David Bogen Co., Inc. R701 Schematic

David Bogen Co., Inc. R701

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Product Information:
Model:R701
Manufacturer:David Bogen Co., Inc.
Description:AM-FM Tuner

Schematics Content

Page 1:

R701 SPECIFICATIONS

POWER CONSUMPTION: 60 watts, 117 volts, 60 cps.
TUBES: 1-6BK7 - A, 1-6AB4, 4-12A17, 2-68A6, 1-6BE6, 3-6AU6, 1-6ALS, 1-6X4 (14 tubes including rectifier).
SENSITIVITY:
FM: Input required for 30 db quieting: 3 microvolts.
AM: 5 microvolts.
FREQUENCY RANGE:
FM: 88.108 MC.
AM: 530-1650 KC.
HUM & NOISE:
FM, AM: -65 db below 100 % modulation.
TV, PHONO: -65 db below 2 volts.
AUDIO OUTPUT: 3 volts at 6000 ohms.
DISTORTION: 3 volts at.2 %
TONE CONTROL:
At 60 cycles: 17 db boost, 19 db cut.
At 10,000 cycles: 15 db boost, 18 db cut.
At 15,000 cycles: 17 db boost, 21 db cut.
FREQUENCY RESPONSE:
FM: 20-20,000 cps +.5 db.
AM: 20-4,000 cps +.5 db normal position. 20-7,500 cps 5.5 db Hi - Fi position.

PHONO PREAMPLIFIER: 35 db gain and 21 db equalization at 30 cyclos.
AM SELECTIVITY:
Normal: at 8 KC: 6 db.
Hi - Fi: at 15 KC: 6 db.
FM SELECTIVITY:
180 KC: 6 db.
Discrimination peak to peak separation: 375 KC.
ANTENNA INPUT:
AM: low impedance loop or high impedance external antenna,
FM: 300 ohms.
CONTROLS: 1. Volume, 2. Bass, 3. Function Switch (Of, phono, AM normal, AM Hi - Fi, FM, TV), 4. Treble, 5. Tuning.
FM DRIFT:
+ 20 KC with AFC defeated.
+3 KC with AFC in,
SIZE: 15 " x 8 1/2 " x 9.
SHIPPING WEIGHT: 17 lbs.

CONNECTIONS: All connections are made at the rear of the chassis.
Power input: AC power is supplied to the tuner through the attached line cord. Plug this cord into an AC receptacle.
AC power output: The two AC receptacles are supplied with AC power when the tuner is turned on. By plugging other units of the reproducing system into these receptacles, power control can be centralized.
Antenna: All antenna connections are made to the numbered terminal strip. In areas of normal signal strength a loop antenna, made from the cable supplied with the tuner, will provide good reception with low noise on both the AM and FM bands. Tack the cable around the rear of the cabinet to form a single or double turn loop of the largest possible cross-sectional area. Connect the two lead lugs to terminals 1 and 4, and the shorting jumper between terminals 2 and 3. In areas where FM signals are weak, an outdoor FM antenna may be used in con junction with the indoor loop for AM, Connect an FM antenna to terminals 1 and 2, the shorting jumper between terminals 2 and 3, and the loop to terminals 3 and 4. In AM fringe areas an external antenna may be used to increase AM sensitivity. Connect the AM antenna to terminal 4, disconnect the Jumper from terminals 2 and 3, and connect the FM antenna to terminals 1 and 2.
Audio input: The signals from a TV set and a record player can be connected to the tuner at the jacks marked TV and PHONO. When the connections are made, the signal to be delivered to the amplifier is selected by the control knob on the front of the chassis.
Audio output: The amplifier used with the tuner is to be connected to the jack marked OUTPUT. The output of the tuner may be simultaneously recorded without affecting the operation of the amplifier by connecting a recorder to the DETECTOR jack. In order to reduce the possibility of hum pickup, the connections to the tuner should be made with single conductor shielded wire, not exceeding 7 feet in length.

CONTROLS:

Selector: Turning the selector knob from OFF to PHONO: 1) Supplies power to the A.C. receptacles on the rear of the chassis. 2) Supplies power to warm up the tuner tubes. 3) Supplies signal from the record player to the OUTPUT and
DETECTOR jacks.

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Further movement of the selector knob selects AM NORM, AM HI - FI, FM, and TV. For most programs the AM NORM position will provide reception with a minimum of background noise and interference. The AM HIFI position enables the listener to take full advantage of the high-fidelity programs broadcast by some AM stations.

AFC DEFEAT: If, while attempting to tune in a weak FM station, the tuner " jumps to a stronger adjacent station, hold down the pushbutton marked AFC DEFEAT, located on the front of the chassis. This will disconnect the Automatic Frequency Control and permit tuning of the weak station, Release the button when the station is tuned in. The AFC will then center the station and hold it in tune. If recordings are being made, it is recommended that the tuner be adjusted to the exact frequency of the station being recorded. This may be accomplished by defeating the AFC as described above, tuning the station to its exact frequency, and releasing the AFC DEFEAT pushbutton.

PREAMPLIFIER: A preamplifier is included in the Model R701 to supply the additional amplification and equalization needed when a magnetic type phono pickup, such as the G.E. cartridge is used. Since the preamplifier is not required when the phono pickup is a crystal type, it can be disconnected by the switch at the rear of the chassis. Place this switch in the MAG position when using a magnetic pickup, and in the CRYS position when using a crystal pickup.

SERVICE: The tuner should not require any service other than a periodic check of vacuum tubes. The critical adjustments all have a high degree of stability over long periods of time and should not be tampered with. The adjustment of a modern high fidelity receiver such as the R701 should be made by competent, experienced personnel with proper visual alignment equipment. Ordinary meters or aural methods are in general unsatisfactory for alignment,

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ALIGNMENT PROCEDURE

Note: Use insulated screwdriver for adjustment

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INSTALLATION. INSTRUCTIONS: Installation of the R701 tuner should be carefully planned, specifically with the following in mind:

1) Ventilation: Adequate air circulation will prolong the life of the tuner. This can best be accomplished by providing air vents near the top and bottom of the cabinet enclosure,

2) Ease of manipulation: Tuner should be mounted so that the dial can be read easily; control knobs should be kept clar of any cabinet projections.

3) Ease of accessibility: Tuner should be mounted in such a way that it may be easily removed for servicing. Tubes, pilot lights and connections at the rear of the chassis should be readily accesible.

4) Loop antenna: If a loop antenna is used, it should be kept as far as possible from any metal parts to insure good signal pick up.

5) Tuner position: Tuner may be mounted either horizontally or vertical

ASSEMBLY INSTRUCTIONS:

1) Cut out front panel in accordance with attached front panel template, 2) Mount 4 shockmounts on side of chassis as indicated by dotted sketch on front panel template.

3) Mount the escutcheon in the opening of the escutcheon plate, Fasten securely by bending the tabs at the top and bottom edges of the escutcheon firmly over the escutcheon plate,

4) Place the escutcheon assembly on the mounting surface, carefully
aligning all cutouts, Fasten to the mounting surface with two # 2 woodscrews as indicated on the template. Bend the tabs extending from the protruding angle bracket of the escutcheon plate firmly over the mounting surface,

5) Move the tuner forward on the mounting surface until the glass dial is 1/16 " behind the protruding bracket, Check centering of shafts and dial in the cutouts, Mark with an awl the position of 4 holes on the chassis mounting board through the center of the shock mounts.

6) Cut out the 4 marked holes with a " drill, and fasten the tuner chassis by inserting the # 10 machine screws from the bottom of the mounting board.

7) Mount knobs on shafts and make all rear connections.

MATERIAL SUPPLIED WITH TUNER:
5 knobs
1 escutcheon
1 escutcheon plate with two # 2 woodscrews
4 phono plugs
4 shockmounts with 8 self-tapping screws
4 # 10 machine screws
1 loop antenna cable

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R 701 TUNER FRONT PANEL TEMPLATE

INSTALL SHOCK MOUNT TO SIDE OF CHASSIS WITH 2 SELF TAPPING SCREWS AS SHOWN

MOUNTING SURFACE FOR TUNER WITH SHOCK MOUNTS ATTACHED.

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NOTE
1. ALL RESISTORS TO BE 1/2 WATT.: 20 % UNLESS OTHERWISE SPECFIED.
2. ALL CAPACITORS WITH DECIMAL VALUES ARE NED AND ARE PAPER CAPACITORS, 400 DCWB: UNLESS OTHERWISE SPECIFIED.
3. ALL CAPACITORS WITH WHOLE NUMBER VALVES ARE IN MMFD AND ARE CERAMIC CAPACITORS, UNLESS OTHERWISE SPECIFIED.

SCHEMATIC R 701 AM - FM TUNER