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





Alchemist TS-D1 DAC

The new Alchemist TS-D1, 24-bit 96 kHz compatible DAC will support all sampling rates up to and including the very latest DVD standard of 96 kHz. Therefore making it the obvious affordable upgrade for the latest generation of CD/DCC/DAT/DVD and Mini Disc machines. Bringing true audiophile status to otherwise mediocre performers. It offers the choice of either Coaxial or Optical input connection, along with a digital record output to allow digital recording onto Mini Disc, CDR or DAT types machines.

The TS-D1 is based around the latest surface mount microchips from Crystal and Burr Brown making it the most up to date DAC available today. These coupled with many proprietary filtering enhancements also make it perform beyond its diminutive size.

The TS-D1 is just the beginning of an exciting new range of products that will include a MM/MC phono stage, remote controlled preamplifier and power amplifiers amongst others, all utilizing the extrusion that gives them their unique identity.

 


Specifications

DAC-Type 24-bit, 8x Oversampling, Multi Level Delta Sigma

Sampling Rates:  Supports all sampling rates in range 16 kHz - 96 kHz

Data Types:  16, 18, 20 and 24 Bit SPDIF

Level (0 dB) :  2 V RMS

Total Harmonic Distortion (+n) :  -96 dB

Linearity:  ±0,3 dB to 100 dB

Signal-to-Noise Ratio :  104 dB

Dynamic Range:  104 dB

Master Clock :  256 Fs

Digital Filter:  8x Oversampling, 80 dB stopband attenuation

De-emphasis (44,1 kHz):  Digital domain <0,2 dB error

Dimensions (W x H x D):  154 x 45 x 170 mm

Weight:  3 kg (packed)


 

Denon TU-900 tuner

Digital Display Servo Locked FM Stereo Tuner

Features:

Precise station selection tuning is ensured as the tuner is provided with both a dial scale and a digital adops the auto servo lock touch tuning system, to gain high Signal-to-Noise Ratio and low Distortion.

IF amplifier stage combines low distortion (0,025% mono) high selectivity (90 dB or better) with a 2-system (wide, narrow) IF amplifier circuit and a double filter pilot canceller circuit.

Provided with a high sensitivity front-end with a linear frequency type 5-gang variable capacitor that suppress intermodulation distortion

The audio amplifier stage is of DC configuration and specifically designed for the purest amplification possible.

The MPX stage achieves low distortion through a pilot canceller circuit and improving the separation with a unique separate correction circuit. A 440 Hz oscillator offers convenient air check.

Incorporates 2-output circuit system for amp and deck etc.

 

Precise Tuning with Excellent Performance

The Denon TU-900 employs a "Precise Tuning" system, with tuning accuracy 10 times higher than conventional system. In addition, tuning is quicker and more precise thanks to the automatic touch sensitive servo lock tuning system that automatically disengages the servo locking circuit when the tuning knob is touched with the hand.

It's almost like magic.

Featuring both and easy-to-read analog dispay scale and a digital readout. It is equipped with an automatic servo-lock touch sensor system, making tuning easier and more accurate. And, for improved performance, it is constructed with a high-sensitivity front-end, a wide and narrow 2-band IF amplifier, a wide band detection circuit, and MPX circuit with a pilot signal canceller, a pure DC amplifier, and an array of other features that make possible a high Signal-to-Noise Ratio ratio of 88 dB , a low distortion factor of 0,025%, and superb separation of 60 dB.

 

Dual-Gate MOS FET and a 5-Gang Variable Capacitor

Denon didn't just improve the Signal-to-Noise Ratio , but went all the way to tackle the task of improving sensitivity to 1,7 µV (9,8 dBf). And, inter modulation distortion has been suppreeed by increasing the interference wave removal capacity, obtaining an image-spurious-IF interference wave ratio of more than 110 dB.

 


Specifications

Type:  Digital display FM Stereo Tuner

Receiving Range:  88 - 108 MHz

Usable Sensitivity:  1,7 µV (9,8 dBf)

Effective Selectivity (±400 kHz): 

Wide :  50 dB

Narrow :  90 dB

Signal-to-Noise Ratio;

Mono :  88 dB

Stereo :  85 dB

Total Harmonic Distortion

Monaural (100 % mod.) Wide / narrow :  0,025% / 0,1%

Stereo (90% mod.) Wide / Narrow :  0,035% / 0,3%

Capture Ratio:  1,0 dB

AM Suppression:  70 dB

Image Rejection:  90 dB

IF Rejection:  100 dB

Spurious Response:  90 dB

Frequency Response :  20 Hz - 15 kHz (+0,2 dB -1,5 dB)

Stereo Separation: 

Wide :  60 dB

Narrow :  45 dB

Muting Operation Level :  26 dB

Output Level (100% mod.): 

Deck :  0,6 V

Amp :  3,3 k

Level Check Frequency:  440 Hz

Tuning Indicator:  by LED

Tuning Strength Indicator:  by 5 Leds

Antenna Terminals:  75 , 300

Power Supply:  AC 120 V, 200V/220 V/ 240 V 50 Hz

Power Consumption:  14 W

Dimensions (W x H x D):  505 x 83 x 344 mm

Weight:  6,1 kg

Akai GXC-65D cassette deck

From Akai new sound in cassettes

Akai gives you the most perfect cassette recording in the world today.

That's a mighty big claim. But we can prove it. Our GXC-65D Stereo Cassette  Recorder is innovatively engineered with ADRS. This exclusive system eliminates almost all high frequency distortion above 8,000 Hz.

But we didn't stop there.

We combined ADRS with Dolby, and then added Akai's exclusive GX (Glass and Crystal ferrite) head.

The clear, undistorted signal is a pleasure to behold. And a greater pleasure to hear. What's more, the GXC-65 D is equipped with Akai's Invert-O-Matic - automatically reverses the cassette inside the recorder for continuous repeat/reverse. And the Invert-O-Matic mechanism is unconditionally guaranteed for two years - parts and labor.

So you can stop sitting around waiting for perfect cassette recording. Listen to the GXC-65D - your ears will make up your mind for you.

 


Illustrated below are the actual output curves of 13,000 Hz signal from a Dolby equipped cassette deck without ADRS, and a comparable curve from the new Akai GXC-65D.

 


Specifications

Track System:  4-track, 2-channel stereo system

Tape Speed:  1-78 ips ±2%

Wow and Flutter:  less than 0,12% RMS

Frequency Response:

Chrom Tape :  30 to 18,000 Hz

LN Tape :  30 to 16,000 Hz

Signal-to-Noise Ratio:  better than 58 dB with Dolby

Distortion:  less than 2% at 1,000 Hz "0" VU recording

Crosstalk:  better than 25 dB

Erase Ratio:  better than 70 dB

Bias Frequency:  61 ±3 kHz

Bias Leak:  less than -50 VU

Outputs:

Line :  0 ±1,5 dB (0,775 V) using a 333 Hz pre-recorded tape

DIN :  0,4 V

Phone :  30 mV at 8

Speaker :  6 W each channel at 8

Inputs:

Mic :  more than 0,4 mV / 4,7 k

Line :  more than 50 mV/ 200 k

DIN :  more than 7 mV (low), 70 mV (high)

Recording Capacity:  1 h stereo recording using C-60 cassette tape

F.Fwd and Rwd Time :  68 sec (C-60)

Heads:

Recording/Playback:   P4-330, 4-track, 2-channel GX rec/playback head

Gap /  Impedance :  1,4 - 1,9 microns/1,200  ±20% at 1 kHz

Erase Head :  E4-150, 1-track, 1-channel erase head

Gap  /Impedance :  0,3 mm / 195  ±10% at 100 kHz

Motor:  Hysteresis Synchronous Outer-roter motor

Typ :  HM-12CS

Revolutions :  1,500 / 1,800 rpm at 50/60 Hz

Power Supply:  100 to 240 V AC 50/60 Hz

Power Consumption:  50 W (recorder type), 20 W (deck type)

Dimensions (W x H x D):  415 x 180 x 290 mm (16,6" x 7,2" x 11,6")

Weight:  9,2 kg (20,2 lbs)


 

Audio Research D-70 power amplifier

If a preamplifier is viewed as the control center of a music system, then an amplifier can be regarded as the "engine" which power the system.. There is a misnomer among the audio community that amplifiers have no distinct "sonic signature" of their own, and that amplifiers varying widely in design and construction exhibit only minimal sound differences. Whit thirty years of design experience Audio Research has discovered this is not the case.

Claims for amplifier similarity have been strictly based on static performance measurements made into purely resistive loads. This is a poor test basis, similar to comparing a racing engine to a road model at identical idling speeds and concluding that they are equal in performance. In fact, amplifiers vary widely in their sonic character and recent advances in amplifier technology make this easily demonstrable .

From a performance standpoint, amplifiers must meet the same criteria for preamplifiers including clarity. High Definition , harmonic accuracy and dynamic range. Perfect linearity under difficult load coditions is impossible to achieve. However, Audio Research has been responsible in extending amplifier performance to new limits for nearly two decades.

 

Design Criteria

When designing a high performance power amplifier, the engineer is faced with four primary considerations:

  • Audio quality
  • Construction quality
  • Power
  • Costs.

So successfully blended are these criteria that Audio Research amplifiers now extend state-of-the-art. Performance without sacrifice in power, construction quality or at unreasonable cost.

Because Audio Research has given continuous attention to improving all aspects of amplifier design for many years. Audio Research now manufactures amplifiers which appear modest in price compared to state-of-the-art. Models of just a few years ago. Yet the performance capabilities of these amplifiers are so great that they overwhelm recent state-of-the-art. Amplifieres built without cost constraints.

 


Features

Patented Audio research cross-coupled and fully balanced circuitry

Front panel power switch relay coupled for smooth and reliable turn-on

Front panel LED indicators for line and screen

Front panel fusing for line and screen

Sonically selected components for optimum sound performance

Near military grade construction used hroughout

 


Specifications

Power Output:  65 watts per channel minimum continuous at 16 ohms from 20 Hz - 20 kHz with less than 1% Total Harmonic Distortion

Power Bandwidth:  10 Hz to 60 kHz (-3 dB points)

Input Sensitivity:  95 V RMS for rated output

Input impedance:  75 k Ω nominal

Noise:  greater than 90 dB below rated power, broadband unweighted

Dimensions (W x H x D):  19" x 7" x 16,5"