decreasing within the amplifier. They are a sign that your amplifier is
operating normally, and are not a cause for concern.
More on 'thunks'
In greater detail, REDGUM amplifiers make audible 'thunks' when
powered up and down, but usually only the latter ones are noticeable
to people. A REDGUM amplifier has no need to mask this sound with a
troublesome relay in the speaker line. In fact, customers can be
reassured that this sound is a healthy sign that the amplifier is flexible
enough to cope with such rapid changes in the power supply.
What actually causes the 'thunks' is best explained for the process
during the powering down of a REDGUM integrated amplifier (35W,
60W or 120W), which has both channels run from a shared power
supply. When the system is turned off, the first and weaker 'thunk'
comes from both speakers together, as the power in the supply (which
is common to both channels) “settles” below the voltage required for
stable operation. The voltage available to the amplifier continues to fall
till eventually the output stage of one of the channels goes into
conduction, thus grabbing and dumping the remaining stored power
into the speaker line of that channel. This dumping causes the
remaining supply of power to collapse, causing the third and loudest
'thunk', but only through the channel where the power was dumped.
As a result, the second channel is left with virtually no power to access
from the shared supply. Since the separate output stages of the
channels have reached their critical cut-off voltages sequentially, the
second channel is deprived of the power required to produce a sound
of the same proportions as the loud 'thunk' from the first channel.
Because of component tolerances, the final 'thunk' sound is usually
heard from the same channel.
This same process occurs with the 170W and 300W Monoblock
REDGUM amplifiers, but with both channels producing their final
‘thunks’, each in their own time. Each channel has its own power
supply, so the fall in voltage affects only that channel, causing it to
collapse as described above.
Input source selection
Rotate the input selector to choose which component will play through
your amplifier.
Note
Always make sure that the volume is turned down before changing the
input source, so protecting your equipment.
