Aftermarket Audio Installation Kits

The Mercedes sound system has been constantly evolving throughout its history, changing as modern technology improves. The central component of that sound system, which has not changed, is the Bose amplifier. Bose amplifiers driving Bose speakers, gives Mercedes the rich quality of sound synonymous with their automobiles.


Becker Independent Amplifiers
Bose / Becker Distributed Amplifiers
(D2B Fiber CD Changers)
D2B Fiber
MOST Fiber

2V Preamp
4V Preamp
Fiber Optic

Similarly, as audio technology improves, owners of older models will desire to upgrade to keep pace with modern advancements, yet retain the performance of the Bose system. In most cases, with careful integration, the factory head unit can be upgraded to an aftermarket unit and still retain the Bose performance. If your Bose amplifier is not sounding as you think it should or possibly is malfunctioning, send it in for a free sound check.

W140 1991-1993 Bose Beta System, Aftermarket Head Unit Kit

As depicted to the right, the stereo layout of an early '90s W140 with the Bose Beta system is a carefully laid out system of 11 speakers and components. Integrating into this system is a bit tricky because the tuner is in the trunk, along with the antenna and amplifier, the head unit is in the front and connected with a digital data cable to the rear. The MBCluster installation kit carefully replaces key components and integrates virtually any aftermarket head unit into the system while maintain the Bose audio experience.

The installation is non-destructive to your OEM wiring, no cutting or splicing is involved. The integrated mobile CTEL telephone system is unaffected and remains operative and compatible with the new stereo system. The aftermarket head unit can be any single DIN height unit that drive a standard 2V preamp output. The antenna is invisibly integrated into the data cable and connects the rear mounted OEM antenna mast to the new head unit. Installation time can be as little as half an hour!

As can be seen above, the aftermarket kit uses the same OEM connectors found on your original HU and tuner, for ease of installation. We source these connectors from other old head units and tuners from local used parts suppliers. If your old head unit and tuner are otherwise inoperative, we can use your old HU and tuner to produce your kit, which saves time and money. The harness from the new head unit is integrated into the kit, making this a true plug and play kit! When deciding on your new head unit, browse your local electronics retailer such as Best buy or Future Shop to see the latest mobile audio technology.

The Alpine and Sony wiring diagrams can be seen above, for information purposes. Alpine and Sony have a wide range of high end head units with numerous useful options such as Bluetooth, MP3, and Auxiliary Input. They also have different output wires in their wiring harness (Blue & Blue/White), which feed antenna and amplifier enables separately. This is an especially neat feature because it lets you keep the antenna down while listening to CDs or MP3s, and up only when listening to the tuner. Other manufacturers have a shared blue wire that powers both simultaneously which means the antenna is always up when the head unit is on. Alpine and high-end Sony products are recommended. The wiring kit for either of these manufacturers is what we usually produce, and their harnesses are a part of the kit.

When ready to order your kit, these are things which you will want to do first :

  • Verify the health of your Bose Beta amplifier, or send it in for a free sound check. Your stereo can only sound as good as your amplifier sounds!
  • Purchase your new aftermarket head unit from your local retailer. High end Sony and Alpine are recommended, we have their wiring harnesses already in stock. Others are permitted, but you will have to send in their wiring harnesses to complete the kit.
  • If you don't mind giving up your old head unit and tuner for disassembly, you can send it in for us to make the kit. Alternatively we can source old tuners and head units from the local wrecking yard.

Sending In Your Unit

  1. Fill out the online Repair Form, and include it with your unit :
  2. International customers, ex. United states, Europe, must fill out the customs documented, and follow the shipping instructions available here.
  3. Bundle the unit up in ample padding and place it in a sturdy box. Address is located at the bottom of the Repair Form. Please note : Only USPS may be used for American shipping! Canadian shipments may use private couriers such as UPS, FedEx, etc., all other countries must use their federal postal services.
  4. Once we have received the unit and diagnosed the fault, we will e-mail an update. If you are satisfied with the diagnosis, we will begin repair accordingly. Final payment is done using the easy PayPal system, with Invoice sent in the email exchange. If for whatever reason, you have decided to decline service, or service is not possible for your unit, a shipping charge is required to send it back.


Aftermarket HU Installation Kit - Bose Beta


Used compatible OEM radio tuner, W126, R129, W140 style, for parts, if requested.


Used compatible OEM head unit, BE1480 / BE1435 style, for parts, if requested.


Pricing is in Canadian Dollars (CAD).

Note: All Canadian residents must add their province's applicable taxes (HST or GST).

United States and other foreign countries do not add taxes.

Bose Beta Aftermarket Amplifier Conversion Kit

Due to the scarcity of good used Bose Beta amplifiers, and the difficulty in rebuilding them, MBCluster now offers an aftermarket amplifier conversion kit to replace those aging, buzzing, popping, failing units. The kit uses off-the-shelf consumer audio equipment to accurately replicate the performance of the OEM Mercedes 11-speaker, 7-channel Bose Beta amplifier. There are many different speaker configurations to choose from, depending on which amplifiers and filters are desired to drive the system.

The most important consideration, obviously, is the selection of amplifier intended to be used in the system. Many factors affect this decision such as quality, price, performance, reliability, and physical size. The amplifier and related equipment can be mounted anywhere in the vehicle, but we have selected the CD-Changer cavity to be the easiest and most convenient location. Once the OEM CD-Changer is removed ample room is available in the remaining trunk cavity to be filled with the desired audio equipment. Since this convenient location is limited in size, amplifier dimensions must be carefully reviewed to ensure proper fitment. The measurements of the cavity seen below are roughly: Length=42cm x Width=16cm x Depth=16cm.

The speakers in the system are Bose speakers and have unique frequency responses and impedances, so the audio equipment must be specially selected and tuned correctly to properly replicate the OEM amplifier. The tweeters require high-pass filters, mids require full-pass or band-pass, and the bass requires low-pass. The speaker connections can be full channel, bridged, or tri-mode, depending on the capabilities of the amplifiers selected. The following examples illustrate the possible configurations that can be used, each have pros & cons. The best setups have all configuration done on the amplifier itself without relying on passive external circuits for tweaking.

Configuration 1 : Single 5-Channel or 6-Channel Amplifier

  • requires full-pass filter on 5th channel / 6th channels
  • use passive crossiver network to take either 5th channel or 5,6 channel bridged and split frequencies
  • front channels require 2-Ohm stabalization
  • window speakers run in series
  • tweeter and bass are run in mono mode, combined L+R channels
  • amplifier example: NVX JAD900.5 Full Range 900W RMS 5-Channel Class D Car Stereo Amplifier
  • amplifier example: JL AUDIO XD600/6v2 Car Sub Speaker 6-Channel Class D XD Amplifier 600W

Configuration 2 : Single 6-Channel Amplifier

  • similar to above, except using L and R channel seperately to drive tweeter and bass
  • Some amplifiers can be found to have filters of 5th and 6th channel seperately
  • amplifier example: JL AUDIO XD600/6v2 Car Sub Speaker 6-Channel Class D XD Amplifier 600W
  • amplifier example: Soundstream STL6.620 620W Stealth 6 Channel Class AB Car Amplifier

Configuration 3 : Single 5-Channel Amplifier

  • most cheaper 5 channel amplifiers have low pass on 5th channel
  • window speakers run in series
  • can run front speakers in series from one channel without stabalization
  • can run tweeter through high pass filter and adjust attenuation if necessary
  • amplifier example: Dual DA560D 5 Channel 1200W Peak/790W RMS Compact Car Audio Stereo Amplifier

Configuration 4 : Single 5-Channel Amplifier + Single Mono or Bridged 2-Channel Amplifier

  • selecting good quality, small, high/full pass, mono amplifier or 2-channel bridgeable amplifier not easy!
  • window speakers run in series
  • front channels require 2-Ohm stabalization
  • amplifier example: Dual DA560D 5 Channel 1200W Peak/790W RMS Compact Car Audio Stereo Amplifier
  • amplifier example: Pyle PLMPA35 2-Channel 300-Watt Mini Amplifier with 3.5mm Input
  • amplifier example: 500W Kinter MA-150 CD DVD MP3 USB 2 Channels HI-FI Stereo Amplifier

Configuration 5 : Single 4-Channel Amplifier + Single 2 Channel Amplifier

  • requires full-pass on 2/4 channel amplifiers
  • window speakers run in series
  • tweeter runs on left or right channel, window runs on other (sound not combined)
  • requires external high/low pass filters, with attenuation for adjustment
  • front channels require 2-Ohm stabalization

Configuration 6 : Dual 4-Channel Amplifier

  • requires high/low-pass capabilities & bridgeable per channel pairs (most common type)
  • bridges 2 channels for tweeter, but can run the bass as stereo
  • requires full/high/low-pass & bridgeable capable compact amplifier
  • amplifier example: Rockville RXD-F20 Micro Car/ATV Amplifier 1600w Peak 4 Channel 4x100W
  • amplifier example: Dual DA954D Digital Compact Series Class D Amp (4 Channels, 600 Watts)
  • amplifier example: Kenwood-compact-4-channel-digital-amplifier-600W KAC-M3004
  • amplifier example: MB QUART NA1-320.4 4-Channel 320 Watt RMS Compact Amplifier
  • amplifier example: Alpine KTP-445U 4 Channel Compact Size Car Amplifier

Configuration 7 : Single 4-Channel Amplifier

  • in theory, can run the system on a single 4 or even 2 channel amplifier
  • requires full-pass capabilities on all channels, 2 Ohm minimum impedence
  • run 2 channels to rear speakers in stereo
  • run 1 channel to front speakers in series, to meet 2 Ohm minimum
  • run 1 channel to external 2-way crossover network, and drive bass and tweeters, adjust tweeter attenuation using crossover to balance sound

The selection of the desired speaker configuration, amplifier, and any external passive components is done by you. We can aid in your selection by providing recommendations, but all equipment must be purchased independently by the customer in order to fulfill any product registration or warranty requirements by the manufacturer. All equipment can then be shipped to MBCluster for kit assembly, tuning and bench testing. All brackets and other fabrication requirements must be done by the installer. When all equipment has been acquired, contact us to build your kit.

Frequently Asked Questions :

  • Q: What does the kit include?
    A: Modified Bose Beta amplifier which plugs into the existing OEM location, with 1.5m of wiring allowing you to hook up the aftermarket amplifiers in the CD-Changer cavity.

  • Q: What do I need to send you first?
    A: After you have decided which speaker configuration from the examples above you wish to install, and have purchased the associated audio components, pack them into a box along with your old malfunctioning amplifier. If you do not wish to use your old amplifier, or do not have one, we can supply one for a small fee.

  • Q: Where do I get a mounting bracket for the new equipment?
    A: Unfortunately since there is so much diversity in equipment, there is no mounting bracket readily available. All installations require a custom bracket to be fabricated depending on the equipment. Ensure there is ample room to access the amplifier feeds and knobs for adjustment. Another good addition would be a well vented, translucent cover to protect the amplifier from possible mechanical damage.

  • Q: How many watts does the new amplifier need to be?
    A: Good question, there are no specs on a Bose Beta amplifier. However internally, the amplifier contains two 10 amp fast blow fuses which supply the two pairs of rear and window circuits. Taking the window speakers (bass) as an example, that's 2 channels, so 5 amps per channel. P=VI, P=(13.8V * 5A)= 69W. So an rms value of 69W per channel is more than sufficient to feed the power hungry bass, so anything in that range will be more than sufficient for all channels. If you decide to use the configuration which drives the bass in series, then it is 69W*2=138W, bridged mono.

    Another good reason to use a weaker amplifier, is that they will be smaller. Since space is a big consideration for mounting within the cavity, a smaller amplifier is an easier, cleaner and better install.

    A final benefit to using a weaker amplifier, clarity. Since car amplifiers have no volume control, they amplify at a fixed amount. A stronger amplifier wants to amplify a greater amount, and the only adjustment is to reduce the input gain, to balance it out. A weaker amplifier amplifies less, can use more available input range, and therefore, less noise to amplify. Keeping the input range closely mapped to the output range maximizes the usage of the amplifier in its sweetest range, this is what you want. Weaker is better, and more power is worse!

  • Q: What adjustment do you need to do?
    A: Since we are trying to reproduce the OEM amplifier, we must tweak all the settings to reproduce its behavior. I.e., must adjust input gain, and frequency response. The front center tweeter, for example, is a tiny 4" tweeter, so if we drive the full power capability of the amp into it, it will blow up. So we must adjust the gain levels and frequency response to properly drive the speaker within tolerance. Once the correct adjustment is attained, no further adjustment needs to be done.

  • Q: What speaker configuration would you recommend?
    A: Probably the most readily available, cheapest, most easily maintained configuration is the dual mini 4-channel amp configuration (Configuration 6). Compatible amplifiers should be readily available, and the adjustments can all be done solely within the amplifier.

  • Q: Is this kit compatible with your aftermarket head unit kit?
    A: Absolutely! Both kits are designed to be direct plug in replacements for the original equipment, requiring no cutting or splicing of the original wiring harness. If an aftermarket head unit kit is desired, its best to send those components in as well, and the entire system can be tuned properly.


Aftermarket Bose Beta Amplifier Kit


Used Bose Beta amplifier for kit


Pricing is in Canadian Dollars (CAD).

Note: All Canadian residents must add their province's applicable taxes (HST or GST).

United States and other foreign countries do not add taxes.

1994-2001 Standard Bose Amplifier

For audio installations of 1994-2001 Non-Fiber Bose systems, no custom kit is required as this system can be easily installed with existing aftermarket audio accessories, which are listed below. The installation can be done by us, or by any qualified and reputable audio installation shop. This system can be installed one of two ways :

  1. Using a high end aftermarket unit which drives a 4V preamp output. This will give a clean and linear preamp signal to drive the Bose amp. You will need to research at your local audio store which head units have this ability. Also, a Ground Loop Isolator (GLI) is needed to compensate for the input preamplifier ground differential, which fixes the popping noise issue with pre-amping these Bose amps.

  2. Drive speaker out directly from the head unit to amplifier input. This may seem counter intuitive at first, meaning an amplified signal being re-amplified, however this is, in fact, how your OEM system is configured. No GLI is needed in this case, as the speaker outputs are never completely muted, and thus have no ground differential. The drawback with this system is the volume maxes out quite quickly, as opposed to using a preamp which comes in gradually and softly.

These are audio accessories which are needed for installation.

  • BHA1784R Radio harness adapter - Connects to the OEM wiring harness
    BAA7 European Radio antenna adapter - For European vehicles
  • GLI Ground Loop Isolator - For eliminating on/off and muting amplifier pop on preamp signal inputs
    The 2 channel GLI is used on the R129 and which is 2 channel system, all others use 4 channel

Fiber Optic D2B/MOST Amplifier

In early 2K, Mercedes changed from standard copper wire to fiber optic technology to transfer audio information. The first fiber system implemented the D2B standard, and afterwards changed to the MOST standard. This also signaled the end of low-cost aftermarket audio upgrades. The fiber optic audio system is integrated into the COMMAND, TELE AID, and MCS navigation system, thus component substitution is more complicated.

There are products on the market which do integrate into the fiber system such as the Dension GWL1DB1. This unit basically mimics the factory CD changer to get access to the audio network. The CD changer gets unplugged and looped back, then the GWL1DB1 is plugged into the network, and hijacks all the CD changer commands and reuses them for its own iPOD connection. This way, the other members of the fiber community such as TELE AID, and MCS still operate and communicate to the amplifier as normal.

The following connectors represent the D2B standard, and are available from your local dealership.

  • D2B Fiber Optics - Connectors, External Kits, etc.
    Q682 0671 / A203 540 33 08 - CD Kit (Bose)
    Q682 0670 / A203 540 34 08 - CD Kit (non Bose)
    A000 545 33 84 - D2B Splice Connector
    A036 545 07 28 - D2B Straight Connector
    A036 545 08 28 - D2B 90 Degree Connector (top)
    A036 545 09 29 - D2B 90 Degree Connector (bottom)

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MBCluster | 8 Blacktoft Drive | Scarborough, Ontario, Canada | M1B 2M6 | (416)724-2149 | Email :

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