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POWER CONNECTIONS
The power transformer of the 1570B Amplifier has primary taps for 117 and 128 volts and is shipped with the 128 volt
tap (white lead) connected. Use of the 128 volt tap for all line conditions will extend component and tube life, reducing
maintenance to a minimum. Do not connect the 117 volt tap unless 24-hour line checks show that the line does not exceed
117 volts. For your convenience, these two leads are equipped with ring type terminals, the one in use being connected to
one terminal of the interlock microswitch and the unused terminal insulated with plastic tubing.
POWER OUTPUT
When making power output measurements, connect a jumper across the terminals of the
thermal breaker. Continuous sine wave output in the full power range may operate the
breaker, giving false readings, if the jumper is not used. In motor drive or other applica-
tions which require continuous sine wave full power output of the 1570B, the thermal
breaker should likewise be bridged out of the circuit.
CONTROLS
Two controls are provided: Volume control and AC power switch. Provision has been
made for mounting an accessory relay to provide plate power keying by remote control.
The mounting holes are located near the center of the chassis and are suitable for a Potter-
Brumfield type PR-3 relay or equivalent which should be mounted under the chassis.
Select a relay having the desired coil voltage. If control wiring and microphone lines are
carried in the same conduit, use a DC type relay. The white wire from the cable form to
terminal 6 on V-9 tube socket should be transferred from this terminal to one contact on
the relay. Connect the other relay contact to terminal 6, V-9 socket.
SERVICING
When the top cover is removed for tube replacement, etc., an interlock switch interrupts the AC line voltage to the power
transformer. Do not attempt service work on this amplifier with AC line voltage on, as approximately 1,000 volt potentials
occur at various points. Discharge all filter condensers before making continuity or resistance measurements. Routine ser-
vicing may then be done using the schematic for pertinent data reference. If high voltage measurements must be made,
proceed with caution.
C1
.0002 mfd. ±10%, 600v ceramic, Erie GP2-331
C2, 3
.22 mfd., 400v, Astron BP4-22
C4, 5
.1 mfd., 600v, CD PM6 P 1
C6
40x40 mfd., 500v, Mallory FP288
C7, 11
120 mfd., 200v, Mallory FP121
C8
6 mfd., 1000v, Tobe-Deutchmann TAB-1006
C9
,0056 mfd. ±10%, 600 v ceramic, Erie 811
C10
.0022 mfd. ±10%, 600v ceramic, Erie GP-2
R1
1000 ohms ±10%, 1/2 watt
R2
330,000 ohms ± 5%, 1 watt
R3, 21
100,000 ohms ±10%, 1/2 watt
R4, 5, 9, 10, 17
100,000 ohms ±10%, 1 watt
R6, 7
2.2 megohms ±10%, 1/2 watt
R8
1800 ohms ±10%, 1/2 watt
R11, 12
330,000 ohms ± 10%, 1/2 watt
R13
82,000 ohms ±10%, 1/2 watt
R14
600 ohms, 5 watt, Ward Leonard Type 5
R15, 16
100 ohms ±10%, 1/2 watt
PARTS LIST
R18
75,000 ohms, 20 watt, Ohmite Brown Devil
R19
5 ohms, 50 watt, Ohmite 0400A
R20
10 ohms ±10%, 1/2 watt
P1
Altec Lansing 12435
BR1
Klixon CA3 Thermal Breaker
PL1
G . E . M a z d a # 4 4
T1
Peerless 16492
T2
Peerless 6410
L1
Peerless 17173
L2
Peerless 17266
S1
Altec Lansing 12763
S2
Interlock, V3-1 Microswitch
RS1, 2
G.E. 1N1695 Silicon Rectifier
V1
12AX7 Vacuum Tube
V2
6SN7GTB Vacuum Tube
V3, 4
6W6GT Vacuum Tube
V5, 6
811-A Vacuum Tube
V7, 8, 9, 10
5R4GY Vacuum Tube
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