MODEL
HF
89
STEREO DUAL
POWER
AMPLIFIER
general
description
GENERAL
The very
finest techniques
known to
the audio art are
applied in the
HF-89 stereo high
fidelity
dual power am-
plifierto insure
the utmost in
audio quality
under the most
demanding
circumstances. The
HF-89can be
used with the
superb
EICO HF85 stereophonic
preamplifier or with any
good
self-powered
stereo preamp.
Each power amplifier
of the HF-89 is
conservatively
rated
at
50
watts and employs
the thoroughly
proven
cathode-
coupled phase
inverter-driven
circuit, preceded by
a
direct-coupled
voltage
amplifier. Ultra
linear connected,
fixed-biased,
push-pull
EL34's are used in
the output
stage
and provision is
madefor both
bias
and
dc
balance
adjustments.
The very
low impedance
characteristic
of
silicon diode
rectifiers gives
the common
power
supply
for the two
amplifiers very
good
regulation. As
a result,
signal
conditions
in
one
amplifier have
negligible
effect
on the
operating conditions
of the
other amplifier
—
a
very
worthwhile
feature
in
a high
quality design.
To
insure
long
life for the
silicon diode
rectifiers, electro-
lytics,
and tubes,
asurgistor is included
to
limit
the
start-
ing
surge
currents.
SPECIFICATIONS
Output Power;
100
watts (two
50watt amplifiers) contin-
uous,
200
watts
peak
IM
Distortion (60
&
7000 CPS
at 4;
1);
0. 5%
at 100
watts
Harmonic
Distortion:
Less
than
0.
25%
from 30 to
1
5,
000
cps
and less than
1% from 20 to
20,
000
cps
within
Idbof
1
00
watts
Frequency
Response:
±0. 5db 5 cps
-
lOOkc
Rise
Time:
2.
5usec
Square-Wave Response:
Essentially
undistorted
to
20,
000
cps
Inverse
Feedback:
18db
Stability
Margin:
13 db
Damping
Factor:
above
12,
20 cps to 20kc
The
intrinsic quality
of
the driving circuit,
the output
tubes,
and
the
output transformers
in
the HF-89
is unsur-
passed.
IM
distortion at
normal listening levels drops to
below 0.
1%,
and
even at
100, 000
cps
a total of
60
watts
undistorted output
is
available
to insure unimpaired tran-
sient (square
wave) response
even
at
very high
power
levels.
The
low
end is extremely solid and full,
as
an
undistorted
total
power output of
78
watts at 15
cps
and
28
watts
at 10
cps
would imply. Furthermore,
the high
circuit
and
component quality results
in
less feedback
required
to achieve these very low distortion figures, so
that the
HF-89
amplifiers have a
very
healthy
stability
margin
to insure
perfect
results in
any
application.
The
methods of stereo recording are
such
that, at
moments,
practically
all
the sound is
in
one channel or the other.
For this reason, the best stereo installations require an
amplifier
in each
channel as
powerful
as that
used in
the
best monophonic installations. 50
watt amplifiers
have
been found very worthwhile in the
best monophonic instal-
lations and
actual
50watt
amplifier will be found equally
worthwhile in the best
stereo installations.
Channel
Separation:
60db
Sensitivity:
0. 55V
for full output
Hum:
Better
than 90db
below full output
Controls: Level Ch.
1,
Level
Ch.
2,
"Service
Selector"
switch, ON-OFF switch
Speaker Connections:
4, 8,
and
16
ohms
Tubes:
1-ECC83/12AX7,
2-6SN7GTB,
4-EL34, 2silicon
diode rectifiers
(power),
1
selenium
rectifier (bias); sur-
gistor protected
for long life
Pbwer Source: 1 1
7V,
60
cps
Power Consumption:
215watts
at
no
signal, 270 watts
at
1
00
watts out
Size;
15“
x
11"
x
6"
Shipping
Weight:
37
1/2
lbs.
1
COPYRIGHT© 1960
ELECTRONIC
INSTRUMENT COMPANY, Inc.
To Next Page
Loading...
