With this amplifier,
you can obtain the best of both worlds. Technics' "New Class A"
amplifier circuit combines class A output with stable load condition on all
stages. Also, the undistorted sound quality of class-A and the efficient. High
output power of class-B are available within a single amplifier. You don't have
to trade efficiency and price for sound quality, or switching distortion for
high output. The SU-V6's facts and figures support these claims: 70 watts per
channel, both channels driven into 8 ohms, from 20 Hz to2O kHz with no more
than 0,007%total harmonic distortion. The most important fact, though, is that
this integrated amplifier's faithfully reproduced sound exhibits the effortless
smoothness of true class-A amplification And yet all this is available at a
fraction of a conventional class-A amplifier's cost.
New Glass A and
Straight DC Provide Both Quality and Quantity
Quality of
reproduced sound and quantity of output power are the two general aims we were
striving to develop in the advanced circuitry incorporated in the SU-V6. To
test the success of our circuit designs, we have employed a new method of
analysis called 3DA (first used in the development of the SU-8099 integrated
amp), which stands for "3-Dimensional Analysis." With the aid of a
computer, this system enables us to test performance at 4,000 points and
express the results in 3-dimensional graphic form. From our extensive research
using 3DA, we have found that performance requirements within the audio
spectrum are best satisfied by building amplifiers that exhibit good
performance characteristics from 0 Hz (DC) at the bottom of the frequency range,
all the way up to nearly 100 kHz in the ultra-high range ( it's undesirable to
go much higher than this point, given currently available circuit components).
To achieve performance within these considerations, we have used a number of
advanced circuit configurations, the two most important of which are "New
Class A" and "Straight DC."
New Class A with
Synchro Bias for Better High Frequency Response
Transistor
switching is a major cause of high frequency distortion in class B and class AB
amplifier designs. ln class B designs, two output transistors are used for each
channel. The "upper" transistor handles the positive half of the waveform and the
"lower" transistor handles the negative half. But problems occur when
the signal crosses the zero point; one transistor turns off and the other turns
on. During this crossover, "switching distortion" is generated. This takes the form of brief
pulses with very sharp peaks, which produce high-order harmonic distortion. NFB
(negative feedback) does not cope
with switching distortion effectively, despite its use fulness in combating
ordinary forms of distortion. This switching distortion can also result in
intermodulation distortion which muddies reproduced sound to a greater degree than might be expected from a simple
examination of an oscilloscope trace. In class A, the same transistor handles
the entire waveform, but a large idling current is required to operate the
transistor even when there is no audio input signal. Although this prevents any
form of switching distortion, it also results in very low efficiency. Large
heat sinks must be provided to dissipate the substantial amount of excess heat
that is created. Price is corresponding high In our New Class A circuitry, the
output transistor bias current is synchronized with the positive and negatives
wings of the input signal so that the output transistors are always in an
active state. With this remarkable circuitry, switching distortion is
eliminated since the transistors are never allowed to switch off. Because of
this synchronized operation, e call his
"synchro bias." Besides
preventing switching distortion in the output waveform, it also
presents linear load conditions to the voltage amplification stage. Pre-driver load fluctuation is also minimized. The
result is the virtual elimination of "crossover distortion."
"Straight
DC" Configuration for Direct
Coupling Between DC Power Amp Section and High Level Input Signals
The SU-V6's design
takes full advantage of the excellent low-range frequency response, phase
linearity, and low distortion inherent in our refined DC power amp design. By
increasing the gain of the power amp section, we have made it possible to
directly couple high level inputs, such as tuner, tape, and AUX sources, to the
power amp input. The resulting improvement in low range fidelity is a good
example of what can be achieved with an innovative, yet uncomplicated, approach
to integrated amp design. In fact, you could view this configuration as simply
a phono equalizer and a DC power amp.
While
this characterizes the "simple is best" philosophy. Some additional
innovations were necessary to obtain the desired performance goals. First of
all, a high-gain amp is required to raise typical "high level" inputs
of 150 mV- 200 mV to output levels of 70 W-100 W. Furthermore, any tendency
toward temperature dependent DC drift
must be avoided since the amp's gain extends
all the way down to DC in the low range. To obtain high gain, Technics'
SU-V6 amp employs a linear cascode, 3-stage Darlington configuration which
provides excellent open-loop performance. As a result, only 45 dB NFB is required to achieve the 0.007% THD
rating at 70 W output. To combat DC drift, 1-chip dual FET's are used for the
first stage differential amplifier. Since this prevents mutual temperature differences, DC drift is
reduced to a mere ± 10 mV from -10°C to +50°C.
Concentrated Power
Block (CPB) Prevents Distortion from Electromagnetic Induction
With the strikingly
clean high range response obtained from our New Class A synchro bias circuitry,
we made sure that nothing would interfere with proper performance under
practical signal handling conditions. Our concentrated power block was
developed to prevent electromagnetic induction between those portions of the
circuitry which handle large amounts of current and those which handle smaller
signals. The power supply and output stage were concentrated in one integrated
unit to create the shortest possible connections. With the addition of low
impedance laminated bus lines, the power supply loop was minimized. Another
advantage of CPB is that it virtually eliminates significant differences in performance between individual
units. Consequently you can expect a maximum 0,007% THD for anv individual
SU-V6 amp.
ICL Phono EQ Circuit
Employing Ultra-Low Noise FETs Permits Direct MC Cartridge Connection
The first stage of
the phono equalizer is a differential amplifier with ultra-low noise dual FETs.
As a result, no input capacitors are necessary. A mere increase in equalizer
gain, rather than an additional pre-preamp or step-up transformer, is all that
is needed for MC cartridge compatibility. When the amp is in the straight DC
mode, the only capacitor in the entire amp circuit, whether the input is MC or
MM, is the EQ output capacitor.
Heavy Duty Power
Supplies
In an audio
amplifier the, power supply must be able to meet the changes in impedance
presented by the speaker systems Depending on the frequency this figure
can range from below 4 ohms up to as
high as 30 ohms for a speaker system rated at 8 ohms. In the SU-V6 independent
rectifier and ripple filter circuits
are provided for the left and right channels to assure truly stable DC
power. Furthermore the power transformer coils float in a special resin within shielded cases to prevent power supply
hum.
Independent
Recording Selector with 2-Way Dubbing
With this versatile
arrangement you can record from one
source while listening to another since the input and recording selectors are
separate. Tape inputs are positioned on both the input selector and the
recording selector so that you can record while listening to another source
(such as a disc) if you wish.
Remote Action
Switches Eliminate Excess Wiring
Remote action
switches are employed on the input selector, recording selector, and phono
selector. Therefore, switching takes place at the ideal location within the
circuitry. This contributes to sound quality by minimizing the chances of
signal degradation due to extensive wiring.
Specifications
Continuous Power
Output
20 Hz - 20 kHz (both
channels driven)
80 W x 2 at 4 Ω
70 W x 2 at 8 Ω
40 Hz - 16 kHz (both
channels driven)
80 W x 2 at 4 Ω
70 W x 2 at 8 Ω
1 kHz ( both
channels driven}
90 W x 2 at 4 Ω
74 W x 2 at 8 Ω
Total Harmonic
Distortion Rated Power
At 20 Hz to 20 kHz
0,02% at 4 Ω
0,007% at 8 Ω
At 40 Hz to 16 kHz
0,02% at 4 Ω
0,007% at 8 Ω
At 1 kHz
0,01% at 4 Ω
0,007% at 8 Ω
Total Harmonic
Distortion Half Power
At 20 Hz to 20 kHz : 0,007% at 8 Ω
At 1 kHz 0,003% at 8 Ω
-26 dB power at 1 kHz : 0,05%
at 4 Ω
50 mW power at 1 kHz : 0,08%
at 4 Ω
Intermodulation
Distortion Rated Power
At 250 Hz : 8 kHz = 4 : 1, 4 Ω : 0,02%
At 60 Hz : 7 kHz = 4 : 1 SMPTE, 8 Ω :
0,007%
Poer Bandwidth both
channels driven, - 3 dB
T.H.D. 0,03%, 5 Hz - 60 kHz (4 Ω )
T.H.D. 0,02% , 5 Hz - 60 kHz (8 Ω )
Residual Huma and
Noise (Straight DC): 0,3 mV
Damping Factor : 30 (4 Ω ); 60 (8 Ω )
Headphones Output Level/Impedance:
560 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/47 k Ω
Tuner, Aux : 150 mV/36 k Ω
Tape 1, Rec/Play : 170 mV/39 Ω
Tape 2 : 150 mV/36 k Ω
Phono max. Input
Voltage at 1khz (rms, T.H.D. 0,01%)
Mm : 150 mV
MC : 10 mV
Signal-to-Noise Ratio (Rated Power 4 Ω )
Phono MM : 78 dB (86 dB, IHF A)
Phono MC : 68 dB (68 dB, IHF A, 250 µV input)
Tuner, Aux : 92 dB (106 dB, IHF A)
Signal-to-Noise Ratio (-26 dB Power 4 Ω )
Phono MM : 67 dB
Phono MC : 65 dB
Tuner, Aux : 68 dB
Signal-to-Noise Ratio (50 mW power 4 Ω )
Phono MM : 64 dB
Phono MC : 62 dB
Tuner, Aux : 65 dB
Frequency Response
Phono : RIAA
standard curve ±0,5 dB (30 Hz - 15 kHz)
Tuner, Aux, Tape
(Straight DC) : DC ~150 kHz (-3 dB) +0, -3 dB (20 Hz - 20 kHz)
Tone Controls
Bass : 50 Hz ±10 dB
Treble : 20 kHz ±10 dB
High-Cut Filter
: 7 kHz -6 dB/oct
Subsonic Filter
: 20 Hz -12 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 : ±1,0 dB
Channel Separation:
AUX, 1 kHz : 55 dB
General
Power
Requirements: AC 110/120/220/240 V 50/60
Hz
Power
Consumption: 760 W
Dimensions (W x H x
D): 430 x 153 x 351 mm (16-15/16" x
6-⅓2" x 13-13/16")
Weight: 12,5 kg (27,6 lbs)
