Marantz SC-8 Service Manual

MARANTZ MODEL Sc-8 STEREO CONSOLE AMPLIFIER
INTRODUCTION
This
service
manual
was
prepared
for
use
by
Authorized
Warranty
Staions
and
contains
service
information
for
the
Marantz
Model
Sc-8
Stereo
Console
Amplifier.
Servicing
information
and
voltage
data
included
in
this
manual
are
intended
for
use
by
knowledgeable
and
ex-
perienced
personnel
only.
All
instructions
should
be
read
carefully.
No
attempt
should
be
made
to
proceed
without
a
good
understanding
of
circuitry
operation.
The
parts
list
furnishes
complete
ordering
information.
Most
replacement
parts
should
be
ordered
from
the
Marantz
Company.
However,
a
simple
description
is
included
for
parts
which
can
be
obtained
locally.
1.
SHOCK,
FIRE
HAZARD
SERVICE
TEST
CAUTION: After servicing this appliance and prior to
returning
to
customer,
measure
the
resistance
between
either
primary
AC
cord
connector
pins
(with
unit
NOT
connected
to AC mains and its Power switch ON), and the face or front
Panel of product and controls and chassis bottom.
Any resistance measurement less than 1 Megohms should
Cause unit to be repaired or corrected before AC power is
applied, and verfied before return to user/customer.
Ref. UL Standard No. 1270. Para. 66. 3. D (Mandatory Test
after servicing Electrical Appliances, effective 7-1-83).
2. FEATURES
@ MC Head Amplifier (13 transistors for each channel)
The MC head amplifier uses a push-pull amplifier in the
first stage which consists of 4 very low noise NPN tran-
sistors and 4 very low noise PNP transistors. It uses
also push-pull transistors in the second stage and an
SEPP circuit in the output stage.
The feedback circuit impedance is reduced és much as
possible to improve the S/N ratio, and a voltage gain of
26 dB (20 times) is obtained at a rated input level of
110 uV.
@ PHONO Amplifier (11 transistors for each chamel!)
The PHONO amplifier uses full push-pull citcuits con-
sisting of 11 transistors for each channel, sc low TIM
distortion and a high S/N ratio are obtained.
The first stage is a push-pull circuit consisting of very
low noise, high Gm N channel and P channel FETs,
combined with a cascode current Miller circuit so that
degradation of characterisitics of following crcuits due
to input stage impedance fluctuations is prevented.
The second stage consists of an emitter follower buffer
amplifier and a push-pull voltage amplifier.
The output stage uses an SEPP circuit which s adequate
to any type of load. The equalizer elements have very
low impedance compared with conventiona equalizer
circuits, so a S/N ratio of 90 dB is obtained a the rated
input level.
The equalizer elements used are metal filn resistors
with tolerance of 1% and polypropylene capei tors with
tolerances of 2%, so RIAA phono equalizationaf /0.2 dB
is obtained over the audio range from 20 Hz to?O kHz.
The input impedances of 27 kQ, 47 kQ and 00 kQQ are
provided to allow different cartridges to be connected
when the PHONO 1 input is selected.
The output stage is provided with a relay tc snute un-
desireable noise when the power is switched ON and OFF,
and with an EQ subsonic filter to reduce turnta #e rumble
and flutter noise.

Marantz SC-8 Specifications

General

Brand	Marantz
Model	SC-8
Category	Amplifier
Language	English