10
REPLACEMENT OF LOW LEVEL TUBES
Phono tubes are type 12AX7/ECC83; you may wish to use low noise tested tubes.
Line stage tubes are type 8416, no substitute types are acceptable.
We strongly recommend that you use only tubes specifically selected and tested by
VAC for this application.
Before replacing tubes, all power must
be turned off. Allow 15 minutes for the
tubes to cool down and voltages to
discharge before removing the top
cover. The voltages inside the unit may
be lethal in normal operation. NEVER
OPERATE THE PREAMPLIFIER WITHOUT
THE COVER INSTALLED.
Install new tubes firmly in their sockets,
noting the location of holes in the socket
and pins of the tubes, taking care to
make sure that pin pattern corresponds
to holes in tube socket. Replace the
cover before reconnecting and operating
the preamplifier.
In the event that trouble is encountered,
check all signal, speaker and power
connections. If the problem persists,
follow all safety precautions stated earlier
in this section, and check that all tubes are
correctly seated in their sockets. If
possible, try another tube. If the problem
persists, please consult your VAC dealer
or contact the factory directly.
Tubes are like the tires on a car; they will eventually need replacement. Murphy's Law states
that a tube will probably fail right at the start of a long holiday weekend. Therefore, many
audiophiles keep a spare tube of each type on hand, just in case!
VAC can test tubes for concerned customers.