Conrad-johnson design Sonographe SC-1 User manual

Congratulations. In the Sonographe SC-1 you have acquired a precision
audio preamplifier of extraordinary musicality. It is the result of a decade
of research by conrad-johnson design into the application of solid state
devices to the reproduction of recorded music. The circuit design has
been executed with quality component parts and each unit has been
painstakingly hand assembled. The completed instrument has been
subjected to a rigorous quality inspection program.
Every effort has been made to provide you with an audio instrument
capable of achieving a believable illusion of live music when listening to
high quality recordings. This manual contains many important sugges-
tions on how to realize the full potential of your SC-1. Please take a few
minutes to read it.
Sonographe SC1 Owner’s Manual 1

LIMITED WARRANTY FOR THE SONOGRAPHE SC-1
1.conrad-johnsondesign,inc.warrantstotheoriginalpurchaserthatthe
Sonographe SC-1 will be free of defects in materials and workmanship
for a period of two years from the date of original purchase.
2. conrad-johnson will repair defective units without charge for labor or
parts subject to the following conditions:
a) The unit must not have been altered or damaged through
misuse, abuse, negligence, accident, or improper operation.
b) The purchaser must provide evidence of purchase at the time
service is requested.
c) All repairs must be undertaken at the factory or other service
center designated by conrad-johnson design, inc. Units submitted
for warranty repairs must be shipped in the factory packing carton
to conrad johnson design or its designated service center, freight
and insurance prepaid by the owner, and will be returned to the
owner, freight and insurance prepaid by conrad-johnson design.
Replacement cartons are available from the factory for a nominal
charge.
d) Normal wear and maintenance are not covered by this warranty.
3. Where permitted by law, conrad-johnson design’s liability shall be
limited to that set forth in this warranty. No other warranty of any kind,
expressed or implied, is made by conrad- johnson design, inc., and all
implied warranties, including merchantability and fitness for a particular
"purpose", which exceed the obligations and time limits set forth herein
areherebydisclaimed.conrad-johnsondesign,inc.shallnotbeliablefor
incidental or consequential damages. Some states do not allow the
exclusion or limitation of incidental or consequential damages, or limita-
tions on how long an implied warranty lasts, so the above limitation or
exclusion may not apply to you.
4. This warranty gives you specific legal rights, and you may also have
other rights which vary from state to state. Questions about warranty
service should be addressed to:
Service Department
conrad-johnson design, inc.
2733 Merrilee Drive
Fairfax, VA 22031
Sonographe SC1 Owner’s Manual 2

INSTALLATION
Because the SC-1 dissipates very little heat(less than 10 watts) ventila-
tion is not an important consideration, allowing greater flexibility for
custom or built-in installations. Of course, reasonable judgement must
be exercised to see that the SC-1 does not obstruct ventilation required
by amplifiers or other equipment in the system. In custom installations,
the unit may be mounted either horizontally or vertically.
To minimize hum pickup, the SC-1 should be mounted well away from
amplifier power transformers. All ac power cords should be dressed
away from input cables- especially phono cables.
The SC-1 requires an ac power line providing between 90 and 130 volts
at 50 to 60 Hz. The SC1 is also available connected for operation on
220 and 240 V, 50/60 Hz ac lines.
CONNECTION
Phono input: This input provides the amplification and equalization
required by moving magnet and high output moving coil cartridges. The
input impedance is the industry standard 47,000 ohms shunted by
approximately 100 picofarads capacitance. This is well suited to nearly
all moving magnet and many high-output moving coil cartridges. If
necessary, the input impedance can be lowered by soldering a resistor
across ( from center pin to ground) the input jack. To achieve a desired
input resistance of RD, use the following formula to compute the re-
quired additional parallell resistance RA:
RA = 47000*RD/(47000-RD)
Some moving magnet cartridges require higher capacitance for opti-
mum performance. Decreasing the input capacitance may be achieved
by soldering a suitable value capacitor across the phono input jack. Use
polystyrene capacitors for this purpose.
Tuner, cd, video, tape 1, tape 2: These are high level inputs and are
electrically equivalent. They present a 50k ohm load to the source. The
outputsofyourtaperecordersshould beconnectedto tape1andtape2.
Sonographe SC1 Owner’s Manual 3

Record output: The two pairs of record outputs connect the selected
signal to your recorders or external processing loop (eg. equalizer). The
output signal is not affected by the level control. Connect "record out" to
the inputs of your tape recorders or external processors.
Main output: Connect this output to the input of your amplifier(or
crossoverin abi-ampedsystem). Werecommendthe useofan amplifier
with an input impedance of 20k ohms or higher.
CONTROLS
PHONO, TUNER, CD, VIDEO, TAPE 1: This selector switch is used to
choose an input. The selected source will be available at the source
position of the tape monitor switch and at both record outputs. Note that
dubbing between tape decks is possible only from tape 1 to tape 2. Also,
since tape deck 1’s output is fed back to its own record input, care must
be taken not to select Tape 1 while the tape deck is in record mode.
Similarly, if tape loop 1 is used for an external signal processor, Tape 1
should never be selected (and, of course, there is no reason to select it
since the external processor is not itself a program source). Failure to
observe these precautions will create an unstable feedback system and
may generate a "howling" sound.
TAPE 1, SOURCE, TAPE 2: This monitor switch allows you to listen to
either of two tape decks or the source selected by the selector switch.
This control also permits the user to listen to a tape as it is being
recorded. The tape deck will record whichever source has been se-
lected, and the quality of the recording can be monitored by switching
between Source and Tape 1 or Tape 2. Remember-do not select Tape 1
on both switches at the same time. The resultant feedback may damage
your system.
REV, STEREO, MONO: The setting of this switch does not alter the
signal at the record outputs. Reverse passes the left channel input to
right channel output and vice-versa. Stereo gives normal stereo opera-
tion. Mono passes the sum of left and right inputs to both channel
outputs.
BALANCE: Permits continous control of location of stereo image from
left to right. In the full counterclockwise position only the left channel will
Sonographe SC1 Owner’s Manual 4

be heard. Similarly, the full clockwise position will reproduce only the
right channel. In normal use this control will be centered.
LEVEL: The SC-1 volume control is an extremely precise control,
maintaining channel to channel accuracy to within 1/2 dB throughout its
rotation.
GETTING THE MOST FROM YOUR SC-1
The Sonographe SC-1 offers a remarkable level of sophistication and
refinement in music reproduction, but it cannot transform an inferior
stereosystem. Onlyhigh quality amplifiersand loudspeaker systemswill
be capable of fully revealing the capabilities of the SC1.
Given a system of high quality components, there remain a number of
important details which must be attended to.
ABSOLUTE PHASE
Musical notes are heard through the ear’s response to waves of alter-
nating rise and fall of air pressure. Musical transients are exclusively
positive: that is, the initial effect is a rise in pressure. The ear is capable
of distinguishing these positive transients from the musically unnatural
alternative of a negative transient (an initial fall in air pressure). In terms
of your stereo system, these transients are created by your loudspeak-
ers. If the speakers respond to musical transients by first moving out,
they are creating a rise in pressure, and the system is said to be "phase
correct". If they respond by moving in, they create a fall in pressure and
the system is said to be phase inverting. Each component in the stereo
system is either phase correct or phase inverting (including the source
andspeakers-these arenormally phasecorrect). Itis ofno consequence
if an individual component is phase inverting, as long as the system as
a whole is phase correct. This will be the case as long as the number of
phase inversions is even (or zero).
The SC-1 is phase correct. If your system has an odd number of
inversions, then you must add one phase inversion. This is conveniently
done by reversing the positive and negative connections to your speak-
ers (be sure to reverse both channels).
Sonographe SC1 Owner’s Manual 5

If you are not sure about the phase of every piece in your system, you
can establish correct absolute phase by careful listening. When the
system is in correct phase, transients will be noticeably cleaner and
moresharplydefined.The effectisespecially apparentonplucked string
sounds. A final warning-not all recordings are phase correct (including
some "audiophile" recordings), so listen to several before concluding
your investigation of absolute phase.
AC LINE POLARITY
Each piece of electronic equipment in your system is subject to minute
ac leakage currents to the chassis. Since the chassis of components in
a system are usually connected via the ground side of the interconnect
wires, these leakage currents are superimposed on the musical signals.
It is possible to minimize these current flows by carefully selecting the
way in which each component is plugged into the wall outlet. Because
tthe power cord on the SC-1 is not polarized, it can be plugged in two
ways. It will normally sound better in one orientation than in the other.
The same will be true of any electronic device in your system.
THE IMPORTANCE OF WIRES
Interconnect and speaker wires are an important element in your stereo
system. Interconnects are available which will permit a reference quality
system to blossom and fulfill its promise of musical reality. Others will
strangle the system to the point where it becomes no better than
average. To complicate matters, our experience suggests that the
choice of interconnects will be system dependent- those that are ranked
first on a given system may be a poor choice for a different system.
Consult your Sonographe dealer for recommendations for your specific
system.
TIP
Warm up the SC-1 before listening: The sonic performance of the SC-1
improvesnoticeablyasthe unitwarmsup. Themidrangebecomes more
lucid, the highs smoother, and the soundstage expands. The warm up
period can be expected to last several hours. Consequently, we recom-
mend that the SC-1 be left on at all times. The low power consumption
of the unit makes this practical.
Sonographe SC1 Owner’s Manual 6

Questions: If you have questions about the installation or function of
your SC-1 do not hesitate to call Customer Service at [phone].
SPECIFICATIONS:
Gain:
Phono stage-41dB
Line Stage-26dB
Output: 7.5 V RMS
Phase: Phase correct.
Response: 5 Hz to 100KHz
Signal to Noise Ratio (20Hz-20KHz):
Phono: 78 dB
Line 85 dB
Distortion:
THD .05%
IM .05%
Output impedance: less than 300 ohms
Dimensions: 18" x 3.75" x 11.5"
SERVICE
In the event your Sonographe SC-1 stereo preamplifier requires sevice,
repack it with the original packing material and ship via United Parcel
Service (UPS) to: Service Department
conrad-johnson design, inc.
2800R Dorr Ave.
Fairfax, VA 22031
Be sure to include a copy of your sales receipt from the original
purchase, along with a note explaining the problem you are having in as
much detail as possible. If the problem is intermittent, please indicate. If
you do not have the original packing material, replacements are avail-
able from conrad-johnson design for a nominal charge.
Sonographe SC1 Owner’s Manual 7