LYDKRAFT ApS
Mose Allé 20, DK-2610 Rødovre
Denmark
1
User
’
s
Manual
TUBE-TECH LCA 2B
compressor and limiter
DESCRIPTION:
The TUBE-TECH LCA 2B is a two-channel unit with an independent compressor and
limiter per channel. The unit is all tubebased (except for the power supply and si-
dechain circuit). Output gaincontrol is placed between the VCA and output stage. The
VCA (1 dual triode) is placed between the input transformer and the output stage (2
dual triodes). The audio signal is picked up after the VCA and fed to the sidechain
circuit. The control signal from the compressor and from the limiter is combined and
sent to the link switch and to the control amp, which feeds the VCA. The bi-directional
link busses are accessible at two 1/4" stereo jack sockets on the rear panel. The
channels can be linked together for stereo applications and also linked to other LCA
2B's via the two link busses and a standard stereo jack/jack cord.
The compressor has six attack/release presets as well as manual control. The limiter
attack/release is fixed and equipped with an on/off switch.
The LED display is fed from the control amp. The limiter LED is fed from the limiter
buffer.
The audio path is fully symmetrical from input to output.
Input and output have fully floating transformers.
All DC voltages are stabilised, except the anode voltage for the output stage, which is
only filtered.
COMPRESSOR INTERCONNECTION:
The sidechain sockets for interconnection of several compressors are located on the
rear panel.
A switch (LINK 1, LINK 2) on the front selects which compressors are interconnected,
and on which bus they are connected. If you select LINK 1 on both channels, they will
perform exact the same gainreduction.
Having several connected compressors in a rack, you can select which compressors
you will have working together.
By selecting e.g. LCA 2B no 1, ch. 1 on link 1, LCA 2B no 2, ch. 2 on link 1 and LCA
2B no 3, ch. 1 on link 1, they are now interconnected and all three will perform the
exact same compression.
The interconnection implies, that the unit, which 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 the threshold fully counter clockwise on the
reminding compressors.
It is of course possible to have all the interconnected compressors control each other
simultaneously.
(150205)
