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





Hitachi HT-61S turntable

 

Full-Automatic Direct-Drive Turntable

Fully automatic operation with all controls on the front panel provides outstanding convenience in each model; the HT-61S (HT-R10) gives you a few extras. In short, these turntables leave nothing to be desired. This TH-R10 can be used with the RM-1000 remote control center for extra convenience, too.

 

Automatic disc Size/Speed Selection

The HT-61S/R10 uses a light beam to sense the size of the record on the platter and automatically set the lead-in for either 30-cm or 17-cm, so the stylus will lower to exactly the right place. At the same time, platter speed is automatically set to the corresponding speed; 33-⅓ or 45 rpm. This makes operation surer and more convenient, putting the HT-61S/R10 another step above ordinary turntables.

 

All Controls Up Front

All Control functions are located on top of the turntable's front panel. They are accessible when the dust cover is down, preventing the possibility of jarring the tonearm during play. And thanks to the use of IC logic circuitry, it only takes a feather touch to operate all controls.

 


Other features:

Quartz Lock Plus High Torque Equals Speed Accuracy,

Unitorque Motor,

Gimbal-Suspension Straight Tonearm,

Photo Sensor Arm Return System

Resonance-absorbing base

Anti-feedback insulator feet

Removable, hinged dust cover

High quality headshell ideally matched to tonearm

Optional remote control capability for HT-R10

 

Specifications:

Type:  Full automatic, 2-speed, quartz lock , direct-drive

Platter:  Aluminum alloy diecast 310 mm outer diameter

Motor:  Brushless coreless, slotless "Unitorque" motor; DC motor for arm movement.

Speed:  33-13 and 45 rpm

Speed Change System:  Electronic changeover system

Signal-to-Noise Ratio:  78 dB (DIN-B)

Wow and Flutter:  0,025% WRMS

Speed Accuracy:  0,003%

Speed Drift

Time :  0,003% (30 sec - 303 min)

Temperature :  0,003% (5 - 35°C)

Tonearm

Type:  Static-balanced, straight

Headshell:  ADC type

Tracking Error: 

Adjustable Force Range:  0 - 3 g / 1 turn of the balance weight (directly readable in 0,1 g steps)

Acceptable Cartridge Weight:  4 - 10 g

General

Dimensions (W x H x D):  435 x 365 x 110 mm (17-1/8" x 14-3/8: x 4-5/16")

Weight:  6 kg (13 lbs 3 oz)

Hitachi HT-60S turntable

 

Full-Automatic Direct-Drive Turntable with Quartz Lock, 

Unitorque Motor, Gimbal-Suspension Straight Tonearm 

and Photo Sensor Arm Return System

 

This model feature a sleek, clean design, convenient operation, and the superior quality and reliability that advanced Hitachi technology makes possible. They combine the proven excellence of Hitachi's Unitorque motor and quartz-lock PLL servo system with the latest improvements in tonearm design from the Hitachi Audio R&D labs; gimbal-suspension straight tonearm with photo-sensor return system. Fully automatic operation with all controls on the front panel provides outstanding convenience in each model; the HT-61S (HT-R10) gives you a few extras. In short, these turntables leave nothing to be desired. This TH-R10 can be used with the RM-1000 remote control center for extra convenience, too.

 

Unitorque - A Unique Motor

The HT-60S is direct-drive turntables - the  platter is driven directly by the motor. Overall performance, then, is directly dependent on motor performance. Other turntables use either multi-pole DC motors or AC motors, which have various disadvantages. AC motors are extremely inefficient and subject to vibrations; DC motors suffer from uneven torque - they rotate in a series of "steps" or "puls", which must be smoothed out by adding more poles/slots or extra servo circuitry - complicated, unreliable, costly measures which are only partially effective.

The Unitorque motor prevents these problems from occurring at all. It is a brushless, slotless, coreless motor with perfectly smooth, even torque (hence the name, Uni-Torque) its unique design employs two star-shaped flat coils positioned in such a way that their independent torques combine to produce constantly even torque throughout each rotation. A 240-pole magnetic rotor provides added stability. The Unitorque motor thus features precision, reliability and efficiency superior to other types of motors.

 


Quartz Lock Plus High Torque Equals Speed Accuracy

Complementing the Unitorque motor is a quartz-lock PLL (Phase-Locked-Loop) servo system. While conventional servo systems must rely on a reference voltage (subject to fluctuation due to variations in supply and temperature), these two models use a quartz crystal oscillator, whose pulses never vary in the slightest degree. They are compared to pulses directly from the motor so even infinitesimal speed variations can be detected and corrected. And thanks to the high torque of the Unitorque motor, this process occurs much faster than in conventional systems. It all adds up to outstanding speed accuracy; wow and flutter is an extremely low (0,025%). As an added touch, a quartz lock indicator is provided to inform you when the turntable has reached operating speed and the quartz PLL circuit has locked in.

 

Gimbal-Suspension Straight Tonearm

The HT-60S employ Hitachi's new straight-line tonearm design, developed through an extensive testing process. Its low mass characteristics provide superior tracking capabilities, and bring out all the performance possibilities of high compliance cartridges. And its highly symmetrical, precise construction eliminates much of the resonance that conventional cartridges suffer from. The tonearm is mounted on a gimbal support system. This gimbal suspension allows free movement in both vertical and horizontal directions, for optimum balance during tracking. This means lighter, more sensitive tracking for better reproduction quality with less stylus and record wear. An easy one-touch anti-skating control further increases tracking accuracy by counteracting the force which pulls the tonearm toward the center of the record.

 

Photo-Sensor Arm Return System

This Hitachi systems is clearly superior to conventional arm return methods. Ordinarily, auto-cut and auto-return are triggered by mechanical contacts or linkages connected to the base of the tonearm. They cause a certain amount of drag, inhibiting tonearm movement sufficiently to produce distortion. In addition, they are subject to wear and mechanical failure,

The photo-sensor system is much more sophisticated. The only thing that touches the tonearm assembly is a light beam. It passes from an LED to a photo-sensitive cell. When the arm, reaches the end of the record, a thin plate attached to the base cuts the light beam. This change in light intensity causes the cell to activate a switching circuit, which in turn activates a small arm-drive motor. This entire system is located far away from the main drive mechanism, so it does not affect reproduction quality at all. Phot-sensor arm return - an elegant innovation that improves performance and reliability.

 

Full Automatic Convenience

All tonearm movements are automatically controlled, and driven by a separate DC motor. Pushing the start button initiates arm movement to the correct position over the record and then lowers the arm. This button can also be used to interrupt play (cut). At the end of the record, as described above, the photo-sensor system returns the arm, then shuts off the motor. A repeat function is also included to let you hear a record more than once without having to touch the unit.

  

 

Specifications:

Type:  Full automatic, 2-speed, quartz lock , direct-drive

Platter:  Aluminum alloy diecast 310 mm outer diameter

Motor:  Brushless coreless, slotless "Unitorque" motor; DC motor for arm movement.

Speed:  33-13 and 45 rpm

Speed Change System:  Electronic changeover system

Signal-to-Noise Ratio:  78 dB (DIN-B)

Wow and Flutter:  0,025% WRMS

Speed Accuracy:  0,003%

Speed Drift

Time :  0,003% (30 sec - 303 min)

Temperature :  0,003% (5 - 35°C)

Tonearm

Type:  Static-balanced, straight

Headshell:  ADC type

Tracking Error: 

Adjustable Force Range:  0 - 3 g / 1 turn of the balance weight (directly readable in 0,1 g steps)

Acceptable Cartridge Weight:  4 - 10 g

General

Dimensions (W x H x D):  435 x 365 x 110 mm (17-1/8" x 14-3/8: x 4-5/16")

Weight:  6 kg (13 lbs 3 oz)

Denon DR-330 cassette deck

 

 

Denon DR-330 Features:

3-head tape Tension Servo System Stereo Cassette deck

Denon's new tension servo semsor maintains optimum tape tension

F-alloy combination head offers wide frequency response 25 Hz - 21 lhz (±3 dB), high sensitivity and low distortion. Quartz locked PLL servo motors drivers the capstan for higher tape transport stability

Double Dolby noise reduction system

 

Specifications

Type:  Vertical tape loading 4-track, 2-channel stereo

Heads: 

1 x Record/Playback F-alloy head

1 x Erase double gap Ferrite head

Motors:

Capstan :  1 x Quartz Lock PLL DC servomotor

Reel :  1 x DC motor

Tape Speed:  4,8 cm/sec

Fast Winding/Rewinding Time:  approx. 85 sec (C-60 cassette)

Recording Bias:  appox. 85 kHz

Overal Signal-to-Noise Ratio (at 3% T.H.D. level):  more than 67 dB

Overal Frequency Response:

Metal Tape :  25 - 21,000 Hz (at - 20 dB)

CrO₂ Tape :  30 - 20,000 Hz (at - 20 dB)

FeCr Tape :  30 - 19,000 Hz (at -20 dB)

LH Tape :  30 - 19,000 Hz (at -20 dB)

Channel Separation:  more than 40 dB (at 1 kHz)

Crosstalk:  more than 65 dB (at 1 kHz)

Wow and Flutter:  less than 0,04% WRMS

Inputs Sensitivity/Impedance

Microphone :  0,35mV (-67 dB) / 10 k

Line :  70 mV (-21 dB)/ 50 k

Outputs Level/Impedance

Line :  775 mV (0 dB)/ 10 k

Headphone ;  1,2 mW/ 8   - 2 k

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

Power Consumption:  25 W

Dimensions (W x H x D):  434 x 117 x 300 mm

Weight:  7,0 kg

Denon DR-320 cassette deck

3-Head Tape Tension Servo System Stereo Cassette Deck

Denon's new tension servo system

3-head configuration, with Denon's new tape transport system provides better tape contact to the heads

Double Dolby system further improves the performance of the 3-head system by eliminating tape hiss

Full DC amplifiers are built into both the record and playback system for wide frequency response

ACA-10 side wooden cabinet is available

 

 


Specifications

Type:  Vertical tape loading 4-track, 2-channel stereo

Heads: 

1 x Record/Playback F-alloy head

1 x Erase double gap Ferrite head

Motors:

Capstan :  1 x DC servomotor

Reel :  1 x DC motor

Tape Speed:  4,8 cm/sec

Fast Winding/Rewinding Time:  approx. 90 sec (C-60 cassette)

Recording Bias:  appox. 85 kHz

Overal Signal-to-Noise Ratio (at 3% T.H.D. level):  more than 67 dB

Overal Frequency Response:

Metal Tape :  25 - 21,000 Hz (at - 20 dB)

CrO₂ Tape :  30 - 20,000 Hz (at - 20 dB)

FeCr Tape :  30 - 19,000 Hz (at -20 dB)

LH Tape :  30 - 19,000 Hz (at -20 dB)

Channel Separation:  more than 40 dB (at 1 kHz)

Crosstalk:  more than 65 dB (at 1 kHz)

Wow and Flutter:  less than 0,04% WRMS

Inputs Sensitivity/Impedance

Microphone :  0,35mV (-67 dB) / 10 k

Line :  70 mV (-21 dB)/ 50 k

Outputs Level/Impedance

Line :  775 mV (0 dB)/ 10 k

Headphone ;  1,2 mW/ 8  - 2 k

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

Power Consumption:  25 W

Dimensions (W x H x D):  434 x 117 x 300 mm

Weight:  7,0 kg