Nakamichi NHMD100 4channel power Amplifier User Manual

: June 5, 2024
: Nakamichi

Table of Contents

INTRODUCTION
Accessory List
Specification
Dimensions(Unit: MM)
POWER CONNECTION LEADS
- CONNECTION CHANNEL MODE
PANEL CONTROL AND FEATURES
INTERFERENCE
TROUBLESHOOTING
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**Nakamichi NHMD100 4channel power Amplifier User Manual

**

INTRODUCTION

Thank you for your purchase of our Nakamichi product and we warmly welcome you to the Nakamichi family! Do keep your original invoice and purchase receipt in a safe place in case of future service and warranty claims. You may also contact your appointed Nakamichi service agent for any future technical support requirements.

Accessory List

User Manual: 2pcs
Amplifier: 1 pc
Mounting Screw(cD4x2Omm): 4pcs
Mounting Bracket Screw(cD4x6mm): 4pcs
Remote Control: 1 set
Fixing frame (34x20mm): 4pcs
L-type wrench(L=77mm): 1 pcs
L-type wrench(L=90mm) : 1 pcs
High input line(L=30mm) : 1 pcs

Specification

N-power Output@40: 100Wx4
N-power Output@20: 125Wx4
N-power Output@40(bridged): 200Wx2
Max power T.H.D: 2500W
Frequency Response: 1170 20Hz
Signal To Noise Ratio +A: i9s0dB
Sensitivity: 0.15V-8V
Unit Dimensions(LxHxW): 222x120x48mm
Net Weight: Approx. 1.4kg
Box Dimensions(LxHxW): 295x218x75mm
Gross Weight: Approx. 2.5kg
All specifications subject to change without notice.

Dimensions(Unit: MM)

POWER CONNECTION LEADS

Notes on the power supply
Connect the +12V power input lead only after all other leads have been connected. Be sure to connect the ground wire of the unit securely to a meatal part of the car. A lose 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 like the two power terminal so a thinner connecting wire is acceptable. Standard 18 GAUGE is fine and the standard colour is yellow. 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 still splice into it. With this method, the unit will turn on automatically with the radio.

Use the power supply lead with a fuse attached whose value is the same as original fuse. Place the fuse in power supply lead as close as possible to the car battery. During a full power operation, Maximum current will run through the system. Therefore. Make sure the that the leads to be connected to the +12V and GND terminals of the unit respectively must be larger than 8-Gauge(AWG.8).
POWER CONNECTION LEADS

CONNECTION CHANNEL MODE

PANEL CONTROL AND FEATURES

A ROMOTE LEVEL CONTROL INPUT
Attached the included remote level control here to control the volume level to the subwoofer independently.

B. CHANNEL CONTRO L
Depending on the switch selected, the amplifier will operate in 2CH or 4CH input mode.

C. LOW LEVEL RCA INPUT
These RCA input jacks connect with your source unit RCA low level outputs or via optional adapter with your source unit speaker high level outputs. The use of high quality twisted pair car audio cables is recommended to reduce the possibility of audio signal deration.

D. HIGH LEVEL INPUT
The high-level input should only be used when your receiver lacks RCA output. if there are no RCA output available, connect the speaker output from the receiver to the amplifier’s high level input connector. Be sure to note the polarity to avoid audio phase problems.

E. POWER AND PROTECTION INDICATOR
The protection red LED will light up and flash if there is a fault present in the amplifier. Please disconnect the amplifier and resolve the foult before reconnecting the amplifier. The power indicator green LED will light up when the amplifier is working correctly.

F. DSP DIRECT CONTROL
Depending on the selected switch, the amplifier can select DSP mode on or off.

G. SPEAKER GAIN CONTROL
The gain control will match the amplifiers sensitivity to the source signal voltage.

H. CH3/CH4 SPEAKER CROSSOVER CONTROL
Depending on the selected switch the amplfier will operate at full or hpf or bpf mode.

I. CHI /CH2 SPEAKER CROSSOVER CONTROL
Depending on the selected switch the amplfier will operate at full or hpf mode.

J. CH3/CH4 SPEAKER HIGH PASS CROSSOVER FREQUENCY
Controls high frequency of the amplifier between 15Hz to 500Hz.

K. CHI /CH2 SPEAKER HIGH PASS CROSSOVER FREQUENCY
Controls high frequency of the amplifier between 50Hz to 500Hz/500Hz to 5KHz.

L. CHI /CH2 SPEAKER HIGH PASS CROSSOVER FREQUENCY
Depending on the selected switch can controls high frequency of the amplifier between dube 1 times or 10 times.

M. CH3/CH4 SPEAKER LOW PASS CROSSOVER FREQUENCY
Depending on the selected switch can controls high frequency of the amplifier between dube 1 times or 10 times.

N. CH3/CH4 SPEAKER LOW PASS CROSSOVER FREQUENCY
Controls high frequency of the amplifier between 50Hz to 500Hz/500Hz to 5KHz.

O. CH3/CH4 BASS BOOST The BASS BOOST
feature will increase the sound level in the bass frequencies.

P. SPEAKER CONNECTIONS
Connect your speakers and woofers to there terminals, ensuring proper polarity during connection. Never connect the speaker cables to the chassis ground.

Q. GND(-) = GROUND CONNECTION
Connect this coble directly to the metal frame of the vehicle, ensuring that the metal frame has been strpped of all paint down to the bare metal. Use the shortest distance possible. It is atways a good idea to replace the vehicle battery groudn terminal or any other factory ground points.

R. POWER ON CONTROL OF AMPLIFIER
The amplifier REM-IN should be connected to the REM-OUT of the source unit. The source unit will control the amplifier to automatically turn on or off.

S. +12V = POWER SUPPLY
Connect this terminal through a fuse or circuit breaker to the positive terminal of the vehicle battery or the positive terminal of an isolated audio system battery.

INTERFERENCE

All cables can create interference. The power cable and cinch / RCA audio cables are very prone to interference from other sources, while remote cables are less prone. Interference is often caused by the generator, ignition, or any other electronic pads or systems. Most of these problems can be eliminated by correct and careful wiring during setup. Here are some guidelines to follow.

Use only a shielded audio cable for the wiring between the low level input of the amplifier and the RCA or DIN output of the radio.
Lay the signal, speaker and power cables separately with enough distance from one another and also from each other car cable. Ir not possible, you can lay the circuit and ground cable together with the serial cables. Audio and speaker cable should be as far away from these as possible. The REM cable to the automatic antenna output of the radio can be laid together with the signal cables.
Avoid ground loops by laying the ground wiring of all components towards a central point in a star layout. You can locate fne best point by measuring the voltage directly at the battery, and comparing the voltage value with the chosen ground point and the positive terminal of the amplifier. If the measured voltage is only slightly different. you’ve found the correct central location. Other wise please look for another point. You should measure with the ignition point for earth switched on.
If there are pickups from external electrical sources into the speaker cables, divide the core leads and twist them together.
If there are noises from the car electrics, add an interference suppression choke into the power wiring.
If there are humming noises, use thicker ground cables or add further ground cables to the chassis.
To reduce contact resistance and bad and loose contacts, please solder the cable ends or use multi core cable ends, spade terminals or others. Gold Plated spade terminal are free of corrosion and have the lowest contact resistance.
Should all these measures not bring about any success, the use of a ground loop isolator may solve the problem.

TROUBLESHOOTING

If you experience operation or performance problems with this product, compare your installation with the electrical wiring diagram on the previous pages. lf problems persist, read the following troubleshooting tips which may help eliminate the problems.

SYMPTOM POSSIBLE CAUSE ACTION TO TAKE

NO OUTPUT|

low or no remote turnon input

| Cheek remote turn-on voltage output at attire, and correct as needed
“use blown| Check powerwire hteally and reverted colony. repair as needed and replace fuse

nower wires not connected

| Cheek power wire and ground connections and repay of replace os needed

audio input not connected or no output from source

| Chock input comedians me sisal integrity. repelt or replace of needed

Sceoker wires not connected

| Check speaker wires and reps or replace os needed
AUDIO
CYCLES ON AND OFF|

Speaker are down

| Check system with known waking speaker and reps a replace speaker as needed

Thermal protection engages when amplifier heat sink temperature exceeds 75C

| .moke sure there is proper ventilation for amplifier and improve ventilation as needed

.coseorpact oudo nput

| -Check input connection and repot or replace os needed
OUTPUT|

Amplifier lecel sensitivity set too high: exceeding max mum output capabilty of amplifier

|

lie set gain referring to the tuning sectional the manual for detailed instructions
1mi:el:once load to amplifier too law impedance

| Check speaker impedance bad. if below 20 stereo Cr 40 mono rewire speakers to achieve a higher impedance

Stored speaker wires

| cheat speaker wk.* connections and repel or replace as needed
no

Speaker t connected to amplifier properly

| Check specter wiring one repair of replace as needed refer to the installation section of this manual for detoxed instructions
infernal crossover not set properly for speaker|

llesetaossoven referring to the multi-cross crossover

configuration moron of this manual
DISTORTED OUTPUT !CONED]| Ore re down| Chock system with known working speaker and repair or replace as needed
POOR BASS RESPONSE|

speaker wired wrong oddity causing concelatian at low frequencies

| Check speaker polarity and few* as needed Reset crossovers referrng to the multt-cross
Crossover set incorrectly| .0 OSSOVO. configuration soorion of this manual for Saralee instructions
DISTORTED OUTPUT
(CONED)| -Impedance load to amplifier too low| Check speaker impedance bpd. E below 20 stereo et 40 mono rewire speaker to achieve o higher impedance