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 Research Classic 60

 Audio Research now proudly introduces the Classic,  new , moderately priced stereo hybrid amplifiers that come surprisingly close to the benchmark set by the acclaimed Classic 150 hybrid monaural amplifier.
It doesen't take a "golden ear" to immediately perceive the emotinal power and sonic authority the Classic 60 bring to any good musical program. Silences are more silent by an order of magnitude; the soundstage is broad, deep tall; instrumental timbres have an uncommon truth to them; dynamics soft and loud are unbelievably convincing.
 And the Classic 60 are designed to provide years of trouble-free service. You don't need to be a technican to use and enjoy them. Quite simply, the Classic 60 bring world-class audio performance within reach of most music lovers. Audition one today at your nearest Audio Research dealer.
For effortless musicality and value second to none,  it has to be the Classis 60.
The Classic 60 Hybrid Stereo Power Amplifier resembles the long-popular D115 in Audio Research's family of High Definition power amplifiers. But its lineage is strictly Classic 150. which means nothing less than state-of-the-art. In design, construction, musicality and operational convenience, at an affordable price.
Like the Classic 150, the Classic 60 proceeds from the notion that power ratings don't always describe a power amplifier's real capabilities. Far more important are such qualities as dynamic stability, lucidity, subtlety. And to achieve those, audio Research has used its traditional partial cathode coupling along with triode operation of the Classic 60's eight 6550 power output tubes. Additional circuit improvements as well as the usual rigorous parts selection and manufacturing Audio Research is noted for also contribute sonically.
 Translated into the language of listening, this signifies stunning bandwidth, a noise floor virtually beneath audibility and musically fulfilling SPLs at dramatically lower gain settings. Dynamics, timbers of individual instruments, soundstage and musical emotion all surge out rom a black velvet of silence.

Simply put, the Classic60 resolves far more of a musical program than amplifiers rated at two, three or four times its seemingly modest 60 WPC.
But the Classic 60 is easily up to the task of driving all but the most demanding loudspeakers, even in spacious listening rooms. And while it shows modest preamplifiers in their best light,it also shines when coupled with premiere designs, such as Audio Research's Sp14 or Sp15.
 Convenience figures high on the Classic 60's list of attributes, as well. For example, DC balance of the output tubes is maintained automatically, while tube biasing continuously adjust to changes in incoming line voltage. Performance stays razor-sharp without bother some tweaking or adjustments. And quiet fan cooling, along with triode operation, means significantly longer tube life. A Classic 60 owner can look forward to years of low-maintenance performance.
Specifications
Power Output:  60 watts (minimum continuous at 16 Ω from 15 Hz - 20 kHz with less than 1,0% T.H.D.)Power  Bandwidth:  12 Hz to 40 kHz (-3 dB Points)
Input Sensitivity:  0,55 V RMS for rated output
Input Impedance:  100 k Ω nominal
Output Regulation:  approx.0,3 dB (16 Ω load to open circuit , damping factor approx. 30)
Negative Feedback:  20 dB
Slew Rate:  20 volts/microsecond
Rise Time:  2,0 microsecond
Hum and Noise:  less than 2,0 mV RMS, 84 dB below rated output (20 kHz bandwidth unweighted, inputs shorted)
Power Supply Energy Storage:  approx. 280 joules
Power Requirements:  105 -125 V AC 60 Hz (210-250 V AC 50 Hz)
Power Consumption:  500 watts at rated output; 700 watts maximum, 370 watts at "idle"
Tubes Required: 
for Power Output :  4 x matched pair 6550 (low gas);
for Drivers :  4 x 6FQ7/6CG7
Dimensions (W x H x D):  approx. 480 x 180 x 400 mm (19" x 7" x 15,75")
Handles extend :  41 mm (1-5/8") forward of the front panel
Weight:
Net :  28,6 kg (63 lbs)
Shipping :  34,5 kg (76 lbs)

Audio Research Classic 30


Audio Research now proudly introduces the Classic 30; new , moderately priced stereo hybrid amplifiers that come surprisingly close to the benchmark set by the acclaimed Classic 150 hybrid monaural amplifier.
It doesen't take a "golden ear" to immediately perceive the emotinal power and sonic authority the Classic 30 bring to any good musical program. Silences are more silent by an order of magnitude; the soundstage is broad, deep tall; instrumental timbres have an uncommon truth to them; dynamics soft and loud are unbelievably convincing.
And the Classic 60-30 are designed to provide years of trouble-free service. You don't need to be a technican to use and enjoy them.
Quite simply, the Classic 30 bring world-class audio performance within reach of most music lovers. Audition one today at your nearest Audio Research dealer.
Putting the state-of-the art. Within everyone's reach… the Classic 30
It's tempting to regard the Classic 30 as merely the smaller sibling of the Classic 60 and Classic 150.
But the skeptical music lover or audiophile who auditions the Classic 30 is in for quite a shock. Because this "little" hybrid stereo amplifier - rated at 30 WPC - packs a sonic authority and eloquent musical veracity that larger, more conventional power amplifiers might envy. Our engineer have discovered that sometimes less is very definitely more.
Of course, the Classic  30 features almost all the same technology as its bigger brothers, scaled down for more modest applications. It has four 6550s instead of eight, two 6FQ7 driver tubes instead of four; no fans, because it runs remarkably cool without any help whatever.
But this smaller design still retains a similar degree of exceptional musical resolution. Even at low gain settings, the Classic 30 is far more musically lucid than amplifiers objectively far more powerful.
The Classic 30 is at its pristine best with moderately efficient loudspeakers in smallto medium sized listening rooms; with program materials that demand high resolution and subtlety rather than pure muscle. In that context, it reveals the same sonic mastery as its more powerful siblings.
But don't take our word for it. Audition a Classic 30 today and discover just how much more music can come alieve , with" less"
Specifications
Power Output:  30 watts (minimum continuous at 16 Ω from 17 Hz - 20 kHz with less than 1,0% T.H.D.)Power  Bandwidth:  15 Hz to 50 kHz (-3 dB Points)
Input Sensitivity:  ,4 V RMS for rated output
Input Impedance:  100 k Ω nominal
Output Regulation:  approx.0,4 dB (16 Ω load to open circuit , damping factor approx. 23)
Negative Feedback:  19 dB
Slew Rate:  15 volts/microsecond
Rise Time:  3,5 microsecond
Hum and Noise:  less than 0,5 mV RMS, 93 dB below rated output (20 kHz bandwidth unweighted, inputs shorted)
Power Supply Energy Storage:  approx. 150 joules
Power Requirements:  105 -125 V AC 60 Hz (210-250 V AC 50 Hz)
Power Consumption:  300 watts at rated output; 400 watts maximum, 200 watts at "idle"
Tubes Required: 
for Power Output :  2 x matched pair 6550 (low gas);
for Drivers :  2 x 6FQ7/6CG7
Dimensions (W x H x D):  approx. 480 x 180 x 370 mm (19" x 7" x 14,5")
Handles extend :  41 mm (1-5/8") forward of the front panel
Weight:
Net :  20,9 kg (46 lbs)
Shipping :  28,2 kg (62 lbs)

Aiwa AD-F880

 Superior 3-Head Fidelity with Advanced Features
The AD-F880 is a quality 3-head deck with a variety of advanced features for superb high fidelity performance.
The 3-head design incorporates AIWA's super DX recording and playback heads which feature cores are wound with PC-OCC (Pure Copper-Ohno Continuous Casting) copper wire having ultra high conductivity for greater musical resolution.
The die-cast alloy Bias Shield Head Block minimizes interfrence between the recording and playback heads.
 AIWA's original micro-grain surfaced dual capstan drive improves tape transport performance, while the ATMS (anti-modulation tape stabilizer) damps out resonance for clearer sound reproduction.  The manual recording calibration system and bias fine adjustor allow optimum recording performance with any tape formulation you use.  Dolby B and C noise reduction systems work to reduce unwanted tape hiss, while Dolby HX professional circuitry works during recording to extend high frequency response with any type tape.
Convenience extras like wireless remote control, feather-touch IC logic controls, an electronic tape counter with memory rewind and repeat, and more make the Ad-F880 the kind of deck you can depend on for quality cassette performance.

Specifications
Track:  4-track, 2-channel
Tape Speed:  1 lps (4,8 cm/sec)
Frequency Response
Normal tape (0 VU):  20 - 11,000 Hz (±3 dB)
CrO₂ tape (0 VU):  20 - 14,000 Hz (±3 dB)
Metal tape (0 VU):  20 - 17,000 Hz (±3 dB)
Normal Tape, (at -20 VU):  20 - 17,000 Hz (±3 dB)
CrO₂ Tape, (at -20 VU):  20 - 18,000 Hz (±3 dB)
Metal Tape, (at -20 VU):  20 - 19,000 Hz (±3 dB)
Signal-to-Noise  Ratio:  
Dolby B (Metal):  68 dB
Dolby C  (Metal, above 5 kHz):  78 dB
Wow and Flutter (WRMS):  0,035%
Forward and Rewind Time for C-60 Tape:  60 sec.
Head: 
REC :  Super DX Head
PB:  Super DX Head
Erase Head:  Double-gap Sendust Head
Motors:  DC servo motor x 1, and DC motor x 1
Input Sensitivity /Impedance  (Line-In):  50 mV/50 kΩ
Output Level Impedance:
Line Out:  0,45 V/47 kΩ or higher
Headphone:  0,8 mW/32 Ω
Power Source:  AC  110-120/220-240 V, 50/60 Hz
Dimensions (W x H x D):  430 x 126 x 317 mm
Weight:  5,2 kg

Denon PMA-850

Solid State Stereo Integrated Amplifier
A new series of Denon amplifiers, incorporating a wide dynamic range, low noise MC amplifier. It reaches the highest class in the most fundamental characteristic of amplifiers both in distortion factor and Signal-to-Noise  separation. By coupling all stages with a pure complementary circuit from MC amplifier to power amplifier using both PNP, NPN transistors, an ultra low distortion rate of 85 W +85 W was achieved.
Features:
An DC power amplifier placing importance on a quick build-up characteristic by incorporating, a new amplifying element. Distortion factor less than 0,01% (20 Hz - 20 kHz).
Torodial core power transformer which has an independent coil for left and right channels for exceptional regulation.
Employment of an ultra low noise transistor permits a high Signal-to-Noise  ratio, head amplifier for MC type cartridge (74 dn IHF-A), and equalizer amplifier (89 dB IHF-A)
Provided with direct couple switch for direct connection of equalizer amplifier and power amplifier
A unique design of two tone color, imparting a sense of high class structural grace.

Specifications:
Type Amplifier:  All stage pure complementary pushpull system DC circuit
Power Amp Section
Rated Output (Both channel driven):
110 W RMS (at each channel) : 1 kHz (T.H.D. 0,05%, 4 Ω)
85 W RMS (at each channel) :  20 Hz to 20 kHz (T.H.D. 0,01%, 8 Ω)
Total Harmonic Distortion (at rated output, 20 Hz to 20 kHz):  less than 0,01%
Intermodulation Distortion (60 Hz : 7 kHz = 4 : 1)a rated output:  less than 0,02%
Power Bandwidth (both channels driven, 8 Ω):  5 Hz to 100 kHz
Transmission Characteristic:  DC to 100 kHz +0 dB, -1 dB (at 1 watta output)
Frequency Response (at 0,5 W output, -1 dB):  5 Hz - 100 kHz +0 dB -1 dB
Input Sensitivity/Impedance (20 Hz - 20 kHz):  1 V RMS/50 k Ω  ±10 %
Output Impedance:  less than 0,16 Ω
Signal-to-Noise  Ratio (IHF, A network at input terminal Shorted):  122 dB
Output Terminals:
Speaker :  A & B = 4 - 16 Ω load; A + B = 8 - 16 Ω load
Headphone :  for stereo headphone
Pre Amplifier Section
Pre Amp Output:
Max. Output :  25 V at 50 k Ω
Rated Output :  1 V
T.H.D. :  0,003% at 3 V output
Equalizer Amp Output:
Max. Output :  25 V at 50 k Ω load (T.H.D. 0,01%)
Rated Output :  320 mV
Input Sensitivity/Impedancce
Phono MM 1, 2  :  2,5 mV RMS/ 50 k Ω
Phono MC 3 :  0,37 mV (cartridge impedance 40 Ω)
Tuner :  320 mV / 40 k Ω
Aux, Tape :  320 mV / 40 k Ω
RIAA Deviation (20 Hz to 20 kHz):  ±0,2 dB
Signal-to-Noise Ratio (IHF, A network)
Maximum Allowable Input Phono:  200 mV RMS (1 kHz)
Phono MM :  better than 89 dB (input terminal shorted)
Phono MC :  better than 74 dB (input terminal 40 Ω)
Tuner, Aux, Tape :  better than 105 dB (input terminal shorted)
Aux to pre Out Frequency Response Tone Defeat:  5 Hz to 100 kHz +0 dB, -1 db
Tone Control Frequency Response:
Bass :  100 Hz ±8 dB
Treble :  10 kHz ±8 dB
Filter Characteristic:
Subsonic  :  20 Hz  at 12 dB/oct
High Cut :  9 kHz at 12 dB/oct
Loudness Control Characteristic:
Low Range :  100 Hz +7 dB
High Range :  10 kHz +6 dB
Muting level:  -20 dB
Power Source:  AC 120 V 60 Hz, AC 220/240 V 50/60 Hz
Dimensions (W x H x D):  434 x 164 x 400 mm (17-5/64" x 6-29/64" x 15-3/4")
Weigh:  17 kg (37,5 lbs)