Nakamichi FHA400 Amplifier User Manual
Introduction
Thank you for your purchase of a Nakamichi product. Keep your original invoice and purchase receipt for future service and warranty claims. Contact your appointed Nakamichi service agent for technical support.
Accessory List
| User Manual | 1pcs |
| Amplifier | 1pc |
| Mounting Screw (M3x6mm) | 8pcs |
| Mounting Screw (M4x16mm) | 4pcs |
| Mounting Bracket | 4pcs |
Specifications
| N-power Output @4Ω | 4 x 150W |
| N-power Output @2Ω | 4 x 190W |
| N-power Output @4Ω (Bridged) | 2 x 380W |
| MAX Power | 3800W |
| T.H.D | ≤0.2% |
| Frequency Response | 20Hz-32kHz |
| Signal To Noise Ratio | ≥105dB |
| Sensitivity | 0.35V-9V |
| Fuse Size | 40Ax2 |
| Unit Dimensions(LxHxW) | 384x190x62mm |
| Net Weight | Approx. 4.7kg |
All specifications subject to change without notice.
Dimensions (Unit: MM)
The amplifier has a width of 384mm, a height of 191mm, and a depth of 62mm.
Power Connection Leads
Notes on the power supply: Connect the +12V power input lead only after all other leads have been connected. Securely connect the ground wire of the unit to a metal part of the car. A loose connection may cause a malfunction of the amplifier.
REMOTE: The unit is turned on by applying +12Volts to this terminal. This terminal does not draw heavy current. A standard 18 GAUGE wire is sufficient. If the radio is equipped with a power antenna control wire, it can drive this terminal. If the power antenna wire is already in use, you can splice into it. This method will turn the unit on automatically with the radio.
Use the power supply lead with a fuse attached whose value is the same as the original fuse. Place the fuse in the power supply lead as close as possible to the car battery. During full power operation, maximum current will run through the system. Ensure the leads connected to the +12V and GND terminals are larger than 8-Gauge (AWG.8).
Connection 1: 4-Channel Mode
This diagram shows how to connect four speakers to the amplifier in a 4-channel configuration. Each speaker (2-8 Ω) is connected to a corresponding channel output (1/L, 2/R, 3/L, 4/R).
Connection 2: 3-Channel Mode
This diagram illustrates connecting three speakers. Two speakers (2-8 Ω) are connected to channels 1/L and 2/R. A third speaker (4-8 Ω) is connected to the bridged output of channels 3/L and 4/R.
Connection 3: 2-Channel Mode
This diagram shows connecting two speakers. Two speakers (4-8 Ω) are connected to the bridged outputs of channels 1/L & 2/R and 3/L & 4/R respectively.
Panel Controls and Features
The front panel features various controls and connection terminals:
- A. Power Indicator: A green light indicates the amplifier is working normally. A red light indicates the amplifier is in protection mode.
- B. GND (-): Ground Connection. Connect this cable directly to the metal frame of the vehicle, ensuring the metal frame is stripped of paint down to the bare metal. Use the shortest possible distance. It is advisable to replace the vehicle battery ground terminal or any other area ground points.
- C. REM: Power amplifier control line.
- D. +BATTERY: Power Supply. Connect this terminal through a fuse or circuit breaker to the positive terminal of the vehicle battery or an isolated audio system battery.
- E. FUSE: Do not use a fuse with a different value and NEVER replace the fuse with a wire or coin.
- F. SPEAKER CONNECTIONS: Connect your speakers and woofers to these terminals, ensuring proper polarity. Never connect speaker cables to the chassis ground.
- G. Low Pass Frequency Range Regulation.
- H. Mode Selection Switch.
- I. High Pass Frequency Range Regulation.
- J. BASS BOOST: This feature increases the sound level in the bass frequencies.
- K. Volume Regulator.
- L. Signal input.
Interference
Cables can cause interference. Power and RCA audio cables are more prone than remote cables. Interference sources include generators, ignition systems, and other electronic parts. Correct and careful wiring can eliminate most problems.
- Use only shielded audio cables for wiring between the low-level input of the amplifier and the RCA or DIN output of the radio.
- Lay signal, speaker, and power cables separately, with sufficient distance between them and other car cables. If not possible, circuit and ground cables can be laid with serial cables. Audio and speaker cables should be as far as possible from these. The REM cable to the automatic antenna output of the radio can be laid with signal cables.
- Avoid ground loops by laying ground wiring of all components towards a central point in a star layout. Measure voltage at the battery and compare it with the chosen ground point and the amplifier's positive terminal. If the measured voltage is only slightly different, you have found the correct central location. Otherwise, look for another point. Measure with the ignition point for earth switched on.
- If external electrical sources pick up into speaker cables, divide the core leads and twist them together.
- If there is noise from the car electrics, add an interference suppression choke into the power wiring.
- If there are humming noises, use thicker ground cables or add more ground cables to the chassis.
- To reduce contact resistance, solder cable ends or use multi-core cable ends, spade terminals, or others. Gold-plated spade terminals are corrosion-free and have the lowest contact resistance.
- If these measures do not succeed, a ground loop isolator may solve the problem.
Troubleshooting
| Symptom | Possible Cause | Action to Take |
|---|---|---|
| NO OUTPUT | • Low or no remote turn-on input | • Check remote turn-on voltage output at amplifier and correct as needed. |
| • Fuse blown | • Check power wire integrity and reversed polarity, repair as needed and replace fuse. | |
| • Power wires not connected | • Check power wire and ground connections and repair or replace as needed. | |
| AUDIO CYCLES ON AND OFF | • Audio input not connected or no output from source | • Check input connections and signal integrity, repair or replace as needed. |
| • Speaker wires not connected | • Check speaker wires and repair or replace as needed. | |
| • Speaker are blown | • Check system with known working speaker and repair or replace speaker as needed. | |
| DISTORTED OUTPUT | • Thermal protection engages when amplifier heat sink temperature exceeds 90°C | • Make sure there is proper ventilation for amplifier and improve ventilation as needed. |
| • Loose or poor audio input | • Check input connections and repair or replace as needed. | |
| • Amplifier level sensitivity set too high; exceeding maximum output capability of amplifier | • Reset gain referring to the tuning section of the manual for detailed instructions. | |
| DISTORTED OUTPUT (CONT'D) | • Impedance load to amplifier too low | • Check speaker impedance load, if below 2Ω stereo or 4Ω mono, rewire speakers to achieve a higher impedance. |
| • Shorted speaker wires | • Check speaker wire connections and repair or replace as needed. | |
| • Speaker not connected to amplifier properly | • Check speaker wiring and repair or replace as needed. Refer to the installation section of this manual for detailed instructions. | |
| POOR BASS RESPONSE | • Internal crossover not set properly for speaker | • Reset crossovers referring to the multi-cross crossover configuration section of this manual. |
| • Speaker are blown | • Check system with known working speaker and repair or replace as needed. | |
| • Speaker wired wrong polarity causing cancellation at low frequencies | • Check speaker polarity and repair as needed. | |
| • Crossover set incorrectly | • Reset crossovers referring to the multi-cross crossover configuration section of this manual for detailed instructions. | |
| • Impedance load to amplifier too low | • Check speaker impedance load, if below 2Ω stereo or 4Ω mono, rewire speakers to achieve a higher impedance. | |
| DISTORTED OUTPUT (CONT'D) | • Short in power wire or incorrect power connections | • Check power and ground connections and repair as needed. |
| • Fuse used is smaller than recommended | • Replace with proper fuse size. | |
| • Too much current being drawn | • Check speaker impedance load, if below 2Ω stereo or 4Ω mono, rewire speakers to achieve a higher impedance. | |
| • Short in power wire or incorrect power connections | • Check power and ground connections and repair as needed. |
