Description
Rondson AM-4120D 4-Zone Matrix Amplifier — 4x120W Class D with Bluetooth, FM Tuner, MP3 Player, RS232 and Priority Override for Commercial PA Systems
The Amplifier That Runs a Building, Not Just a Room.
Most venues outgrow a single-zone amplifier within months of opening. Staff need music in the restaurant but announcements only in the lobby. The gym wants a different source entirely. The car park needs emergency priority override. Patching this together with separate units, passive splitters and volume controls is exactly how installations become unreliable, unmaintainable and expensive to fix.
The Rondson AM-4120D was engineered to solve this from day one. A true 4-zone Class D matrix amplifier in a single 1U rack space, it handles source selection, zone routing, paging, priority management and media playback in one unit — with RS232 integration for sites that need it embedded in a wider control system.
4x120W Class D. Built for All-Day Commercial Duty.
Class D topology is the professional standard for permanent commercial installation for one reason: efficiency. The AM-4120D converts mains power into audio output with significantly less heat dissipation than AB-class equivalents, which means lower running temperatures, reduced thermal stress on components and longer service life across continuous operating cycles.
Active fan cooling works alongside a thermal protection circuit that monitors internal temperature and initiates shutdown before damage can occur. Overload detection and output short-circuit protection guard the amplifier stage against the kinds of wiring faults that happen in the real world — particularly on 100V distributed networks where speaker circuits may run hundreds of metres through a building.
| Performance Specification | Value |
|---|---|
| Output power per zone | 120W |
| Total system output | 480W across 4 zones |
| Total harmonic distortion | <1% |
| Signal-to-noise ratio | ≥66dB |
| Frequency response | 80Hz – 16kHz (±3dB) |
| Power consumption | 650W |
| Power supply | AC 220V / 50Hz |
| Cooling | Active fan with thermal cutout |
Matrix Routing. Every Source to Every Zone, Simultaneously.
The word matrix is frequently misused in PA specification sheets. On the AM-4120D it means what it should mean: every one of the five audio sources can be independently routed to any or all four output zones at the same time, each with its own volume level and tonal character. There is no shared bus, no crossover compromise between zones, no source conflict.
| Routing Architecture | Detail |
|---|---|
| Output zones | 4 fully independent |
| Source inputs | 5 simultaneous |
| Per-source volume | Independent on each input |
| Per-source bass EQ | ±10dB at 100Hz per channel |
| Per-source treble EQ | ±10dB at 10kHz per channel |
| Cross-zone source sharing | All sources routable to all zones concurrently |
A hotel running this unit can broadcast FM radio in the spa, stream Bluetooth from a staff phone in the restaurant, play a USB playlist in the lobby, take a live mic announcement across all four zones simultaneously and cut the lot with a fire alarm priority trigger — without touching the amplifier once it is commissioned.
Every Audio Source a Commercial Venue Actually Needs
| Input | Type | Sensitivity / Impedance | Purpose |
|---|---|---|---|
| MIC/LINE CH 1–3 | Balanced XLR/TRS | 2.5mV–175mV / 600Ω–10kΩ | Microphones, mixer feeds, line sources |
| Phantom power | Configurable per channel | 48V standard | Condenser microphones, active DI boxes |
| AUX CH 5–6 | Stereo RCA | 350mV / 10kΩ | Media players, satellite receivers, DJ equipment |
| TEL input | Dedicated | 350mV / 10kΩ | Telephone interface for paging or hold music |
| Remote MIC | RJ45 | 387mV / 10kΩ | Remote 4-zone paging microphone station |
| Priority input | Dedicated with level trim | Configurable | Fire panel relay, emergency override, scheduled alerts |
| Bluetooth | Integrated module | — | Wireless streaming from any paired device |
| FM tuner | Integrated module | — | Live broadcast radio across any zone |
| MP3 player | USB + SD card | WAV format | Local media without external playback hardware |
Onboard Media. No External Players Required.
Equipment rooms are already full. Every external device is another power supply, another cable run, another point of failure, another thing someone switches off by accident. The AM-4120D eliminates the media player entirely.
| Onboard Source | Carrier | Format | Capability |
|---|---|---|---|
| USB port | USB-A | WAV | Continuous playlist from USB drive |
| SD card | SD slot | WAV | Independent or backup media library |
| FM tuner | Antenna input | Broadcast FM | Live radio without streaming data costs |
| Bluetooth module | Internal | Any | Wireless from phone, tablet or laptop |
Load a USB drive with the day’s background music. Use the SD card as a backup if the USB is removed. Tune the FM for live radio when nothing else is scheduled. Let a manager stream via Bluetooth for an event. Four media options, zero external hardware.
Speaker Outputs for Every Installation Type
| Output | Format | Typical Application |
|---|---|---|
| 100V constant voltage | Line output | Commercial distributed ceiling speaker networks, long cable runs |
| 70V constant voltage | Line output | Installed systems to US or legacy 70V specifications |
| 4Ω low impedance | Speaker terminal | Direct-connected passive cabinet speakers |
| 16Ω low impedance | Speaker terminal | High-impedance passive speaker configurations |
| Zone line outputs x4 | 1.7V balanced | Feed to sub-amplifiers, recording devices, zone processors |
| Mix output | 3.95V unbalanced | Subwoofer amplifier feed, master recording send |
| Monitor output | Variable level | On-site audio monitoring without zone interruption |
The combination of constant voltage and low-impedance outputs in a single unit makes the AM-4120D equally suited to a ceiling speaker network across a hotel floor and a pair of passive PA cabinets in a hall — without requiring adapters or external transformers in either case.
Priority Override Engineered for Life-Safety Compliance.
Emergency announcement capability is not a checkbox feature on the AM-4120D — it is a proper priority management architecture. The dedicated priority input accepts a relay trigger or audio signal from a fire alarm panel, emergency alert system or scheduled announcement controller, and cuts all programme material across the designated zones with independent level control so the override is always heard at the correct level regardless of what the background volume was set to.
Priority level control is independently configurable for five signal paths:
- MIC 1 input
- Remote paging microphone
- Telephone input
- External priority input
- System remote control
PA mute and music cut functions give the commissioning engineer further control over how each zone responds when priority is active — whether the zone goes silent, drops to a reduced background level or plays only the priority source.
RS232. Designed for System Integration from the Start.
| Control Interface | Connector | Capability |
|---|---|---|
| RS232 serial | DB9 | Full bidirectional control for AMX, Crestron, Extron, KNX and third-party BMS |
| RJ45 paging | RJ45 | Remote 4-zone paging microphone station |
| Zone line outputs | Balanced terminal | Feed to zone processors or secondary amplifiers |
The RS232 port gives a control system programmer full access to volume, source routing, zone muting, priority triggering and status monitoring without physical access to the amplifier. For hotels, corporate campuses, hospitals and transport venues running centralised AV control, this is the connection that turns the AM-4120D from a standalone amplifier into a fully integrated system component.
Technical Specifications
| Parameter | Specification |
|---|---|
| Model reference | AM-4120D |
| Amplifier class | Class D |
| Output power | 4 x 120W |
| Output zones | 4 |
| Constant voltage outputs | 100V and 70V line |
| Low impedance outputs | 4Ω and 16Ω |
| Zone line output level | 1.7V balanced per zone |
| Mix output level | 3.95V unbalanced |
| MIC/LINE input sensitivity | 2.5mV / 600Ω – 175mV / 10kΩ balanced |
| AUX input sensitivity | 350mV / 10kΩ balanced |
| TEL / Remote MIC input | 350mV – 387mV / 10kΩ |
| Bass equalisation | ±10dB at 100Hz |
| Treble equalisation | ±10dB at 10kHz |
| Frequency response | 80Hz – 16kHz (±3dB) |
| Signal-to-noise ratio | ≥66dB |
| Total harmonic distortion | <1% |
| Playback format | WAV |
| Power supply | AC 220V / 50Hz |
| Power consumption | 650W |
| Protection | Thermal, overload, short-circuit, active fan cooling |
| Grounding switch | Fitted |
| Rack format | 1U |
| Dimensions L x W x H | 484 x 395 x 88mm |
| Weight | 7.3kg |
| SKU | 02622 |
| EAN | 3701567911248 |
What’s in the Box
| Item | Detail |
|---|---|
| AM-4120D matrix amplifier | 1U rack mount, 484 x 395 x 88mm |
| IEC mains lead | Standard IEC power cable |
| Weight | 7.3kg |
| SKU | 02622 |
| EAN | 3701567911248 |
Where the AM-4120D Belongs
| Venue | Installation Rationale |
|---|---|
| Hotels | Lobby, restaurant, gym and conference suite as independent zones. Front desk paging via RJ45. Fire panel wired to priority input. RS232 links to property management AV control. |
| Shopping centres | 100V line feeds distributed ceiling speakers across retail floors. Priority override handles timed announcements and emergency evacuation. RS232 enables scheduled source switching throughout trading hours. |
| Sports and leisure centres | Pool hall, gym floor, group exercise studios and reception running separate sources without audio bleed between zones. USB playlist for fitness classes. Bluetooth for instructor devices. |
| Hospitals and healthcare | Zoned background music for wards, waiting areas and reception without crossover. Priority input for hospital-wide PA. Low-distortion output critical for speech intelligibility in clinical environments. |
| Houses of worship | Phantom-powered balanced inputs for condenser lectern and choir microphones. Four zones covering nave, vestry, overflow room and external grounds independently. Monitor output for front-of-house sound operator. |
| Corporate headquarters | RS232 integrates with centralised AV and room booking control platforms. Per-floor background music zones. Reception paging routed to specific areas without building-wide broadcast. |
| Schools and universities | Priority mic overrides all zone music for timetable announcements and emergency alerts. Bluetooth from teaching devices. USB for scheduled assembly and common area playlists. |
| Restaurants and bars | Bar, dining room, kitchen pass and terrace as independent zones with different source and volume per area. RCA AUX for live act or DJ input. Bluetooth for management device during event setup. |
| Transport and transit hubs | Constant voltage outputs drive large distributed speaker networks across platforms, concourses and car parks. Priority for safety announcements. RS232 for automated time-scheduled source and zone management. |
| Conference and event centres | Four breakout rooms or event spaces managed from a single 1U rack position. Balanced line inputs for conference system feeds. RS232 for AV control room management without per-room amplifiers. |
Supply, Installation and System Design
Supply
The Rondson AM-4120D is available for immediate despatch as a complete unit including IEC mains lead. Supplied with full manufacturer documentation. Compatible with all standard 19-inch rack enclosures. Suitable for single-unit purchase, multi-unit project orders and ongoing distributor supply agreements.
SKU 02622 | EAN 3701567911248
Trade accounts, installer pricing, project quotations and bulk order enquiries welcome. Lead times confirmed at point of order.
Professional Installation
Volume Music Solutions provides end-to-end commercial audio installation across the United Kingdom. Our engineers design, install and commission complete public address and background music systems built around the AM-4120D and the wider Rondson professional amplifier range.
Installation scope includes:
100V constant voltage speaker network design and load calculation. Ceiling speaker and wall speaker installation. Cable routing, trunking and termination to BS7671 and IET wiring regulations. RS232 serial control programming for AMX, Crestron, Extron and third-party building management systems. RJ45 remote paging microphone wiring and commissioning. Fire alarm relay interface and priority override integration to BS5839 compliance requirements. Multi-zone system commissioning, gain structure setting and audio optimisation. Full system handover with as-built documentation and operator training.
System Design and Consultancy
Not sure whether the AM-4120D is the right amplifier for your project? We provide free pre-sales technical consultancy. Tell us your zone count, speaker quantities, source requirements and control system preferences and we will specify the correct amplifier, speaker load configuration and ancillary equipment before you commit to purchase.
Contact Volume Music Solutions
Volume Music Solutions is a UK-based professional audio and AV systems integrator supplying and installing commercial PA systems, distributed audio, public address amplifiers, constant voltage speaker networks and multi-zone background music systems for the hospitality, retail, healthcare, education, transport, corporate and leisure sectors.
We work with independent AV installers, main contractors, facilities managers, architects, interior designers and end-user clients at every scale from a single-room installation to a full multi-building distributed audio network.
Based in Buckingham. Projects delivered across the whole of the UK.
📞 Call us to discuss your project with a qualified audio systems engineer
📧 Email us with your venue type, zone layout, speaker specification and control requirements for a written quotation
📝 Use the contact form for non-urgent enquiries and we will respond within one working day
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