Tube Tech LCA 2A Stereo Compressor - Manual (Page 4)

LYDKRAFT Aps
Ved Damhussøen 38, DK 2720 Vanløse
Denmark
4
ADJUSTMENT PROCEDURE:
CAUTION:
Before making any adjustment let the unit heat-up at least 30 min.
Always check the DC voltages at the power supply.
When the VCA tube has been replaced, adjustment of:
BASIC GAIN
GAIN REDUCTION
BALANCE
shall be carried out
The adjustment procedure refers to channel 1. The trimpots in
brackets is for channel 2.
At the sidechain jacksockets at the rear of the unit, the tip is
link 1 and the ring is link 2.
ADJUSTMENT OF BASIC GAIN:
1) Turn the THRESHOLD-control for the compressor and limiter
fully counter-clockwise.
2) Apply a signal of 1 kHz, 0,0 dBm to the input of the com-
pressor.
3) Turn the GAIN-control fully clockwise (+20).
4) Adjust the preset GAIN P3 (P103) (located on amp/psu PCB) to
an output-reading of +20,0 dBm.
ADJUSTMENT OF GAINREDUCTION:
1) Turn the THRESHOLD-control for the compressor and limiter
fully counter-clockwise.
2) Apply a signal of 0,0 dBm, 1 kHz to the input of the compres-
sor.
3) Adjust the GAIN-control to an output-reading of 0,0 dBm.
4) Apply a DC-voltage of +5,000 V into the sidechain jacksocket
(tip).
5) Set the LINK-switch at LINK 1 and observe that the outputlevel
has dropped to -20,0 dBm.
6) If this is not the case, adjust the level with P 7 (P107) at
the sidechain PCB, to obtain a drop of exactly -20,0 dB.