It is normal for a vacuum tube power amplifier to run quite
warm, and if used for prolonged periods, hot to the touch.
All components within are, however, operated at safe,
conservative levels and will not be improperly affected
thereby, providing the requirements outlined above are
adhered to.
IMPORTANT:
Use the best available speaker wires and
interconnects. Audio Research cannot emphasize this
enough. As better components and systems are developed,
it becomes increasingly important to avoid the limitations
of inferior system interconnections.
It is important sonically that your entire system be
connected so that the audio signal arriving at the speakers
has correct, or “absolute” polarity (i.e., non-inverted).
Connect the black or “-” speaker terminal to the wire that
connects to the “0” terminal on the VSi55. Connect the red
or “+” speaker terminal to the wire that connects to the “4 ”
or “8” terminal on the VSi55. and tighten the speaker
terminals securely to ensure best sonic results.
MATCHING
: It is important to use as close as possible an
impedance match between the amplifier and speaker for
optimum transfer of power to the speaker with minimum
distortion. In the case of speaker systems with significant
variations in impedance throughout the frequency spec-
trum, such as most electrostatic types, determine the best
impedance match empirically for best overall sonic results.
Connect the VSi55 input to the source components using
only the highest grade of audio interconnect cables. To
avoid sonic degradation use the shortest practical length
of cables.
AC POWER CONNECTIONS:
It is essential that the VSi55
amplifier be connected to a wall AC power receptacle, or
a similar heavy-duty source. If it is connected to conve-
nience receptacles on preamplifiers
,
etc., the full sonic
capabilities of both the VSi55 and the preamplifier will be
compromised.
For the very best sonic performance, the VSi55 should be
connected to its own AC power circuit branch, protected by
a 15 or 20 amp breaker. The other audio equipment should
be connected to a different power circuit and breaker.
Avoid the use of extension cords. If they must be used on a
temporary basis, use 14-gauge or heavier cords.
The VSi55 utilizes a compatible grounding system that gen-
erally does not require a “ground lifter” adapter plug on the
AC power cord to minimize hum. The 14-gauge power cord
supplied with the VSi55 has a standard three-prong
grounding plug to provide maximum safety when it is con-
nected to a grounded wall receptacle. If there is any
question regarding the safety of grounding procedures, be
certain to seek competent help with the installation.
If electronic crossovers or other AC powered equipment are
used with the VSi55 it may be necessary to use “ground
lifter” adapters on the power plugs of that equipment to
minimize system hum. Generally, the lowest hum is
achieved when the only direct connection between audio
common “ground” and true earth ground occurs in the
preamplifier, through its grounded power cord. Other
equipment in the system should have some form of isola-
tion to prevent ground loops and associated hum.
Operating Procedure
Start-up:
1
.
Make sure you have read and complied with the
INSTALLATION AND CONNECTION instructions prior
to attempting operation.
2.
Secure all rear-panel connections between VSi55, and in-
put sources,
subwoofer amplifier (if applicable) and
loudspeaders.
3
.
Make sure the VSi55 is properly connected to a grounded
high-current power receptacle via the supplied
14-gauge, 3-prong grounded power cord (see AC POWER
CONNECTIONS).
4.
Turn Power switch to “on”. The Mute LED will flash for
approximately 30 seconds while power supply stabilizes,
indicating operation of automatic muting circuit. After
this automatic muting period the LED will stay on, indi-
cating that your VSi55 is in the “mute” position. Adjust
the Volume control to the minimum level, as indicated
by illumination of the first (left-most) Volume LED.
When the “o p e r a te” position is manually selected the
Mute LED will turn off, indicating the VSi55 is ready for
operation.
Not e :
If the mute indicator LED fails to flash, check the
appropriate fuse for possible failure. An extra fuse for
A.C. power is included with your VSi55.
5.
Press Input selector for desired source; set remaining
switch options to desired positions.
6.
Activate selected input source, then deactivate Mute
switch and adjust Volume control as necessary.
7
.
Your VSi55 should now operate satisfactorily. However,
a full stabilization or warm-up time of approximately one
hour is recommended for best sonic performance.
Shut-Down:
1.
Set Mute switch to “Mute” position.
2.
Adjust Volume control to minimum setting (left-most
first volume LED lit).
3.
Push VSi55 Power switch to “off ” position.
Model VSi55
3
VSi55 Manual / 3-03 /
2-
17
-03
