Atec PA-138 User Manual

PA-138

abworks Inc.

L

Linear Power Amplifier

State of the art linear technology brings quiet, direct

coupled capability to vibration and acoustic test systems.

GENERAL DESCRIPTION

The Labworks PA-138 Linear Power Amplifier is a high
quality, air-cooled, direct-coupled audio amplifier primarily
intended for use with small vibration systems. Although this
amplifier has been designed to directly drive low impedance
loads, it can be used in any application requiring continuous
duty high quality audio power.

PA-138 Amplifiers feature protection from both over current
and over temperature insuring long term reliability. The

amplifier has full interlock capabilities as well as peak voltage
and RMS current bar graphs to monitor output.

Two operational modes are incorporated in the design. These
amplifiers can be used as either a wide-band, highly damped
voltage source, or as a high impedance current source. DC
and AC coupled signal inputs are provided. PA-138 Amplifiers
are designed for standard 19 in. rack mounted installation and
require 100, 120, 220 or 240V, 48 to 60 Hz power.

FEATURES

■

Linear output stage provides low noise and distortion.

■

Automatic over temperature and over current protection.

■

Direct coupled input and output allows DC operation.

■

Two operational modes, voltage or current source.

■

External interlock circuitry.

2950 airway ave., a-16, costa mesa, ca 92626 • [phone] • fax [phone]

L

abworks Inc.

2950 airway ave.
a-16, costa mesa, ca 92626 [phone]

PA-138 SPECIFICA TIONS*

Output Voltage (continuous)

10 Hz to 20 KHz

open circuit 31.0 V rms
4Ω load 26.0
2Ω load 23.5
1Ω load 20.0

DC to .1 Hz

open circuit 45.0 Vdc/pk
4Ω load 36.5
2Ω load 22.0
1Ω load 11.0

Random Voltage Output

2.5 sigma peak volts
open circuit 18.0 V rms
4Ω load 16.0
2Ω load 15.0
1Ω load 14.0

3.0 sigma peak volts
open circuit 15.0 V rms
4Ω load 13.0
2Ω load 12.5
1Ω load 11.5

Maximum continuous dissipation

Ambient Temp = 40°C 400W

50 200
60 0

Frequency response (DC coupled input)

DC to 10 KHz -0.6 dB
DC to 20 KHz -2.5
AC coupling @ 1.0 Hz -0.5

Slew rate 2 V/µsec
Harmonic distortion

(10V, DC-10k) <0.65% @ 1Ω

Signal/noise ratio

(ref 20V out) 100 dB minimum

Input impedance

DC coupled 10 kΩ
AC coupled 47 uF in series with 10 kΩ

DC offset 5 mV max
Voltage mode gain 48 (34 dB) max
Current mode gain 22 Amps/Volt max
Voltage source regulation <0.1 dB (∞- 1Ω load,

30 Hz/10 V rms)

Current source regulation <0.1 dB (0-2Ω load,

30 Hz/10 A rms)

Front panel controls Power, mode switches,

gain adjust

Front panel indicators

Internal power, interlock trip

Front panel metering

Type (2) 19 seg. horiz. bar graphs
Scale

Voltage 0-40V pk
Current 0-16 A rms

Resolution

Peak voltage 5% of full scale
True rms current 5% of full scale
Accuracy (voltage & current) ±5% abolute

Interlock circuit

Type <1 Vdc= fault or N.C. switch
Response time 3 ms. max
Action Output drives to ground
Reset Gain pot full down or

> 1.5V @ RST

Indicator

Flashing front panel "Trip" light

Cooling 2-speed fans

Noise level: low/high speed <45 dB/<55 dB

(switches @ approx. 1/2 diss.)

Self protection

Over current, over temperature

Line protection

Dual line fuses (10A @ 100, 120 Vac)

(5A @ 220, 240 Vac)

Input power 1,000 VA max

Voltage 100, 120, 220 or 240 Vac
Frequency 48 to 62 Hz

Dimensions 3.5" H x 19" W x 13" D
Weight 24 lbs

*Specifications subject to change. Consult factory for latest specifications.

PERFORMANCE GRAPHS

N

1.0%

1 K

1Ω

5.0%

.5Ω

300

100

THD

Hz

Output
Impedance

Ω

30

10

30

100 300 1000

Current Source Mode Performance

Current
Response

Hz

30

25

20

15

10

5

0

0

0

-2

-4

4Ω

2Ω

O

Volts

rms

Amps

rms

510152025

Output Capability

DC input

dB

AC input

0.1 1.0 10 100 1K 10K 30K.01
Voltage Source Mode Response Performance

I

T

A

P

I

S

S

I

D

.

T

N

O

0.6%

C

.

X

A

M

0.0

-2.5

dB

-5.0

-2

dB

-4

0