User Manual

10
3
Phi Alpha Preamplifier tube complement
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.