II. Features, III. Installation | QSC Audio SPA-3 specs

Kit contents

These parts are included along with your SPA-3 module:

Qty	QSC part #	Description		shield
2	CO-000137-00	3-pin "Euro-style" plug

2	SC-040181-PP	#4-40	× 1 1/8" black screw
1	SC-080051-PP	#8-32	× 5/16" black screw	SPA-3 input connections

The screws are for mounting the SPA-3 to an amplifier or accessory bracket (see INSTALLATION), and the two plugs are detachable terminal blocks for the SPA-3’s two balanced inputs (see the illustration above).

II. FEATURES

The heart of the SPA-3 is a Crystal Semiconductor digitally controlled dual-channel gain control. The user controls are pushbuttons for adjusting the amount of attenuation, for bypassing (unity gain), for changing the adjustment increment, and for displaying the firmware version.

Both channels feature electronically balanced input circuitry. The pseudo-balanced outputs connect to the amplifier through the DataPort. The attenuation can be adjusted from 0 to 32 dB and can also be bypassed. A green LED for each channel indicates that its pre-attenuation circuitry is passing a signal. The settings are non-volatile and are retained when the amplifier is turned off.

To improve common-mode noise rejection, an optional XF-1 input isolation transformer can be installed on each channel by a qualified technician.

III. INSTALLATION

CAUTION: Always turn the amplifier off when installing or removing the SPA-3.

Connecting inputs

The signal wires attach to each “Euro-style” terminal block as shown in the illustration at the top of this page. Pay attention to signal polarity. Strip the wires approximately 0.35 inch (9 mm). The screw head above each terminal opens and closes its clamp; after inserting the wire in the terminal, tighten the clamp firmly.

If the input signal is unbalanced, use the + terminal for the signal conductor and both the - and shield terminals for the shield.

The terminal blocks plug into their respective jacks on the SPA-3. Attaching the SPA-3 to the amplifier

PowerLight 2 and two-channel CX, DCA amplifiers

Line up the SPA-3’s DataPort connector with the one on the amplifier’s rear panel. Press the SPA-3 onto the amplifier and secure it to the chassis with the three screws included (see the illustration above).

PowerLight, ISA, and four-channel CX and DCA amplifiers

An SPA-3 will not physically mount on one of these amplifiers. A DPX-4 accessory bracket, however, can hold up to four SPA-3 units. Use a DataPort cable to connect the SPA-3 to the amplifier. The SPA-3 will draw the power it needs from the DataPort of PowerLight, CX and DCA amplifiers, but if used with an ISA series amplifier, it will require an external 15-volt DC power supply capable of 300 mA, such as a QSC DPX-1.

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.