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CONVENIENCE
Units wired for 200-240 VAC are supplied without convenience outlets to conform to Regulatory
OUTLETS
Safety requirements.
LINE LEVEL
INPUTS
PHONO SECTION
The ground terminal near the MC/MM switch is provided for turntable frame grounding via the extra
(When Installed)
ground wire provided on most turntables.
For units wired for
100-
120 VAC, the Power Switch controls the Switched Convenience Outlets only.
As soon as the 915 is plugged into the AC line, power is applied to the circuitry (regardless of the
position of the front panel Power Switch). Therefore, all connections should be performed with the unit
unplugged.
For all units, when power is applied, the Ready Light will glow red for several seconds, indicating that
the Audio and Headphone Outputs are muted. Once the delay period has passed and the power
supply has stabilized, the light will turn green. The preamplifier is now ready to enjoy.
The muting will reactivate immediately (and the Ready Light turn red) upon loss of AC line voltage,
(or operating the Power Switch on 200-240 VAC units), or if line voltage falls below a level which
precludes proper operation of the preamplifier’s circuitry.
Units wired for
700-
720 VAC have a total of five outlets for connection of associated components. The
Unswitched Outlet is powered at all times, which should generally be used for a turntable or tape deck.
The remaining four Switched Outlets are powered when the front panel Power Switch is engaged, as
indicated by the switch’s green pilot light.
The maximum power available from these outlets is 1200 watts total. This total power may be drawn
from a single outlet, or a combination of outlets. Since some power amplifiers consume more than
1200 watts at maximum output, check the power amplifier’s rating before connecting to these
convenience outlets.
The inputs labelled CD, Tuner, Video, Aux 2, and Phono/Aux 1 (when the Phono Option is not
installed), are identical line level inputs. The names chosen for these inputs are for convenience only,
and may be used interchangeably, or for any other type of line level source. These inputs are selected
via the rotary front panel Selector Switch.
The Phono/Aux 1 input is converted from a line level input to a high gain RIAA phono input when the
Phono Option is installed. See Phono Section.
The 915 Preamplifier is available with an optional Phono Amplifier section. This option may be
installed at time of purchase, or at a later date. Inclusion of this option is indicated by the presence
of a switch button protruding from the rear panel opening marked MC/MM. Otherwise, this opening
will be filled by a plastic cover.
The MC/MM switch should be set to MC for low output (typically 0.2
-
0.5 mV) moving coil cartridges,
and set to MM for high output (2
-
5 mV) moving coil cartridges or moving magnet cartridges.
NEVER OPERATE THE MC/MM SWITCH UNLESS THE VOLUME CONTROL IS TURNED FULLY
DOWN. The very high gain present in the Phono Amplifier can result in switching transients capable
of blowing amplifier or speaker fuses, and possibly damaging some loudspeakers.
As supplied from the factory, the phono cartridge input termination is 47,000 ohms in parallel with 220
pF
in the Moving Magnet mode, and 100 ohms in the Moving Coil mode. The value of capacitance
and resistance is user selectable via plug-in components. See “Installing Cartridge Loads” for further
information and instructions.
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