,:[1,,

3
o
l"l rl
n 99
g!!
**':*".1,=;;;|
,:[1,,
r€Tery
::!::r,r:;,;Ji
The serious music lover wants an audio system that
will reproduce the original musical performance
with as much fidelity as possible. Each component
must either pass signals without adding coloration,
or must provide just the right amount of compensation
to previously modified signals. The SU-7700
performs these functions beautifully. While its
most apparent attributes are excellent specifications
and elegant styling, it can be fully appreciated
only when heard with other components of equally
high quality. The transparent and "effortless"
rendition of very demanding program material
will delight even the most critical listener.

50 watts per channel, minimum RMS, both channels driven, at 8 ohms
from 2OHz to 2O kHz,with no more than O.O8o/o total harmonic distortion.
At 1,OOOHz, this figure rises to S3watts per channel at 8ohms.
Power When You Need lt-Fidelity Always
50 watts per channel, minimum RMS, both
channels driven, at 8 ohms, from 20 Hz to
2Q kHz, with no more than 0.08% total
harmonic distortion. That says it in a
nutshell, but have you considered what
this performance means for practical
listening enjoyment? SuPPose Your
speakers are low-efficiency, or that you
want to drive two pairs at once. Suppose
your musical tastes run to popular music
irvitn a lot of floor-shaking low bass'
Under most conceivable home listening
situations, the SU-7700 will provide all
the power you need. But the real
accomplishment of Technics engineers
has been to hold total harmonic distortion
down to 0.08%, and to control this rather
awesome power right down through the
lowest audible lrequencies, so power
bursts won't create transient distortion
that can momentarily degrade fidelity.
Combined with other components ot equal
oualitv, vour SU-7700 will provide power
virnen'it's needed, and muiical fidelity all
the time.
Current Mirror Loading Attains Extremely High S/N Ratio in Equalizer and Low Distortion
in Power Circuits
A classic dilemma in amplifier design is to By virtue of current mirror loading, the
achieve higher operating current (for gain) gain producing effect of a given operating
without a correspondingly higher level current is magnified. The results are a
of noise. To solve this problem, Technics higher S/N ratio in the equalizer and a
has employed current mirror loading in lower distortion rating in the power
the dilferential amplifier first stage of the amplif ier.
equalizer circuit and the power amplifier.
78dB
S/N Ratio al 2.5 mV Phono lnput
Sensitivity
The 78 dB phono signal-to-noise ratio is
the equivalent of a 1/8,0001h noise
component in the music signal. In real
terms, this means that on well cared-for
records, noise won't interfere with your
enjoyment of the music, even during very
soft passages. Significantly, the S/N ratio
should be even better than 78 dB with
high output cartridges, as this figure was
obtained at a relatively high sensitivity
level of 2.5 mV.
This extreme
"quietness" of the
phono equalizer is
the result of
advanced current ffi,:'"
mirror circuit
design and
use of low
noise lC.
0.08%
Total Harmonic Distortion
(20 Hz-20 kHz) at Rated oulput
In hi gh-f idelity amplif iers, only distortionfree
power counts. At any power level,
from a whisper to the roar of the full
50 watts per channel, the total harmonic
distortion of the SU-7700 never exceeds
an imperceptible 0.08%, and is typically
much less. Note, too, that this also applies
to the entire range of frequency response,
from 20 Hz to 2O kHz. Use of matched
transistor pairs in a single package and
already mentioned
current mrrror
loading contribute to
this low distortion
f igure.
Single packaged pair
transistor

Subsonic Equalizer Filter
A subsonic f ilter in the NFB loop of the
phono equalizer removes inaudible but
nevertheless troublesome ultra-low
frequencies which could cause intermodulation
distortion in conventional
circuits. Rumble, low-frequency noise
resulting f rom warped records, as well as
tonearm/cartridge resonances are cut off
at the source with a steep 12 dB/oct slope
below 30 Hz. Typically, a resonance peak
of the tonearm/cartridge assembly appears
in the 5 Hz to 10 Hz area, as shown below.
It is clearly noticeable as a useless
"pumping" movement of the woofer cone.
Cut-off at the input means that such
subsonic "garbage" can do no harm at any
downstream signal stage. Conventional
subsonic filters, on the other hand, are
inserted into the preamplif ier after much
of the intermodulation has alreadv been
generated.
RIAA Gompensation Accurate Within
*0.2 dB
The playback equalization characteristic
of the SU-7700 varies by only +0.2 dB
(30 Hz-15 kHz) from being a perfect
inverse of the RIAA recording characteristic
for phonograph records. In the past,
precision of this order would have been
difficult to find even in very eixpensive
amplifiers. We achieved it through use of
+1ok tolerance metallic f ilm resistors and
+2o/o polypr opylene capacitors.
Two-Way Dubbing
The tape selector circuit permits two tape
decks to be connected at the same time to
the SU-7700. Dubbing may be performed
between the two decks in either direction.
Additionally, as the tape monitor and
recording mode switches operate
independently, you can use the SU-7700 to
listen to a record or FM program while
tape dubbing is in progress.
41 Step Volume Control
To provide precise, repeatable volume
settings, the volume control has 41 clicksrops.
Tone Controls with Deleat at "0" Position
Using-newly developed controls, the bass
and treble control circuits are disconnected
lrom the main circuits when the respective
control knob is set at the center ("0")
position. ln this state, the main circuit is
reduced to an equalizer amplifier, plus a
power amplifier- the simplest possible
circuit, and one in which potential sources
of distortion are minimized. When the
tone controls are used, their negative
feedback circuits provide low distortion
equalization that would be considered
excellent by any standards. With these
controls, equalization is variable over a
wide range of +12 dB.
High Filter
Cuts out high frequency noise such as
record scratches and taoe hiss.
Direct Reading Power Meters
The large scale meters provide direct
readout (at 8 ohms) of amplifier output
power in watts, with instantaneous tracing
of signal peaks. To improve linearity at
low output, a germanium diode is used for
rectification. Two ranges are provided
(x1 and x0.1) for accurate monitoring of
all output levels.
Muting Circuit Eliminates Power On/Off
Switching Noise
To eliminate the unpleasant noises which
are heard from the speakers when power
is turned on or off, the SU-7700 is
equipped with a muting relay which
operates in conjunction with a protective
circu it.
Stabilized Power Supply
To insure that adequate power, at constant
voltage, is available for every output
requirement, the SU-7700 features a
balanced positive-negative power supply
using transistors and zener diodes.
Main/Remote Speaker Facililies
Two pairs of speakers may be connected
and fed separately or together. Two
pushbutton selectors permit operation of
main speakers only, remote speakers
only, or'both pairs simultaneously.
Heat sinks
Electrolytic capacitor
10,000aFx2
Power transistors
Power transformer
Protection relay and
pop noise muting circuit
Current mirror loaded
differential amplif ier
Low noise phono equalizer circuit

1. Power on/olf switch
2. Phones jack
3. Main sDeaker switch
4. Remote speakers switch
5. Meter range seleclor
6. High filter switch
7. Loudness switch
8. Bass control
9. Treble control
Technical Specifications
10. Mode selector
11. Rec/Mode selector
12. Taoe monitor switch
13. Inout selector
14. Equalizer subsonic lilter switch
15. Volume control
16. Balance control
17. Direct reading power meters
'1.
Ground terminal
2. Phono inputs
3. Tuner inputs
4. AUX inputs
5. Tape deck 1, REC outputs
6. Tape deck .1, PLAY inputs
7. Tape deck 2, REC outputs
8. Tape deck 2, PLAY inPuts
9. REC/PLAY terminal
(tape deck 2)
10. SDeaker terminals (main)
11. Soeaker terminals (remote)
AMPLIFIER SECTION
1 kHz continuous power output
both channels driven 2 x 70W (4o)
2x53W (8o)
40 Hz-16 kHz continuous power output
both channels driven 2x60W (4o)
2x50W (8o)
20 Hz-20 kHz continuous power output
both channels driven 2 x 60W (4o)
2x50W (8o)
Power bandwidth
both channels driven at 4rl
I Hz-55 kHz, -3 dB
Total harmonic distortion
rated power at 40 Hz-16 kHz, 4a 0.08%
rated power al 1 kHz,4a 0.08%
-26 dB power at 1 kHz,4a 0.1%
50 mV power at 1 kHz, 4a 0.15%
lntermodulation distortion
rated power at 250 Hzi I kqz=4:1, 4a
0.08%
Frequency response
5 Hz-80 kHz, -3 dB
10 Hz-40 kHz, - 1 dB
Damping factor
50 (8o), 25 (4o)
Input sensitivity & impedance
PHONO
2.5mV147 ka
TUNER
150mV/47 ko
AUX
150mV/47 kfl
PLAYBACK, TAPE 1 180mV/47 ko
PLAYBACK. TAPE 2 150mV/47 ko
REC/PLAY, TAPE 1,2 180mV/47 ko
PHONO maximum input voltage
150mV
(1 kHz, RMS)
s/N
rated power PHONO
AUX
-26 dB power PHONO
AUX
50 mW power PHONO
AUX
63 dB
83 dB
55 dB
58 dB
53 dB
53 dB
Tone controls
BASS 50 Hz, +12 dB--12 dB
TREBLE 20 Hz, +12 dB__12 dB
EQ subsonic filter 30 Hz, -12 dB/oct
High filter
8 kHz, -6 dB/oct
Loudness control (volume at -30 dB)
'100
Hz, *8 dB
Output voltage & impedance
REC OUT, TAPE 1, 2 150mV/1.2ka
REC/PLAY output 30mV/82 ko
Load impedance
MAIN or REMOTE 4-16o
MAIN + REMOTE 8-16o
GENERAL
Power consumption
450W
Power suppfy 110V/120V1220V1240V
50/60 Hz
Dimensions 4'10 x 139 x 334 mm
(WxHxD) (16t"x5+*"x13+")
Weight
9.7 ks (21.4 lb.)
POWER AMPLIFIER SECTION
1 kHz continuous power:
both channels driven 70W+70W (4o)
53W+53W (8o)
2O Hz-20 kHz continuous power:
both channels driven 60W+60W (4o)
50W+50W (8o)
Total harmonic distortion:
O.O8%o
(rated power, 20 Hz-2O kHz)
0'O35Yo
(half power, 20 Hz-20 kHz)
0.01%
(half power, 1 kHz)
lntermodulation distortion: 0'08%
(60 Hz: 7 kHz=4:1, SMPTE)
Power bandwidth:
(both channels driven at 8f,)
8 Hz-55 kHz, -3 dB
Residual hum and noise:
0.6mV
Damping factor:
50 (8o), 25 (4a)
Load impedance:
MAIN or REMOTE 4-16a
MAIN & REMOTE
PRE-AMPLIFIER SECTION
Input sensitivity and impedance:
PHONO
2.5mV/47 k0
TUNER/AUX
150mV/47 ko
TAPE DECK 1 PLAYBACK
180mV/47 ko
TAPE DECK 2 PLAYBACK
TAPE REC/PLAY input
150mV/47 ko
180mV/47 ko
PHONO maximum input voltage:
(1 kHz, RMS) 150mV
Signal/noise (lHF A):
PHONO
TUNER
Frequency response:
PHONO RIAA
TUNER, AUX
8-16o Tone controls:
BASS
50 Hz. + '12 dB- - 12 dB
TREBLE 20 kHz, + 12 dB-- 12 dB
Loudness control (volume at -30 dB):
'100
78 dB
97 dB
standard curve +0.2 dB
5 Hz-80 kHz,
+0 dB, -3 dB
20 Hz-20 kHz, +0.5 dB
Hz, +8 dB
Filter :
EQ SUBSONIC 30 Hz, -12 dB/oct
HIGH
8 kHz, -6 dB/oct
Output voltage:
TAPE'DECK 1.2 REC OUT 150mV/1.2 ko
TAPE DECK 1 REC/PLAY output
Somvtaz xo
GENERAL
Power consu+nption:
450W
Powersupply: 110V/120V1220V/240V
50/60 Hz
Dimensions 410 x 139 x 334 mm
(wxHxD):
(16&"x5-1t"x13+")
Weight:
9.7 ks (21.4 lb.)
@Technics
Matsushita Electric
Specifications are subject to change without notice' Printed in Japan