control chooses how fast/slow the compressor responds to a
attack
release
) of the input signal.
)or
LINK:
2. Manual.
Attack time: from 1 mS to 60 mS
Release time: from 0.06 S to 2 S
Interconnects several compressors on link 1 or link 2.
If the compressor is left in the off position, it works entirely
independently.
(981214)
LYDKRAFT ApS
Mose Allé 20, DK 2610 Rødovre
Denmark
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