Kenwood KR-4070 AM-FM Stereo Receiver
Model: KR-4070
Brand: Kenwood
Introduction
The purpose of this manual is to acquaint you with the operating features of your new receiver. You will notice that in every detail of planning, engineering, styling, operating convenience, and adaptability, Kenwood has sought to anticipate your needs and desires. We suggest that you read this manual carefully. Knowing how to set up your receiver to the best advantage will enhance your listening pleasure right from the start. You will also become aware of the ease with which you can adjust your receiver to meet your special requirements.
Serial Number
Record your SERIAL NUMBER on the spaces designated on the warranty card. You will find the serial number on the back of the unit.
After Unpacking
After unpacking, we recommend you inspect and examine the unit for any possible shipping damage. If your unit is damaged or fails to operate, notify your dealer immediately. If your unit was shipped to you directly, 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. We recommend you retain the original carton and packing materials to prevent any damage should you transport or ship your unit in the future.
Precautions on Installation
- Avoid locations subject to direct sunlight.
- Avoid high or low temperature extremes.
- Keep the unit away from heat radiating source and magnetism generating source.
- Choose locations with as little vibration and dust as possible.
WARNING:
TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.
Important!
1. Units shipped to U.S.A. and Canada are designed to operate on 120 volts AC only and are not equipped with an AC Voltage Selector Switch. Therefore, the following description on such a switch should be disregarded.
2. Units shipped to all other countries are equipped with an AC Voltage Selector Switch on the rear panel. The following description on this switch, "AC Voltage Selection", should be carefully read.
AC Voltage Selection
This unit operates on 120 volts, 220 volts or 240 volts AC. The AC Voltage Selector Switch is set to the voltage generally available in the country where the unit is shipped. It is important to make sure, before connecting the power cord to your AC outlet, whether the setting position of this switch corresponds to your voltage. If not, it must be changed to the proper setting in accordance with the direction below.
NOTE:
Our warranty does not cover damage caused by excessive line voltage due to improper setting of the AC Voltage Selector Switch.
AC Voltage Selector Switch Diagram
The AC Voltage Selector Switch features a stopper plate, a screw, and a lever. To change the voltage setting:
- Remove the screw and stopper plate.
- Slide the lever to your line voltage (AC 120V~, AC 220V~, or AC 240V~ position).
- Lock the lever with the stopper plate and screw.
Features
- Low noise cascade junction type FET and frequency linear type precision 3-ganged variable capacitor are employed in the FM front end. These are followed by a high selective IF section and a phase locked loop system IC in the MPX circuits. These highly reliable elements ensure stable FM reception.
- The AM section is equipped with a high selectivity ceramic filter and a high performance dual-in-line type IC, promising optimum reception.
- Employs large size signal and tuning meters.
- Employs a large dial stroke of 10-5/8" (270 mm).
- Equipped with a convenient muting circuit which automatically silences interstation noise at the FM AUTO position.
- Delivers 40 watts per channel, minimum RMS at 8 ohms, from 20 Hz to 20 kHz with no more than 0.1% total harmonic distortion.
- The power amplifier section employs a differential amplifier with high stability and low distortion in the first and second stages, and a direct-coupled circuit in all stages.
- Features the ASO detection limiter system for the protection circuit, safeguarding the power transistor.
- The pre-amplifier is equipped with an operational IC amplifier of single-in-line type, ensuring low noise, low distortion, and an increased dynamic range.
- Designed to improve stability in power source and sound quality by employing two electrolytic capacitors of 7500µF.
- Features decreased wiring in compliance with a large-sized P.C.B.
- Supports two pairs of speaker systems.
- Equipped with a massive heat sink.
Interconnecting Diagram
The interconnecting diagram illustrates how to connect various components to the Kenwood KR-4070 receiver. It shows connections for:
- FM Antennas: Outdoor FM Antenna (using 75Ω coaxial cable) and T-Type FM Antenna (using 300Ω feeder). A note specifies that if a 75 ohm antenna is used, the 300 ohm terminals should not be used, and vice versa.
- Tape Deck: Connections for Line Output and Line Input.
- Rear Panel Inputs/Outputs: Antenna terminals (FM, AM, GND), Input jacks (Phono L/R, Aux L/R), Tape jacks (Rec/Play L/R), and AC Outlet.
- AM Antenna: AM Ferrite Bar Antenna (internal) and provision for an AM Outdoor Antenna.
- Speakers: Speaker Systems A (Lch, Rch) and Speaker Systems B (Lch, Rch) connect to the rear panel speaker terminals.
- Turntable: Connects to the PHONO input jacks.
- AC Power: Connection to an AC Outlet.
Controls and Their Functions
The front panel of the Kenwood KR-4070 features the following controls:
1. Power/Phones/Speakers Switch
A combined switch for power, headphones, and speaker selection:
- POWER OFF: Receiver is off.
- PHONES: Speakers are cut off; headphones can be used.
- A: To listen to speakers connected to the SPEAKERS A terminals.
- B: To listen to speakers connected to the SPEAKERS B terminals.
- A+B: To listen simultaneously to speakers connected to both the A and B SPEAKERS terminals.
2. Phones Jack
Insert a stereo headphone plug here for private listening. Speakers are silenced when the SPEAKERS switch is set to PHONES position.
3. Bass and Treble Controls
- BASS Control: Turning clockwise increases low frequencies; counterclockwise decreases them.
- TREBLE Control: Turning clockwise increases high frequencies; counterclockwise decreases them.
4. Balance Control
Adjusts the volume balance between the left and right channels. Turning towards the left accentuates the left channel; turning towards the right accentuates the right channel.
5. Volume Control
Adjusts the volume simultaneously for both channels (right and left) to your preferred listening level.
6. Loudness Switch
Boosts bass and treble tones at low listening levels to compensate for the ear's reduced sensitivity to low and high frequencies at such levels. It should be turned off at normal and high listening levels.
7. Tape Switch
Depress this switch when using a tape deck for tape playback or monitoring during recording. For functions other than tape playback, ensure it is set to the "SOURCE" position.
8. Selector Switch
Selects the program source:
- AM: To receive AM broadcast.
- AUTO/MUTING: To receive FM mono and stereo broadcasts. Automatically switches between mono and stereo. This position also silences interstation noise on the FM band.
- MONO: To receive FM mono broadcast.
- PHONO: To operate a turntable connected to the PHONO jacks.
- AUX: To select the source connected to the AUX jacks.
9. Tuning Knob
Selects the desired AM or FM station while observing the SIGNAL and/or TUNING meters for optimum tuning.
10. FM Stereo Indicator
Lights up when an FM stereo broadcast is being received (when the SELECTOR switch is set to AUTO/MUTING). It does not light for FM mono broadcasts.
11. Tuning Meter
Used for precise tuning to the center of an FM channel. Turn the tuning knob until the meter pointer is centered for maximum separation and minimum distortion.
12. Signal Meter
Indicates signal strength for AM and FM. Maximum deflection indicates the best receiving condition.
Connecting Instructions
Speaker Connection
To connect a single pair of speakers, connect the right speaker to the [R] terminal and the left speaker to the [L] terminal of the SPEAKERS A set. If the (+) or (-) leads of either channel are reversed, center-channel separation will be adversely affected. To connect an additional pair, use the SPEAKERS B terminals similarly. Sound will not be heard if the SPEAKERS switch is set to A+B and only one pair of speakers is connected, as the circuits are in series. Ensure bare speaker wires do not touch adjacent terminals. Soldering or twisting speaker lead tips is recommended to prevent short-circuits.
NOTE: The impedance of each speaker should be 4 ohms or more when one or two pairs are used.
Phasing of the Speakers
To determine speaker phasing:
- Set the SELECTOR switch to FM (MONO).
- Adjust the VOLUME control to a desired listening level.
- If sound comes directly from the front, speakers are in phase. If sound comes from both sides with a noticeable loss in low frequencies, speakers are out of phase. Reverse the leads on one speaker in this case.
Turntable Connection
Connect the two shielded audio cables from your stereo turntable to the INPUT PHONO jacks [L] (left channel) and [R] (right channel). If your turntable has a grounding wire, connect it to the unit's GND terminal to avoid hum.
Tape Deck Connection
Recording
Connect the left channel input of the tape deck to the [L] of the TAPE REC jack and the right channel input to the [R] of the TAPE REC jack.
Playback
Connect the left channel output of the tape deck to the [L] of the TAPE PLAY jack and the right channel output to the [R] of the TAPE PLAY jack.
DIN Connector (Rec/Play Connector)
If your tape deck has a DIN connector, use a DIN connecting cord to connect it to the TAPE REC/PLAY connector. This enables recording and playback with a single cord. Note that the REC/PLAY connector corresponds to TAPE REC and PLAY signals, controlled by the TAPE switch. The PLAY and REC jacks should not be used when a DIN cord is connected.
AUX (Auxiliary Inputs)
High-level AUX input jacks are for miscellaneous sources, such as extra tape decks, TV sound outputs, and other external components.
AC Outlets
The AC outlets on the rear panel can supply power to other components (e.g., turntable, tape deck):
- SWITCHED outlet: Controlled by the POWER switch on the front panel (200 watts maximum capacity).
- UNSWITCHED outlet: Delivers power at all times (200 watts maximum capacity).
NOTES: 1) Units shipped to European countries may not be equipped with AC OUTLETS. 2) Do not connect equipment exceeding the capacity of each outlet.
FM Antenna Connections
FM broadcast signals travel in a direct path and can weaken behind obstructions or at distances from the transmitter. A good FM antenna is crucial for optimal reception.
FM Outdoor Antenna
Recommended for areas far from the transmitting station. Non-directional antennas are best for multi-directional reception. For directional antennas, orient for best reception, indicated by maximum SIGNAL meter deflection. Keep FM antennas away from roads to avoid ignition noise.
NOTE: Consult an audio dealer for detailed FM outdoor antenna installation information.
T-type Antenna
Suitable for areas close to the transmitting station. Be aware that reflections can cause poor stereo reception. Minimize reflections by careful orientation or by using a more directional outdoor antenna. Spread the antenna arms horizontally and position for best reception while listening to an FM station, then secure to a wall or ceiling.
AM Antenna Connection
Position the ferrite bar antenna for best reception while listening to AM. The ferrite bar antenna on the rear panel provides optimum AM reception. For fringe areas or locations with poor reception due to steel frame buildings, an AM outdoor antenna should be connected to the AM terminal.
NOTE: Keep the AM ferrite bar antenna away from the rear panel.
Ground
Connect the GND terminal on the rear panel to ground using a buried grounding rod or iron-made water pipe to reduce noise and ensure safety. Never use a gas pipe for grounding.
DIN-Type Antenna Jacks
Units shipped to European countries are equipped with DIN-type antenna jacks on the rear panel.
NOTE: Consult an audio dealer for detailed information on making connections.
Precautions for Safety
- Switch off the unit and disconnect the power plug immediately if any abnormality (smell, smoke, etc.) occurs.
- Never connect or disconnect the power plug with wet hands. Hold the plug itself when connecting/disconnecting.
- Disconnect the power plug during thunderstorms. It is also safe to disconnect the antenna feeder (or coaxial cable) if an outdoor antenna is installed. Do not touch the disconnected antenna feeder or cable.
- Disconnect the power plug when leaving your house for an extended period.
- The power cord must not be pulled strongly, bent forcibly, scratched, or extended with an extra cord, as this can cause electric shock or fire.
- Do not place heavy objects on the power cord.
- Do not place items containing water (vases, etc.) on or near the unit.
- Do not insert inflammable materials (paper, celluloid, etc.) or metal objects (needles, hairpins, coins, etc.) into the unit.
- Never dismantle the case or touch internal parts. Never modify internal parts, as this can lead to electric shock.
Operating Instructions
Initial Setup
Before turning on the unit, set the controls and switches as follows:
- TAPE: "SOURCE"
- LOUDNESS: "OFF"
- VOLUME: "MIN"
- BALANCE: Center Position
- TREBLE: Center Position
- BASS: Center Position
Next, turn on the unit and set the SPEAKERS switch to "PHONES", "A", "B", or "A + B" as appropriate.
FM Reception
- Set the SELECTOR switch to FM AUTO/MUTING.
- Turn the TUNING knob to select your station. Best reception is achieved when the TUNING meter pointer is centered and the SIGNAL meter pointer deflects to the extreme right.
- Adjust volume and tone quality.
NOTE: If FM stereo broadcast signal is extremely weak, noise may be unavoidable. In such cases, setting the SELECTOR switch to FM MONO can improve relative signal strength, though stereo effect will be lost. This can substantially eliminate noise.
AM Reception
- Set the SELECTOR switch to AM.
- Turn the TUNING knob to select your station. Best reception is obtained when the SIGNAL meter pointer deflects to the extreme right.
- Adjust volume and tone quality.
Playing Record
- Set the SELECTOR switch to PHONO.
- Operate the turntable.
- Adjust volume and tone quality.
Using the AUX Jacks
To play a component connected to the AUX jacks:
- Set the SELECTOR switch to AUX.
- Operate the connected component.
- Adjust volume and tone quality.
Tape Deck Operation
Playback
- Set the TAPE switch to PLAY (depressed position). The SELECTOR switch can be in any position.
- Operate the tape deck.
- Adjust volume and tone quality.
Monitoring
If using a 3-head type tape deck, you can check sound quality by momentarily comparing the recorded signal with the source signal:
- Set the TAPE switch to PLAY to monitor the recorded sound.
- Set the TAPE switch to SOURCE to monitor the source signal before recording.
Recording
- Set the SELECTOR switch to the desired source to be recorded.
- Operate the selected source (component) and the tape deck.
- Adjust recording levels using the tape deck's controls.
- To check recording conditions, set the TAPE switch to PLAY (depressed position).
NOTE: Recording is not affected by the unit's controls such as VOLUME, BASS, TREBLE, LOUDNESS, and BALANCE.
Tape-To-Tape Dubbing (Duplicating)
- Connect two tape decks as shown in the diagram.
- Set the SELECTOR switch to AUX and operate the tape deck connected to the AUX jacks as the program source.
- Record the program onto the tape deck connected to the TAPE jacks, controlling the recording level with that deck's controls.
- To check recording conditions, set the TAPE switch to PLAY (depressed position).
Precautions on Cleaning
Do not use volatile liquids such as alcohol, thinner, gasoline, or benzine when cleaning the unit's surface. Use a silicon cloth or a soft dry cloth.
Points to be Checked Prior to Servicing
| Condition | Correction |
|---|---|
| Occurs Only During AM Reception Continuous low frequency buzz. Most noticeable at night on weak signal stations. | Erecting a 10-meter outdoor antenna and securing good ground conditions should reduce interference considerably. Complete elimination is difficult. |
| Continuous high frequency whine increases at night. | Turn TV off (neighboring TV sets may also be a cause). Impossible to eliminate from receiver side. |
| Occurs Only During FM Reception Continuous hiss or buzzing interference with broadcast. Becomes louder during stereo. | Erect an outdoor FM antenna if only an indoor T-type is used. An antenna with more than 5 elements may be necessary if you are located at a considerable distance from the transmitting station. |
| During AM, FM or Turntable No sound from LEFT and RIGHT. | Check connections from receiver output to speakers. Set to appropriate volume level. Always set to SOURCE except when using tape decks. Check receiver output and speakers connections. |
| Sound only from one side. | Check connections from receiver output to speakers. Set to appropriate volume level. Always set to SOURCE except when using tape decks. Check receiver output and speakers connections. |
| During Record Playback Only No sound from LEFT and RIGHT, or sound only from one side. | See that the turntable output cord is firmly plugged into the receiver input. |
| Sound audible but background hum occurs. | Keep turntable output cords away from AC cords. Choose cord paths that keep hum at a minimum. Twist LEFT-RIGHT turntable output cords together. Reverse turntable AC plug connections. Connect turntable ground wire to the GND terminal. |
| Howling noise occurs when volume is raised or bass response is increased. | Increase distance between turntable and speakers. Choose speaker locations carefully. Remember, loose flooring can induce howling. |
Specifications
Amplifier Section
| Parameter | Value |
|---|---|
| Power Output | 40 watts* per channel, minimum RMS at 8 ohms, from 20 Hz to 20 kHz with no more than 0.1% total harmonic distortion |
| Both Channels Driven | 40 + 40 watts @ 8 ohms @ 1,000 Hz 47 + 47 watts @ 4 ohms @ 1,000 Hz |
| Dynamic Power Output | 190 watts @ 4 ohms |
| Total Harmonic Distortion | 0.1% @ rated power into 8 ohms 0.05% @ 1 watt into 8 ohms |
| Intermodulation Distortion (60 Hz: 7 kHz = 4:1) | 0.1% @ rated power into 8 ohms 0.05% @ 1 watt into 8 ohms |
| Power Bandwidth | 10 Hz to 40,000 Hz |
| Damping Factor | 40 @ 8 ohms |
| Speaker Impedance | Accepts 4 ohms to 16 ohms |
| Input Sensitivity/Impedance/Signal to Noise Ratio (IHF A Curve) | Phono: 2.5 mV/50k ohms/73 dB AUX: 150 mV/45k ohms/95 dB Tape: 150 mV/45k ohms/95 dB |
| Maximum Input Level for Phono | 190 mV (rms), T.H.D. 0.1% @ 1,000 Hz |
| Output Level/Impedance | Tape REC (Pin): 150 mV/100 ohms (DIN): 30 mV/80k ohms |
| Frequency Response | Phono: RIAA standard curve +0.3 dB, -0.3 dB AUX and Tape: 15 Hz to 70,000 Hz +0 dB, -1.0 dB |
| Tone Control | Bass: ±8 dB @ 100 Hz Treble: ±8 dB @ 10,000 Hz |
| Loudness Control (-30 dB) | +9 dB @ 100 Hz +5 dB @ 10,000 Hz |
FM Tuner Section (IHF)
| Parameter | Value |
|---|---|
| Usable Sensitivity | 10.8 dBf (1.9 µV) |
| 50 dB Quieting Sensitivity (Mono) | 15 dBf (3.1 µV) |
| 50 dB Quieting Sensitivity (Stereo) | 37.2 dBf (40 µV) |
*Measured pursuant to Federal Trade Commission's Trade Regulation rule on Power Output Claims for Amplifier in U.S.A.
FM Tuner Section (Continued)
| Parameter | Value |
|---|---|
| Signal to Noise Ratio at 65 dBf (Mono) | 72 dB |
| Signal to Noise Ratio at 65 dBf (Stereo) | 67 dB |
| T.H. Distortion at 65 dBf (Mono) | 0.15% |
| T.H. Distortion at 65 dBf (Stereo) | 0.25% |
| Frequency Response | 20 to 15,000 Hz +0.5 dB, -2.0 dB |
| Capture Ratio | 1.0 dB |
| Alternate Channel Selectivity | 60 dB |
| Spurious Response Ratio | 75 dB |
| Image Response Ratio | 45 dB |
| IF Response Ratio (Balanced) | 95 dB |
| AM Suppression Ratio | 53 dB |
| Stereo Separation | 43 dB @ 1,000 Hz 35 dB @ 50 to 10,000 Hz |
| Sub Carrier Product Ratio | 40 dB |
| Antenna Impedance | 300 ohms balanced and 75 ohms unbalanced |
| FM Frequency Range | 88 MHz to 108 MHz |
AM Tuner Section
| Parameter | Value |
|---|---|
| Usable Sensitivity | 16 µV |
| Signal to Noise Ratio | 50 dB |
| Image Rejection | 50 dB |
| Selectivity | 34 dB |
General
| Parameter | Value |
|---|---|
| Power Consumption | 300 watts at full power |
| A.C. Outlet | Switched 1, Unswitched 1 |
| Dimensions | W: 18-7/16" (468 mm) H: 5-7/8" (149 mm) D: 14-3/16" (360 mm) |
| Weight (Net) | 20.7 lbs (9.4 kg) |
Note: Kenwood follows a policy of continuous advancements in development. For this reason, specifications may be changed without notice.
Warranty Information
Limited Warranty
Kenwood is proud of its audio equipment, which has gained a worldwide reputation as a leader. Kenwood extends to you, as an owner of a new Kenwood product, the warranty set forth below.
Scope of Warranty
Each Kenwood product listed is warranted against defects in material and workmanship. During the warranty period, an authorized Kenwood service center will provide, free of charge, both parts and labor necessary to correct any defect. Periodic checkups and voltage/line frequency conversions are not covered. Implied warranties are limited to the duration of the stated warranty period. Kenwood is not liable for any loss or damage, direct or consequential, arising out of the use of or inability to use this product. Some states do not allow limitations on implied warranty duration or exclusion of incidental/consequential damages, so these limitations may not apply to you. This warranty gives you specific legal rights, and you may have other rights which vary from state to state.
Warranty Period
The Kenwood products listed below are warranted for the stated period from the date of original purchase:
| Product Type | Warranty Period |
|---|---|
| Receivers, Tuners, and Amplifiers | 2 years |
| Speakers | 3 years |
| Cassette Deck | 1 year |
| Turntables (except stylus) | 1 year |
| Headphones | 1 year |
Purchaser's Responsibilities
To qualify for warranty service, the purchaser must:
- Retain the sales slip or other proof of purchase, or send in the warranty registration card.
- Notify the nearest authorized Kenwood service center or Kenwood as soon as possible after discovering a defect, providing model, serial, and warranty registration numbers, and a detailed description of the problem, including electrical connections to associated equipment.
- Make the Kenwood product available to an authorized service center for inspection and service, or ship it, fully insured and shipping charges prepaid, in its original or equivalent container to Kenwood.
Proper Maintenance and Use
Proper maintenance and use are important for performance. Read your Owner's Manual. Kenwood's warranty will not apply to failures determined to be due to:
- Improper maintenance or repair, including installation of non-conforming parts or accessories.
- Misuse, abuse, neglect, including improper installation.
- Accidental or intentional damage.
Printed in Japan B50-1630-00 (KMUXWL) (G)
