Audio Research HIGH DEFINITION PH9, Manual

Page: 7 / 22

7
Installation
In your system
• To ensure normal component life and
safe operation this unit must be operated
only in an upright position. Adequate
airflow and proper cooling can occur
only if there is no restriction above and
behind the unit and on either side.
• The special non-marring elastomer feet
provide adequate spacing and stability
only on a smooth, hard surface, and also
assist to isolate the phono preamplifier
from spurious vibrations. For upright
stability and best performance, never
operate the unit while it is sitting on a
soft surface such as a thick rug or carpet.
• Due to its weight, this preamplifier must
be supported on a surface specifically
rated for such a load. Check with the
manufacturer of your support system to
be sure it is rated to handle this weight.
• If the unit is to be operated in an
enclosure such as an equipment rack,
make certain that adequate airflow
above and to each side of the unit is
provided. Audio Research recommends
a minimum of 6-8 inches (15-20 cm) of
clearance above the PH9 to maintain
proper ambient operating temperature.
• The ‘ambient’ operating temperature
should never exceed 86° F and 30° C.
Improper installation will cause premature
tube failure and will affect your warranty,
as well as the service life of the unit.
• It is normal for a vacuum tube preamplifier
to run quite warm, and if used for
prolonged periods, hot to the touch. All
components within are operated at safe,
conservative levels well within tolerances.
A Note about Vacuum Tubes
The vacuum tubes in your PH9 have been
burned in, tested and electrically matched
to provide the best performance and
reliability of your preamplifier. That said,
vacuum tubes must be replaced from time
to time. The 6H30 tubes in the PH9 should
have an expected life of approximately
4,000 hours, while the 6550WE tube in the
power supply should have a life expectancy
of approximately 2,000 hours. These life
expectancies are only approximate.