Infinity Primus 9004A 4-Channel Amplifier

Description

Key Specifications

• Line-level input: ~0.2 V – 5.0 V infinity-caraudio.com.au+1

• High-level input (speaker-level): ~0.5 V – 15 V infinity-caraudio.com.au+2fasmoto.com+2 |
  | Crossovers / Filters |

• Variable High-Pass Filters (HPF): 32 Hz – 320 Hz infinity-caraudio.com.au+1

• Variable Low-Pass Filters (LPF): also 32 Hz – 320 Hz infinity-caraudio.com.au+1 |
  | Bass EQ | Switchable bass boost at 45 Hz, 6 dB or 12 dB options infinity-caraudio.com.au+2fasmoto.com+2 |
  | Protection Features | On-board protection: over-temperature (OTP), over/under voltage (OVP / UVP), over-current (OCP), short-circuit etc. infinity-caraudio.com.au+1 |
  | Operating Voltage | 9 – 16 V DC (automotive standard) infinity-caraudio.com.au+1 |
  | Signal-to-Noise Ratio | > 75 dB (line-in, REF to 1 W) fasmoto.com+1 |
  | Quiescent Current Draw (Idle) | < ~1.5 A fasmoto.com+1 |
  | Fuse / Power Wiring Requirements | Fuse size: 2 × 20 A (two fuses) in listings; wiring gauge should match current demands. infinity-caraudio.com.au+2fasmoto.com+2 |
  | Physical Dimensions & Weight | Approx: 50.6 mm (H) × 145 mm (W) × 268.6 mm (L); weight ~ 1.806 kg fasmoto.com+1 |

Features & Design Highlights

• Compact footprint for a 4-channel amp of this power class, making it easier to mount in limited space. infinity-caraudio.com.au+1

• Bass EQ switchable (45 Hz, 6 dB or 12 dB), which helps with low-end reinforcement especially if speakers are unable to handle deep bass. infinity-caraudio.com.au+1

• Variable crossovers (HPF & LPF) allow you to tailor frequencies to what your speakers or subwoofers need, reducing distortion and improving clarity. infinity-caraudio.com.au+1

• Full onboard protection circuits ensure safety in real-world use — protecting against overheating, voltage issues, etc. infinity-caraudio.com.au+1

What to Expect in Real-World Use

Strengths

• Good all-rounder for driving a full set of speakers (front + rear) in a car with decent power. The 90 W × 4 (4 ohm) is strong for most door speakers and coaxial sets.

• When bridged, you can get 220 W to two channels for a more powerful setup (e.g. front mids, or small subwoofer), as long as the amp is properly set up and the load is safe.

• Bass boost at 45 Hz can help compensate for speaker/vehicle limitations (doors not sealed, etc.) and give more punch without needing a separate subwoofer (though a sub will still outperform in deep bass).

• Good options for tuning: filter knobs and input sensitivity let you match with both after-market head units and factory (weak) sources.

Limitations / What to Be Careful Of

• Although 90 W × 4 is good, pushing it hard (especially at 2 ohm) will stress both the amp and your power supply (battery, alternator) and wiring. Overheating or voltage sag can degrade performance.

• Peak power rating (880 W) is marketing-oriented; sustained output is what matters and will be closer to RMS ratings. Don’t expect “880W” continuous.

• Deep bass performance (below ~30 Hz) will depend heavily on your speakers / enclosure / subwoofer; this amp alone won’t produce very deep bass unless paired with able subs.

• Because of its size and power, good ventilation and solid installation are important. Poor airflow / loose mounting will reduce reliability.