Power Base Series; Input Ground Lift:; Reset (- Page 14

Power Base Series

  Power Amplifiers

Page 14

Required AC Mains:

 Current, frequency and voltage

requirements are provided on each unit’s back panel.
All models draw 90 watts or less at idle.

Power Base-1: Draws up to 6 amps of current.

Power Base-2 : Draws up to 10 amps of current.

Power Base-3 : Draws up to 15 amps of current.

Low-Voltage Power Supply:

 A ±24 VDC fanformer

supply (fan motor winding) regulated to ±15 VDC.

AC Connector:

 An appropriate AC line cord and plug

are provided. 120 VAC, 60 Hz units have a standard
3-wire, 15-amp grounded connector (NEMA 5-15P).

Controls

Power:

 A front panel rocker switch used to turn the

amplifier on and off.

Level:

 A back panel rotary potentiometer for each chan-

nel used to control the output level.

Stereo/Mono:

 A three-position back panel switch used

to select Stereo, Bridge-Mono or Parallel-Mono mode.

Sensitivity:

 A three-position switch inside the back

cover plate used to select the input sensitivity for both
channels: 0.775 volts or 1.4 volts for standard 1 kHz
power, or 26 dB voltage gain (see Section 2.3).

Input Ground Lift:

 A two-position back panel switch

used to isolate the phone jack and chassis grounds.

Reset (

Power Base-3 only):

 A back panel push but-

ton used to reset the circuit breaker that protects the
power supplies.

Indicators

Power:

 This amber indicator shows the on/off status of

the low voltage power supply.

Input/Output

Input Connector:

 Balanced ¼ inch phone jacks. See

Section 5 for XLR and barrier block accessories.

Input Impedance:

 Nominally 20 K ohms, balanced;

10 K ohms, unbalanced.

Output Connector:

 Two sets of color-coded 5-way bbinding

posts (for banana plugs, spade lugs or bare wire).

Output Impedance:

 Less than 10 milliohms in series

with less than 2 microhenries.

DC Output Offset:

 Less than 10 millivolts.

Output Signal

Stereo:

 Unbalanced, two-channel.

Bridge-Mono:

 Balanced, single-channel. Channel 1

controls are active; Channel 2 controls should be
turned down and not used.

Parallel-Mono:

 Unbalanced, single-channel. Channel

1 controls are active; Channel 2 controls should be
turned down and not used.

Protection

Power Base amplifiers are protected against shorted,
open or mismatched loads; overloaded power supplies;
excessive temperature, chain destruction phenomena,
input overload and high-frequency blowups. They also
protect loudspeakers from input and output DC, as well
as providing protection from turn-on/turn-off transients.

If operating conditions are unreasonable, the patented
ODEP circuitry proportionally limits the drive level to pro-
tect the output transistors, particularly in the case of el-
evated temperature. A thermal switch imbedded in the
transformer protects the power supplies from overload.
In the rare event that a transformer overheats, the ther-
mal switch removes power, waits until the unit has cooled
to a safe temperature and then resets itself.

Turn On:

 Four second delay with no dangerous tran-

sients. Contact us if you need to change the delay.

Construction

Durable black finish on steel chassis with special “flow-
through” ventilation from front to side panels.

Cooling:

 Internal heat sinks with forced-air cooling

for rapid, uniform heat dissipation.

Dimensions:

 Standard 19-inch (48.3 cm) rack mount

width (EIA RS-310-B), 3.5-inch (8.9 cm) height and
16-inch (40.6 cm) depth behind the mounting surface.

Approximate Weight:

 Center of gravity is 6 inches

(15.2 cm) behind front mounting surface.

120 VAC, 60 Hz Units:

Power Base-1: 30 pounds (13.6 kg) net; 34 pounds
(15.4 kg) shipping weight.

Power Base-2: 34 pounds (15.4 kg) net; 38 pounds
(17.2 kg) shipping weight.

Power Base-3: 36 pounds (16.3 kg) net; 40 pounds
(18.2 kg) shipping weight.