Marantz 4070 - Performance Verification; Test Setup and Preliminary Steps; Total Hum and Noise Measurement

14, PERFORMANCE VERIFICATION
Test Procedure
A. Test Equipment
Refer to Table 1 for required test equipment.
B. Preliminary Procedures
1.
Make
the
test
setup
shown
in
Figure
1
with
the
instrument
controls
set
in
the
following
positions:
Line Switch off
Variable-line switch variable
Watt Meter Switch on
Variac 0 (fully CCW)
Load 8 ohms (0.5 mfd — off)
Audio Generator frequency 1 KHz
Output 5V range
Gain minimum
AC Volt Meter 30V range
2.
Make
sure
that
connections
between
the
resistive
load
and
the
system
terminals
of
the
Model
4070
have
negligible
resistance
compared
with
the
resistance
of
the
load
itself.
Appreciable
resistance
in
wiring
adds
to
the
total
load,
resulting
in
inaccurate
measure-
ments
of
output
power.
3.
Connect
amplifier
output
to
load
and
connect
AC
cord
to
line
power.
Connect
a
shorting
plug
to
the
PHONO
input
jack
of
the
model
4070.
4. Remove the top cover.
C. Total Hum and Noise Test
1.
With
shorting
plugs
connected
to
the
CD-4/AUX
input
jacks
and
a
8-ohm
resistive
load
connected
across
the
speaker
system
output
terminals,
connect
a
distortion
analyzer
across the load.
NOTE:
In
this
test
and
tests
that
follow,
if
distortion
analyzer
used
does
not
contain
a
built-in voltmeter, a VTVM may be substituted.
(MOMENTARY
O
O
O
SWITCH)
€ ome? 6
Om
0
aT]
0.5 MFO 8 OHMS 4 OHMS *
300V
40.5%
-05%
100W 100W
AC AMMETER
0 TO 10 AMPERES C)
Figure
2.
Amplifier
Output
Load
Box
Simplified
Schematic