Nakamichi FHA100
Class D Monoblock Sub Amp — ₹37,299
250W RMS at 4Ω. 400W RMS at 2Ω. Class D efficiency. Variable LPF, subsonic filter, and 12dB bass boost. This is the dedicated subwoofer amplifier your car system is missing — and here's exactly why it matters.
What the FHA100 Actually Is
A dedicated Class D monoblock amplifier built for one job — driving a subwoofer with clean, sustained high-power output.
A subwoofer is the hardest-working driver in your system. It moves more air, demands more power, and runs at higher continuous output than any speaker in your doors. Powering it off a bridged 4-channel amp is a compromise — it works, but the amp wasn't designed for mono sub duty, and both the sub and the amp's other channels suffer for it. The Nakamichi FHA100 is the solution: one channel, built entirely for bass.
250W RMS into 4Ω, 400W RMS into 2Ω. Class D means up to 90% efficiency — the amp barely heats up even at sustained high output. The built-in crossover suite (variable LPF, variable subsonic filter, 12dB bass boost) means you don't need an external crossover — everything a sub amp needs is already on board. At ₹37,299, this is the most feature-complete dedicated monoblock at this price in the Indian market.
1000W peak ≠ 1000W usable. The 1000W figure is a momentary burst rating. The figures that matter are RMS: 250W @ 4Ω and 400W @ 2Ω — these are continuous, sustained power ratings at rated distortion. Match your subwoofer's RMS rating to these figures, not the peak.
How Much Power, At What Load
Nakamichi FHA100 — Complete Spec Sheet
| Specification | Detail |
|---|---|
| Model | Nakamichi FHA100 |
| Amplifier Class | Class D (Monoblock) |
| Channels | 1 (Mono) |
| RMS Power @ 4Ω | 250W × 1 |
| RMS Power @ 2Ω | 400W × 1 |
| Total Peak Power | 1000W |
| Frequency Response | 15Hz – 250Hz |
| Signal-to-Noise Ratio | ≥ 90dB |
| THD (Total Harmonic Distortion) | < 0.2% |
| Low-Pass Filter (LPF) | 50Hz – 250Hz, variable |
| Subsonic Filter (SSF) | 15Hz – 50Hz, variable |
| Bass Boost | 0dB – +12dB @ 45Hz |
| Remote Bass Level | Remote bass port (optional knob) |
| Input | Gold-plated RCA inputs |
| Output Terminals | Heavy-duty terminal blocks |
| Chassis | Extruded aluminum heat sink |
| Operating Voltage | 9V – 16V DC |
| Protection | Thermal · Short circuit · Low/high voltage · Reverse polarity |
| In the Box | FHA100 unit · Mounting hardware · Spare fuses · Manual |
| Price | ₹37,299 (incl. tax) |
Class D for Subwoofers — The Right Tool for the Job
Class D switches its output transistors at ~100kHz — essentially on/off, not linear. The transistors are never in a partially-on state, so they dissipate almost no energy as heat. A 400W Class D amp produces roughly 45W of heat. A 400W Class AB amp produces ~220W of heat. In a car boot, thermal management is everything — Class D wins decisively at subwoofer power levels.
The FHA100 at 400W output draws approximately 37A from a 12V battery (400 ÷ 0.9 efficiency ÷ 12V). A Class AB amp delivering the same 400W would draw ~55A. 18A less load on your alternator means less voltage drop at the battery, which means every other component in your system performs more consistently — including the FHA400 on the speaker channels.
Class D's switching frequency is 80–150kHz. The resulting artefacts (switching noise, intermodulation products) appear far above 20kHz — the limit of human hearing. At bass frequencies (15–250Hz), a good Class D amp is indistinguishable from Class AB. This is why every serious subwoofer amp — from budget to reference — is Class D.
A monoblock has one job. No sharing power supply headroom between channels, no crosstalk between channels, no compromise. 100% of the FHA100's power supply goes to one output stage, into one subwoofer. A bridged stereo amp doing sub duty shares its power supply with the other channels — the monoblock eliminates this entirely.
Most sub amps spec 20Hz as the lower limit. The FHA100 goes to 15Hz — below the rated lower limit of most human hearing. In practice this means infrasonic content (20–30Hz in electronic music, film soundtracks, bass drops) is reproduced faithfully rather than attenuated. In a ported enclosure tuned to 30–35Hz, this is the difference between feeling the bass and just hearing it.
The FHA100 adds reverse polarity protection on top of the standard protection suite. Connect the power and ground cables backwards during installation — the amp survives. Without this, reversed polarity destroys the amp instantly. In the chaos of a boot installation with multiple cables, this single protection has saved more amps from being immediately bricked than any other circuit.
LPF · Subsonic Filter · Bass Boost — What Each One Does
Quick setup: LPF = 80Hz, SSF = 25Hz (ported) or 15Hz (sealed), Bass Boost = 3dB. These starting points work for 90% of builds. Tune from there — tighten the LPF if the sub sounds muddy, increase SSF if you hear the cone bottoming out on bass drops, add bass boost only if the sealed box sounds thin at the bottom end.
Impedance, Wiring, and Getting 400W From the FHA100
| Sub Configuration | Final Load (Ω) | FHA100 Output | Notes |
|---|---|---|---|
| 1× single voice coil 4Ω sub | 4Ω | 250W RMS | Standard — most single sub builds |
| 1× single voice coil 2Ω sub | 2Ω | 400W RMS | Maximum output — 2Ω SVC sub required |
| 2× 4Ω SVC subs — parallel wired | 2Ω | 400W RMS | Dual sub, each sees 200W — check each sub's RMS rating |
| 2× 8Ω SVC subs — parallel wired | 4Ω | 250W RMS | Each sub sees 125W — verify sub's minimum impedance |
| 2× 4Ω SVC subs — series wired | 8Ω | ~150W est. | Not recommended — significant power reduction |
| Load below 2Ω | <2Ω | Do not use | FHA100 is not rated below 2Ω — protection will fire or damage occurs |
Want 400W from one sub? Use a 2Ω SVC (single voice coil) subwoofer, or a dual voice coil (DVC) sub with two 4Ω voice coils — wire the voice coils in parallel to present a 2Ω load to the FHA100. Ask us at Car Concepts Shop — we'll confirm the correct wiring for your specific sub before you buy.
What Protects the FHA100
Which Subwoofer to Run with the FHA100
| Subwoofer | RMS Rating | Amp Output | Notes |
|---|---|---|---|
| Morel Kinetic KS124 12" Best Match | 350W @ 4Ω | 250W @ 4Ω | Slightly underpowered but clean — sub handles the power easily. Add a 2Ω sub to access 400W. |
| Morel Kinetic KS104 10" | 300W @ 4Ω | 250W @ 4Ω | Good match — 250W is 83% of rated power. Clean daily driver setup. |
| JBL Stadium SW1228 12" | 300W @ 4Ω | 250W @ 4Ω | 250W is within JBL's RMS range. Solid pairing. |
| Any 2Ω SVC or DVC sub wired to 2Ω | 350–400W | 400W @ 2Ω | Full power mode — match sub's RMS to 400W for perfect pairing. |
| Sub rated under 200W RMS Caution | <200W | 250W @ 4Ω | FHA100 overpowers it — overpowering causes thermal failure. Match or step down gain carefully. |
Common Questions — FHA100
A monoblock Class D amplifier is simpler and cheaper to manufacture than a 4-channel Class AB amplifier. Class D uses far fewer components in the output stage — no large output transformers, no matched pairs of bipolar transistors per channel, no complex biasing circuits. The FHA400 has four fully independent Class AB output stages, each requiring its own matched transistor pairs, bias circuitry, and heat sink area. Manufacturing cost scales with channel count and topology complexity, not just power output.
Less critical than with a ported box, but still useful. A sealed enclosure naturally rolls off below its resonant frequency and provides acoustic control of cone excursion. However, recorded content sometimes contains infrasonic noise (20Hz and below from studio equipment, wind, vehicle vibration in recordings) that the sub will attempt to reproduce at full cone excursion. Setting the SSF to 20–25Hz in a sealed build removes this without affecting audible bass. In a ported box, the SSF is mandatory — set it 5Hz below the port tuning frequency.
At 400W RMS, Class D efficiency ~90%, the FHA100 draws (400 ÷ 0.9) ÷ 12V = ~37A continuous. At 1000W peak burst it draws approximately 93A. Use 4-gauge power and ground for runs up to 4m, 2-gauge for longer runs. Install an 80A inline fuse on the power cable within 30cm of the battery positive terminal. Never rely on the amp's internal fuse as primary protection — by the time the amp's fuse blows, the power cable may already be on fire.
No. The FHA100's frequency response is 15Hz–250Hz — it rolls off above 250Hz, meaning it will not reproduce midrange or high frequencies. It is engineered exclusively as a subwoofer amplifier. For door speakers, use the FHA400 (20Hz–20kHz full range response). Using the FHA100 on a speaker channel would produce bass-only output and likely damage a tweeter from the unfiltered low-frequency output.
Yes, strongly recommended. The FHA100 is installed in the boot and adjusting bass boost by reaching back there is impractical. The remote bass knob mounts on your dash or centre console and lets you adjust the sub output level from the driver's seat in real time — different music, different roads, different passengers, different volume preferences. It's the most-used control in any system once you have it. Ask us to include it when you order the FHA100.