Conrad-johnson design Sonographe SA120 User manual

Sonographe Owner’s Manual:
SA120 Power Amplifier

Congratulations on your purchase of the Sonographe SA120 FET
amplifier. The SA120 is a precision audio amplifier, remarkable for its’
musicality. Designed for durability as well as sonic purity, the circuit has
been executed with quality componenet parts. Each unit has been
carefully hand assembled and subjected to a rigorous quality inspection
program.
Please take a few minutes to read this manual so that you will better
understand the features and capabilities of your SA120.
Sonographe SA120 Owner’s Manual 1

LIMITED WARRANTY FOR THE SONOGRAPHE SA120
1. conrad-johnson design, inc. warrants to the original owner that the
Sonographe SA120 will be free from defects in material and workman-
ship 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
are hereby disclaimed. conrad-johnson design, inc. shall not be liable
for incidental or consequential damages. Some states do not allow the
exclusion or limitations 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.
2800 R Dorr Avenue
Fairfax, VA 22031
Sonographe SA120 Owner’s Manual 2

REGISTERING THE WARRANTY
Please return the enclosed card to the factory within 30 days of pur-
chase to register the warranty. Proper registration of the warranty is
important! It will enable us to inform you of any alterations in the design
of a given model and of any new products we offer which are likely to be
of interest to you.
Sonographe SA120 Owner’s Manual 3

INSTALLATION
Because the SA120 amplifier dissipates considerable heat it is essential
that proper attention be paid to ventilation. The unit should be mounted
horizontally on a flat hard surface so that the heat sinks are unob-
structed. At least six inches of clearance should be provided above the
unit, and at least two inches on the sides. The cabinet or shelf should
be open at both front and back. For more restricted installations, cooling
fans are recommended.
To minimize hum pickup, keep the unit well away from the preamplifier
and turntable and route power cords away from input cables.
THE SA120 IS TO BE OPERATED ONLY ON AC LINE VOLTAGE OF
108 TO 125 VOLTS.
The SA120 is also available wired for 100, 220 or 240 volt, 50/60 Hz
current.
Sonographe SA120 Owner’s Manual 4

CONNECTION
INPUT: Connect the preamplifier to your SA120 amplifier at the RCA
type connections located on the amplifier heat sinks.
OUTPUT: Five way binding posts are provided for connection of your
loudspeakers, with correct spacing to accept a standard "double ba-
nana" plug. They will also accept spade lugs, bare wire, or pin connec-
tors.
The two channels should be connected in correct "relative phase".This
means that when the same signal is applied to both channels, the right
and left channels speaker diaphragms should move synchronously-in
and out together. Terminals on the speakers are usually coded - one
designated "C", "earth", "ground", "-" or black, the other designated "+"
or red.
"In phase" connection of the speakers can normally be achieved by
taking care to connect the wire from the red (+) amplifier terminal
marked on each channel to the red or "+" coded terminal on each
speaker.
In phase connection of the speakers can be readily ascertained by ear.
With the preamplifier mode switched into the MONO position, play a
record of a solo vocalist. With the speakers in phase the voice should
be clearly focused between the two speakers. With the speakers con-
nected out of phase, the voice will be diffused, with no identifiable
source. Relative phase may be reversed by switching the "+" and "-"
leads at one speaker only.
Sonographe SA120 Owner’s Manual 5

GETTING THE MOST FROM YOUR
SONOGRAPHE SA120
The Sonographe SA120 offers a remarkable degree of refinement in
music reproduction, but it cannot transform an inferior stereo system.
Onlytheverybestloudspeakersystemswillbecapableoffullyrevealing
the capabilities of this precision instrument. On the other hand, the
SA120 is capable of revealing faults in the phono system which may not
be discernable with an amplifier of lower resolution.
Proper set-up is important in any high-fidelity system. Before installing
the SA120, be sure that your phono system has been set up carefully
according to manufacturer recommendations. Adjustment of the car-
tridge vertical tracking angle can be especially critical with modern
stylus configurations.
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 your
stereo system, these transients are created by your loudspeakers. 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
systemiseitherphasecorrectorphaseinverting(includingthecartridge
and speakers-these are normally phase correct). It is of no conse-
quence 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). 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
on either your cartridge or your speakers (be sure to reverse both
channels).
Sonographe SA120 Owner’s Manual 6

Your Sonographe SA120 is phase correct. If you are not sure about the
phase of every component 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 more sharply defined.
The effect is especially apparent on plucked string sounds. A final
warning-not all records are phase correct (including some "audiophile"
recordings), so listen to several before concluding your investigation of
absolute phase.
THE IMPORTANCE OF WIRES
Interconnect and speaker wires are an important element in your stereo
system. Interconnects are available which will permit your system to
blossom and fulfill its promise of musical reality. Others will strangle the
sytem to the point where it becomes no better than average. To compli-
cate 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.
QUESTIONS?
If you have any questions about the installation or function of your
SA120 do not hesitate to call the conrad-johnson group’s Customer
Service at (703) 698- 8581.
Sonographe SA120 Owner’s Manual 7

SPECIFICATIONS:
Power: 120 watts per channel RMS both channels driven into 8 ohms
from20Hzto 20KHz with no more than 1% total harmonic distortion or
intermodulation distortion.
Sensitivity: 1.1V to rated power.
Phase: Phase correct (non-inverting)
Frequency response: 20Hz to 20KHz +0, -.25dB
Hum and noise: 90dB below full power output.
Input impedance: 100K ohms.
Dimensions: 16.75D x 19W x 5.25H inches.
Weight: 40 lbs.
Fuses: The AC line fuse is user replaceable on the SA120. It is a type
3AG 7 amp slow-blow (5 amp slow-blow for 220 or 240V operation).
NEVER REPLACE THE FUSE WITH A TYPE OR VALUE DIFFERENT
FROM THAT ORIGINALLY SUPPLIED BY THE FACTORY. If the fuse
blows repeatedly, contact your dealer, or the conrad-johnson group
service department.
Sonographe SA120 Owner’s Manual 8

SERVICE
In the event your Sonographe SA120 stereo amplifier requires service,
repack it with the original packing material and ship via United Parcel
Service (UPS) to:
conrad-johnson design, inc.
Service Department
2800R Dorr Avenue
Fairfax, VA 22031
Be sure to enclose 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 at a nominal charge. If the unit is
under warranty, be sure to enclose a copy of your receipt as proof of
purchase.
Sonographe SA120 Owner’s Manual 9