Zapco ST-750D Amp Mono 1-Channel Class D Compact Subwoofer Amplifier 400w RMS
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The Zapco ST-750D is a mono Class D compact subwoofer amplifier rated at 400W RMS at 4 ohms and 750W RMS at 2 ohms. It accepts both RCA and speaker level inputs and includes a subsonic filter, making it a space-efficient solution for bass upgrades. It is part of Zapco's ST-D Compact Series.
Key specifications
- Model: ST-750D
- Channels: 1 (mono), Class D
- Power @ 4 ohms: 1 x 400W RMS
- Power @ 2 ohms: 1 x 750W RMS
- Inputs: RCA and speaker level
- Signal to noise ratio: >98dB
- Frequency response: 10Hz – 250Hz ±1dB
- Operating voltage: 6.5V – 17V
- Dimensions: 124 x 50 x 254 mm (W x H x L, overall)
ST-750D Mono Class D Compact Amplifier
The ST-D Compact Series reduces the chassis dimensions of Zapco's earlier ST-III amps — down to 12.4 cm (W) and 5 cm (H) compared with the ST-III's 16 cm (W) and 5.8 cm (H). The result is a smaller footprint without sacrificing control or output.
Despite the compact size, the ST-750D offers full control flexibility: RCA or speaker level inputs, variable input gain, variable electronic crossover, and variable bass boost. If you need multi-channel coverage alongside your subwoofer, the Zapco ST-4B 4-channel amplifier is a compatible partner from the same ST range.
Features
- Mono, bass, Class D
- RCA and speaker level inputs
- Variable input gain control
- Variable electronic crossover
- Variable bass boost control
- Subsonic filter
Explore the full range in Zapco Amplifiers.
Specification
| Power @ 4Ω | 1 x 400 watts RMS |
|---|---|
| THD @ Rated Power | <0.5%THD |
| Power @ 2Ω | 1 x 750 watts RMS |
| Signal to Noise Ratio | >98dB |
| THD + Noise | <0.5% |
| Frequency Response | 10Hz to 250Hz ±1dB |
| Operating Voltage | 6.5v to 17v |
| Net Dimensions (mm) | 124(W) x 50(H) x 213(L) |
| Overall Dimensions (mm) | 124(W) x 50(H) x 254(L) |
What's Included
- Zapco ST-750D
Zapco
About the Zapco ST-750D
From our tech experts at CEN
A monoblock subwoofer amplifier from Zapco, Class D, rated at 400w RMS.
Who it suits
Anyone driving a subwoofer that needs controlled, honest power. Zapco amplifiers are bought by people who care what the power figure actually means rather than what it says on the box.
Our tech experts advise
Matching the amplifier to the speakers matters more than headline watts, and gains want setting with a meter. It needs a fused feed from the battery on the correct cable gauge. Installation is priced per vehicle, so get in touch with your make, model and year and we will confirm what it needs. See car audio installation.
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Frequently Asked Questions
Q: How do I choose the right amplifier for my speakers or subwoofer?
A: Match the amplifier's RMS output per channel to the RMS handling of your speakers or subwoofer at the same impedance. The Specification tab lists the power figures. If in doubt, contact CEN with your setup and we will recommend a match.
Q: What wiring do I need to install this amplifier?
A: You will need an amplifier wiring kit sized to the amplifier's power draw, typically including power and earth cable, a fuse, RCA leads and a remote wire. CEN stocks complete wiring kits, and the amplifier's fuse rating is the guide to the cable gauge required.
Q: What class of amplifier is this and does it matter?
A: Class D amplifiers are compact and efficient, ideal for subwoofers and modern installs. Class AB designs are traditionally favoured for outright sound quality on mid and high frequencies. The class is listed in the Specification tab where provided.
Q: Will an amplifier work with my factory head unit?
A: Yes, in most cases. If your head unit has no RCA outputs you will need a line output converter to feed the amplifier a clean signal. CEN stocks line output converters and can advise the right one for your vehicle.
Q: Can CEN install this amplifier?
A: Yes. CEN offers professional amplifier installation from our Nottingham premises, including secure mounting, wiring and setup. Contact us to book.
Q: How much power does the Zapco ST-750D produce?
A: It is rated at 1 x 400 watts RMS at 4 ohms and 1 x 750 watts RMS at 2 ohms.
Q: Can the ST-750D connect to a factory head unit?
A: Yes. It has both RCA and speaker level inputs.
Q: Does the ST-750D have a subsonic filter?
A: Yes. It has a subsonic filter, variable electronic crossover and variable bass boost.
