Kenwood KR-770 - User Manual

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AM-FM

STEREO

RECEIVER

KR-770

INSTRUCTION

MANUAL

CONTENTS

CONTROLS. INDICATORS

AND

CONNECTORS

SAFETY PRECAUTIONS ....

....... .........

.. .

SYSTEM CONNECTION

DIAGRAM

............

.......

..... .

SYSTEM

CONNECTIONS

. .

. . .. ..... .. ...

......... .

OPERATING INSTRUCTIONS

........ .........

.....

... . .

IN CASE OF DIFFICULTY .

..........

...

.. .

....

.......

.. ..

. .

SPECIFICATIONS .....

.....

.........

.. ................ .

MEMO

. .

........

. ... ..

. ..

FOR

YOUR

RECORDS

1 1

Record the serial number. found on the

back

the

unit. in the spaces designated on the

warranty

card. and in

the space provided

below

. Refer

the model and serial

numbers whenever you call

upon

your

Kenwood dealer

for

information

service on

this

product.

Model

KR-770

Serial

number

____

_____

UNPACKING

Unpack the

unit

carefully and make sure

that

all

accessories and cables are

put

aside so

they

will

not

be lost.

Examine the

unit

for

any possibility

shipping

damage.

your

unit

damaged

or fails

operate,

notify

your dealer

immediately

your

unit

was

shipped

you di-

rectly,

notify

the shipping

company

without

delay. Only the

consignee (the person or

company

receiving the

unit)

can file

a claim against the carrier

for

shipping

damage.

recommend

that

you retain the original

carton

and

packing materials

for

use should you transport

ship

the

unit in the

future

INSTALLATION

PRECAUTIONS

(a)

Avoid

locations

subject

direct

sunlight.

(b) Avoid high

low

temperature

extremes.

(c)

Keep the

unit

away

from

heat radiating sources.

(d)

Choose a

location

that

is relatively free

vibration

excessive dust.

(e)

Make sure

power

off

before making any system con-

nections.

WARNING:

TO PREVENT FIRE

SHOCK HAZARD,

DO NOT EXPOSE THIS APPLIANCE TO

RAIN

MOISTURE.

,·-

$KENVVOOD

----~~-POR;;NT~-~

U.S.A.

AND

CANADA

Units

shipped

the

U.S.A. and Canada are designed !

for

operation

120

volts

AC only. These units are

not

equipped

with

an AC Voltage Selector

switch

and

the discussion

such a

switch

that

follows

should be

disregarded.

ALL

OTHER

COUNTRIES

Units

shipped

countries

other

than

the U.S.A. and !

I Canada are equipped

with

Voltage Selector 1

1tch

on the rear panel Refer

the

following

pa- !

graph

for

the

proper

setting

this

switch

. • i

- -

...

- - . -

VOLTAGE

SELECTION

This

unit

operates

120

220.

240

volts

. The

AC Voltage Selector

Switch

on the rear panel is set

the

voltage

that

prevails in the area

which

the

unit

is shipped.

Before connecting the

power

cord

your AC outlet. make

sure

that

the

setting

position

this

switch

matches your

line

voltage

not.

must

set

your voltage in accor-

dance

with

the

following

direction

Note

-------

---

-----

- -

Our

warranty

does

not

cover damage caused by excessive line

voltage due

improper

setting

the AC Voltage Selector

Switch

'"""

''""il"

120V

Position •

220V

osit

ion

240V

osition

Lever

• J@

1. Remove

screw

and

sto

pper plate.

2. Slide lever to your line voltage.

3. Lock lever

wit

stopper

plate

and

screw

AC VOLTAGE SELECTOR

SWITCH

Need help?

Do you have a question about the Kenwood KR-770 and is the answer not in the manual?

The Kenwood KR-770 is an AM-FM stereo receiver designed to provide high-quality audio reproduction and versatile connectivity for various audio components.

Function Description

The KR-770 serves as the central hub for an audio system, integrating an AM/FM tuner, a preamplifier, and a power amplifier into a single unit. It allows users to select and amplify audio signals from multiple sources, including a turntable, tape decks, and auxiliary devices, and output them to a pair of stereo speakers or headphones. The built-in AM/FM tuner supports both automatic and manual tuning, with the ability to preset up to six AM and six FM stations for quick access. Microphone mixing is also supported, allowing users to blend microphone audio with other program sources.

Important Technical Specifications

Audio Section:

Power Output: 80 watts per channel minimum RMS, both channels driven at 8 ohms from 20 Hz to 20,000 Hz with no more than 0.02% total harmonic distortion.
Total Harmonic Distortion (20 Hz to 20,000 Hz from TAPE): 0.02% at rated power into 8 ohms, 0.005% at 1 watt power into 8 ohms.
Intermodulation Distortion (60 Hz: 8 kHz = 4:1 SMPTE): 0.02% at rated power into 8 ohms.
Slew Rate: ±180V/µsec.
Rise Time: 1.0 µsec.
Damping Factor (8 ohms at 1,000 Hz): 60.
Input Sensitivity/Impedance:
- PHONO: 2.5 mV/50k ohms.
- TAPE, AUX: 150 mV/50k ohms.
- MIC: 2.5 mV/50k ohms.
Signal-to-Noise Ratio (A weighted):
- PHONO: 83 dB for 2.5 mV input, 91 dB for 5.0 mV input.
- TAPE, AUX: 105 dB for 150 mV input.
- MIC: 70 dB for 2.5 mV input.
Maximum PHONO Input Level at 1,000 Hz: 240 mV (rms), THD 0.02%.
Frequency Response:
- PHONO RIAA Standard Curve: 20 Hz to 20,000 Hz ±0.3 dB.
- TAPE, AUX: DC Hz to 320,000 Hz -3 dB.
Tone Control:
- Bass (at 500 Hz turnover): ±10 dB at 100 Hz.
- Mid: ±10 dB at 800 Hz.
- Treble (at 2 kHz turnover): ±10 dB at 10 kHz.
Turnover Control:
- for Bass Control: 100 ~ 500 Hz Variable.
- for Treble Control: 2 kHz ~ 10 kHz Variable.
Loudness Control (VOL. -30 dB): +10 dB at 100 Hz.
Subsonic Filter (DC Coupled OFF): 18 Hz 6 dB/oct.
High Filter: 5 kHz 6 dB/oct.
Output Level/Impedance:
- TAPE REC Out (Pin): 150 mV/300 ohms.
- (DIN): 30 mV/80k ohms.

FM Tuner Section:

Usable Sensitivity: 9.8 dBf (1.7 µV).
50 dB Quieting Sensitivity:
- Mono: 16.1 dBf (3.5 µV).
- Stereo: 35.6 dBf (35 µV).
Signal-to-Noise Ratio at 65 dBf:
- Mono: 74 dB.
- Stereo: 70 dB.
Total Harmonic Distortion at 1,000 Hz (at wide band):
- Mono: 0.09%.
- Stereo: 0.1%.
Frequency Response: 30 Hz to 15,000 Hz +0.5 dB, -1.0 dB.
Capture Ratio: 1.0 dB.
Image Rejection Ratio: 80 dB.
Spurious Response Ratio: 90 dB.
IF Response Ratio: 90 dB.
Alternate Channel Selectivity:
- WIDE: 60 dB at 400 kHz.
- NARROW: 75 dB at 400 kHz.
AM Suppression Ratio: 55 dB.
Stereo Separation Ratio (at wide band):
- at 1,000 Hz: 50 dB.
- at 50 Hz to 10,000 Hz: 37 dB.
Subcarrier Product Ratio: 65 dB.
Antenna Impedance: 300 ohms balanced and 75 ohms unbalanced.
FM Frequency Range: 88 MHz to 108 MHz.

AM Tuner Section:

Usable Sensitivity: 18 µV.
Signal-to-Noise Ratio: 50 dB.
Image Rejection: 40 dB.
Selectivity: 60 dB.

General:

Power Consumption: 350 watts at 8 ohms rated power output, 80 watts at no signal.
AC Outlets: Switched 2, Unswitched 1.
Dimensions (W x H x D): 538 mm (21-3/16") x 133 mm (5-1/4") x 365 mm (14-3/8").
Net Weight: 12 kg (26.5 lb).
Gross Weight: 15.5 kg (34.2 lb).

Usage Features

AC Voltage Selection: For international models, a rear panel switch allows selection between 120, 220, or 240 volts AC to match local line voltage. (Note: U.S.A. and Canada units are fixed at 120V AC).
Speaker Connectivity: Supports two sets of speakers (A and B) with proper polarity for optimal sound. Speaker lead tips should be twisted or soldered to prevent short-circuits.
Turntable Connection: Dedicated PHONO input jacks with a ground terminal to minimize hum.
Tape Deck Connectivity: Two sets of TAPE jacks (A and B) for recording and playback, including a DIN connector option for TAPE B. This allows for monitoring recordings in progress and tape-to-tape dubbing.
AUX Jacks: For connecting other high-level signal sources like additional tape decks, TV/VTR sound output, or mic preamps.
Remote Connector: For optional connection to an Audio Program Timer (AT-500) to enable preset tuning and recording while absent.
AC Outlets: Rear panel AC outlets (one unswitched, two switched) to power other audio components, with a total capacity of 200 watts maximum (50 watts for switched outlets).
Tone Controls: Comprehensive bass, mid, and treble controls with adjustable turnover frequencies (100-500 Hz for bass, 2-10 kHz for treble) for precise sound shaping. A TONE switch allows bypassing these controls for a flat frequency response.
DC Coupled/Subsonic Switch: Allows bypassing the tone control circuit for a perfectly flat response (DC COUPLED) or attenuating frequencies below 18 Hz to reduce turntable rumble or warped record effects (SUBSONIC).
High Filter: Reduces signals above 10 kHz to lessen tape hiss and record scratch noise.
Attenuator Switch: Provides a 20 dB audio output attenuation, useful for temporarily lowering volume without disturbing the main VOLUME control setting.
Loudness Switch: Boosts low frequencies at low listening levels to compensate for human hearing characteristics.
Balance Control: Adjusts the relative levels of the left and right channels to correct for source or room imbalances.
MIC Mixing: Allows mixing microphone sound with any selected program source, with a dedicated MIC MIXING control.
Peak Level Indicators: LEDs show the effective power delivered to speakers, calibrated for an 8-ohm load (readings can be adjusted for 4-ohm or 16-ohm speakers).
Digital Frequency Display: Clearly shows AM and FM frequencies for accurate tuning.
Memory and Preset Switches: Stores up to 6 AM and 6 FM stations for instant recall.
Tuned/Lock Indicator: Lights up when an FM or AM station is received and automatically locked.
Auto/Manual Tuning: Supports automatic scanning for broadcast stations (AUTO) and precise manual frequency adjustment (MANUAL). Muting is active in AUTO mode.
Signal Indicators: LEDs show relative signal levels, aiding in optimal antenna placement.
Mode Switch: Allows automatic switching between stereo and monaural FM reception, or forces monaural reception for weak signals.
Stereo Indicator: Lights when a strong stereo FM signal is received.
IF Band Switch: Selects between WIDE (normal use, minimum distortion) and NARROW (for strong adjacent channel interference).
FM De-emphasis Switch: Pre-set at the factory for the expected delivery area (75 µs for U.S.A./Canada, 50 µs for Europe/Oceania), affecting high-frequency response.

Maintenance Features

Cleaning: The cabinet should be cleaned with a silicone cloth or a clean dry cloth. Volatile solvents like alcohol, paint thinner, gasoline, or benzine should not be used.
Ventilation: The unit has slotted ventilation holes on top. These should not be blocked by objects, and care should be taken to prevent metal objects from entering the unit to avoid malfunction or shock hazards.
Service and Modifications: Users are advised not to remove the cabinet or touch internal parts. All servicing should be referred to qualified service personnel. Unauthorized modifications can void the warranty and pose shock hazards.
Power Cord Care: Always grasp the plug body when inserting or removing the power cord. Avoid pulling or stretching the cord, subjecting it to traffic, bending it sharply around furniture, or placing heavy objects on it. Do not route it under rugs or use extra extension cords, as these precautions help prevent fire or shock hazards.
Troubleshooting Guide: The manual includes a comprehensive "In Case of Difficulty" section with common problems, their causes, and suggested remedies, allowing users to resolve minor issues before seeking professional service.