SPA-3 STEREO PRECISION ATTENUATOR

I.DESCRIPTION

The SPA-3 is a stereo preci-

 

 

SPA-3 SPECIFICATIONS

 

sion

attenuator

accessory

 

GENERAL INFORMATION

 

for use with DataPort-

 

equipped QSC amplifiers. It

Operating temperature

0–70° C

mounts directly to the back

Input type, each channel

Differential balanced (transformer balancing optional)

of two-channel CX, DCA, and

Input impedance

28.4 kΩ balanced, 14.7 kΩ unbalanced

PL2 models, but it can be

Output impedance

95 Ω, quasi-balanced

used

with

the

others

 

 

Maximum RMS output voltage

+18 dBu

(PowerLight, ISA, and four-

 

 

Equivalent input noise (ref. to max. output level)

less than -100 dBr

channel CX

or

DCA

 

 

Dynamic range

116 dB

amplifers)

by

using a

 

 

THD @ 1 volt

< 0.03%

DataPort cable and a re-

Frequency response

20 Hz–20 kHz, ±0.2 dB

mote mounting rack. Ampli-

fiers from the ISA series

Common-mode rejection

>50 dB minimum; >60 dB typical

cannot power the SPA-3, so

Power requirements

+15V @ <300 mA via ext. power jack, or from amplifier via pin 9 of DataPort

it requires a 15-volt exter-

 

 

CONTROLS

 

nal DC power supply when

Programming

Pushbutton switches for incremental adjustment: Shift, Up, and Down

used with one of them.

 

 

INDICATORS

 

 

 

 

 

 

 

 

 

 

 

 

Attenuation (each channel)

2-digit 7-segment LED display

 

 

 

 

 

 

 

 

 

 

 

 

Signal presence (each channel)

Green LED

 

 

 

 

 

 

 

 

 

 

 

 

0.5 dB indicator (each channel)

Decimal point

 

 

 

 

 

 

 

 

 

 

 

 

CONNECTORS

 

 

 

 

 

 

Input

Two 3-pin "Euro-style" detachable terminal blocks

 

 

 

 

 

 

 

 

 

 

 

 

DataPort

HD15 male (to amplifier)

 

 

 

 

 

 

 

 

 

 

 

 

External power

2.5 mm coaxial jack; center pin positive

 

 

 

 

 

 

 

 

 

 

 

 

PROGRAMMABLE OPERATING PARAMETERS

 

 

 

 

 

 

Attenuation

0 to 32 dB in 0.5- or 1.0-dB increments

 

 

 

 

 

 

 

 

 

 

 

 

Bypass

Either channel

 

 

 

 

 

 

 

Signal

LED

Up

Down

Shift

Input

Stage

½Micro- controller

Digital

 

 

Potentio-

 

meter

 

 

 

 

To amplifier,

 

 

via DataPort

 

 

Output

 

 

Stage

8.8.

2-Digit

 

7-Segment

Block diagram of one channel of the SPA-3

 

Display

2

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QSC Audio SPA-3 owner manual Description
Page 1 Page 3

SPA-3 specifications

QSC Audio SPA-3 is an innovative power amplifier designed to meet the demanding needs of modern audio applications. With its compact design and advanced technology, the SPA-3 offers a powerful solution for professional audio engineers, venue operators, and like-minded enthusiasts.

One of the standout features of the SPA-3 is its versatility. This three-channel amplifier has a power output of up to 300 watts per channel at 4 ohms, making it suitable for a range of applications from small venues to larger installations. The SPA-3 can be used in various configurations, including stereo, mono bridge, or even as a multi-channel solution, allowing users to tailor their audio setup to their specific requirements.

The SPA-3 utilizes advanced Class D technology, ensuring high efficiency and low power consumption while still achieving impressive sound quality. The lightweight design not only simplifies transportation and installation but also minimizes heat generation, leading to enhanced reliability during extended use. The amplifier incorporates QSC’s proprietary DSP, which enables users to take advantage of features such as customizable EQ settings, delay adjustments, and limiter functions to optimize audio performance for any environment.

Connectivity is another strong point of the QSC SPA-3. The amplifier is equipped with balanced XLR and 1/4-inch TRS inputs, as well as binding post speaker outputs, providing flexibility for various audio sources and speaker types. Additionally, the amplifier features a comprehensive front-panel interface, which includes status LEDs for power, signal, and clipping indications, allowing users to easily monitor performance and troubleshoot any issues.

Durability is a hallmark of QSC products, and the SPA-3 is no exception. The amplifier is housed in a sturdy, rugged chassis designed to withstand the rigors of live performance and installation environments. It also features comprehensive protection circuitry, including over-temperature, short-circuit, and DC protection, ensuring both safety and longevity for the unit and connected speakers.

In summary, the QSC SPA-3 is a powerful, versatile, and efficient amplifier suited for a variety of professional audio applications. With its advanced Class D technology, customizable DSP features, flexible connectivity options, and robust design, the SPA-3 stands out as an exceptional choice for anyone looking to elevate their audio experience.
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