Power your entire audio system with one amplifier—5-channel design delivers 500W to subwoofer plus 90W to each of four speakers.
Product Overview
The Nakamichi NKTA750.5 is a professional 5-channel Class A/B amplifier engineered to power complete automotive audio systems from a single compact unit. Delivering 90W x 4 channels for front and rear speakers plus dedicated 500W subwoofer channel at 2-ohm loads, this versatile amplifier eliminates the need for separate speaker and subwoofer amplifiers—simplifying installation, reducing wiring complexity, and saving valuable mounting space. With 3600W maximum power output, adjustable sensitivity (0.15-8V), less than 0.1% THD distortion, and greater than 90dB signal-to-noise ratio, the NKTA750.5 delivers clean, powerful audio across the full 20Hz-20kHz frequency range. The 420 x 267 x 87mm footprint and 2.6kg weight allow installation under seats, in boots, or behind panels where separate amplifier setups won't fit. Featuring dual 40A fuse protection and efficient Class A/B topology balancing performance with thermal management, this comprehensive amplifier represents the ideal solution for Australian drivers seeking professional audio quality across utes, SUVs, sedans, and 4WDs without the complexity and space requirements of multi-amplifier systems.
Key Specifications
Professional 5-channel Class A/B amplifier
Channels 1-4: 90W x 4 RMS at 2Ω (65W x 4 at 4Ω)
Channel 5 (subwoofer): 500W RMS at 2Ω (350W at 4Ω)
3600W maximum total power output
Full-range frequency response: 20Hz - 20kHz
Greater than 90dB signal-to-noise ratio
Less than 0.1% total harmonic distortion
Adjustable input sensitivity: 0.15V - 8V
Dual 40A fuse protection
Compact dimensions: 420 x 267 x 87mm
Lightweight construction: 2.6kg
Class A/B topology (efficiency + sound quality)
Complete system amplification from single unit
Features & Benefits
Complete System Solution: Single amplifier powers entire audio system—four speaker channels for front and rear speakers plus dedicated high-power subwoofer channel—eliminates need for separate speaker and subwoofer amplifiers, simplifying installation, reducing wiring complexity, cutting costs, and saving mounting space in vehicles with limited installation areas.
Powerful Subwoofer Channel: Dedicated 500W RMS at 2Ω subwoofer channel delivers serious bass output for single or dual subwoofer configurations—provides enough power for 10-inch or 12-inch active subwoofers, bass packs, or passive subwoofer enclosures without requiring separate monoblock amplifier purchase, installation, and wiring runs.
Quality Speaker Amplification: Four channels delivering 90W RMS each at 2Ω provide ample power for component speakers, coaxial speakers, or full-range systems—significant upgrade from factory headunit power (typically 15-25W), ensuring speakers reach full dynamic potential with improved clarity, bass control, and maximum volume without distortion.
Adjustable Input Sensitivity: Wide 0.15-8V sensitivity range accommodates factory headunits with low voltage outputs and aftermarket headunits with high-voltage pre-outs—allows proper gain matching for balanced system performance preventing distortion from over-driving inputs or weak output from under-utilizing amplifier capability, ensuring optimal sound quality.
Low Distortion Performance: Less than 0.1% THD ensures clean, accurate amplification without audible distortion—maintains audio quality at all volume levels during extended listening sessions on long Australian highway drives, regional touring, or daily commuting without listening fatigue from harmonic artifacts common in cheaper amplifiers.
Excellent Signal-to-Noise Ratio: Greater than 90dB SNR provides quiet operation without background hiss or noise—ensures music, podcasts, audiobooks, and hands-free calls sound clear and professional even during quiet passages or low-volume listening, critical for quality audio systems where noise floor matters.
Space-Efficient Design: Compact 420 x 267 x 87mm footprint and 2.6kg weight allow installation under front seats, behind rear seats, in side panels, or boot corners—fits locations where separate amplifier setups requiring multiple units won't accommodate, preserving cargo space in utes and wagons for touring gear and equipment.
Class A/B Efficiency: Class A/B topology balances sound quality with thermal efficiency—delivers clean power without excessive heat generation common in pure Class A designs while maintaining superior audio performance compared to Class D switching amplifiers, ensuring reliable operation during extended use in Australian heat without thermal protection shutdowns.
Technical Specs
Type: 5-channel automotive amplifier
Amplifier Class: Class A/B (high-quality topology)
Total Channels: 5 (4 full-range + 1 subwoofer)
Channels 1-4 Power Output: 90W RMS x 4 at 2Ω / 65W RMS x 4 at 4Ω
Channel 5 Power Output: 500W RMS at 2Ω / 350W RMS at 4Ω
Maximum Power Output: 3600W peak
Frequency Response: 20Hz - 20kHz (full audible range)
Signal-to-Noise Ratio: Greater than 90dB
Total Harmonic Distortion: Less than 0.1%
Input Sensitivity: 0.15V - 8V (adjustable)
Input Impedance: Not specified (verify from documentation)
Channels 1-4 Load: 2-4Ω per channel
Channel 5 Load: 2-4Ω (subwoofer)
Crossover: Built-in (verify specifications)
Bass Boost: Verify from product documentation
Remote Level Control: Verify compatibility
Fuse Rating: 40A x 2 (dual protection)
Operating Voltage: 12V DC nominal (10.5-16V range typical)
Dimensions (L x H x W): 420mm x 267mm x 87mm
Net Weight: Approximately 2.6kg
Cooling: Heatsink with convection (verify fan presence)
Connections: RCA inputs (channels 1-5), speaker-level inputs (verify), high-level inputs (verify)
Protection: Short circuit, thermal, DC offset (typical features)
Frequently Asked Questions
Can this amplifier power my entire car audio system from one unit?
Yes, that's exactly what 5-channel amplifiers do. Connect your front and rear speakers to channels 1-4 (90W each), connect your subwoofer to channel 5 (500W), and you've powered your complete system from a single amplifier. No separate amps needed—simplified wiring, reduced cost, less space required. Ideal for complete system upgrades.
What speaker and subwoofer combinations work best with this amplifier?
Ideal setup: Component or coaxial speakers rated 70-100W RMS on channels 1-4, and single 12-inch subwoofer (500W RMS 2Ω) or dual 10-inch subwoofers (250W each, wired for 2Ω total) on channel 5. Nakamichi NSE1658 6.5" speakers + NBX305A 12" active sub would be excellent pairing.
What power wiring do I need for this amplifier?
Dual 40A fuses mean approximate 80A total draw at maximum output. Use minimum 4-gauge power cable from battery with 80-100A fuse within 450mm of battery connection. Ensure quality ground connection (4-gauge to chassis metal). Verify your vehicle's alternator capacity (100A+ recommended) and battery condition before installation.
Does this amplifier include crossovers and bass boost?
Verify from product documentation. Most 5-channel amplifiers include low-pass crossover for subwoofer channel and high-pass for speaker channels, plus bass boost control. Check specifications for crossover frequencies (typically 50-200Hz adjustable), slopes, and bass boost range (0-12dB typical). External DSP provides more control if needed.
Will this amplifier fit under my front seats?
At 420 x 267 x 87mm (16.5" x 10.5" x 3.4"), it fits under many vehicle seats, but measure carefully. Check height clearance, seat rail positions, and allow airflow space for cooling. Alternative mounting: behind rear seats, side panels, or boot. Secure mounting essential—2.6kg amplifier requires proper brackets preventing movement during driving.
Compatible With / Goes Well With
Ideal Speaker Systems:
Nakamichi NSE1658 6.5" 3-way coaxials (70W, channels 1-4)
Nakamichi NSA-CS1721 6.5" components (70W, front channels)
Nakamichi NSE1648 6.5" coaxials (40W, channels 1-4)
Nakamichi NSE6958 6x9" speakers (75W, rear channels)
Most aftermarket 6.5" or 6x9" speakers rated 60-100W RMS
Compatible Subwoofer Systems:
Nakamichi NBX305A 12" active sub (channel 5: 350-500W)
Nakamichi NBX251A 10" active sub (channel 5: 150-350W)
Single 12" passive subwoofer (500W RMS 2Ω)
Dual 10" passive subwoofers (250W each, wired 2Ω)
Single 10" passive subwoofer (350W RMS 4Ω)
Essential Installation Accessories:
4-gauge amplifier wiring kit (power, ground, remote)
80-100A inline fuse holder (main power)
RCA audio cables (5-channel: 10-16 feet)
Speaker wire (14-16 gauge, adequate lengths)
Distribution block (if multiple power consumers)
Ground wire and ring terminals
Wire management ties and loom
Amplifier mounting brackets or board
System Enhancement Products:
Digital sound processor (advanced tuning)
Bass remote control (subwoofer level adjustment)
Voltage meter (electrical system monitoring)
Capacitor (optional electrical stabilization)
Sound deadening (improved audio quality)
Line output converter (if using factory headunit)
Recommended Headunits:
Aftermarket headunits with 4V+ pre-out voltage
Digital media receivers with subwoofer control
Apple CarPlay/Android Auto headunits
Headunits with time alignment and EQ
6-channel pre-out headunits (front, rear, sub)
Caution: Verify your vehicle's electrical system capacity. 5-channel amplifiers draw significant current at full output—ensure alternator rated 100A+, quality battery in good condition, and proper high-current wiring. Secure mounting essential for 2.6kg amplifier. Adequate ventilation required for Class A/B amplifier cooling. Professional installation strongly recommended for proper electrical system integration, gain adjustment, and system tuning.
Weight
2.6kg.Legendary Products & Support From Authorized Dealers
When you choose Frankies BrandBeast, you're choosing quality and performance. But just as important as what you buy is where you buy it from. Here's why purchasing from an authorized dealer is always the right choice:
▸ Expert Knowledge & TrainingOnly authorized Frankies BrandBeast dealers are factory-trained to sell and install our products. They have the expertise to ensure your purchase is set up correctly and meets your expectations.
▸ Authorized Warranty ProtectionWe offer one of the best warranties in the industry, but only purchases made through authorized dealers are covered. Don’t be misled by unauthorized sellers who can’t provide genuine warranty support.
▸ Reliable Customer SupportIf you ever run into an issue, you’re backed by Frankies BrandBeast’s official manufacturer’s warranty. No need to deal with overseas returns—our local team takes care of everything quickly and efficiently.
▸ Protect Your InvestmentBuying from an authorized dealer ensures you’re getting genuine products, full warranty coverage, and expert support. Ask yourself—is saving a few bucks worth losing all that?
Choose wisely. Buy from Frankies BrandBeast today!
High-Performance Multi-Channel Class D Amplifier from JBL!
Class D DesignEvery Stadium amplifier, including the full-range models, features high-efficiency Class D topology. This technology allows JBL to engineer amplifiers that are more compact, generate less heat, and draw less current from the vehicle’s electrical system.
Low DistortionJBL Stadium amplifiers have been engineered to deliver the lowest distortion possible, enhancing the audio experience regarldess of output level.
Full On-Board ProtectionJBL Stadium amplifiers have on-board circuitry to protect from shorts, temperature, overvoltage and undervoltage. An LED indicator is included on all five models to let the user know when one of these conditions exists.
Proprietary High-Conductivity TerminalsAll JBL Stadium amplifiers come equipped with newly introduced E.A.R.L terminal for better grounding. For 5-channel and mono amplifiers, adapter connector is available in the box for easy installation.
Compact footprintWith it becoming more and more difficult to find spacious locations for amplifier mounting, JBL Stadium amplifiers have been developed in a small compact form factor to allow more location versatility.
Sleek designSometimes, an amp can be as stylish as it is powerful. JBL Stadium amplifiers have a clean, streamlined industrial design.
Full-Range Line OutputsThe full-range Stadium amplifiers (Stadium 5, Stadium 4 and Stadium 2) include full-range line outputs. This allows the audio signal to be routed to additional amplifiers or self-powered subwoofer solutions, increasing your system configuration options.
Uncover Great Sound (The Unveiling of Sound)Stadium mono and full-range, multi-channel amplifiers deliver the efficiency and power you expect from Class D amplifiers – and the performance you expect from JBL. The comprehensive all new E.A.R.L terminal and power adapter (5-channel & mono block) enables easy installation and optimized performance. For the 5-channel and mono amplifier models, the remote bass control allows the user to increase and decrease bass output independent of head unit tone controls. The industrial design not only provides an elegant look, but also enhances power dissipation to ensure long term reliability. Stadium amplifiers give you power to shape your car audio experience in new ways.
JBL Stadium 5 Specifications:
JBL Stadium 5
Class-D Full Range 4-Ohm Stable 5-Channel Amplifier
RMS Power Rating:
4 ohms: 75 watts x 4 chan. (200 watts x 1 chan.)
2 ohms: 100 watts x 4 chan. (350 watts x 1 chan.)
1 ohm: _ watts x _ chan.
1 ohm: ————N/A————
Bridged, 4 ohms: 200 watts x 2 chan. (350 watts x 1)
Total power output: 2300 watts
CEA-2006 Compliant Amplifier
Pulse Width Modulated MOSFET power supply
Wired remote bass level control included
LED power (green) and protect (red) indicators
Soft start turn-on
EARL Ground Terminal and Power Block
5/4/3/2 channel operation
Speaker-level (high-level) inputs
Preamp RCA outputs to daisy chain multiple amps
3-way protection circuitry (thermal, overload, and speaker short protection)
Dual speaker terminals simplify the hookup of multiple speakers
Heavy duty aluminum alloy heat-sink for extreme heat dissipation
Input sensitivity: 0.2V – 2V
Frequency Response: 10 – 320 Hz
Total Harmonic Distortion (THD): 0.01%
Signal to Noise Ratio: 80dB
Variable high-pass filter: 32 – 320 Hz, 12 dB/octave
Variable low-pass filter: 32 – 320 Hz, 12 dB/octave
Variable Bass Boost: 0 to +9 dB bass boost at 45 Hz
Fuse Rating: 30 A x 3
4 gauge power and ground wiring is recommended for installation
Power Specifications – Full Range Channels
RMS Power @ 4 ohms 75 watts x 4 channel
RMS Power @ 2 ohms 100 watts x 4 channel
Bridged RMS Power 200 watts x 2 channel
Power Specifications – Subwoofer Channel
RMS Power @ 4 ohms 200 watts x 1 channel
RMS Power @ 2 ohms 350 watts x 1 channel
RMS Power @ .5 ohm
Power Specifications – Subwoofer Channel
Peak Power @ .5 ohm
Amplifier Specifications
Amplifier Series JBL Stadium Series
Marine Certified No
Amplifier Class D
Number of Channels 5
Total Peak Power Output 2300 watts
Maximum Input Gauge Size 4 AWG
Minimum Impedance Unbridged 2 ohms
Minimum Impedance Bridged 4 ohms
Speaker Level Inputs Yes
Preamp Outputs 1 pair
Built-in Crossover Low-Pass (LP), High-Pass (HP)
High-Pass Crossover Frequency 32 – 320 Hz
Low-Pass Crossover Frequency 32 – 320 Hz
Signal-to-Noise Ratio 80 dB
Bass Boost 0 – 9 dB
Remote bass/level controller Yes
Fan Cooled No
Fuse Rating 30A x 3
Total Fuse Rating 90
Strappable No
CEA-2031 Compliant Yes
Amp Bluetooth Connectivity No
Hi-Res Certified No
What’s in the box:
Amplifier
Wired gain knob (wire attached)
Mounting screws (4)
Three spare fuses
User manual
Legendary Products & Support From Authorized Dealers
When you choose JBL, you're choosing quality and performance. But just as important as what you buy is where you buy it from. Here's why purchasing from an authorized dealer is always the right choice:
▸ Expert Knowledge & Training
Only authorized JBL dealers are factory-trained to sell and install our products. They have the expertise to ensure your purchase is set up correctly and meets your expectations.
▸ Authorized Warranty Protection:
We offer one of the best warranties in the industry, but only purchases made through authorized dealers are covered. Don't be misled by unauthorized sellers who can't provide genuine warranty support.
▸ Reliable Customer Support:
If you ever run into an issue, you're backed by JBL's official manufacturer's warranty. No need to deal with overseas returns—our local team takes care of everything quickly and efficiently.
▸ Protect Your Investment:
Buying from an authorized dealer ensures you're getting genuine products, full warranty coverage, and expert support. Ask yourself—is saving a few dollars worth losing all that?
Choose wisely. Buy from an authorized JBL dealer today!
Infinity 2300W High-Performance Multi-Channel Class D Amplifier: Delivers Big Power for Your Whole System and Fits Almost Anywhere in Your Car! This handsome little black box delivers big power for your whole system and fits almost anywhere in your car. Infinity's Kappa Five 5-channel amplifier can supply four separate speakers with 75 watts RMS each, plus a subwoofer with 350 watts RMS — good news for everyone who likes their music loud. You could also use this amp to power a pair of high-performance speakers with 200 watts RMS each, and a subwoofer with 350 watts RMS. Infinity KAPPAFIVE Features: Terminals The Infinity Kappa Five uses set screw terminals for the +12V power, ground, remote turn-on, and speaker outputs. The terminals are located under a magnetic cover, which can easily be pried off to access the screw heads. The screws can be tightened/loosened with a Phillips-head screwdriver (not provided). Power/Ground The +12V Power and Ground terminals will accept up to 4-gauge wire. It is recommended that you use a minimum of 4 AWG power wire to the battery, with an in-line 100A fuse installed no more than 18" from the battery terminal. A 4 AWG ground wire (minimum) is also recommended, and attached to a metal area close to the amplifier. E.A.R.L. Terminal An Electrical Anti-Rotational Locking (E.A.R.L.) terminal is provided for the ground wire. The terminal is designed for 4-gauge wire and requires a large crimping tool to secure. Three screws are included to attach the terminal to your vehicle's metal chassis. Remote Turn-On The Remote screw terminal will accept up to 8 AWG wire. Typically, an 18 AWG turn-on lead is included in an amplifier wiring kit. Power/Ground Adapter If you wish to use power and ground wire larger than 4 AWG, you can use the included plug-in adapter. The adapter has posts that insert into the +12V, REM, and GND terminals and offers 1/0 AWG power and ground terminals. An 18 AWG screw terminal for the remote turn-on wire is also provided. Speaker Outputs The amp features set screw terminals for connecting four speakers and one subwoofer. The amplifier's minimum speaker impedance is 2 ohms. Line-Level Inputs The amplifier is equipped with three pair of RCA inputs for connecting stereo RCA patch cables from the head unit to the amp. Speaker-Level Input The amp includes six speaker-level adapters (bare wire-to-RCA) for connecting the amp to a factory radio or aftermarket head unit. You should insert the speaker wires from the head unit into the adapters and plug the adapters into amp's RCA inputs. Remote Level Control An RJ-25 modular "phone" jack is provided for connecting the Remote Level Control cable. What's In The Box: 1x 5-Channel amplifier 6x 30A ATO fuses (3 installed) 6x Bare wire-to-RCA adapters 1x EARL ground terminal (for 1/0-gauge wire) 3x Flat-head screws (Length 1/2") 1x Heat shrink tube (Length 1-3/16") 4x Mounting screws (Length 2-3/16") 1x 1/0-gauge power/ground wire adapter 1x Remote bass controller 1x 16.5' Remote cable (RJ25 plugs on both ends) 1x Owner's Manual
Legendary Products & Support From Authorized Dealers
When you choose Infinity, you're choosing quality and performance. But just as important as what you buy is where you buy it from. Here's why purchasing from an authorized dealer is always the right choice:
▸ Expert Knowledge & Training
Only authorized Infinity dealers are factory-trained to sell and install our products. They have the expertise to ensure your purchase is set up correctly and meets your expectations.
▸ Authorized Warranty Protection:
We offer one of the best warranties in the industry, but only purchases made through authorized dealers are covered. Don't be misled by unauthorized sellers who can't provide genuine warranty support.
▸ Reliable Customer Support:
If you ever run into an issue, you're backed by Infinity's official manufacturer's warranty. No need to deal with overseas returns—our local team takes care of everything quickly and efficiently.
▸ Protect Your Investment:
Buying from an authorized dealer ensures you're getting genuine products, full warranty coverage, and expert support. Ask yourself—is saving a few dollars worth losing all that?
Choose wisely. Buy from an authorized Infinity dealer today!
