Zapco ST-5B Amp 5 Channel Class AB Full Range Amplifier 4x70w + 1x250 RMS
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The Zapco ST-5B is a 5-channel Class AB full-range amplifier rated at 4 x 70W + 1 x 250W RMS, part of Zapco's ST-B series. It powers four speakers and a subwoofer from a single unit, with both RCA and OEM speaker-level inputs.
It is compatible with the optional Zapco ST-BR remote level control. The ST-4B is the same series without the subwoofer channel.
Key specifications
- Model: ST-5B
- Channels: 5, full range, Class AB
- Power @ 4 ohms: 4 x 70W + 1 x 250W
- Power @ 2 ohms: 4 x 100W + 1 x 400W
- Bridged: 2 x 180W + 1 x 400W (2 ohms)
- Inputs: RCA and OEM speaker level
- Frequency response: 15Hz – 30kHz ±1dB
- Net dimensions: 182(W) x 52(H) x 351(L) mm
- Overall dimensions: 182(W) x 52(H) x 381(L) mm
ST-5B 5-channel Class AB amplifier
Stable into 4 ohms bridged or 2 ohms stereo load.
- MOSFET power supply
- RCA and OEM speaker-level input
- Variable input gain control
- Variable full / LP / HP electronic crossover
- Variable bass boost
- Power @ 4Ω: 4 x 70 + 1 x 250 watts
- Power @ 2Ω: 4 x 100 + 1 x 400 watts
- Power @ 4Ω bridged: 2 x 180 + 1 x 400 (2Ω)
- THD @ rated power < 0.2%
- Signal to noise ratio > 90dB
- Channel separation > 45dB
- Frequency response: 15Hz – 30kHz ±1dB
- Input sensitivity: 0.25V – 5V
- Net dimensions: 182(W) x 52(H) x 351(L) mm
- Overall dimensions: 182(W) x 52(H) x 381(L) mm
Explore the full range in 5 Channel Amplifiers.
Specification
| Power @ 4Ω | 4 x 70 + 1 x 250 watts |
|---|---|
| Power @ 2Ω | 4 x 100 + 1 x 400 watts |
| Power @ 4Ω Bridged | 2 x 180 + 1 x 400 (2Ω) |
| Frequency Response | 15Hz to 30KHz ±1dB |
| Net Dimensions (mm) | 182(W) x 52(H) x 351(L) |
| Overall Dimensions (mm) | 182(W) x 52(H) x 381(L) |
More specs
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What's Included
- Zapco ST-5B
Zapco
About the Zapco ST-5B
From our tech experts at CEN
A 5-channel amplifier from Zapco, Class AB, rated at 70w RMS.
Who it suits
Drivers building a front stage that needs each channel doing a defined job. 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.
Explore the full Zapco range at CEN, with fast UK dispatch and expert advice from our Nottingham team. Shop all Zapco
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Have it Fitted By Our Team
Our team fits car audio, stereos, dash cams and vehicle security at our workshop in Beeston, Nottingham. Tell us your vehicle and we'll confirm the parts and a fitted price.
- 1
Tell us your vehicle
Make, model and year, and what you'd like fitted.
- 2
We confirm the parts
Fascia, wiring and interfaces checked for your car, with a fitted price.
- 3
Fitted at our workshop
Bring it to our Beeston workshop and we do the rest.
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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-5B produce?
A: At 4 ohms it delivers 4 x 70 watts plus 1 x 250 watts. At 2 ohms it delivers 4 x 100 watts plus 1 x 400 watts.
Q: Can I add a bass remote to the ST-5B?
A: Yes. The Zapco ST-BR remote level control is compatible with the ST-5B.
Q: Can the ST-5B work with a factory stereo?
A: Yes. It has OEM speaker level inputs as well as RCA inputs.
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