RetroSound Quadraphonic 4 Channel Amplifier Full Range Class D Amp 4x45w RMS
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The RetroSound Quadraphonic is a 4-channel full-range Class D car amplifier delivering 45W RMS x 4 at 4 ohms. It is part of the RetroSound classic car audio range, designed to add power to a classic car stereo system via a direct connection to a RetroSound radio or any aftermarket head unit with low-level RCA outputs.
Key specifications
- Channels: 4, full-range Class D
- Power output: 45W RMS x 4 at 4 ohms
- Peak output: 55W x 4
- Frequency response: 28Hz - 28kHz
- Signal to noise ratio: >90dB
- Input sensitivity: 200mV - 6.0V
- Crossover: switchable high-pass (HPF/FULL), fixed 100Hz, 12dB per octave
- Fuse: 15A ATC
- Dimensions: 179 x 71 x 42mm
RetroSound® Quadraphonic 4-channel Amplifier
The Quadraphonic is a plug-and-play amplifier built for classic car installations. It connects directly to a RetroSound radio — such as the RetroSound Europa Motor 4 — or to any aftermarket head unit with low-level RCA outputs, delivering 45W RMS to all four speakers.
Built-in switchable 100Hz high-pass filters (HPF/FULL) are available for both front and rear channels. Dual gain control lets you match input sensitivity to your radio's output for accurate audio reproduction. To add bass, pair it with the RetroSound SUB8100 8 inch amplified under-seat subwoofer for a complete, easy-to-install system.
The Class D digital circuitry offers advanced shielding, thermal overload protection, and an ultra-low current draw. At just 179 x 71 x 42mm, it fits behind the dashboard or almost anywhere space is tight — a practical advantage in classic cars.
- 4-channel amplifier
- Full-range Class D digital circuitry
- 45W RMS x 4 channels full-range at 4 ohms
- Built-in switchable 100Hz high-pass filters (HPF/FULL) for front and rear channels
- Advanced circuitry and thermal overload protection
- Directly connects to a RetroSound radio
- Compatible with any aftermarket radio with low-level RCA outputs
- Compact size: 179 x 71 x 42mm (7.05" x 3" x 1.65")
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Specification
| Frequency Response | 28Hz-28KHz |
|---|---|
| Dimensions | (inches) 7.05” x 3” x 1.65” |
| Dimensions | (cm) 17.9 cm x 7.1 cm x 4.2 cm |
More specs
| |
What's Included
- Quadraphonic Amp
- Screws
RetroSound
About the RetroSound Quadraphonic
From our tech experts at CEN
The RetroSound Quadraphonic is a 4-channel full-range Class D car amplifier, rated at 45W RMS x 4 at 4 ohms. At just 179 x 71 x 42mm, it is designed for classic car installations where space behind the dashboard is limited. It connects directly to a RetroSound radio or any aftermarket head unit with low-level RCA outputs.
Who it suits
Classic car owners who want more power than their head unit alone delivers. Built-in switchable 100Hz high-pass filters and dual gain control suit a range of speaker setups. Those wanting a subwoofer channel alongside may prefer the RetroSound Technophonic 5-channel amplifier.
Our tech experts advise
Adjust the dual gain control to match your head unit's output level — input sensitivity covers 200mV to 6.0V. Switch front and rear channels to HPF to protect full-range speakers, or leave them in FULL mode to pass all frequencies. Installation cost is priced per vehicle; visit our Nottingham car audio fitting page for details.
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Have it Fitted By Our Team
Our team fits car audio, stereos, dash cams and vehicle security at our workshop in Beeston, Nottingham. Tell us your vehicle and we'll confirm the parts and a fitted price.
- 1
Tell us your vehicle
Make, model and year, and what you'd like fitted.
- 2
We confirm the parts
Fascia, wiring and interfaces checked for your car, with a fitted price.
- 3
Fitted at our workshop
Bring it to our Beeston workshop and we do the rest.
Unit 25 Technology Drive, Beeston, Nottingham NG9 1LA
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Frequently Asked Questions
Q: How do I choose the right amplifier for my speakers or subwoofer?
A: Match the amplifier's RMS output per channel to the RMS handling of your speakers or subwoofer at the same impedance. The Specification tab lists the power figures. If in doubt, contact CEN with your setup and we will recommend a match.
Q: What wiring do I need to install this amplifier?
A: You will need an amplifier wiring kit sized to the amplifier's power draw, typically including power and earth cable, a fuse, RCA leads and a remote wire. CEN stocks complete wiring kits, and the amplifier's fuse rating is the guide to the cable gauge required.
Q: What class of amplifier is this and does it matter?
A: Class D amplifiers are compact and efficient, ideal for subwoofers and modern installs. Class AB designs are traditionally favoured for outright sound quality on mid and high frequencies. The class is listed in the Specification tab where provided.
Q: Will an amplifier work with my factory head unit?
A: Yes, in most cases. If your head unit has no RCA outputs you will need a line output converter to feed the amplifier a clean signal. CEN stocks line output converters and can advise the right one for your vehicle.
Q: Can CEN install this amplifier?
A: Yes. CEN offers professional amplifier installation from our Nottingham premises, including secure mounting, wiring and setup. Contact us to book.
Q: How many channels does the RetroSound Quadraphonic have?
A: It is a 4-channel amplifier delivering 45 watts RMS per channel at 4 ohms, with a peak output of 55 watts per channel.
Q: Does the Quadraphonic work with radios other than RetroSound?
A: Yes. It connects directly to a RetroSound radio and also works with any aftermarket radio that has low-level RCA outputs.
Q: What is in the box with the Quadraphonic amplifier?
A: The Quadraphonic amplifier and screws.
Q: Is the high-pass filter on the Quadraphonic adjustable?
A: No. Front and rear channels each have an HPF/FULL switch. In HPF mode only frequencies above a fixed 100Hz (12dB per octave) go to the speakers, which suits a system with a separate subwoofer; FULL sends the full range.
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