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





Yamaha CR-620 receiver

Natural Sound FM/AM Stereo Receiver

Pure, low distortion power and wide NDCR

FM section with NFB-PLL-MPX

Completely independent tape recording and audition

Continuous Loudness Control

 

The Power Section

Distortion Cut in half - to an incredible 0,05%

Our first complete receiver line, with 0,1% distortion, astounded the audio world. Others rushed to improve their performance specs, but no other manufacturer has equalled that figure for its whole line. Now, in the new Yamaha receiver line, Intermodulation DIstortion and Total Harmonic Distortion are reduced even further to 0,05%. Makers who had not succeeded in matching the 0,1% figure are going to find it even harder to attain the new Yamaha level of 0,05%.

What SVR means in Reducing Dynamic Crosstalk

With many conventional power supply circuits, a loud signal in one channel will draw heavy current which produces a spurious signal - distortion - in the other channel. Supply Voltage Rejection (SVR) must be high if this form of distortion is to be kept well below the level of audibility. The special power supply circuit of the CR620 is even more effective, and gives a higher SVR, than expensive dual power supplies, providing a marked improvement in detailed accuracy in the loudest and most complex passages.

 


The Pre Section

Supern Signal-to-Noise Ratio

Precision circuit design gives the CR620 outstanding Signal-to-Noise characteristics. This results in an extra measure of clean quiet music performance

Accurate RIAA Equalization

The CR620 boasts an equalizer section with only ±0,5 dB deviation from RIAA characteristics, for faithful reproduction of everything recorded on the disc. And at 120 mV (1 kHz), the phono dynamic range is amply wide enough for top quality enjoyment of high cutting level discs with high output cartridges.

Continuously Variable Loudness Control

The CR620 features the same continuous type loudness compensation control as on the Prestigious C-1 control amp, letting you retain an unvarying, natural tonal balance at any and all listening levels, compensating perfectly for the ear's constantly changing loss of sensitivity to bass and treble frequencies at lower levels.

Record One Program while listening to another

This Yamaha original feature lets you choose a source for recording by the Rec Out selector while listening to that source, or any other, selected by the Input switch. You can record an FM program while listening to a favorite record on your turntable, and you can let a friend tape a record or copy tapes without having to give up listening to the tuner.

Full Tone and Filter Controls

Tone Controls

The bass and treble controls on the CR620 have turnover frequencies carefully chosen for the best control of tonal quality to suit your mood, the music, and the acoustic of your room. In the flat position the response is completely unaffected by the tone control circuits.

Filters

Both high and low filters are provided, with 12 dB/ocatave cutoffs, to reduce record scratch or tape hiss noise above 10 kHz, and to cut turntable rumble or subsonic noise from warped records or line noise below 25 Hz

 


The Tuner Section

Direct Assessment of Differential Gain

The world famous CT-7000 tuner offered switched narrow/wide selection modes for ideal reception under all conditions. Now, however, direct visual cheks of the critical differential gain linearity enabled Yamaha engineers to give you the best of both mode settings in the CR620; the high selectivity of the narrow mode (70 dB) and the low distortion of the wide mode (0,25% for stereo at 1 kHz) - without the need to choose between them.

FM/Original: Direct Comparison

The CR620 was developed by comparing reproduction of a sound source heard first through the amplifier section alone, and then as received by the tuner section after FM modulation. That way our music specialists could switch back and forth to compare, immediately detecting any sound coloration introduced by the tuner, and correcting for the last measure of fidelity.

Unique Negative Feedback Multiplex Section

Full negative feedback applied overall to the whole FM multiplex demodulator section reduces distortion in this unique Yamaha circuit to the level where it cannot be measured even on the most sensitive test equipment. Phase-locked loop circuitry adds the ultimate in stability for FM reception quality found in no other receiver of its class.

Special Sharp Cut-off MPX Filter

This high performance filter performs the difficult job of suppressing the 19 kHz pilot sinal (which can interfere with other audio equipment) while retaining full treble response to a5 kHz. Sharp cut-off and low distortion combine to give the best possible audio quality.

Signal Strength and Quality Meter

In addition to a center-zero FM tuning meter for precise FM tuning, the CR620 features a signal strength meter which doubles to show signal quality for FM reception. The presence of multipath signals often appears as needle flutter during FM signal strength readings.

Superb AM Tool

AM quality on the CR620 is also excellent. For top sound quality the AM signal is passed through the FM multiplex section to take advantage of its low distortion characteristics. Special equalization then compensates for the built-in FM frequency deemphasis curve.

 


Specifications

Audio Section

Minimum RMS Output Power per Channel (from 20-20,000 Hz at no more than 0,05% T.H.D.)

40 Watts at 4

35 Watts at 8  

Continuous RMS Power (both channel driven, 1 kHz)

50 Watts at 4

40 Watts at 8

Total Harmonic Distortion (20 - 20,000 Hz)

Phono to Rec Out :  0,12% , 2 V output

Aux, Tape to Sp Out (8 ) :  0,02% at 20 W

Intermodulation Distortion (Aux, Tape) :  0,05% at 35 W

Input Sensitivity/Impedance

Phono :  2 mV/ 50 k

Aux, Tape 1, 2 :  120 mV/45 k

Maximum Input Level

Phono :  120 mV at 1 kHz

Output Level/Impedance

Rec Out terminals (Phono):  120 mV/ 200  (rated); 7,2 V (max. 1 kHz)

Frequency Response

Phono RIAA Deviation :  ±0,5 dB

Aux, Tape 1, 2 to Sp Out :  20 Hz to 20 kHz ±0,5 dB

Tone Control Characteristics

Bass Turnover Frequency :  350 Hz

Bass Boost/Cut :  ±13 dB at 50 Hz

Treble Turnover Frequency :  3,5 kHz

Treble Boost/Cut :  ±10 dB at 20 kHz

Filters and Loudness Control Characteristics

Low :  25 Hz (12 dB/oct.)

High :  10 kHz (12 octave)

Loudness Control :  level-related equalization

Signal-to-Noise Ratio (IHF-A network)

Phono :  92 dB (for 10 mV, shorted)

Aux, Tape :  97 dB

Residual Noise :  0,11 mV

Noise Distortion Clearance Range (NDCR) for 0,1% into 8  , 20-20,000 Hz, from 100 mW to 35 watts with Vol -20 dB (Phono Input to Sp Out)

Power bandwidth (IHF) :  10 Hz to 50 kHz (at 0,05% T.H.D.)

Damping Factor (at 1 kHz):  40 into 8

FM Section

Tuning Range:  88 - 108 MHz

Usable Sensitivity:

300  :  10,3 dBf / 1,8 µV

75  :  10,3 dBf /0,9 µV

50 dB Quieting Sensitivity:

Mono :  15,3 dBf (3,2 µV)

Stereo :  38 dBf (43,5 µV)

Image Response Ratio (98 MHz):  50 dB

IF Response ratio (98 MHz):  75 dB

Spurious Response ratio (98 MHz):  75 dB

AM Suppression Ratio (98 MHz):  56 dB

Capture Ratio:  1,0 dB

Alt. Channel Selectivity (IHF):  70 dB

Signal-to-Noise Ratio (at 65 dBf, IHF)

Mono :  77 dB

Stereo :  73 dB

Mono Distortion (at 65 dBf)

At 100 Hz :  0,15%

At 1 kHz :  0,15%

At 6 kHz :  0,3%

Stereo Distortion (at 65 dBf)

At 100 Hz :  0,25%

At 1 kHz ;  0,25%

At 6 kHz :  0,4%

Intermodulation DIstortion (IHF)

Mono :  0,1%

Stereo :  0,2%

Sub-Carrier Product Ratio:  50 dB

Stereo Separation

At 50 Hz :  30 dB

At 1 kHz :  40 dB

At 10 kHz :  30 dB

Frequency Response

50 Hz to 10 kHz :  ±0,5 dB

30 Hz to 15 kHz :  +1,0 -3,0 dB

Muting Threshold:  19,2 dBf (5 µV)

AM Section

Tuning Range:  525 to 1605 kHz

Sensitivity (IHF, Bar Antenna):  316 µV/m (50 dB/m)

Selectivity (1,000 kHz):  25 dB

Signal-to-Noise Ratio:  50 dB (at 80 dB/m)

Image Response Ratio (1,000 kHz):  50 dB

IF Response Ratio (1,000 kHz):  40 dB

Spurious Response Ratio (1,000 kHz):  55 dB

Total Harmonic Distortion :  0,6% (at 80 dB/m)

Tuner Section Output Level /Impedance

FM (100% mod at Rec Out) :  450 mV/6,5  k

AM (30% mod at Rec Out) :  120 mV/6,5 k

General Section

Semiconductors:  68 Transitors; 3 ICs; 1 FET; 29 Diodes; 5 Zener Diodes, 4 LEDs; 4 Ceramic Filters

Power Requirements:  AC 110/ 120/ 130/ 220/ 230/ 240 V switchable, 50/60 Hz

Power Consumption:  190 W

Dimensions (W x H x D):  508 x 167 x 395 mm (20" x 6-3/8" x 15-1/2")

Weight:  12,5 kg (27 lbs 8 oz) U.S.A. and Canada 11,5 kg (25 lbs 5 oz)

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