Zapco Z-150.2 II — 2-Channel Class AB Car Amplifier

Zapco Z-150.2 II — 2-Channel Class AB Car Amplifier

The Z-150.2 II is a two-channel Class AB amplifier from Zapco's Z-II series, rated 165 watts RMS per channel at 4 ohms, 275 watts per channel at 2 ohms, and 550 watts bridged into 4 ohms. Signal-to-noise is better than 100dB with THD under 0.1%, across a 15Hz to 30kHz bandwidth.

The Z-II series shares a common control architecture across the 2-, 4- and 6-channel models, adapted to the expected use of each. The two-channel is the base of that design.

Crossover Range and the X10 Multiplier

The crossover section is what makes this amplifier flexible enough to sit almost anywhere in a system. Both the high-pass and low-pass filters have their own frequency selector, and each has an X10 multiplier switch that shifts the adjustment range from 15Hz–500Hz up to 150Hz–5,000Hz.

That range is the practical point. With the multiplier off, the high-pass can act as a subsonic filter as low as 15Hz for bass duty. With it on, the same filter reaches into tweeter territory. One amplifier covers subwoofer, midbass, midrange, or high-frequency duty without changing hardware.

A three-position crossover mode switch sets how those filters are applied: high-pass only, full-range with the crossover out of the signal path entirely, or both filters active for band-pass operation. Used for bass, the low-pass becomes the subwoofer crossover while the high-pass serves as a variable subsonic.

Inputs and Multi-Amplifier Installs

Inputs are Zapco's proprietary RCA connectors, with pass-through RCA outputs so multiple amplifiers can be daisy-chained from a single front-to-back RCA run. In a multi-amplifier build that removes a set of interconnects from the vehicle and simplifies the signal path.

Also on the endplate: variable gain, variable bass boost adjustable from 0dB to 12dB, a port for Zapco's optional dash-mount bass control, and power and protect LEDs.

System Application

At 165 watts per channel into 4 ohms it suits a stereo pair of component woofers or a full-range front stage. At 2 ohms it delivers 275 per channel, and bridged it produces 550 watts into 4 ohms for a single subwoofer channel.

The crossover range means it also works as a dedicated midrange or tweeter amplifier in an active multi-amplifier system, band-passed to the range you need.

Installation Considerations

Four ohms is the minimum load when bridging. Each channel sees half the load in bridged mode, so a 4-ohm bridged load presents 2 ohms per channel. Zapco specifies not bridging into a 2-ohm woofer.

When band-passing for midrange use, the high-pass filter sets the bottom of the band and the low-pass sets the top. Reversing them produces no output.

Size power and ground wire from the total fuse value of the amplifiers on the circuit and the distance from the battery. Use the same gauge for ground as for power, keep the ground run short, and secure it to a clean, solid surface — preferably the vehicle frame.

Specifications

• Configuration: 2-Channel, Class AB
• Power: 165W RMS × 2 @ 4Ω
• Power: 275W RMS × 2 @ 2Ω
• Power: 550W RMS bridged @ 4Ω
• Minimum bridged load: 4Ω
• Frequency response: 15Hz–30kHz
• THD: <0.1%
• Signal-to-noise ratio: >100dB
• Crossover: variable HP and LP, 15Hz–500Hz or 150Hz–5,000Hz via X10 multiplier
• Bass boost: 0dB–12dB variable
• Optional: dash-mount bass control (sold separately)

HF Audio Perspective

The Z-150.2 II earns its place through range rather than output. The X10 multiplier means the same amplifier can run a subwoofer at 15Hz or a tweeter at 5kHz, which matters when a system grows and channels get reassigned.

In an active build, that flexibility lets you standardize on one amplifier across several roles rather than matching a different model to each driver. Decide what each pair of channels is being asked to do, confirm the impedance the drivers present, and the crossover section will cover the rest.