VTSP-3A Owner’s Manual
Please read the Owner’s Manual Completely BEFORE operating the unit
7
The VTSP-3A incorporates an infra-
red remote control for convenient
operation of many of the preampli-
fier’s front-panel functions. This
remote uses 38kHz modulation and
detection of this signal initiates the
VTSP-3A’s decoder circuitry, which
is otherwise dormant in order to
prevent the unwanted noise usu-
ally associated with remote control
circuitry. A flashing red light in the
display window indicates the initia-
tion of the remote control decoding
process in the VTSP-3A. When the
red light is off, this circuitry goes to
“sleep” mode.
The VTSP-3A utilizes two extremely
low distortion precision electronic
stepped attenuators (one for each
channel) in a fashion similar to
the VTSP-1A/166, and VTSP-2. The
VTSP-3A has a total of 100 vol-
ume steps, and the precise volume
level is shown as three digits in the
front-panel display window. The use
of electronic stepped attenuators
ensures continued high-quality per-
formance without any of the oxida-
tion and corrosion that degrades
conventional mechanical stepped
attenuators and volume control
potentiometer wiper contacts.
At startup, the display on the
VTSP-3A goes through a lamp test,
and then successively displays the
model of the unit “SP3A” and the
time in seconds from 60 (while the
filaments and high voltage are slowly
brought on) until the unit automati-
cally un-mutes. The input display will
show the last input in use from the
last time the unit was on. When the
countdown is complete the mute will
be disengaged (if it was not on the
last time the unit was shut down),
the function displays will indicate the
last state of use, and the volume will
be ramped up to a relatively low level
of 10. At this point the user will be
able to change the settings.
The VTSP-3A incorporates circuitry to
switch the phase of the audio signal
by 180 degrees for absolute polarity
control. The amber “Invert” light
on the front panel will indicate if the
phase is being inverted. The phase
switching circuitry of the VTSP-3A is
designed so that no coloration is add-
ed in either mode and the true effects
Features
