SP-300.4 MINI — 4-CHANNEL CLASS D AMPLIFIER 300W RMS x4
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SUPER POWER AUDIODESIGNED IN ITALY
MMXXVI
300 watts RMS
× four.
Four channels for a complete system: front and rear, or two speakers plus a bridged subwoofer. Two independent filter blocks and two input levels, so each pair does its own job. Designed in Italy, verified with Audio Precision instruments before it leaves the line.
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Power measured, not promised
RMS @ 14.4 V · ≤ 1% THD+N · CONTINUOUS POWER, NOT PEAK · MINIMUM LOAD 2 Ω PER CHANNEL, 4 Ω BRIDGED
Why this amplifier
Front and rear from a single amplifier, or two speakers plus a subwoofer on a bridged pair. Bridge CH1 with CH2, or CH3 with CH4 — the guide is printed on the terminal panel.
CH1/CH2 high-pass or off; CH3/CH4 off, low-pass or high-pass. Both variable from 50 to 250 Hz, each pair with its own input level: door speakers filtered high and a subwoofer filtered low, from the same amplifier.
310 × 112 × 46 mm and only 46 mm tall. Under a seat or in a false floor, with the boot still usable and the cable runs short.
Short-circuit, thermal and voltage protection with LED diagnostics. This model carries no fuse on board, so the 125 A external fuse is not an option: it is part of the installation.
Wiring, loads and impedance, filters, gain calibration and the complete specifications.
⇩ Download the manual (PDF)English · Rev. 1.0 · September 2026 · 1.4 MB
Not a box. A case.
The SP-300.4 MINI arrives in a black wooden case with the SP mark and the tricolour on the lid. A rigid shell during shipping, the safest way to store or carry the amplifier afterwards — and a box people keep.
In the case: amplifier · collector’s wooden case · printed user manual.
Not included: power and speaker cable, external fuse holder and RCA cable — these are installation materials, chosen to suit your vehicle.
Technical specifications
| POWER OUTPUT — RMS @ 14.4 V, ≤ 1% THD+N | |
|---|---|
| 4 channels, 4 ohm | 4 × 300 W |
| 4 channels, 2 ohm | 4 × 400 W |
| Bridged 4 ohm | 2 × 900 W |
| Minimum load, 4-channel | 2 ohm per channel |
| Minimum load, bridged | 4 ohm |
| AUDIO | |
| Topology | Class D, 4 channels |
| Frequency response | 10 Hz – 50 kHz |
| Signal-to-noise ratio | ≥ 90 dB |
| Input sensitivity | 200 mV – 6 V |
| Minimum source level | 100 mV |
| Inputs | RCA low level, CH1 – CH4 |
| FILTERS | |
| Filter modes CH1/CH2 | HPF · OFF |
| Filter modes CH3/CH4 | OFF · LPF · HPF |
| High-pass filter | 50 – 250 Hz, variable, CH1/CH2 and CH3/CH4 |
| Low-pass filter | 50 – 250 Hz, variable, CH3/CH4 only |
| Bass boost | Not fitted on this model |
| POWER SUPPLY AND PROTECTION | |
| Supply | 12 V negative ground, 14.4 V nominal |
| Remote turn-on | +12 V |
| On-board fuse | None fitted |
| Required external fuse | 125 A, as close to the battery as practical |
| Recommended cable | 4 AWG |
| Protections | Short circuit, thermal, voltage |
| Indicators | POWER (green) · PROTECT (red) |
| MECHANICAL AND QUALITY | |
| Dimensions L × W × H | 310 × 112 × 46 mm |
| Mounting points | 4 |
| Construction | Aluminium, heat-dissipating fins, rubber bumpers |
| Terminals | Direct-insert, screw clamp |
| PCB | 2-layer, surface-mount technology |
| Verification | Audio Precision quality control |
| Packaging | Collector’s wooden case |
MANUFACTURER’S LABORATORY DATA · PEAK OR “BURST” FIGURES USED IN SOME MARKETS ARE NOT RMS AND ARE NOT LISTED
Complete the system
Before you install it
- No fuse on board: the external fuse is mandatory. Unlike the other MINI amplifiers, the SP-300.4 MINI has no on-board fuse. Fit a 125 A fuse as close to the battery as practical, sized to the cable.
- Respect the minimum load: 2 ohm per channel, 4 ohm bridged. A lower impedance trips the protection and, if it happens repeatedly, damages the output stage.
- Bridge inside a pair only: CH1 with CH2, or CH3 with CH4. Never bridge across the two pairs.
- Leave the fins clear. The aluminium fins are the entire cooling system: never cover the amplifier with carpet, luggage or foam.
- 12 V systems only, negative ground. Professional installation is recommended: damage caused by incorrect installation is not covered by the warranty.
What installers ask
spaudio@spaudio.it · +39 340 807 8778
Accepted payment methods
Visa · Mastercard · Maestro · American Express · PayPal · Apple Pay · Google Pay · Shop Pay · Klarna
SP Audio — Super Power Audio. Designed in Italy by Audiocar Import & Export SRLS, Milan, official SP Audio distributor for Europe.