E17
Preamplifier Operation
14 Preamplifier Operation
Many operational and control features of Naim preamplifiers are common to all and are based
on a similar user interface. This section of the manual describes those features and the user
interface, drawing attention to differences between products where they occur. Table 14.9
sets out some variations in user interface between products.
Front panel controls are duplicated on the remote control handset which may also provide
some extra functions. See Sections 15 and 16 for more information.
14.1 Automatic Input Switching
With
Automatic Input Switching
engaged the appropriate
source input will be selected as soon as any handset function
for that (Naim) source component is operated. For example, if
the tuner input is selected and the
cd
play key is pressed on the
handset, the preamplifier will automatically switch to the
cd
input.
Automatic Input Switching can be programmed to operate on any
combination of the cd, tuner, av and hdd (NAC 152 XS only) input
buttons (and sockets to which they are assigned).
To enable Automatic Input Switching, first switch the
preamplifier into program mode by pressing and holding the
handset
prog
key (with the handset in preamplifier mode).
The front panel
mon
button (NAC552
mono
and NAC 152XS
mute
buttons) will illuminate if automatic switching is already
enabled. If it is not enabled it can be switched on by pressing
the same button.
With automatic switching enabled, pressing the button again
will reveal the inputs selected for auto switching by their
indicators illuminating for a short time. Repeated operation
of the button will sequentially select through each possible
combination of cd, tuner, av and hdd (NAC 152 XS only) inputs
and auto switching disabled (all indicators off). When the
desired inputs selected for auto switching are indicated, stop
pressing the button.
Automatic Input Switching only becomes operational on exit
from program mode by pressing and holding the handset
prog
key.
Note:
The preamplifier will leave program mode automatically if
no control commands are received for five minutes.
Note:
In a few cases some further equipment configuration
may be required for auto switching to operate correctly. Please
contact your retailer or local distributor for advice.
14.2 AV Bypass
AV Bypass
enables an audio-visual processor to be integrated
such that its volume control takes over command of signals
connected to selected preamplifier inputs. On the NAC 552 AV
Bypass may be selected on DIN input sockets
4
and
5
. On all
other preamplifiers it may be selected on only the
av
input.
To select AV Bypass, first switch the preamplifier into program
mode by pressing and holding the handset
prog
key (with the
handset in preamplifier mode). The front panel
source mute
button (NAC 202
mute
button, NAC 152 XS
av
button) will
illuminate if AV Bypass is selected. If it is not enabled it can be
switched on by pressing the same button twice.
With AV Bypass enabled on the NAC 552, pressing the
source
mute
button again will reveal the inputs selected by their
indicators illuminating for a short time. Repeated operation of the
button will sequentially select each combination of the available
inputs, and AV Bypass disabled. When the desired inputs are
indicated, stop pressing the button. The selected inputs will then
be enabled for AV Bypass. The handset can also be used to select
AV Bypass. See table 14.9.
AV Bypass only becomes operational on exit from program
mode by pressing and holding the handset
prog
key.
Note:
The preamplifier will leave program mode automatically if
no control commands are received for five minutes.
Note:
The AV Bypass feature must be used with care. It
effectively by-passes the preamplifier volume and balance
controls leaving any signal connected to an AV Bypass input to
be passed to the power amplifier and speakers at full volume.
In order to reduce the potential for inadvertent mishap, any
subsequent modifications to input assignment will automatically
disable previously set up AV Bypass inputs. Additionally, if an
input is selected which has AV Bypass enabled, the preamplifier
volume and balance handset functions will be disabled and
their indicators will turn off. This will be flagged by the volume
or balance indicators flashing if either handset function is
operated.