What is stereo?

There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.

H.H. Scott '59

Audio Analogue Puccini amplifier

 Stereo Integrated Amplifier
Power Output (both channels driven, 8 Ω):  2 x 40 W
Input Sensitivity/Impedance (RMS):
Phono MM :  10 mV /47 k Ω
Phono MC :  1 mV / 100 Ω
Line :  1 V / 50 k Ω
Signal-to-Noise Ratio
Phono MM :  better than 70 dB
Phono MC :  better than 60 dB
Line :  better than 80 dB
Phono MM :  better than 80 dB
Phono MC :  better than 70 dB
Line :  better than 90 dB
Tape Output Level/Impedance (RMS):  1 V / 600 Ω
Total Harmonic Distortion:  less than 0,196 % (at 40 W, 8 Ω, 1 kHz)
Damping Factor:  better than 100 (at 1 kHz, 8 Ω, 1 W)
Slew Rate:  better than 10/µsec
Bandwidth:  20 Hz - 20 kHz (±0,1 dB);  5 Hz - 20 kHz (+3 dB)
Channel Separation (at 1 kHz, unused input shorted):  better than 80 dB
Inputs:  Phono MM/MC, Tuner, CD, Video, Aux, Tape
Nominal Voltage Supply:  115 V AC, 230 V AC; 50/60 Hz
Max. Power Consumption:  170 VA
Dimensions (W x H x D):  445 x 85 x 365 mm (17,52" x 3,35" x 14,4")
Weight:  7 kg (15,5 lbs)

Harman/Kardon HK 725 pre-amplifier

Harman Kardon introduces low negatiwe feedback design for inaudible TIM distortion
For the last few years,, audio manufacturers have been rushing to bring you newer,lower T.H.D. levels in their amplifier sections. And every year, they've accomplished this the simplest way they could. By adding negative feedback, a form of electronic compensation. Unfortunately, this "cure" for T.H.D. - typically 60 - 80 dB of negative feedback - creates another form of distortion. Transient Intermodulation Distortion, or TIM, which does far more to degrade the music than T.H.D. at Harman Kardon, we lowered T.H.D. the right way. With unique circuit design (US Patent #4.176.323) that lets us use just a fracrtion of the negative feedback typically used. The result is our new HK 700 series High Technology Separates. Built around our low negative feedback amp/preamp combination that delivers a crystal clear, totally transparent 65 watts per channel. You can also choose from a full-featured digital tuner, a phase locked analog tuner, and the most advanced cassette deck on the market.

The HK 725 High Technology pre-amplifier
Many of the critics from the most widely recognized audiophile publications consider the HK 725 one of the best preamplifiers on the market
As with all our components, the KH 725 was designed with careful attention to even the finest details. Instead of the typical 4-stage phono section, we used 8 stages. And we used FET front ends on both our low and high level stages. These provide higher Signal-to-Noise ratio than other designs. Instead of conventional rotary tone controls, we used fixed resistor push-buttons because they provide lower distortion. The HK 725 also allows you to defeat the tone controls altogether, giving you the clearest, cleanest sound possible.
Even our volume controls is unique. With twelve wipers instead of the usual four. This extra bit of engineering not only provides a smoother acting, longer lasting control, but also helps lower distortion as well. And we didn't forget convenience. You get facilities for two tape decks, with 2 way tape copy that allows you to monitor any source you like while copying from one deck to another. Plus loudness, subsonic and high cut filters to help you contour your system to your listening environment.
The Harman kardon HK 725 stereo preamplifier is housed in a relatively small metal cabinet that matches its associated model HK 770 power amplifier. Individually, or in conjunction with the power amplifier, the sound quality is best described as "exceptionally clean" particularly with respect to the deep bass. An unusual feature is switch-selected bass and treble equalization, rather than rotary controls. The bass and treble have eight switches each, four providing boost in steps of 2 dB at 50 Hz and 10 kHz; four providing attenuation in 2 dB steps at the same frequencies. An illuminated switch in the center of each row of buttons provides a tone control defeat. Subsonic and high cut filters round out the equalization. Switching is provided for automatic tape duplication from, or to, either of two recorders. A panel-mounted headphone jack allows the signal to be monitored without going through the associated power amplifier. One unswitched and two switched AC convenience outlets are provided.
Frequency Response : less than 1 Hz to beyond 150 kHz   +0 -1 dB
Total Harmonic Distortion: 
Phono :  0,009%
High Level :  0,005%
Intermodulation Distortion:  0,009% at 2 volts output
RIAA Equalization:  ±2 dB (20 -20,000 Hz)
Signal-to-Noise Ratio:
Phono :  90 dB IHF-A
High Level :  106 dB IHF-A
Phono Overload:  250 mV at 1 kHz
Input Sensitivity/Impedance:
Phono :  2,3 mV/47 k Ω
High Level :  145 mV/23 k Ω
Slew Rate:  Greater than 200 volts/µsec to output with IHF standard
Tone Control Range
Low :  ±8 dB at 50 Hz
High :  ±8 dB at 10 kHz
Dimensions (W x H x D):  385 x 72 x 320 mm (15,2 x 2,9 x 12,6 inches)
Weight:  4,2 kg (9,25 pounds)

Harman/Kardon HK 770 power-amplifier

The HK 770 is certainly one of the most sophisticated stereo power amps you can buy. With 65 watts per channel, and plenty of extra headroom, the  HK 770 can easily handle the most demanding of transients.
Unlike most conventional amplifiers, negative feedback levels in the HK 770 are kept below 20 dB, reducing TIM distortion to inaudible levels. Also unlike conventional power amps, the brawn behind the Kh 770 comes from a pair of independent power supplies. We use two discrete rectifier circuits. Two sets of electrolytic capacitors. And two massive toroidal transformers, which eliminate the stray magnetic fields that cause hum.
Our twin power supply design provides you with two distinct benefits.
First, it eliminates the possibility of channel-to-channel interference. It also prevents one channel from draining the power available to the other. Each power supply is further divided into high and low level stages. This ensures that the power requirements of the high level stages do not drain current at the expense of the low level stages
Unlike most power amps, the HK 770 gives you, accommodations for two pairs of speakers with independent speaker switching. Plus a power display that allows you to monitor performance. And for more accuraate power readings at low listening levels, display aensitivity can be increased by a factor of 10. The HK 770 packs a lot of power and lot of technology into a surprisingly compact amplifier.
The Harman Kardon HK770 Stereo Power Amplifier is FTC rated for 8 ohms at 65 watts RMS per channel, 20 Hz to 20 kHz, at less than 0,03% Total Harmonic Distortion. Test results were considerably better than even the low claimed distortion, resulting in some of the lowest distortion figures ever attained from a power amplifier. The sound quality reflects the low distortion, being exceptionally clean, particularly in the deep bass. Special construction techniques result in an unusually small cabinet for an amplifier of this power rating. The front panel has left and right LED dual range output power indicators calibrated 0,05-100 watts and 0,005-10 watts into 8 ohms.
The LED power output indications were essentially precise, with a virtually flat 20 Hz to 20 kHz Frequency Response. An output power hold-off prevents power supply turn-on transients from being fed to the speakers. One unswitched AC convenience outlet is provided.
Power Output:  65 watts (RMS per channel into 8 Ω, both channels driven simultaneously from 20 Hz to 20 kHz with less than 0,03% T.H.D.)
Power Bandwidth:  less than 8 Hz to 100 kHz at 32,5 watts per channel with less than 0,03% T.H.D.
Total Harmonic Distortion:  0,006% at rated output
Intermodulation Distortion:  less than 0,01% at rated output, both channels driven at different operating frequencies
Frequency Response:  below 1 Hz to 250 kHz +0, -3 dB
Damping Factor:  greater than 50
Slew Rate:  150 V/µsec into 8 Ω at rated power output, both channels driven
Square Wave Rise Time (20 kHz):  1,5 µsec into 8 Ω at rated power output, both channels driven
Square Wave Tilt:  less than 2% at 20 Hz
Total TIM Distortion:  less than 0,007% at rated output
Total Interface I.M. Distortion:  less than 0,007%
Power Supply Crosstalk:  greater than 100 dB (20 Hz to 20 kHz) unused channel sherted input
Amplifier Configuration:  Twin toroidal transformers with positive and negative supplies plus high and low voltage supplies for output and driver stages
Signal-to-Noise Ratio:  123 dB (IHF-A)
Input Impedance:  35 k Ω
Sensitivity:  1,2 V for rated output
Dimensions (W x H x D):  385 x 72 x 320 mm (15,2" x 2,9" x 12,6")
Weight:  10,1 kg (22,2 lbs)

Harman/Kardon HK 715 tuner

High Technology Digital Tuner
The HK 715 represents the state-of-the-art. In tuners today. Digital quartz-locked tuning is by far the most accurate tuning system available. Because the digital control system automatically locks in to the dead center of the broadcasst frequency every time. There's no guessing, no fine tuning.
The HK 715 also lets you store up to 8 of your favorite stations either AM or FM in memory. Once a station has been stored, you simply touch the appropriate preset memory buttonto recall it at any time.. Without the need to scan in either direction.
The HL 715 also shares many of the same features that make our KH 710 such an outstanding tuner. Like a precise balance between sensitivity and selectivity. And an MPX null circuit, which canceles the 19 kHz subcarrier signal with less distortion than filters.

Usable Sensitivity:  1,7 µV (IHF)
50 dB Quieting [mono/stereo]:  3,0 µV / 34 µV
Signal-to-Noise Ratio:
Mono :  -79 dB
Stereo :  -77 dB
Total Harmonic Distortion:
Mono :  0,07%
Stereo :  0,09%
Capture Ratio:  1,0 dB
Alternate Channel Selectivity:  70 dB
Image Rejection:  80 dB
IF Rejection:  105 dB
Spurious Response Rejection:  105 dB
AM Rejection:  65 dB
Stero Separation:  50 dB aat 1 kHz
Output level/Impedance:  780 mV/2 k Ω
AM Usable Sensitivity:  200 µV/m
AM Signal-to-Noise Ratio:  -60 dB
Am Selectivity:  40 dB
AM Alternate Channel Selectivity:  37 dB
AM Image Rejection:  50 dB
AM IF Rejection:  45 dB
Dimensions (W x H x D):  385 x 72 x 320 mm (15,2" x 2,9" x 12.6")
Weight:  4,2 kg (9,25 lbs)

Harman/Kardon HK 705 cassette deck

The Harman/Kardon HK 705 is the first available cassette recorder that incorporates the new Dolby HX "Headroom-Extension" system. The HX process extends the high-frequency overload capability of a Dolby-B equipped cassette deck during reocrding by reducing both the record bias and equalization at those moments  when strong treble content  in present in the music. By lowering the bias, the high-frequency capacity of the tape is enhanced; though this is at the cost of some increase in low-frequency distortion, this distortion is less than would be generated by treble overload - saturation.

HX- processed tapes are playback-compatible with all Dolby-B recorders, and the claimed benefits in high-frequency headroom are roughly equivalent to those porvided by the new metal-tape formulations.
The HK705 is a slim, front-loading deck that uses a single Sendust record/playback head and a capstan driven by a DC servo-motor. A second motor is used to pull the cassette inside the deck after it is laid onto a tray that pops out from the of the unit when the eject button is pressed. When the cassette is locked into place, an angled miror permits viewing the amount of tape remaining on a side through a window in the entry slot. Access for routine cleaning is provided by a removable tab on the top of the deck.
Control of the tape motion is provided through a series of mechanically interlocked piano-key levers.  A Record Mute button is provided for inserting a quiet space between selections, and a Tape End  light begins to blink when approximately three-digit  counter contains a "memory rewind" feature that works with the zero setting,permitting quick return to a selected spot on the tape.
Twelve peak-reading  LEDs per channel form the vertically oriented level indicators, which are calibrated from -20 to +8 dB with the 0 dB point marked as Dolby level (200 nWb/m). A vertical row of pushbuttons adjacent to the LED indicators provides bias and equalization switching for four tape types; Metal, cr02 Ferrichrome and Ferric. Additional front-panel pushbuttons are provided to insert a  subsonic (below 20 Hz) filter and to activate either the regular Dolby noise reduction system or its HX version. These latter two buttons are illuminated.

The large record-level control uses concentric knobs to permit independent adjustment of the left and right channels. An output-level control, which affects both channels equally, also varies the level at the headphone jack, one that is designed to accept headphones with 8 Ω (or higher) impedance (660 Ω) mikes. The rear panel of the HK 705 has phono-jack input and output connectors, an FM-multiplex switch, and a ground post.

Sansui SC-1330 cassette deck

Stereo Cassette Deck
A metal tape compatable Dolby  cassette deck with direct cassette loading and record level indicator with an almost instantaneous peak rise and moderate decay. An unusual feature is automatic wind past the leader at the touch of a button. A record mute disables the input  signal while the tape drives, allowing removal of unwanted sounds while recording.
The fluorescent bargraph record level meter is referenced to0db , representing the signal peaks, rether than the more common 0 VU, though 0 VU is also indicated on the indicator scale. There are selectors for Normal, CrO₂, FeCr and Metal tape bias and equalization. Other features include; end of tape stop/disengage, optional timer controlled start or record, reset counter, and record mute.

Concentric-clutched L & R record level
Ganged L & R output level
Line, Microphones / line, Headphones
Track:  4-track; 2-channel stereo
Tape Speed:  4,8 cm/s (1=7/8 ips)
Heads:  record/Playback; FH Head Erase; Double Gap Ferrite Head
Motor:  Electronically Controlled DC Motor
Wow and Flutter:  within 0,05% WRMS
Fast Wind Time:  approx. 75 sec. C-60
Frequency Response (Rec/Pb)
Normal Tape (-20 VU) :  20 to 18,000 Hz (20 to 15,000 Hz ±3 dB)
Metal Tape (-20 VU) :  20 to 18,000 Hz (20 to 16,000 Hz ±3 dB)
Metal (0 VU) :  20 to 13,000 Hz ±3 dB
Signal-to-Noise Ratio:
Metal Tape (without Dolby NR) :  better than 59 bd (weighted)
Metal Tape (with Dolby NR) :  better than 69 dB (above 5 kHz)
Erasure Factor
MetalTape :  more than 70 dB at 1,000 Hz
Input Sensitivty/Impedance (0 VU, 1 kHz)
Mic :  0,3 mV/200 Ω - 5 k Ω
Line Rec :  70 mV/100 k Ω
Output Level (0 VU, 1 kHz)
Line Out (play) :  390 mV
Phones :  65 mV/8 Ω
Bias Frequency:  85 kHz
Power Requirement
Voltage :  100, 120, 220, 240 V 50/60 Hz
Consumption :  12 W rated
Dimensions (W x H x D):  430 x  160 x 320 mm  (16-15/16" x 6-5/16" x 12-5/8")
Weight:  6,85 kg (15,1 lbs)

Marantz PM-200 amplifier

PM-200 Stereo Console Amplifier

Power Output DIN, 4 Ω per channel:  35 W
Power Output FTC American Standards, 4 Ω per channel:  26 W
Total Harmonic Distortion (at rated Power Ouput):  0,6%
IM Distortion (at rated Power Output)0,6%
Power Output DIN, 48Ω per channel:  30 W
Power Output FTC American Standards, 8 Ω per channel:  20 W
Total Harmonic Distortion (at rated Power Ouput):  0,3%
IM Distortion (at rated Power Output):  0,3%
Power Bandwidth:  20 Hz - 50 kHz
Damping Factor:   8 Ω:  70
Frequency Response
Phono :  ±1,0 dB RIAA
Aux :  20 Hz - 50 kHz ±01 dB
Input Terminals
Sensitivity:  2,8 mV
Capacitance :  250 pF
Impedance :  47 k Ω
Overload Margin :  35 dB
Sensitivity:  150 mV
Impedance :  25 k Ω
Phono Equivalent Input Noise:  0,5 µV
Phono Dynamic  Range (Ratio of input overload to equivalent input noise):  109 dB
Channel Balance (0 to -40 dB / 40 Hz - 16 kHz)
Phono :  3 dB
Aux :  3 dB
Interchannel Crostalk
Phono  (1 khz):  47 dB
Aux (1 kHz):  62 dB
Intersource Crosstalk (Worst Point) :  55 dB
Output Voltage/Impedance, 1 kHz :
Tape Out :  415 mV/ 220 Ω
Power Requirements:  220 V AC , 50 Hz
Power Consumption (at Rated Output, both Channels Driven):  110 W ±20 W
Idling Power:  16 W ±5 W
Dimensions (W x H x D):  416 x 146 x 243 mm (16-3/8" x 5-3/4" x 9-9/16")
Weight:  6 kg (13,2 lbs)

Marantz PM-300 amplifier

The Marantz PM-300 is a stereo amplifier that is FTC rated for 4 ohms at 37 watts per channel, 20 Hz to 20 kHz, at no more than 0,08% Total Harmonic Distortion. At the usual speaker impedance of 8 ohms the rated FTC output power was 30 watts per channel. Overall, this is a nice, moderate cost unit suitable for smaller installations. The output power meters, though having essentially a flat frequency response, had acceptably accurate readings only when the output power was 6 watts 8 ohms, or higher. The meters are calibrated from 0 to 60 watts into 8 ohms and from 0 to 120 watts into 4 ohms. Its equalization of 50 Hz; 1,000 Hz and 10,000 Hz. There is also a 20 Hz low filter. Another convenience feature is the single switched and unswitched AC outlets. In our specifications we show the power output measured into an 8 Ω load to be 3 watts more than the manufactures claimed rating. Marantz emphasises the 4 Ω rating because they say speaker impedances are usually 5-6 ohms, not 8 ohms.
Power Output Rating per Channel:
37 W at 4 Ω RMS
33 W at 8 Ω RMS
Total Harmonic Distortion (at RMS 8 Ω):  0,025%
Intermodulation Distortion:  0,03%
Damping Factor:  60 (8 Ω , 1 kHz)
Frequency Response:  15 Hz - 50 kHz
Signal-to-Noise Ratio: 
Phono :  87 dB
Line :  98  db
Input Sensitivity/ Impedance: 
Phono :  2,8 mV/47 k Ω
Line :  150 mV/ 25 k Ω
Bass :  +12/-15 dB at 50 Hz
Mid :  +5,5/-6 dB at 10 kHz
High :  +10/-9 dB at 10 kHz
Low Filter Attenuation:  3 dB at 20 Hz
Dimensions (W x H x D):  416 x 146 x 243 mm
Weight (net):  6,2 kg 

Dual C830 cassette deck

The Dual C830 is a machine that not only handles ferric, chrome, ferrichrome andd metal tapes, it has two values of bias for both ferric and chrome tapes, thereby providing an optimum bias match for all commonly used formulations. Though it has a three-head system with simultaneous record-play, there is no simultaneous Dolby decorder; the simultaneous monitor exactly reproduces the recorded sound - the Dolby decoder is active only in the play mode. A record limiter cuts in at 0 dB record level with a fasy attack and release, thereby protecting against unsuspected excessive signal pecks. The record level indicator is not frequency compensated and indicates the true peak value after record pre-emphasis is applied. The 12-step LED record level indicator is very easy to read.
The C830 has a direct-access front loading mechanism, automatic stop at the end of play and a memory reset counter. It also features adjustable headphone volume, microphone/line input mixing and fade-erase during playback.
Comes in a metal cabinet

Type:  Single cassette tape deck
Track System:  4 Tarack, 2 Channel Stereo
Heads:  1 for Record/Playback;  2 for Erase
Tape Speed:  4,75 cm/s
Pitch:  Control range ±4%
Wow and Flutter :  ±0.035% (WRMS)
To DIN, playback only :  ±0,07%
To DIN, recording/plauback :  ±0,10%
Frequency Response  (ref. To DIN tolerances):
Standard Fe Tape :  20 - 17,000 Hz
CrO₂ Tape :  20 - 18,000 Hz
FeCr Tape :  20 - 19,000 Hz
Pure Metal Tape :  20 - 20,000 Hz
Signal-to-Noise Ratio (with Dolby NR)
Fe Tape : 67 dB
CrO₂  Tape :  67 dB
FeCr Tape :  69 dB
Metal :  69 dB
Channel Separation (at 1000 Hz)
Between Stereo Channels :  40 dB
Between Channels (in opposite direction) :  70 dB
Erasure (at 1000 Hz):  70 dB
Oscillator Frequency (push/pull oscillator):  105 kHz
Inputs Sensitivity/Impedance:
Microphone Jack :  0,3 mV/5 k Ω
Amplifier/Receiver DIN Jack :  1 mV/10 k Ω
Amplifier/Receiver RCA Jack :  80 mV/47 k Ω
Outputs Load/Impedance
Amplifier/Receiver DIN Jack :  0-580 mV/10 k Ω
Amplifier/Receiver RCA Jack :  0-580 mV/2 k Ω
Headphones Jack :  4 - 2000 Ω
Fast Wind Time (C-60 cassette):  60 sec.
Line Voltage:  115 volt and 230 volt
Line Frequency:  50/60 Hz
Power Conssumption:  15 W
Dimensions (W x H x D):  440 x 150 x 360 mm (17,2" x 5,9" x 14,2")
Weight:  20 pounds

Dual C839 RC cassette deck

The Dual 839 is so different from all other cassette decks that, rather than list its many features, we'll guide you through them as if the 839 were in front of you.
First, the 839 is bi-directional in record and playback. This doubles the length of every cassette. You'll notice there's no door between you and the cassette compartment. Insert a cassette and it will lock in precise alignment.
That's Dual Direct Load and lock system. (a subtle but important touch; any slack in the tape is immediately taken up.)
Follow us carefully on his next one. Even when the tape is in motion, you can pull it out and replace it with another,  and the previous mode resumes automatically. Useful? When the tape nears the end at a crucial moment, you can have a new tape in place without missing beat.
The 839 is just as innovative in playback. If a tape made on another deck is too sharp or too flat, no problem. Playback pitch can be varied over an 8 percent range.  And previously recorded tapes with clicks, pops and disc jockey interruptions can be cleaned up electronically - smoothly and permanently. Dual's fade/edit control lets you do that with complete confidence, because it functions in playback.
Back to recording. He peak-level LED indicators react faster than any other metering system. And more accurately, because they're equalized. They read the full processed signal - including the high frequency boost other decks add but only Dual reads. No more risk of overloading a tape into distortion.
There's still more. Much more. Full metal record and playback. 6-way bias/equalization. Two-motor, twin-capstan drive system.
Computer logic solenoid-activated controls. Switchable multiplex filter. Switchable limiter. Line/mic mixing. Two-way memory stop with automatic replay. Headphone level controls. And operation by external timer or optional wireless remote control.
What about the 839's audible performance? The specifications can give you a hint. Wow and flutter ±0,3 percent WRMS. Frequency Response from 20 Hz to 20 kHz, ±3 dB. Signal-to-Noise  is better than 69 dB
Type:  Single cassette tape deck
Track System:  4 Tarack, 2 Channel Stereo
Heads:  1 for Record/Playback;  2 for Erase
Tape Speed:  4,75 cm/s
Pitch:  Control range ±4%
Wow and Flutter :  ±0.03% (WRMS)
To DIN, playback only :  ±0,06%
To DIN, recording/plauback :  ±0,09%
Frequency Response  9ref. To DIN tolerances):
Standard Fe Tape :  30 - 18,000 Hz
CrO₂ Tape :  30 - 19,000 Hz
FeCr Tape :  30 - 19,000 Hz
Pure Metal Tape :  30 - 20,000 Hz
Signal-to-Noise Ratio (with Dolby NR)
Fe Tape : 64 dB
CrO₂  Tape :  64 dB
FeCr Tape :  67 dB
Metal :  67 dB
Channel Separation 9at 1000 Hz)
Between Stereo Channels :  35 dB
Between Channels (in opposite direction) :  60 dB
Erasure (at 1000 Hz):  70 dB
Oscillator Frequency (push/pull oscillator):  105 kHz
Inputs Sensitivity/Impedance:
Microphone Jack :  0,25 mV/10 k Ω
Amplifier/Receiver DIN Jack :  0,5 mV/6,3 k Ω
Amplifier/Receiver RCA Jack :  40 mV/82 k Ω
Outputs Load/Impedance
Amplifier/Receiver DIN Jack :  0-580 mV/10 k Ω
Amplifier/Receiver RCA Jack :  0-580 mV/2 k Ω
Headphones Jack :  4 - 2000 Ω
Fast Wind Time (C-60 cassette):  65 sec.
Line Voltage:  115 volt and 230 volt
Line Frequency:  50/60 Hz
Power Conssumption:  40 W
Dimensions (W x H x D):  440 x 150 x 360 mm

Revox B780 receiver

In its B780 receiver Revox has achieved a truly symbiotic relationship between tuner and amplifier. Each retains its identity; the circuitry and performance of both the B760 Digital Frequency Syntesizer FM Tuner and the Revox B750 Integrated Amplifier are combined in the B780. instaed of trading flexibility for single-unit convenience, however, the capabilities of each unit have been enhanced by their merger into the Revox B780.
What makes the B780 more than the sum of its component parts is a microprocessor unit that takes over switching functions that would normally require an inordinate number of hard-wired connections and printed circuits. At the same time that it serves to increase the reliability of the B780, the microprocessor control system makes the receiver even easier to use.

As the nerve center for your entire component high-fidelity system, the Revox B780 provides connection and control facilities for two loudspeaker systems and for fourstereo sources in addition to its built-in FM tuner; a phono cartridge, two tape recorders, and an auxiliary source, such as a Tv set, AM tuner, or the like. Each input is fully buffered, and so, can be used independently. That is to say, if you wish, you can record an FM broadcast on your open real deck at the same time as you are listening to the playback of an LP. in place of the usual rotary "Selector Switch", your choice of input signals is electronically routed through the amplifier via individual pushbuttons ( with lighted indicators) that command the microprocessor to switch to the appropriate source. Even when the B780 is turned off, the microprocessor retains the last-selected program source in its memory, so when you turn the unit on again. It "wakes up" properly switched to that input.
Lighted digits show which program source is going to the recorder circuits. These pushbutton choices are also retained in the microprocessor memory, giving you the convenience of mechanical switching with vastly improved reliability.

The same principle of all pushbutton operation is applied throughout the tuner section of the B780. there is no conventional FM dial for the selected station frequency, as it is indicated ( to two decimal places ) on a digital red-out. There is no conventional FM dial for selected station frequency, as it is indicated on a digital read-out. There is no conventional tuning knob, with its dial cord and pulleys; rather; pushbuttons cause the tuner to scan upward or down-ward in frequency in 50 kHz incrementes, stopping at each receivable station, or at each stereo station, or switching into mono when the station's signal strength is not adequate for proper stereo reception.
Because of its quartz-crystal controlled frequency synthesizer, tuning is always exact; only by using a laboratory FM generator and distortion analyzer could such precision be obtained with normal manual tuning. And the pushbutton memory system of the B780 allows you to store the frequencies of up to 18 favorite stations for instant recall.
Long awaited, the Revox B780 receiver embodies the most up-to-date technology, in its most convenient form, in the service of the one goal that inspire all Studer Revox products; to bring you the most faithful possible reproduction of musical sound.
Tuner Section
Tuning Range:  87,50 - 107,975 MHz
Tuning Accuracy:  ±0,0025%
IHF (30-dB) Monophonic Usable Sensitivity:  19,µV / 300 Ω (10,8 dBf)
IHF (IHF-T-200) Monophonic 50 dB Quieting Sensitivity:  2,5 µV / 300 Ω (13,2 dBf)
IHF (IHF-T-200) Stereophonic 50 dB Quieting Sensitivity:  30 µV / 300 Ω (34,8 dBf)
Image Rejection:  106 dB
IF Rejection:  110 dB
Spurious Response Ratio:  106 dB
Capture Ratio (at 65 dBf):  2 dB
Selectivity Adjacent Channel:  16 dB
Selectivity Alternate Channel:  78 dB
 AM Suppression:  70 dB
Subcarrier Product Rejection:  72 dB
Frequency Response:  30 Hz - 15 kHz ±1 dB
Deemphasis:  50 or 75 µs (switchable) with built-in Noise Reduction Unit 25 µs
Total Harmonic Distortion(at 65 dBf):
At 100 Hz :  0,15% (mono);  0,35% (stereo0
At 1 kHz :  0,1 (mono);  0,25% (stereo)
At 6 kHz :  0,2% (mono);  0,2% 9stereo0
Stereo Separation [Mono]:
At 100 Hz :  40 dB
At 1 kHz :  42 dB
At 10 kHz :  33 dB
Signal-to-Noise ratio 9at 65 dBf):
Mono :  78 dB
Stereo :  74 dB
Muting Thresholds:
Mono :  17,3 - 37,3 dBf
Stereo :  25,2 - 65,2 dBf
Antenna Inputs:
60 -75 Ω coaxial
240 - 300 Ω balanced
Audio Outputs:
75 kHz deviation/400 Hz equals 0,7 volt at the output Tape 1
15 kHz deviation/400 Hz produces 70 watts/ 8 Ω at the output Speakers A/B
Oscilloscope Output:
Vertical :  50 mV /75 Ω, RF =1 Volt
Horizontal :  75 kHz deviation = 2,8 Volt pp
Amplifier Section
Power Output:  70 watts/channel min. RMS into 8 Ω from 20 Hz - 20 kHz with no more than 0,05% T.H.D.
Total Harmonic Distortion:   0,03% at rated output
IHF Intermodulation Distortion (14 kHz/15 kHz):  less than 0,03% at rated output
TIM Distortion (Otala, lowpass 10 kHz):  less than 0,08% at rated output
Dynamic Headroom:  1 dB
Slew rate:
15 V/µs ( limited by internal low pass filter)
30 V/µs (without low pass filter0
Frequency Response:  20 Hz - 20 kHz +0 dB/-0,7 dB
Damping Factor:  better than 100 at 8 Ω and 1 kHz
Inputs Sensitivity (for 70 watts [8 Ω])/Impedance
Aux, Tape 1, 2 :  150 mV/50 k Ω
Phono :  3 mV/47 k Ω, 220 pF
PWR In :  1 V/50 k Ω
Input Overload Margin (phono, Aux, Tape 1, 2):  better than 30 dB
DIN Connector Tape 2/Out:  5,5 mV/R 10 Ω
Speakers A, B :  23,7 V (8 Ω)
Tape 1 :  135 mV/R min. 47 k Ω
Pre Out (DIN connector) ;  0,85 V/R min. 10 k Ω
Pre Amp Out (jack) :  0,85 V/R min. 47 k Ω
Phones :  11,8 V/R 220 Ω
Signal-to-Noise Ratio (RMS value, unweighted 20 Hz - 20 kHz relative to 70 W/8 Ω)
Aux, Tape 1, 2 :  better than 90 dB
Phono 1 + 2 9ref. 5 mV, A-weighted):  better than 82 dB
Crosstalk (at 1 kHz):  better than 70 dB
Phono Equalization:  20 Hz - 20 kHz ±0,5 dB (in accordance with IEC 98, MOD 4 1976, consistent with RIAA)
Tone Controls:
Bass  :  ±8 dB at 120 Hz
Treble :  ±8 dB at 8 kHz
Presence ;   ±8 dB at 3 kHz
Low :  50 Hz, -3 dB (12 dB/oct)
High :  8 kh, -3 dB (12 dB/oct)
Loudness (Vol-40 dB):  100 Hz +5 dB , 10 kHz +6 dB
General Section
Semiconductors:  122 Transistors;  99 Diodes;  19 variable capacity Double Diodes:  46 ICs:  1 micro-processor; 4 K x 8 Bit, 5 Bridge Rectifiers, 9 7-Segment Displays
Electric Current Supply:  100, 120, 140, 200, 220, 240 V AC ±10% (voltage selector) 50/60 Hz
Power Consumption:  550 W max.
Dimensions (W x H x D):  452 x 151 x 420 mm (17,8" x 6" x 16,5 ")
Weight:  17 kg (37 lbs)

Technics SL-10 turntable

Technics SL-10 is a compact, Quartz Direct-Drive turntable that represents a notable departure from conventional design. Although the unit has the same width and depth dimensions as an LP record jacket, it is fully automatic and plays discs in a totally sealed cabinet. A linear tracking tonearm with its drive system and a micro-computer electronic control block are contained in the lid section of the cabinet. The lower section contains a unique integral rotor platter DD motor plus its driving and quartz-phase-locked control  circuit. 
To use the SL-10, just place a record on the turntable, close the lid and press the start button. Stylus contact points are determined by a precision opto-electronic detection system. Perhaps the most amazing aspect is that the unit can be stood upright, as well as kept in the usual horizontal position, during record play. The SL-10 can also be stored in upright position, along with records, when not in use. An advanced coreless DC motor drives the arm and an optical sensor located near the stylus tip determines operation. 
The opto-electronic system utilizes deflection angle detection and is said to be far more accurate than systems that operate near the suspension. Thus cartridge/groove geometry is always maintained near the ideal relationship, says technics. There is no lateral tracking error since the SL-10's linear tracking arm has the same geometry as the cutter heads used to make records.
Turntable Section
Type:  Quartz automatic  turntable
Drive Method:  Direct drive
Motor:  Brushless DC motor
Drive Control Method:  Quartz-phase-locked control
Turntable Platter:  Aluminum die-cast, diameter 300 mm (12 inches)
Turntable Speeds:  33-1/3 rpm and 45 rpm (auto speed select)
Speed Deviation:  within ±0,002%
Wow and Flutter:  0,012% (WRMS);  0,025% (JIS C5521) ±0,035% peak (IEC 98 A weighted)
Rumble:  -56 dB (IEC 98 A unweighted);  -78 dB (IEC 98 A weighted)
Tonearm Section
Type:  Dynamic balanced linear tracking tonearm
System:  4-pivot gimbal suspension
Effective length:  105 mm (3-21/32")
Tracking Error Angle:  within ±0,1°
Effective Mass:  9 g (including catridge)
Resonance Frequency:  12 Hz
Tonearm Drive Motor:  Coreless DC motor
Cartridge Section:
Type:  Moving Coil stereo cartridge, Coreless twin-ring coil type
Cantilever:  pure Boron pipe
Damper:  TTDD (Technics Temperature Defense Damper)
Frequency Response:  10 Hz to 60 kHz (10 Hz to 10 kHz ±0,5db)
Output Voltage:  0,2mV at 1 kHz (5 cm/s zero to peak lateral velocity )
Channel Separation:  better than 25 dB at 1 kHz
Channel Balance:  within 1 dB at 1 kHz
DC Resistance:  30 Ω
Impedance:  30 Ω pure resistance
Compliance (Dynamic):  12 x 10¯⁶ cm/dyne at 100 Hz
Vertical Tacking Angle:  20°
Stylus Pressure Range:  1,25 ±0,25 g 912,5 ±2,5 mN)
Stylus Tip:  0,2 x 0,7 mil (5 x 8 µm) Elliptical stylus , Block diamond tip
Effective Mass:  0,23 mg
Weight:  6,0 g 9cartridge only)
Replacement Cartridge:  EPS-310MC
MC Pre-preamp Section:
Rumble:  -70 dB (IHF A)
Frequency Response:  20 Hz to 20 kHz ±0,5 dB
Output level:  2,5 mV
Overall Distortion:  0,02% (connected to technics SU-70AII)
Power Supply:  110 - 120 / 220 - 240 V, 50 Hz or 60 Hz DC 12 V (DC input jack)
Power Consumption:  20 W  (AC); 6 W (DC)
Dimensions (W x H x D):  315 x 88 x 315 mm (12-1/2 " x 3-1/2 " x 12-1/2")
Weight; 6,5 kg (14,3 lbs)