Tube Tech SMC 2B Multiband Opto Compressor - Manual (Page 5)

Lydkraft ApS
Mose Allé 20, DK2610 Rødovre
Denmark
5
HIGH BAND:
1) Turn all the THRESHOLD-controls fully counter-clockwise.
2) Turn the HIGH BAND GAIN-control fully clockwise.
3) Turn the LOW BAND and MID BAND GAIN-control fully counter clockwise.
4) Set the X-OVER HIGH at 1,2k.
5) Apply a signal of 10 kHz, (approx. -20 dBU) to the input and adjust the input level
for an output reading of 0,0dBU.
6) Move the jumper on the high band side chain PCB (top most PCB) to “ADJUST”
and observe that the output level has dropped to -10,0 dBU in both channels.
7) If this is not the case, adjust the balance P 6 to an equal reading for both channels.
8) Adjust the gain reduction with P 5, to obtain a drop of -10,0 dB.
9) Repeat step 7 and 8.
10) Adjust the high band display with P 7 so the green -10 LED turns on and the
green -7 LED just turns off.
CALIBRATING OF GAIN POTS:
When any of the gain potentiometers have been replaced, they will need to be re-
calibrated, to minimise the level difference between the two channels.
Two resistors on each gain pot, are used to adjust the channel difference:
R24, R124 at OUTPUT GAIN
R21, R121 at HIGH GAIN, R22, R122A at MID GAIN, R123, R123 at LOW GAIN
HIGH, MID and LOW band potentiometers:
Only one gain pot is calibrated at a time. The two others are turned fully
anticlockwise (off).
1) Turn the OUTPUT GAIN at max. gain (clockwise).
2) Turn the gain on the band to be calibrated, at max. gain (clockwise) and check that
the difference between the two channels, are less than 0,1dB.
3) Set the gain pot to “0” dB.
4) The potmeter in the channel with the lowest level is adjusted to match the other
channel, by changing the resistor, until the level is within 0,1dB.
The resistance range is normally within 274K

to 510K

(130711)