Technics SU-8080

 Features

Tone, Volume  and Balance Controls;

Speaker Selector;

Recording Mode Switch;

Tape-Monitor Selector;

Input Selector;

Main Amp Operationand Input Switch;

Phono Capacitance and Resistance Input Selector;

Mode Mono/Stereo Selector;

EQ Subsonic Filter Switch;

High-Filter and Loudness Switch;

Muting Switch;

Headphone Jack.

A fact which is often lost sight of in these days of proliferating audio products is that the first and foremost purpose of an amplifier is to amplify. To amplify the program source as accurately as possible, neither adding to nor subtracting from the natural beauty of your music. Technics terms this Waveform Fidelity, and it's what we continuously strive to achieve in all our fine components. ln the SU-8080, our audio engineers have gone all out in their ouest for absolute Waveform Fidelity. Major features include our newly-designed Integrated DC Amplifier, totally separate power supplies for each channel, a fantastically quiet equalizer circuit, direct high level input to the DC power amplifier, and dozens of other innovations. Read the following specifications and then listen to this amplifier perform. We're confident that you'll want to hear a whole lot more from the SU-8080.

New Integrated DC Amplifier for Maximum W aveform Fidelity

The power amplifier of the SU-8080 is a newly-designed DC amplifier to ensure the maximum in Waveform Fidelity. lt features a first stage differential amplifier, a purely resistive loaded voltage amplifier, an emitter follower and a two-stage Darlington-connected fully complementary output stage.

For complete low frequency reproduction all the way down to  0 Hz, all coupling capacitors have been totally eliminated from the SU-8080 circuits. No capacitors will be found anywhere in the signal path: in the output stage, between stages, or in the NFB loop. Since capacitors cannot pass DC or any frequencies close to it, their use-and they are used in nearly all other amplifiers-places a distinct limit on lower range frequency response.  Another advantage of the DC circuitry is the orrection of another problem found in conventional amplifiers: phase dislocation of bass frequencies.  Overall, then, the DC amplifier simply performs better and permits much more accurate reproduction of the input signal and therefore better Waveform Fidelity.  And that, we repeat, is the name of the game.

To obtain the best from a DC amplifier, one should avoid using it with a non-DC preamplifier.  That's why the SU-8080 is designed so that high level inputs from Tape, Tuner, Aux etc., can be routed directly to the power amplifier without passing through any other circuits. That's what we mean by an "integrated" DC amplifier. When operated in this fashion, the DC power amplifier has a gain oI 42 dB (above 0.02 Hz). And compared to a conventional amplifier, the SU-8080 delivers aconsiderably lower level of distortion as measured between the high level input terminals and the speaker terminals. When necessary, tone controls and/or filters can be switched in from the front panel, in which case the power amplifier gain is 28 dB. The amplifier produces 72 watts per channel, minimum RMS, into 8 ohm  from 20Hz to 20,000 Hz with a phenomenally low THD of less than 0.02% at full rated power. When power drops down to 36 watts, the maximum level at which it would normally be used in most home applications, THD is an incredibly small 0.0015% (1kHz).

ln the first stage differential amplifier, the SU-8080 employs current mirror loading and Technics' unique dual packaged transistors which are well matched for thermal stability. Current mirror circuit construction means that only the initial stage has any bearing on the amp's DC balance. In order to always keep the DC base potential strictly at zero, a DC bias has been provided for proper operation. Whenever there is a danger of pure DC leaking into the DC amplifier -  an undesirable situation from the standpoint of speaker protection - you  need only switch in the Low Cut Filter. This effectively cuts off  all signals below 2 Hz and sliminates any possibility of problems. In addition, should more than ± 2.5V of direct current appear at the output terminals of the power ampliifer, the speakers are electronically disconnected from the amplifier to prevent speaker damage.

 Super Silent Phono Equalizer: 88dB S/N Ratio

To accompany this superb power amplirfer.Technics audio  engineers were not content to include a conventionapl phono equalizer in the SU-8080, and a major effort was launched to find ways to achieve the same kind of superior performance in the equalizer that the DC amplifier  affords.  Efforts centered on the elimination of noise from the equalizer circuits, the kind of noise that you can hear in a conventionl amplifier by placing the input selector  switch to Phono and turning up the volume. lt was found that  to reduce noise (i . e . Increase the S/N ratio) both circuit noise and transistor internal noise would have to be tackled. Conventional  low noise transistors were found to be lacking, and still produced noise after circuit noise had been reduced.

Thus, a transistor newly developed by Technics was employed. This was the M47L, which is beyond compare in its low noise characteristics. lt is used in the first stage differential amplifier operated with a current mirror load to produce an extremely low noise operating current. The result is an un precedentedly high phono S/N ratio in the SU-8080 of 88dB at a sensitivity of 2.5mV (lHF-A). You will notice the difference with a regular high impedance cartridge, but the difference  is really impressive  when using a low impedance  MM cartridge at high volumes. Other important steps in achieving superb phono equalizer performance include the use of Metalized polyester film capacitors as the coupling capacitors for the input and output stages (to ensure that no distortion is present even in the inaudible range), and the use of precision components throuqhout the equalizer circuity.  Metalized film resistors with a tolerance of only  ±1%, and polypropylene capacitors with a tolerance of ±2%  are used exclusively. This permits the achievement of extremely accurate frequency response throughout the entire audio range.Variation from the standard RIAA curve is no more than ±0.2 dB.

The following graph shows the relationship between input voltage and total harmonic distortion of the SU-8080 phono equalizer amplifier.  Total harmonic distortion remains extremely low even in the low frequency range where the effect of NFB is small. High input levels  up to 280mV can be handled without causing distortion or other quality degradations, so  that even high output cartridges tracking discs of high cutting levels will be accommodated without the slighest problem.

Equalizer Subsonic Filter

A sharp subsonic filter built into the equalizer circuit permits the operator to cut off  all sounds below 30Hz (12dBloct) at the flick of a switch. This eliminates low frequency vibrations picked up by the cartridge from warped records, etc., and prevents these sounds from muddying the low frequency range of  your music. 

Switchable Input Resistance/Capacitance Settings

The impedance of the phono input has a subtle but important effect on the quality of sound produced. ln the SU-8080, the input resistance is switchable between 27kΩ and 47kΩ, while the capacitance may be switched between high and low. This gives a total of four  possible combinations, thus allowing the SU-8080 to accommodate the whole range of cartridges available on the market today. (For low output  MC cartridges a separate pre-preamp or step-up transformer  will be needed.)

Additional  Features of  the SU-8080

Completely Independent Power Supplies for Each Channel.

The test of a quality amplifier is how it responds to music transients, those sharp, loud, sudden sounds that occur so frequently in many kinds of music. A poor amplifier cannoth andle these transients and distorts the music in a very noticeable manner. The cause is insufficient power supply capacity for both channels, and often the transients occurring on one channel will end up distorting the music on the other channel  because too much current is drawn away from the one channel to be used in the other. This is known as transient crosstalk. The most elegant way to eliminate this problem is to utilize separate, independent power supplies for each channel. This is exactly  what  Technisc enqineers have built into the SU-8080. lt utilizes two hefty power transformers and four oversized 10,000 µF electrolytic capacitors along with two separatere rectifier circuits for total separation  of  the two supplies. T his completely, solves the problem of transient crosstalk. In addition, the power supply for the voltage amplifie r stage in both the power amp and the preamp are of the constant voltage type which means that both transient distortion in each channel and self-transiend  distortion are greatly suppressed, producing an amplifie r with excellent  dynamic characteristic. The two transformers are arranged on the chassis in such a way that they largely cancel out each other's leakage flux, thus contributing to the excellent S/N ratio.

New Type Tone Controls

When the selector switch on the front panel of the power amp is switched to the "via tone" position, the tone controls are placed in operation and adjustments to the sound may be made. But the tone controls of the SU-8080 have a unique difference, for when they are in their c enter positions, the tone control circuit components (resistors and capacitors) are removed from the circuit and the frequency response is totally flat.

Dynamic Range Unaffected by Muting Circuit

Audio muting is accomplished by altering the power  amplifier's NFB by 14dB. This differs from the conventional method which is to introduce resistance after  the volume control. The virtue of this new approach is that the dynamic range is not altered, although the noise is decreased in volume. lt also means that the audio muting takes place after the tone ampliifer when the selector  switch is in the via tone position.

Precise, Error-Free Volume  Control

The volume control is a precision-crafted continuously variable device to permit accurate adjustment of playing volume level. The circuit utilizes 1% tolerance metal film resistors in the NFB loop of each channel's ampliifer and maintains gain difference  within 0,5 dB, so that the left-right  balance between the channels does not vary when the volume is adjusted up or down.

Versatile Controls

The SU-8080 has facilities to accommodate two tape decks, and dubbing in either direction is possible. The rec mode and tape monitor switches are independent, so you may play records or listen to the FM tuner while dubbing tape-to-tape. This convenient feature permits great flexibility and allows maximum enjoyment of your equipment.

High Filter

An effective high filter engaged from the front panel eliminates irritating high frequency noises such as record scratches and tape hiss.

Specifications

Power Amplifier Section (IHF)

Continuous Power both Channel Driven [1 kHz];

92 W + 92 W at 4 Ω

74 W + 74 W at 8 Ω

Continuous Power both Channel Driven [20 Hz - 20 kHz];

90 W + 90 W at 4 Ω

72 W + 72 W at 8 Ω

Total Harmonic Distortion:

Rated Power at 1 kHz (8 Ω / 4 Ω) :  0,02% / 0,02%

Rated Power at 20 Hz to 20 kHz (8 Ω / 4 Ω) :  0,02% / 0,05%

Half Power at 1 kHz (8 Ω / 4 Ω) :  0,0015% / 0,0015%

Power Bandwidth( both channel driven at 8 Ω):  5 Hz - 40 kHz  -3 dB

Frequency Response:  20 Hz - 20 kHz  +0 -0,1 dB ;  0 Hz - 100 kHz  +0 -3 dB

Signal-to-Noise Ratio (IHF, A):  115 dB

Residual Hum & Noise:  100 µV

Damping Factor:  70 (8 Ω);  35 (4 Ω)

Input Sensitivity/Impedance:  1 V/50 k Ω

Load Impedance:

Main or Remote :  4 -16 Ω

Main + remote :  8 - 16 Ω

Preamplifier Section

Input Sensitivity/Impedance:

Phono 1 and 2 :  2,5 mV/47 k, 27 k Ω

Tuner, Aux :  200 mV/35 k Ω

Deck Pb, Rec :  200 mV/35 k Ω

Phono Maximum Input Voltage:  280 mV

Total Harmonic Distortion:  0,1%

Signal-to-Noise ratio (IHF, A):

Phono 1 and 2 :  88 dB

Tuner, Aux :  100 dB (via tone);  106 dB (direct)

Frequency Response:

Phono 1 and 2 :  RIAA standard curve ±0,2 dB

Tuner, Aux :  20 Hz - 20 kHz  +0-0,1 dB

Tone Controls:

Bass :  50 Hz, -7,5 dB - +7,5 dB

Treble :  20 kHz, -7,5 dB - +7,5 dB

Equalizer Subsonic Filter:  30 Hz  -12 dB/oct

High Filter :  10 kHz  -6 dB/oct

Loudness Control (volume at -30 dB):  100 Hz  +8 dB

Muting:  -14 dB

Output Voltage:

Pre Out :  1 V (rated);  9 V (max.)

Rec Out : 200 mV

Rec/Play :  30 mV

Amplifier Section

1 kHz Continuous Power  (both channel driven):

2 x 92 W at 4 Ω

2 x 74 W at 8 Ω

40 Hz - 16 kHz Continuous Power (both channel driven):

2 x 90 W at 4 Ω

2 x 72 W at 8 Ω

Total Harmonic Distortion:

Rated Power at 1 kHz, (8 Ω / 4 Ω) :  0,02% / 0,02%

Rated Power at 40 Hz - 16 kHz (8 Ω / 4 Ω) :  0,02% / 0,05%

-28 dB rated Power at 1 kHz (4 Ω) :  0,08%

50 mW Power at 1 kHz (4 Ω) :  0,15%

Frequency Response:  20 Hz - 20 kHz  +0 -0,1 dB

Signal-to-Noise Rated Power:

Phono 1 and 2 :  70 dB

Tuner, Aux :  92 dB

-26 dB Rated Power:

Phono 1 and 2 :  65 dB

Tuner, Aux :  67 dB

50 mW Power:

Phono 1 and 2 :  60 dB

Tuner, Aux :  62 dB

Channel Balance : ±1,0 dB

Headphones Level/Output Impedance:  550 mV/330 Ω

General

Power Supply:  110 V, 120 V, 220 V, 240 V,  50/60 Hz

Power Consumption: 490 W

Dimensions (W x H x D):  450 x 140 x 371 mm (17-23/32" x 5-1/2" x 14-19/32")

Weight:  14 kg (30,9 lbs)