Tuning Solutions Mercedes Benz MOST-150 Digital Pre-Amp EW-BZMO-V720

Eway Tech Tuning Solutions MOST150 Fibre Optic Audio System Interface for Mercedes-Benz (EW-BZMO-V720)

Modern Mercedes-Benz vehicles are equipped with sophisticated factory head units (COMAND / MBUX) that control critical vehicle settings, navigation, ambient lighting, climate displays, and safety chimes. Upgrading the factory sound system used to mean choosing between poor sound quality or sacrificing your vehicle's integrated dashboard features. The Eway Tech EW-BZMO-V720 solves this completely by allowing you to keep your original dash unit intact while tapping directly into the uncompressed digital audio stream.

A clean, quiet power supply and direct digital signal integration are essential for true hi-fi audio performance. Built around core Microchip and Texas Instruments (TI) processing architectures with Elna audio-grade capacitors, the EW-BZMO-V720 delivers pure SPDIF optical and coaxial signals directly to your aftermarket DSP or power amplifier without generating switching harshness or distortion.

Key Benefits of Retaining the OEM Head Unit:

• 100% Original Dash Appearance & Functionality: Maintain your Mercedes-Benz factory interior aesthetic, complete dashboard screen displays, steering wheel controls, and central controller dial interaction without installing an aftermarket head unit.
• Pure High-Fidelity Audio Extraction: Instead of tapping into degraded high-level speaker signals, the module extracts pristine, uncompressed digital audio straight from the MOST150 optical bus before any factory equalisation or distortion occurs.
• Full Factory Safety & Alert Retention: Seamlessly preserves essential vehicle safety overlays, including reverse parking sensor chimes, blind-spot warning alerts, Bluetooth hands-free phone calls, and navigation voice prompts.
• Clean Aftermarket DSP/Amplifier Integration: Feeds pristine digital optical or coaxial signals directly into your aftermarket Digital Signal Processors (DSPs) and high-performance amplifiers, giving you full control over your sound stage without modifying factory vehicle coding.

This interface module extracts raw digital audio directly from the factory optic bus and provides dedicated Front and Rear TOSLINK optical and coaxial SPDIF outputs. This allows you to drive single or dual DSP units independently with discrete front and rear zone control. It also features an auxiliary input for connecting an external audio player directly, complete with intelligent automatic signal switching that prioritises external playback while preserving your factory head unit controls, warning chimes, and reverse parking alerts.

Key Features & System Integration:

• MOST150 Fibre Optic Extraction: Taps directly into the high-speed MOST 150 bus to deliver clean, uncompressed digital audio.
• Premium Hardware Architecture: Engineered with Microchip/TI core processing chips and Elna audio capacitors for full-frequency digital fidelity.
• Dedicated Front & Rear Zone Outputs: Equipped with separate Front Speaker (Optical/Coaxial) and Rear Speaker (Optical/Coaxial) digital outputs for precise multi-channel DSP routing.
• External Player Auto-Switching: Allows direct connection of an external high-resolution audio player (via TOSLINK or Coaxial AUX inputs) with automatic input switching and signal priority.
• Status Diagnostic LEDs: Built-in LED indicators for MOST network activity (ACT) and Remote Turn-On (REM-OUT) power state for fast installation troubleshooting.
• Integrated DIP Switch Attenuation: On-board DIP switch configuration allowing precise output gain and media/alarm attenuation tuning.
• Automatic Power Management: Operates directly via fibre optic signal control - following the factory head unit sleep and wake cycles with low-voltage protection, requiring no external ignition (ACC) wiring.
• Full OEM System Retention: Preserves factory steering wheel volume controls, hands-free phone audio, navigation voice cues, and safety reverse parking sensor chime overlays.

Vehicle Compatibility:

Technical Specifications:

• Model Part Number: EW-BZMO-V720
• Core Processing: Microchip / Texas Instruments (TI) with Elna audio capacitors
• Input Signal: MOST150 automotive fibre optic bus
• Output Signals: Dual TOSLINK Fibre Optic / Dual SPDIF Coaxial (Full Frequency Output)
• External AUX Inputs: Independent TOSLINK Optical & SPDIF Coaxial with priority switching
• Operating Voltage: DC 10V to 18V (Fibre signal control, no ACC ignition wire needed)
• Protection: Low-voltage protection with automatic sleep cycle synchronisation

Kit Includes:

• 1x Eway Tech EW-BZMO-V720 MOST150 Converter Module
• 1x Vehicle power and remote trigger wiring harness
• 1x MOST fibre optic patch cable and inline connector coupler

Installation, Wiring & Panel Connection Guide:

1. Power & Output Terminal Harness Pinout

• Left Pin (Battery Power): Connect to a fused continuous +12V battery power supply source.
• Middle Pin (Ground): Connect to a clean, solid metal chassis ground (GND).
• Right Pin (REM Output): Remote turn-on trigger output. Connect to the remote input of your downstream DSP or power amplifier to control system power-up. Verify activation via the REM-OUT Power Indicator LED.

2. Panel Layout & Port Connections

• MOST Optical Port: Connects into the vehicle's MOST150 fibre optic ring. Verify activity via the ACT/Network Activity LED.
• Front Speaker Optical Output: TOSLINK digital optical output for Front channel audio signal to DSP. (Recommended connection when installing a DSP amplifier).
• Front Speaker Coaxial Output: SPDIF digital coaxial output for Front channel audio signal to DSP. (Recommended connection when installing a DSP amplifier).
• Rear Speaker Coaxial Output: SPDIF digital coaxial output for Rear channel audio.
• Rear Speaker Optical Output: TOSLINK digital optical output for Rear channel audio.
• External Optical Input & Coaxial Input: Auxiliary inputs for external high-resolution audio source units.
• Type-C Port: Reserved for MCU firmware service upgrades.
• Configuration DIP Switch Bank: Module setup switches.

3. DIP Switch Configuration Setup (Pins 3 & 4 Media/Alarm Volume Attenuation)

Note: You MUST power off the unit before altering DIP switch settings for changes to take effect.

• 0 dB Attenuation: Pin 3 UP / Pin 4 UP
• -5 dB Attenuation: Pin 3 DOWN / Pin 4 UP
• -10 dB Attenuation: Pin 3 UP / Pin 4 DOWN
• -15 dB Attenuation: Pin 3 DOWN / Pin 4 DOWN

4. MOST150 Optical Loop Integration

• High-Spec Systems (Benz / Harman Kardon / Burmester / Berliner Klang): The high-spec audio interface is natively supported - no additional vehicle activation or software coding is required.
• Vehicles with OEM Factory Amplifier: Disconnect the factory optical plug from the OEM amplifier (located in the boot or under the seat) and insert it directly into the MOST optical input port on the converter module.
• Vehicles without OEM Factory Amplifier: Connect the supplied MOST optical patch cable into the back of the factory head unit (COMAND system) and route to the converter module.
• Optical Loop Continuity: The MOST network operates in a continuous ring. If removing an OEM factory amplifier entirely, install an optical loop bypass coupler on any disconnected factory fibre connectors to keep the remaining vehicle electronics communicating properly.

5. Initial Settings & Post-Installation Setup

• LED Diagnostic Status Check: Turn the vehicle ignition on and verify module operation:
  • ACT (Network Activity) LED (10): Confirms active data communication on the MOST optical network ring.
  • REM-OUT (Remote Output) LED (11): Confirms the remote turn-on trigger is active and supplying power to your aftermarket DSP or amplifiers.
• Factory Head Unit Audio Adjustments: Access the OEM Mercedes audio menu and set Bass, Treble, and Equaliser controls to flat (0) to ensure a clean, uncoloured digital signal is delivered to your aftermarket processors.

Professional Installation Recommended:

Integration with fiber optic vehicle networks requires careful handling of optical cables, proper DC power connections, and correct DIP switch setup. Professional installation by a qualified car audio technician is recommended to prevent damage to the optical loop or vehicle electrical system.

Technical & Safety Disclaimer: Always disconnect vehicle power before altering wiring or changing DIP switch configurations. Verify signal routing, battery polarity, and terminal connections prior to powering up the system. Incorrect wiring or forced bends in fibre optic cables can lead to system malfunction or loss of network communication.