Nakamichi SR-4A

 The nakamichi SR-4A redefines the word "receiver". It offers the same convenience and economy but it's designed like separate audiophile components - each individually optimized, each individually powered, each isolated for minimum interference. And what a receiver: STASIS power amplification for uniform impedance, inherent stability and tremendous peak-current capability, a moving-coil/moving-magnet phono preamp with precise equalization, an effective subsonic filter and more. Like continuously variable loudness and tone controls, independent recording and input selectors with two-way dubbing and two video inputs, a 10-preset PLL Quartz-Lock FM/AM tuner with manual and auto-seek tuning, and wireless remote control.

 Multi-stage power supply

The SR-4A's performance is due in part to its unique power supply. Unlike ordinary receivers, the SR-4A's  transfrmer has separate windings, rectifiers and regulators for each major section; power amplifier, preamplifier, tuner and display. Within the audio circuitry, separate regulators are used for the phono preamp and high-level stages, and the video amplifiers are regulated independently of the audio stages to prevent video noise from intruding. Separate grounds are used for audio, tuner, display and power supply so ripple and RF noise will not enter the audio circuitry. The tuner is even buffered from the other inputs to prevent interference. Critical subregulators are discretely configured with a unique topology that cancels noise on the ground line. This unusually exotic power supply permits each section to operate independently of the others - the major advantage of "separate" components.

Stasis Amplification

Audiophiles who hear the SR-4A are amazed at its effortlessly transparent sound. Music has more detail, more impact, more realism - especially when reproduced on "difficult" top-quality speakers. The reason is our "Stasis" power amplifier - the same concept used in the PA-7 and PA-5 Power Amplifiers.

STASIS is a radically different and superior design in which two amplifiers drive the speaker; a high-quality low-power amplifier and a "Current-Mirror Bootstrap" to supply muscle. The low-power amplifier can be designed for virtually perfect performance, "global" feedback isn't needed as in ordinary power amps. Removing the overall  feedback ensures uniform output impedance and inherent stability, and, since the amplifier is stable, there's no need to isolate it from the speaker with a coil as is usually done. This permits the amplifier to control the speaker more preciselly and realize its full potential. The current bootstrap provides tremendous peak-current reserves - up to 25 ampers into low-impedance loads

 An Audiophile Preamp

Special care was lavished on the SR-4A phono preamp. The input circuit is a direct-coupled discrete design using ultra-high-gm FETs in a balanced differential configuration. These drive a differential gain stage with RIAA equalization obtained via a direct-coupled precision feedback network. The preamp accomodates MM and MC cartridges with a choice of gain (24/32 dB) in the MC position. A deleatable subsonic filter is part of the phono preamp. Theanks to a simulated-inductor ("gyrator") design, it has maximum rejection in the "warp" region, minimum loss in bass response and is free of noise pickup.

Only components of thehighest quality are used. Instead of the noisy distortion-prone electronic attenuator now in vogue as a volume control, we use a motor-driven precision potentiometer for local and remote level control. The loudness control is continuously variable to siut any listener's preference and copper-styrene capacitors and metal-film resistors in the signal path ensure minimum noise and distortion.

An Exceptiona Tuner

The SR-4A's Quartz-PLL Synthesized FM Tuner is far from ordinary. Of course,the quartz-locked design ensures accurate tuning and eliminates drift. But typical tuners of this type have high residual noise due to "reference-frequency jitter" the SR-4A tuner uses a reference frequency twice that of ordinary tuners to improve Signal-to-Noise. A dual-gate MOS FET front-end with high-Q twin vari-cap diodes provides selectivity equivalent to a 4-gang capacitor while a special auto-seek circuit that detects both signal and noise level prevents false stops between or near strong stations.

Specifications

Power Amplifier Section

Continuous Average Output Power (IHF-A):  80 watts per channel (8 Ω, both channel driven, 20-20,000 Hz, no greater than 0,1% T.H.D.)

Dynamic Output Power (both channel driven): 

80 watts per channel into 8 Ω

120 watts per channel into 4 Ω

Dynamic Headroom (IHF-A):  1,3 dB

Frequency Response (IHF-A):  5 Hz - 100 kHz +_0,5 dB

Signal-to-Noise Ratio:  better than 106 dB (rated power)

Total Harmonic Distortion (Rated Power, 8 Ω):  less than 0,1% (20 - 20,000 Hz)

Intermodulation Distortion (Rated Power, 8 Ω):  less than 0,1% (60 Hz :7 kHz = 4 : 1)

Preamplifier Section

Input Sensitivity /Impedance (for Rated Output):

Phono MC (gain; 32/24 dB):  60/180 µV/100 Ω

Phonoo MM :  2,5 mV/47 k Ω

CD, Tape, Video:  200 mV/30 k Ω

Maximum Input Level (1 kHz, IHF-A):

Phono MC (Gain; 32/24 dB):  3,5 / 8 mV

Phono MM :  150 mV

Total Harmonic Distortion (20  20,000 Hz, to Rec Out at 1 V):

Phono MC :  less than 0,003%

Phono MM :  less than 0,002%

RIAA Deviation:  30 - 20,000 Hz ±0,5 dB

Signal-to-Noise Ratio (to speaker output, IHF-A):

Phono MC :  better than 73 dB (32 dB gain); better than 72 dB (24 dB Gain)

Phono MM :  better than 89 dB

Tone Control

Bass:  20 Hz ±10 dB

Treble:  20 kHz ±8 dB

Contour (Variable Loudness):  20 Hz +25 dB; 20 kHz +8 dB

Subsonic Filter (Phono Only):  10 Hz, -12 dB/octave

FM Tuner Section

Frequency Range:  87,5 - 108 MHz

IHF Usable Sensitivity [mono]:  11 dBf (1,9 µV)

-50 dB Quieting Sensitivity [mono/stereo]:  14,7 dBf (2,9 µV) / 37,5 dBf (41,2 µV)

Signal-to-Noise Ratio at 65 dBf [mono/stereo]:  better than 79 dB / better than 74 dB

Frequency Response:  20 Hz - 15 kHz ±1 dB

Total Harmonic Distortion [mono/stereo]:  less than 0,07% / less than 0,09%

Capture Ratio:  1,5 dB

Alternate Channel Selectivity:  60 dB (±400 kHz)

Stereo Separation at 1 kHz:  better than 53 dB

Spurious Response Rejection:  better than 90 dB

Image Rejection:  better than 75 dB

IF Rejection:  better than 80 dB

AM Suppression:  better than 60 dB

AM Tuner Section

Frequency Range:  520 - 1710 kHz

Sensitivity:  53 dBµ/m

Signal-to-Noise Ratio (at 90 dBµ/m):  better than 52 dB

Total Harmonic Distortion (at 90 dBµ/m):  less than 0,3%

Selectivity:  better than 20 dB (±10 kHz)

General:

Power Source:  110, 120, 220 or 240 V AC, 50/60 Hz

Power Consumption:  350 watts max

Convenience Outlets:  2 x switched; 1 x unswitched

Dimensions  (W x H x D):  430 x 100 x 370 mm (16-15/16" x 3-15/16" x 14-9/16")

Weight:  9,8 kg (21 lbs 10 oz)

Nakamichi SR-3E

 Stasis Amplification

Audiophiles who hear the SR-3E are amazed at its effortlessly transparent sound. Music has more detail, more impact, more realism - especially when reproduced on "difficult" top-quality speakers. The reason is our "Stasis" power amplifier - the same concept used in the PA-7 and PA-5 Power Amplifiers.

STASIS is a radically different and superior design in which two amplifiers drive the speaker; a high-quality low-power amplifier and a "Current-Mirror Bootstrap" to supply muscle. The low-power amplifier can be designed for virtually perfect performance, "global" feedback isn't needed as in ordinary power amps. Removing the overall  feedback ensures uniform output impedance and inherent stability, and, since the amplifier is stable, there's no need to isolate it from the speaker with a coil as is usually done. This permits the amplifier to control the speaker more preciselly and realize its full potential. The current bootstrap provides tremendous peak-current reserves - up to 25 ampers into low-impedance loads.

Specifications

Power Amplifier Section

Continuous Average Output Power (IHF-A):  45 watts per channel (8 Ω, both channel driven, 20-20,000 Hz, no greater than 0,1% T.H.D.)

Dynamic Output Power (both channel driven): 

64 watts per channel into 8 Ω

80 watts per channel into 4 Ω

Dynamic Headroom (IHF-A):  1,5 dB

Power Bandwidth:  5 -40,000 Hz

Frequency Response (IHF-A):  5 Hz - 75 kHz  +0 -3 dB

Signal-to-Noise Ratio:  better than 105dB (rated power); better than 85 dB (IHF-A-202)

Total Harmonic Distortion (Rated Power, 8 Ω):  less than 0,1% (20 - 20,000 Hz)

Intermodulation Distortion (Rated Power, 8 Ω):  less than 0,15% (60 Hz :7 kHz = 4 : 1)

Headphone Rated Output (40 ohms):  105 mW

Output Current Capability:  18 A peak per channel

Preamplifier Section

Input Sensitivity (for Rated Output):

Phono MC (gain; 32/24 dB):  60/150 µV

Phonoo MM :  2,5 mV

CD, Tape, Video:  200 mV

Sensitivity (1 watt, IHF-A):

Phono MC (Gain; 32/24 dB):  8,9 / 24 µV

Phono MM :  0,37 mV

CD, Tape, Video :  30 mV

Input Impedance:

Phono MC :  100 ohms

Phono MM :  47 k Ω

CD, Tape, Video :  20 k Ω

Maximum Input Level (1 kHz):

Phono MC (gain; 32/24 dB):  3/8 mV

Phono MM :  140 mV

Record Output Level/Impedance:  200 mV/1 k Ω

Total Harmonic Distortion (20  20,000 Hz, to Rec Out at 1 V):

Phono MC :  less than 0,003%

Phono MM :  less than 0,002%

RIAA Deviation:  30 - 20,000 Hz ±0,5 dB

Signal-to-Noise Ratio (to speaker output, IHF-A):

Phono MC :  better than 73 dB (32 dB gain); better than 72 dB (24 dB Gain)

Phono MM :  better than 80 dB

Tone Control

Bass:  20 Hz ±10 dB

Treble:  20 kHz ±10 dB

 Loudness:  20 Hz +10 dB; 20 kHz +6 dB

Subsonic Filter (Phono only):  20 Hz, -12 dB/octave (cutoff Frequency)

FM Tuner Section

Frequency Range:  87,5 - 108 MHz

IHF Usable Sensitivity [mono]:  11 dBf (1,9 µV)

-50 dB Quieting Sensitivity [mono/stereo]:  21,0 dBf (6,1 µV) / 42,0 dBf (69,0 µV)

Signal-to-Noise Ratio at 65 dBf [mono/stereo]:  better than 74 dB / 69 dB

Muting Threshold:  30 dBf/17,3 µV

Frequency Response:  20 Hz - 15 kHz ±1 dB

Total Harmonic Distortion [mono/stereo]:  less than 0,12% / 0,20%

Capture Ratio:  2,0 dB

Alternate Channel Selectivity:  70 dB (±300 kHz)

Stereo Separation at 1 kHz:  better than 43 dB

Spurious Response Rejection:  better than 90 dB

Image Rejection:  better than 75 dB

IF Rejection:  better than 80 dB

AM Suppression:  better than 60 dB

AM Tuner Section

Frequency Range:  522 - 1611 kHz

Sensitivity:  53 dBµ/m

Signal-to-Noise Ratio (at 90 dBµ/m):  better than 52 dB

Total Harmonic Distortion (at 90 dBµ/m):  less than 0,3%

Selectivity:  better than 20 dB (±10 kHz)

General

Power Source:  110,120,220 or 240 V AC, 50/60 Hz

Power Consumption:  270 watts max

Convenience Outlets:  2 x switched; 1 x unswitched

Dimensions  (W x H x D):  430 x 100 x 370 mm (16-15/16" x 3-15/16" x 14-9/16")

Weight:  8,5 kg (18 lbs 12 oz)

Pro-Ject The Classic

New model Pro-Ject turntables "The Classic" offers vintage look, wood chassis and innovative high-end technology 

This turntable makes use of traditional frame design which was established by the famous turntable manufacturers of the 50's and 60's. It uses a compact simple and elegant form factor. The Classic incorporates a combination of approved belt drive design using a low noise AC motor with an ultra precision frequency DC-driven AC generator (like Speed Box) for ultimate speed stability. Advanced technology is used for decoupling and the completely new designed tonearm. 

 Features:

• Belt drive with manual speed control 33/45 rpm 

• Height adjustable decoupling feet 

• Precision balanced TPE-damped aluminium-platter / felt mat 

• Metal/MDF sandwich chassis floating on TPE suspension 

• 9” carbon/aluminium tonearm with MM & MC capability 

• Japanese ball bearing (base of tonearm) 

• Integrated central vertical cable outlet for unhindered arm movement 

• Ultra low friction Zircon pin-point cardan bearings (top & side) 

• Azimuth and VTA fully adjustable 

• TPE damped counterweight 

• Optionally available with 2M Silver phono cartridge 

• Classic wooden chassis in 3 matt finishes  (walnut, rosenut, eucalyptus) 

PLATTER & SUB-PLATTER

The heavy aluminium main platter construction utilises advanced TPE for optimising resonance behaviour. A drawback for most of the old designs was the platter. Casted platters all have been heavy (which is good for speed constancy and low wow and flutter) but suffered very much from ringing effects which again caused colouration of the sound. The platter of "The Classic" is precisely machined out of a special aluminium alloy again damped with TPE, which offers special damping abilities.

The subplatter / main bearing construction we use is similar system as on the "Debut". It is made of hardened steel/ Bronze bushing/ Teflon bearing mirror, which re-sults in very smooth low noise running smoothness of the bearing

The main difference to the "Debut" bearing are the tolerances which are by factor 10 lower and therefore more precise (0,005%). Especially the subplatter is a very sophisticated part which is accurately machined and guarantees a very good isolation between bearing noise and the platter itself.

CHASSIS & SUBCHASSIS:  Thanks to the modern damping materials TPE (Thermo Plastic Elastomers) we are able to design a very effective, subchassis construction. Isolating the platter and tonearm from the resonances of the motor and main plinth

THE FEET:  As we did not want to risk that the customer always needs perfect audiophile turntable supports, we decided to use damping feet which are a very good compromise to suit most of customer environments. For sure these feet are height adjustable

NEW CARBON/ALUMINIUM TONEARM:

The radical new designed Classic Tonearm is the result of 25 years of experience in me-chanical construction.

The tonearm tube is made out of a sandwich of Carbon and Aluminium: Carbon for stiff-ness and speed, Alu for better damping.

The Cardan bearing assembly with pin-point Zircon bearing provides ultra low friction.

A new expensive Japanese base-ball-bearing allows a better lead of the tonearm wire and increases the free movement of the arm.

The counterweight incorporates a TPE* damp-er which allows us to reduce the amplitude of the tonearm cartridge resonance frequency by 50%.

As typical for Pro-Ject and absolutely not standard at that price range we offer also azimuth and VTA adjustment to use a variety of cartridges. Different counterweight for cartridges up to 25 grams are available as an option.

We supply as standard the Ortofon 2M Silver moving magnet cartridge. This Ortofon cartridge is exclusively designed for Pro-Ject Audio Systems. We improved the sound and dynamics of the recognised 2M series, by implement-ing pure silver coils instead of standard copper. However, as the tonearm offers excellent damping and flexibility as well, its effective mass can be called middle heavy, so it is also a very good partner for MC cartridges

Specifications:

Speed:  33 and 45 rpm with manual speed change

Drive:   belt drive system

Platter:   300 mm aluminium

Mains Bearing:  stainless steel

Wow and Flutter: 

At 33 rpm :  ±0,03%

At 45 rpm :  ±0,05%

Speed Variance:

At 33 rpm :  ±0,10%

At 45 rpm :  ±0,11%

Signal-to-noise Ratio:  -71 dB

Tonearm:  9” carbon/aluminium sandwich tonearm

Effective Arm Length;  230 mm

Effective Arm Mass:  13,5 g

Overhang;  18 mm

Tracking Force:  10 - 30mN

Included Accessories:  15 volts DC / 0,8A power supply;  dust cover

Power Connection:  110/120 or 230/240 Volt - 50/60 Hz

Power Consumption:  5 watt max / < 0,5 watt standby

Dimensions (WxHxD):  460 x 131 x 351 mm  lid closed

Weight(net):  10,2 kg

Sansui SF-1

Omni-Radial Sound Field Speaker System

The sound-in-theround speaker system. For the person who wishes his 4-channel sound system to truly be be sound-in-the-round, Sansui is pround to introduce a system that takes this new music form to its thrilling sound pinnacle. The SF-1 Omni-Radial Sound Field Speaker System is not just another omnidirectional speaker, but a completely new concept in 360 degree sound, for it employs speakers facing both upwards and downwards and makes use of specially-designed reflectors to diffuse the reproduced sound in complete horizontal and broad vertical directions. 

This 2-way 3-speaker system produces a vibrant and reverberant 4-channel system. Among its virtues, it has been designed to accurately reflect the very important, but often overlooked "indirect" sound waves of music reproduction. And these indirect waves are the vital element of the live concert hall sound field. The authentic "live" sound effect that so many speaker systems promise but so few deliver. In addition, sound diffusion is extended in the SF-1 by the use of a new porous foam acoustic diffuser placed behind the Kumiko fretwork grille, a device which also helps to attain ideal dispersion of sound in the very high frequency range. Beautifully designed and finished (like its larger twin speaker system,the SF-2), the SF-1 cabinet is made of solid natural wood and hard chipboard, specially treated to resist heat or stains. The system is actually an expensive piece of fine furniture - and looks it. From the most respected name is stereo, Sansui.

Sansui's Sf-1 system is designed to achieve rich ambience by radiating sound in a full 360 degrees so that it will be reflected off of more surfaces, and so that the distinctively directional signals in the sound will intermingle with the reflected sounds with fine time or phase lags.

How does it achieve this sound radiation?

The SF-1 features a unique tetrahedron construction. Its two woofers and single tweeter are on the same vertical axis.

Sounds emanating by them are dispersed in complete 360-degree horizontal directions - and in broad vertical directions as well - by a top and bottom reflector. When the sounds reach the grilles located on the four sides of the system's enclosure, their vertical distribution is broadend even more by a newly developed porous foam acoustic diffuser.

The result of this new technology is something totally unique in sound. No matter where you place the SF-1, sound literally envelops you from all directions, in a sense, you swim in sound, and it's an experience that does indeed make you wonder why someone hasn't thought of this speaker idea before. Another advantage of the SF-1: you may place it anywhere. No longer are you confined to the corners of your room as you decide where to place your speakers. Freedom, unlimited, for one thing. Sound unlimited, for another. And wouldn't you know that Sansui discovered it.

Two Woofers:  There is one 165 mm (6-1/2") woofer that faces upwards and another that faces downwards. Sound from them is dispersed by top and bottom reflectors in all directions, the better to reflect off of more surfaces (walls, ceiling, floor) and the better to enhance the great sense of ambience and naturalness which the SF-1 provides.

Sealed Tweeter:  This is a 58 mm (2-1/4") diameter unit completely sealed in the back by an over-sized cover to prevent it from interfering with the woofer located directly beneath it. The usually narrow dispersion of the tweeter sound is dispersed in a full 360 degrees by the top reflector above it. Overall, the speaker boasts excellent transient response and sound transparency.

Crossover Network:  The SF-1, despite its compact size, is truly an advanced system, far more versatile than any other omnidirectional speaker in its class or price range. Its crossover network possesses a 6 dB/oct. cut-off characterictic that enables the speaker system to prevent phase deviations between the woofers and tweeter and to provide a very smooth transition between these two different types of speakers. This network is equipped with a volume-type attenuator for the tweeter so that you may adjust that speaker's output level to suit room acoustics and your own listening taste.

Porous Foam Acoustic Diffuser:  This new type of material replaces the usual speaker system cloth cover. It is advantageous for any number of reasons, but especially because it enhances the sounds taht are vertically dispersed by the top and bottom reflectors and helps to diminish their harshness and bite. The end result is a mellow, natural, evenly distributed sound field that you would usually experience only during a live musical performance. 

Heat and Stain Resistant Cabinet:  The SF-1 is a beautiful piece of furniture as well as a beautiful sound experience. Built of solid natural wood and hard chipboard, its cabinet is specially finished on the surface to resist heat and stains. It will not discolor or fade if you accidentally place a coffee cup on it. In form and function, it is very near the peak of omnidirctional speaker systems, and is only exceeded in quality by Sansui's large system , the SF-2.

8-Meter (26-Foot) Long Connection Cable:  To allow you to position the speaker system anywhere in your room, the SF-1 comes with an 8-meter long connection cable. This is the expensive soild cabtyre type cable that gives added strength and effectively shields out noise.

Specifications:

Speaker:

Woofer :  2 x 165 mm (6-1/2") cone type

Tweeter :  1 x 58 mm (2-1/4") cone type

Power Rating:  45 W (Peak)

Impedance:  8 Ω

Sensitivity:  90 dB/W at 1 m

Frequency Range:  55 - 20,000 Hz ( in anechoic chamber)

Crossover Frequency:  2,000 Hz

Crossover Network:  2-way 6 dB/oct.

Dimensions (W x H x D):  370 x 563 x 370 mm (14-9/16" x 22-3/16" x 14-9/16")

Weight:  12,0 kg (26,5 lbs) net; 14,3 kg (31,5 lbs) packed

Finish:  Solid natural wood open pore.

Sansui AU-9900

The AU-9900 is one of the largest and most advanced of any integrated stereo pre/power amplifiers yet introduced in the popular Sansui AU Series, instruments created to deliver the famed Sansui tonal quality al. The high power output levels demanded by today's true audiophiles.

Parallel Push-Pull Power Output Section.

The power amplifier section of this robust stereo component features a diferential amplifier and a 3-stage Darlington system designed in the parallel push-pull format. The results include a continuous power output of 80 watts, min. RMS, per channel, both channels driven into 8 ohms, over a 20 Hz to 20 kHz bandwidth with no more than 0,08% total harmonic distortion.

Stablized, Well-Regulated Power Source

The power supply section is one of the most stable and dependable ever developed, providing plus-minus symmetrical voltages to all circuits as needed. Oversized power capacitors help provide extra stability, while the use of an advanced toroidal transformer further assures better power regulation and exceptionally low induced hum.

Excellent R.I.A.A. Equalization

The phono equalizer consists of two amplifying sections each with a differential amplifier. High frequency roll-off  is made by the CR type circuit and low frequency turn-over is made by the NF type circuit, most accurately and with very low distortion.

Effective Triple Tone Control

Sansui's popular Triple Tone Control circuit is featured in the AU-9900 to provide the best, most flexible tonal adjustment control yet developed. Twelve  trans istors are used in the circuit, itself built around an initial stage using, a differential amplifier. The individual controls for Bass, Midrange and Treble are made still more convenient by the selectable turnover switches for Bass (600 Hz, 300 Hz or 150 Hz) and Treble (8 kHz, 4 kHz or 2 kHz).

Quadruple Protection Circuits

Changes in temperature, line voltage supply or shorts in speaker leads or terminals are instantly detected and can cause no damage to the power transistors or connected speakers thanks to the use of four separate protection circuits. These are: [1] a temperature sensing circuit, [2] a DC voltege detection circuit, [3] an ASO (Area of Safety Operation) circuit, and [4] an overload detection circuit.

Tone Defeat Switch

Like the AU-20000 and AU-11000, this integrated amplifier provides the convenience of being able to cancel all tone control adjustments instantly with a Tone Defeat Switch

Two-Stepped Low/High Filters

The low Filter has positions for 12 dB/oct. attenuation at 20 Hz or 60 Hz;  the high Filter is selectable for 6 dB/oct. cut-off at 7 kHz or 12 dB/oct. cut-off at 12 kHz

Other Valuable Features

Teh AU-9900 provides every convenience needed for professional and semi-professional use, included are a hand-trimmed precision volume comtrol, input/output terminals for up to two stereo decks, with full monitoring and deck-to-deckdubbing, a quick-access Tuner Switch, Mode Switch, Level Selector (0 dB/ -10 dB/ -20 dB) and an Audio Muting Switch.

Specifications

Power Output (min. RMS, both ch. driven, 20-20,000 Hz, no more than 0,05% T.H.D.):

80 watts per channel into 4 and 8 ohms

Load Impedance: 4 and 8 ohms

Power Bandwidth:  20 - 20,000 Hz (at or below rated min. RMS power output and T.H.D.)

Total Harmonic Distortion (overall from AUX): less than 0,05% (at or below rated min. RMS power output and T.H.D.)

Intermodulation Distortion (70 Hz : 7 kHz = 4:1 SMPTE method):

Overall (from AUX) less than 0,05%

Frequency Response (at 1 watt):

Overall (AUX to power output) 10 to 50,000 Hz +0 dB, -1 dB

RIAA Curve Deviation (Phono):  +0,3 dB, -0,3 dB (30 to 15,000 Hz)

Channel Separation (at rated output 1,000 Hz):

Phono 1 and 2 :  better than 55 dB

Tuner :  better than 60 dB

Aux 1 and 2 :  better than 60 dB

Power Amplifier:  better than 70 dB

Tape Monitor :  better than 60 dB

Hum and Noise (IHF):

Phono 1 and 2 :  better than 65 dB

Tuner :  better than 80 dB

Aux 1 and 2 :  better than 80 dB

Power Amplifier:  better than 100 dB

Tape Monitor :  better than 80 dB

Input Sensitivity/Impedance:

Phono 1 :  2 mV, 4 mV, 8 mV / 30 k, 50 k, 100 k Ω

Phono 2 :  2 mV/ 50 k Ω

Max.input Capability:  more than 300 mV rms 0,1% distortion

Tuner :  130 mV /50 k Ω

Aux 1 and 2 :  130 mV / 50 k Ω

Tape Pb  1 and 2 :  130 mV (PIN)

Tape Pb 2 :  130 mV (DIN)

Recording Output:

Tape 1 :  130 mV (PIN)

Tape 2 :  130 mV (PIN); 30 mV (DIN)

Controls:

Bass :  +10 dB; -10 dB at 30 Hz

Midrange :  +5 dB, -5 dB at 1,500 Hz

Treble:  +10 dB, -10 dB at 20 kHz

Tone Selectors:

Bass :  150 Hz, 300 Hz, 600 Hz

Treble:  2 kHz, 4 kHz, 8 kHz

Filters:

Low :  -3 dB at 20 Hz (12 dB/oct); -3 dB at 60 Hz (12 dB/oct)

High :  -3 dB at 7 kHz (6 dB/oct); -3 dB at 12 kHz (12 dB/oct)

Muting:  0 dB; -20 dB

Level Set: 0 dB; -10 dB; -20 dB

Power Requirements

Voltage :  100; 120; 220; 240 V , 50/60 Hz

Consumption:  180 watts Rated

Dimensions ((W x H x D):  460 x 160 x 375 mm (18-1/8" x 6-5/16" x 14-49/64")

Weight [net/packed]:  18 kg (39,7 lbs)/ 20,3 kg (44,8 lbs)

Sansui TU-9900

Professional class tuner for superior stereo receeption under any kind of broadcast conditions.

The   elegance of these tuners speaks for itself because they are deigned to complement the amplifiers you choose. Sansui's indepth research contributes a lot and has helped keep phase distortion down and FM selectivity high, for all of the tuners in the range. The control this tuner gives over an incoming signal puts it into a class way above that of an ordinary FM stereo receiver. With the TU-9900it's very much like having a private line between the tuner and the FM stereo broadcasting studio. The TU-9900 is the ultimate in tuner sophistication. But the same Sansui thought goes into all of the Tuners. This tuner not only look good. Slanted tuning dials, separate signal/tune meters, smooth dial mechanisms and many other convenince features make them a pleasure to use.

Dependable Plus-Minus Power Supply

Musical reproduction from broadcast sources depends heavily on correct and accurate power supply circuitry. The TU-9900 'finst of the Sansui TU Series' incorporates an elaborate feedback type stabilized power supply section for this very reason. It is of the plus-minus dual supply type to guarantee ideal circuit performance at all times.

Superlow Distortion, 0,06%

A wide-band ratio detector and a PLL circuit in the FM multiplex demodulator are employed for lower phase deviation. The TU-9900thus boasts aa very low distortion figure of 0,06% (mono) and 0,08% (stereo) in FM operation to bring its performance up to the quality required by the very best amplifier components.

Selectable FM IF Bandwidth

To enhance both the tonal quality and the reception ability of the TU-9900, Sansui has provided a switch to select either a Wide or Narrow FM IF bandwidth. In the former, two 6-pole LC block filters are put on line to improve the sound quality; in the latter, a narrow-band ceramic filter is added for more effective rejection of adjacent signals.

Automatic Noise Canceller

When receiving weak (or remote) stations, this circuit automatically blends the left and right signals in optimum proportion to the strength of an incoming broadcast to deliver the same noise-free reception of any station regardless of its strength.

High-Performance FM Front-End

The TU-9900 features a sensitivity of 1,5 µV (IHF) thanks to its linear-frequency 5-gang variable capacitor and the three dual-gated MOS FETs and a transitor employed in the high-performance FM front-end.

Quality AM Reception

AM broadcast are received cleanly and quietly with the lowest noise or interference possible thanks to the use of a double-tuned circuit and a dual-element, dual-coil ceramic filter in the AM section.

Positive Action Tuning

The feel and accuracy of the special tuning mechanism in the TU-9900 will be appreciated for years of hard and frequent use. It features an oversized tuning knob a special tension mechanism, and a heavyweight, high-inertia sintered iron flywheel.

Special Features for Tape Recording

Tape buffs will appreciate these three special features:

1.A built-in recording test signal generator is provided to facilitate pre-recording calibration of optimum recording levels.

2.A low-pass filter is included to prevent the carrier frequencies of FM broadcasts from interacting with the bias frequencies of decks in use, thus avoiding the annoying "beat" noise otherwise heard. The filter can be defeated by a front panel switch when not recording.

Other Important Features:

The TU-9900 has an FM Antenna Attenuator Switch to cut down the strength of excessive incoming signals; a Multi-Path Detection circuit to help align antennas, highly accurate Twin Tuning Meters, FM Muting Switch, Dolby FM output terminals, and an Output Level Control.

Specifications:

FM Section

Tuning Range:  88 - 108 MHz

Sensitivity:  1,5 µV (IHF); 0,9 µV (DIN)[1 kHz, mod.30%,S/N26 dB]

Max. Input Capability:  more than 130 dB

Quieting Slope:

Mono Wide :  37 dB 1,5 µV, 51 dB 3 µV

Narrow :  37 dB 1,5 µV, 51 dB 3 µV

Stereo Wide :  39 dB 10 µV, 53 dB 50 µV

Narrow :  40 dB 10 µV, 54 dB 50 µV

Total Harmonic Distortion

Mono Wide :  less than 0,06% (at 1 kHz); less than 0,06% (at 50 Hz); less than 0,08% (at 10 kHz)

Narrow :  less than 0,05% (at 1 kHz); less than 0,05% (at 50 Hz); less than 0,08% (at 10 kHz)

Stereo Wide :  less than 0,08% (at 1 kHz); less than 0,1% (at 50 Hz); less than 0,15% (at 10 kHz)

Narrow :  less than 0,8% (at 1 kHz); less tha 0,8% (at 50 Hz); less than 1,2% (at 10 kHz)

Signal-to-Noise Ratio

Mono :  better than 80 dB

Stereo :  better than 76 dB

Selectivity

Wide :  better than 55 dB (at 400 kHz); better than 22 dB (at 300 kHz); better than 5 dB (at 200 kHz)

Narrow :  better than 90 dB (at 400 kHz); better than 60 dB (at 300 kHz); better than 20 dB (at 200 kHz)

Capture Ratio:

Wide :  less than 1,0 dB

Narrow :  less than 3,0 dB

AM Suppression:  better than 58 dB

Image Frequency Rejection:  better than 100 dB at 98 MHz

IF Rejection:  better than 110 dB at 98 MHz

Spurious Response Rejection:  better than 110 dB at 98 MHz

Spurious Radiation:  less than 34 dB

Stereo Separation: 

Better than 50 dB at 1 kHz (30 dB at narrow)

Better than 40 dB at 50 Hz (30 dB at narrow)

Better than 40 dB at 10 kHz (30 dB at narrow)

Frequency Response:  30 to 15,000 Hz, +0,5 -0,8 dB

Antenna Impedance; 

Balanced :  300 Ω

Unbalanced : 75 Ω

FM Antenna Attenuator:  -30 dB

AM Section

Tuning Range:  535 - 1605 kHz

Sensitivity (Bar Antenna):  45 dB/m at 1,000 kHz

Selectivity:  better than 70 dB at 1,000 kHz (±10 dB)

Image Rejection:  better than 100 dB/m at 1,000 kHz

IF Rejection:  better than 100 dB/m at 1,000 kHz

Total Harmonic Distortion:  less than 1% at 80% Modulation 100 dB/m

Semiconductors:  39 Transistors; 3 FETs, 7 Ics, 39 Diodes, 1 Zener Dioda; 5 LEDs

Power Requirements:  100,120, 220, 240 V, 50/60 Hz

Power Consumption:  20 watts rated

Dimensions (W x H x D):  460 x 160 x 310 mm (18-1/8" x 6-5/16" x 12-1/4")

Weight: 

Net :  9,6kg (21,2 lbs)

Packed :  11,3 kg (24,9 lbs)

Sharp Optonica ST-3636

Optonica ST-3636 features:

FM IF AMP. Section

FM Front-End Circuit

FM IF  Band with Selector Circuit

FM Tuning Auto-Lock Circuit

FM Detection Sections (Quadrature Detector Circuit)

Hi-Blend Circuit

Low-Frequency Amplifier Circuit

Power Supply Circuit

Audio Muting Circuit

FM Detector Circuit. This unit employs "Quadrature Detector" based on newly developed IC, which is substituted for ratio detector and Foster-Seeley's detector that have been sp far used. The basic structure of quadrature detector circuit is as shon.

Multipath Detection Circuit

Multipath Distortion. In any of electric-wave signals broadcasting including FM waves, it would be ideal if the signals emitted by abroadcasting station were caught by a receiver's antenne as they midway. Actually saying, however, there are practically some obtacles (like mountains and  skyscrapers, etc.) between the transniter side and the receiver side, which have the emitted signals undergo a phenomenon of waves reflection, leading to that the signals become distored variously when caughtby the receiver's antenna

A simple exampleconcering this distortion is that in the mountainous area or large cities full of higher buildings, the TV stes get produced images be doubled (this called a ghost). This phenomenon is a sort of multipath distortion and it is caused by the there is a time delay betweenthe direct waves and reflected waves. In the case of radio sets, this is reffed to as that the reproduced sounds contain distortions; particularlyas for stereo broadcasting signals, since their band width is rather wider and so they are apt to be interferred by various objects, not only the distorted sounds are produced but also the stereo separation characteristics will suffer. These phenomena are named a multipath distortion.

Multipath Distortion Detection. Multipath distortion are classified into the two, that is, phase distortion which is found out by the frequency discriminator and AM distortion which is removed by the limiter circuit; the latter AM distortion is actually subject to detection by the multipath detector circuit.

FM Stereo Demodulator Section

Features of PLL Stereo demodulator Circuit.

This set incorporates a stereo demodulator circuit that comprises ICs with the PLL (Phase Locked Loop) system applied. The PLL FM demodulator circuit is provided with such characteristics as mentioned  below.

In order to demodulate stereo composite signals, it is necessary to take a 19 kHz pilot signal out of the stereo composite signals and to make it a 38 kHz signal.  Most of the conventional methods to obtain such a 38 kHz signal are frequency doubling ones which utilize a nonlinearity of the elements. Compared with the conventional type, the recently developed IC-ed demodulator provides more sufficient separation effects.  However, since it also requires 2 or 3 coils like the conventional one, if even one of them is dislocated from the initially adjusted point due to a secular change the separation effects will be deteriorated. Moreover there is such a contradiction that the more the efficiencies of the coils are increased enough to withstand the outer pulse signals like automobil ignition noises, the more the coils suffer secular changes.

To eliminate such disadvantages as above, PLL system is employed in the method to make a 38 kHz signal using a 19 kHz pilot signal.

Variable Air Check Calibrator Circuit

Theis circuit is to make appropriate the recording level in advance when recording FM broadcast into the tape deck or equivalent.

The circuit  is reffered to as this variable air check calibratoe circuit and it is composed of an air check oscillator circuit, air check meter indication circuit and further a circuit by which, when the air check/muting switch is set to 'air check on' position during FM reception, the indication mode of the signal/air check meter will be changed from 'signal level' to 'air check level' indication.

Specifications

FM Section

Tuning Range:  87,6 -108 MHz

IF:  10,7 MHz

Sensitivity (at SN 26 dB, 40 kHz deviation):  1,4 µV

Frequency Response:  30 - 15,000 Hz +1,5 -3 dB

Image Rejection:  110 dB (at 98 MHz)

IF rejection:  100 dB (at 98 MHz)

Selectivity [normal/wide]:  72 dB / 30 dB

Capture Ratio [normal/wide]:  2,5 dB / 1,5 dB

AM Suppression:  45 dB

Signal-to-Noise Ratio:  65 dB (40 Hz deviation)

Distortion [normal/wide]

Mono :  0,6% / 0,25%

Stereo:  0,8% / 0,4%

Stereo Separation:  42 dB (1 kHz)

AM Section

Tuning Range:  520 - 1620 kHz

IF:  455 kHz

Quieting Sensitivity:  400 µV/m

Image Rejection:  55 dB (at 1400 kHz)

IF Rejection:  50 dB (at 600 kHz)

Distortion:  1,5%

Audio Section

FM Output Voltage

Variable : 0 - 0,55 V

Fixed :  0,35V

AM Output Voltage:

Variable :  0 - 0,35 V

Fixeed :  0,2 V

Circuit:  Superheterodyne system, 2-band with PLL stereo demodulator

Featured:  FM muting, FM multipath detection, variable air check calibrator, FM auto lock, FM IF band selector circuit

Semiconductors:  28 Transistor, 36 Diode (1-zener diode); 4 ICs, 3 FET (dual gate, MOS type); 3 LED

Power Source:  AC 110/220/240V, 50/60 Hz

Power Consumption:  24 W

Dimensions (W x H x D):  442 x 144 x 373 mm

Weight:  7,5 kg