Adjustment Of The Right-Hand Channel - Velleman K4040 Manual

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Adjustment of the right-hand channel:

◊ Ensure that all switches of the left-hand channel are OFF (up).
◊ Switch the first switch of SW3 (right DIP switch) ON (down).
◊ Carefully adjust RV5 until the second or third LED lights up (LD4 or LD5). Switch OFF the first switch
(up).
◊ Switch ON the second switch (down).
◊ Carefully adjust RV6 until the second or third LED lights up.
Complete the adjustment for all tubes of the right-hand channel.
Now wait for around 10 minutes.
Repeat the complete adjustment but adjust until one of the two green LEDs lights up. After adjusting all
tubes, the voltages of around 0.4V can be checked.
TEST
The amplifier can now be connected to loudspeakers of 8 or 4 Ohms, the common connection is in the
middle.
IMPORTANT
If 8 Ohm loudspeakers have been connected, then first check that not too much hum can be heard in the
loudspeakers, which is why a preamplifier should not yet be connected. Should too much hum be audible,
then the output transformer of the channel concerned should be turned a little clockwise or anti-clockwise
until the hum weakens. This operation has no effect on the 4 Ohm connection.
!
Note that the amplifier is under voltage. Be careful when turning the transformer because if any of
the leads come away the transformer will be damaged. It is best to place a small loudspeaker close to the
amplifier such that you can turn and listen for the best result.
Now a preamplifier can be connected and the unit can be tested with music.
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