The main function of
an amplifier is to amplify the input signal without adding to or subtracting
anything from the waveforms of the original music. In other often-heard words,
the ideal amplifier should be a straight piece of wire that provides gain without
phase shifts, transient and other types of distortion over a wide frequency
range. Technics sums all this up and calls it "waveform fidelity" and
the SU-8055K is a good example of what we have done to make this kind of
fidelity a reality. A glance at the specifications will show that what we say
is not an idle boast. But we don't want you to just look. Listen to the
SU-8055K and we're confident that you'll hear the qualities we're talking
about.
DC Power Amplifier
Helps Preserve Waveform Fidelity
Waveform fidelity
has been greatly enhanced in Technics SU-8055K by the elimination of coupling
capacitors not only in the signal path but also in the NFB loop. The lack of
something is often a defect. But here, the absence of coupling capacitors means
gain all the way down to 0 Hz and phase linearity in the bass frequencies. The
result, in this DC power amplifier, is waveform fidelity - the accurate
reproduction of musical waveforms.
Big Power and
Matching High Fidelity
This amp offers
plenty of power even if your special interest is thundering popular music with
a lot of bass. It delivers 47 W at 8 Ω, from 20 Hz to 20 kHz with no more than
0,02% Total Harmonic Distortion. Reasons for this high fidelity are manu. A
single-packed, low-noise dual transistor is used in the differential amplifier
first stage for low noise and precise thermal tracking. Current mirror loading
provides high open loop gain without increasing the level of noise. This stage
gets help from the emitter-follower, in driving the Class A voltage
amplification stage. The end result is minimal distortion in the high frequency
range. In addition,, a 2-stage Darlington connection is used in the power
stage, comprising a pure complementary circuit that provides high damping
factor and low distrtion.
Super Quiet Phono
Equalizer
The SU-8055K has an
unbelievably high Signal-to-Noise ratio of 85 dB (at 2,5 mV sens. IHF A) when
using an MM type cartridge, something rerely found in this amplifier's price
class. There is a 3-stage, direct-coupling MM phono equalizer section, with direct
coupling of the PNP-NPN transistors, plus a PNP transistor in the emitter
follower. Low-output MC cartridges, which are growing in popularity, can also
be used without adding an extra pre-preamp (another rarity in a moderate price
amp). For the MC input, S/N ratio is 66 dB (at 170 µV sens. IHF A). A few of
the reasons for low distortion and high gain are the separation of DC and AC in
the negative feedback loop of the equalizer, 100% DC feedback, and the use of
narrow tolerance components for negative feedback.
Treble and Bass
Controls
An advaanced
operatonal IC is used for negative-feedback-type tone controls. Bass and treble
can be easily boosted or attenuated to suit individual tastes without introducing distortion
Accurate Peak Power
Indicators
These easy-to-read
FL meters are used instead of conventional power output meters. They feature
superior accuracy and near-instantaneous response time, and can be switched
between two ranges: 0,1 W- 100 W when you are metering for full peak power:
0,01W - 10 W when metering in the more usual listening range. Brightness of the
meters is switchable between bright and dim.
Versatile Recording
Selector
The SU-8055K has two
tape positions on the input selector as well as on the recording selector in a
logical and practical layout. With this complete separation, you can do such
things as dub from tape to tape while listening to your favorite disc. Or tape
from your tuner while listening to music on another tape.
Rugged Stable Power
Supply
The power supply is
designed to handle the sudden current demands of high energy musical transient
without losing sound clarity or introducing transient crosstalk. This is done
by using two large-capacity 8,200 µF electrolytic capacitors in the bridged full-wave
rectifier circuit and by employing a recently-developed transformer. It also
supplies regulated voltage to the phono equalizer circcuit. The transformer
coils are floated in a special resin to absorb unwanted vibrations. Even at
soft volume levels you can enjoy your favorite music without being bothered by
a noisy transformer.
Other Features
Muting circuit
eliminates shock noise when the power is turned on and off, providing added
speaker protection.
High filter to cut
out high frequency noise such as record scratches and tape hiss. Subsonic
filter reduces low-frequency noise.
Loudness switch for
use when listening at low volume levels. Lows and highs are boosted to make up
for "deficiencies" in the way the human ear responds at low volume
levels.
Front-panel speaker
selector lets you select either of two speaker systems (AorB) both or at once
(A + B).
Specifications
Specifications
Amplifier Section
(IHF)
Continuous Power
both Channel Driven
From 20 Hz - 20 kHz
2 x 48 W at 4 Ω
2 x 47 W at 8 Ω
From 40 Hz - 16 kHz
2 x 48 W at 4 Ω
2 x 47 W at 8 Ω
At 1 kHz
2 x 56 W at 4 Ω
2 x 50 W at 8 Ω
Total Harmonic
Distortion:
Rated Power (20 Hz
to 20 kHz)
0,03% at 4 Ω
0,02% at 8 Ω
Rated Power (40 Hz -
16 kHz)
0,03% at 4 Ω
0,02% at 8 Ω
Rated Power (1 kHz)
0,03% at 4 Ω
0,02% at 8 Ω
Half Power (1 kHz)
: 0,008% (8 Ω)
Half Power (20 Hz -
20 kHz) : 0,01% (8 Ω)
-26 dB Power (at 1
kHz) : 0,15% (4 Ω)
50 mW Power (at 1
kHz) : 0,2% (4 Ω)
Intermodulation
Distortion:
Rated Power (250 Hz
: 8 kHz = 4 : 1 ) : 0,03%
Rated Power (60
Hz : 7 kHz = 4 : 1 SMPTE 8 Ω) : 0,02%
Power Bandwidth(
both channel driven -3 dB):
At 4 Ω : 5 Hz - 30 kHz
At 8 Ω : 5 Hz - 50 kHz
Residual Hum and
Noise: 0,8 mV (0,8 mV, IHF A)
Damping Factor: 18 (4 Ω);
36 (8 Ω)
Headphones Output
Level/Impedance: 440 mV/330 Ω
Load Impedance
Main or Remote: 4 Ω - 16 Ω
Main and
Remote: 8 Ω - 16 Ω
Input
Sensitivity/Impedance
Phono MM : 2,5 mV/47 k Ω
Phono MC : 170 µV/100 Ω
Tuner, Aux : 150 mV/47 k Ω
Tape 1, Rec/Play
: 180 mV/33 k Ω
Tape 2 : 150 mV/33 k Ω
Phono Max.input
Voltage (1 kHz RMS):
MM : 150 mV
MC : 6,5 MV
Signal-to-Noise
Ratio
Rated Power (4 Ω)
Phono MM: 73 dB (85 dB IHF A)
Phono MC : 60 dB (66 dB, IHF A)
Tuner, Aux, Tape
: 86 dB (97 dB, IHF A)
-26 dB Power (4 Ω)
Phono MM : 62 dB
Phono MC : 58 dB
Tuner, Aux, Tape
: 63 dB
50 mW Power (4 Ω)
Phono MM : 58 dB
Phono MC : 56 dB
Tuner. Aux, tape
: 60 dB
Frequency Response;
Phono : 30 Hz - 15 kHz (RIAA standard curve ±0,5 dB)
Tuner, Aux, Tape
: 10 Hz - 60 kHz (-1 dB) ±0,5 dB (20 Hz
- 20 kHz)
Tone Controls
Bass : 50 Hz +10 dB /-10 dB
Treble ; 20 kHz +10 dB / -10 dB
High Filter: 7 kHz, -6 dB/oct
Subsonic
Filter: 30 Hz, -6 dB/oct
Loudness Control
(Volume at -30 dB): 50 Hz , +9 dB
Output
Voltage/Impedance
Rec Out : 150 mV
Rec /Play : 30 mV/82 k Ω
Channel Balance
Aux (250 Hz - 6300
Hz) ±1 dB
Channel Separation
Aux (1 kHz) 60 dB
General
Power Consumption:
500 W
Power Supply: AC 110/120/220/240 V 50/60 Hz
Dimensions (W x H x
D): 430 x 142 x 255 mm 916-15/16" x
5-19/32" x 10-1/32")
Weight: 7,7 kg (17,0 lb)
