Cary Audio Design SLP 05 - Manual (Page 6)

WELCOME
CIRCUITRY
The SLP 05 is a no compromise line stage and headphone amp. The power supply is vacuum
tube rectified and has a 5AR4 vacuum tube rectifier lying on its side inside the unit. The 5AR4
tube has a separate cathode from the filament so any position of mounting is proper. It was
horizontally mounted to keep the power supply the same height as the preamplifier. The
rectifier tube provides the high-voltage (B+) plate voltage. Two separate filter chokes and a fully
regulated shunt coupling capacitor ensure stable and ripple-free voltage resulting in a very low
noise and spacious sound stage.
The preamplifier has eight (8) 6SN7 dual triodes octal socket vacuum tubes. Four (4) of the
6SN7's act as the true balanced main line section. Two (2) of the 6SN7's are operating in the
front end ahead of the gain stage as balanced plus/minus 180 degree input buffer stage. The
remaining two (2) 6SN7's function as a ‘Class A’ push-pull zero feedback headphone amplifier.
This headphone section amplifier has two on board output transformers to transform the high
impedance of the 6SN7's to low impedance for driving the headphones.
There are two power switches to control the AC input voltage to the preamplifier. The large
knob on the power supply is the mains power switch. If one places the power supply in another
location, the main power switch is turned on. A blue LED in the knob indicates the power
supply can be activated by the preamplifier section. Turning the preamplifier power switch
sends 12 volts DC to the power supply relay to turn on the main power transformer that powers
the tube rectification along with all other voltages required to place the SLP 05 in operation.
The two meters on the front of the power supply indicate the B+ plate voltage (210 VDC) along
with the plate current (60 ma.). You will always know at a glance if all is OK with the operating
conditions.
The SLP 05 is engineered and built to provide a lifetime of musical enjoyment with facilities
and features that ensure future compatibility and audiophile performance for many years to
come. This preamplifier is a future collector’s item and deserves to be installed with the finest
ancillary equipment available, such as the CD 306 SACD Pro disc player or the CAD 211FE
power amplifiers.
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