Beolab 3500 with MCL to PowerLink Convertor.

[Kristian Buckhøj]

Hi B&O loving people,

I have a Beolab 3500 mk.1 where the IR doesn’t work, so I can’t put it in MCL input mode. Which means I can’t add a music source to it. But I have seen a few used MCL/ML to PowerLink convertors online, which are fairly cheap. This made me think that I could use one of those to trigger and direct my music source to the speaker via a good old ML cable.

Do any of you have experience with this solution? does it work?

Or would a 8 pin DIN to RCA and 5v trigger, wake up the system? Would be a cheaper and simpler solution.

I know I could get a “new” beolab 3500 for around the same money, but I don’t wanna throw my current speaker when any thing else work fine.

All input or ideas are welcome.

[Madskp]

Hello

First of. the MCL/ML converter will not work for this scenario. The powerlink plug is an input as it can also be used as an amplifier for passive speakers.

 

This thread has a description of different solutions https://forum.beoworld.org/forums/topic/bl3500-and-the-mcl-pl-connector/

Since the IR is not working there are not many solutions available. Several attempts has been made by me and other members to trigger the Beolab 3500 with 5V signals without luck.

The only working solution I know of for a MK1 is the Almando Masterplay (my experience described here https://forum.beoworld.org/forums/topic/bl3500-and-the-mcl-pl-connector/#post-44537 ) but it is not being produced anymore, so you should be lucky to find one

Location: Denmark

[Kristian Buckhøj]

Hi,

Thank you for your feedback. I will definitely take a look at your thread in detail.

It sounds weird that you can trigger it though the ML or MCL ports, since that’s how other B&O products talk to it. Especially since it doesn’t have a build in source player.

I have read that many of these trigger+RCA to DIN doesn’t work with the BeoLab 5, but think that’s because of its internal dsp. Which the BeoLab 3500 doesn’t really have. So again, why wouldn’t it work??

Do you by any chance have the pin out documentation for the ports on the BeoLab 3500? Might try with an esp32 dev board.

I now wonder if my beocenter 9000 can talk to it, but it doesn’t have ML or MCL. It does have link capability via the Beolink (type 2046) box and datalink, which I have. Also the beolink does say MCL 2A on it. Since both devices was able around the same time period, one would think.

Otherwise I might need a new front panel on my BeoLab 3500. Or maybe the IR eye can be connected?

Again thanks for the feedback.

[Kristian Buckhøj]

Okay, so my engineer brain went down a rabbit hole….

There was at some point something called an ML Gateway, which allowed you to control ML device via the network. Sort of Beo intelligens but earlier. To add to this someone as made an Home Assistant (HASIO) integration, which allows you to control it via HASIO. This could be way cooler than my Chromecast audio streamer with some weird cable solution that might not work…..Also I do use HASIO so…  I Have attached the ML gateway Installation guide and here is the HASIO integration 

Also Someone has made a hat for a raspberry pi for controlling ML/MCL device. They also have some documentation for how the data signals look like. Check this link.

With this in mind, it could be possible to make a streamer which and wake and play music on the beolab 3500 using an ESP32. NICE!

I’m unfortunately not good at programming, so I might start with looking at the ML Gateway.

 

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[B3OHACK3R]

Hi,

repairing the BL3500 IR is not that complicated if you know how to solder.
https://forum.beoworld.org/forums/topic/beolab-3500-sometimes-responds-to-remote-control-sometimes-it-doesnt/#post-52572

The ML Gateway alone won’t help you much as it requires a master system (video or audio) to provide power to the ML bus.
The Raspberry adapter can do that and plays well with a BL3500 stand alone (without the MLGW).

[TK]

Just based on my own limited experiments, the 3500 does decipher and respond to Datalink 86 (MCL2), at least to an extent.  Penta status updates seemed to provide 3500 screen updates. and I think I recall an On/Off trigger. At this point I stopped looking at it.  Also of note, there is no “5V” injection option here, as there does not appear to be an “active” pin or similar that one sees on a proper Powerlink speaker. So to have any chance to wake up the speaker via ML/MCL, one would need to address it appropriately- for example using a properly formatted MCL2 command.

In my limited testing, I seem to recall that I could send an MCL2 signal to turn it on and off, and update the source on the screen.  I don’t recall if I could send MCL2 that would manipulate the volume.  I spent a total of 10 minutes on it, so my memory may be a bit hazy.

All that being said, I do not know which 3500 firmware version- if any- is coded to respond to a signal to control ALL of it’s features (On/Off, VolLvl, Mute). The 3500 I have at the shop is on FW 1.0, so it may fall into the “not yet implemented” category and not indicative of the later variants.

[Madskp]

Kristian Buckhøj wrote:

Do you by any chance have the pin out documentation for the ports on the BeoLab 3500? Might try with an esp32 dev board.

You should be able to find the pinout at the diagram for the MCL to 8 Pin DIN connector in this page in the Beotech section https://beoworld.org/wiring-diagrams/ Also if you have the Servicemanual for the LCS9000 (Beolab3500 MK1) it will have a pinout in it.

Kristian Buckhøj wrote:

I now wonder if my beocenter 9000 can talk to it, but it doesn’t have ML or MCL. It does have link capability via the Beolink (type 2046) box and datalink, which I have. Also the beolink does say MCL 2A on it. Since both devices was able around the same time period, one would think.

The Beocenter 9000 does have MCL2 via the speaker 2 connections which is what you use with the MCL2A box. The Beolab 3500 MK1 also have MCL pinout via the 8 Pin DIN connector, but will not work if the SW version is upgraded to 3.x.

Kristian Buckhøj wrote:

Otherwise I might need a new front panel on my BeoLab 3500. Or maybe the IR eye can be connected?

Other front panel or repair would be the best option. I have quite a few BL3500’s in different condition, but the IR is working on all of them. Your name indicate that you live in Denmark. If interested post me a PM and I am sure we can find out something about a replacement for you.

 

Location: Denmark

[Madskp]

Kristian Buckhøj wrote:

Also Someone has made a hat for a raspberry pi for controlling ML/MCL device. They also have some documentation for how the data signals look like. Check this link.

Ah interesting that project seems to be alive again 🙂 nice work @B3OHACK3R although it still seems to require some DIY work to get it running?

B3OHACK3R wrote:

The ML Gateway alone won’t help you much as it requires a master system (video or audio) to provide power to the ML bus.

Just to clarify this, a Beolink Converter type 1611 or a ML powerbox can be used to provide the power, so no music system and TV is needed.

TK wrote:

and I think I recall an On/Off trigger.

Could this be what is used for timer start which I think might have been the only scenario where starting the BL3500 via the MCL/ML bus would be needed in an original  intended B&O setup.

TK wrote:

The 3500 I have at the shop is on FW 1.0, so it may fall into the “not yet implemented” category and not indicative of the later variants.

I tried to assemble a SW update list at one point https://forum.beoworld.org/forums/topic/bl3500-and-the-mcl-pl-connector/page/3/#post-44591

From what it says the SW 1.x versions does not fully inplement Masterlink, and there was an issue with the clock on MCL at one point. But it probably was implemented. I also have a SW 1.0 in my collection

 

Location: Denmark

[B3OHACK3R]

Madskp wrote:

Ah interesting that project seems to be alive again 🙂 nice work @B3OHACK3R although it still seems to require some DIY work to get it running?

There is now an optional software image that just needs to be flashed on a SD card. Strictly speaking its still DIY but the software part can be plug-play with that one.

Madskp wrote:

Just to clarify this, a Beolink Converter type 1611 or a ML powerbox can be used to provide the power, so no music system and TV is needed.

Absolutely.

Madskp wrote:

Could this be what is used for timer start which I think might have been the only scenario where starting the BL3500 via the MCL/ML bus would be needed in an original  intended B&O setup.

On ML side there are two different ways of remote waking the BL3500. Either via the timer function (BL3500 needs to have TIMER ON) or just by sending a virtual Beo4 command for switching on a source. In a traditional ML system without MLGW the only option for a video or audio master to activate link nodes is broadcasting the timer activation command. All devices with TIMER ON will then switch on. With the virtual Beo4 keys you have much better control and it works on all devices I have tested.

[Madskp]

B3OHACK3R wrote:

There is now an optional software image that just needs to be flashed on a SD card. Strictly speaking its still DIY but the software part can be plug-play with that one.

Oh very interesting 🙂 I have not read the full description yet, but will defenetly look into that.

B3OHACK3R wrote:

On ML side there are two different ways of remote waking the BL3500. Either via the timer function (BL3500 needs to have TIMER ON) or just by sending a virtual Beo4 command for switching on a source. In a traditional ML system without MLGW the only option for a video or audio master to activate link nodes is broadcasting the timer activation command. All devices with TIMER ON will then switch on. With the virtual Beo4 keys you have much better control and it works on all devices I have tested.

Great info to understand it. The Almando Masterplay use the TIMER function for it to work btw.

 

Location: Denmark

[B3OHACK3R]

Madskp wrote:

Great info to understand it. The Almando Masterplay use the TIMER function for it to work btw.

Yes, I know 🙂 I suspect they just re-play what they recoded from an audio master sending the timer wake message.

[Kristian Buckhøj]

Thanks for all the amazing feedback!

I think the first step is to fix the front panel and IR, because why not. Then it should work and I can install it. Might need you help @Madskp and yes I’m danish.

But I’m really intrigued by the idea of making a streamer which can communicated directly with the speaker over ML. I quickly ask Gemini if this could be possible with an ESP32, and the answer was yes. It suggest using the spotify connect API for the music streaming. I would prefer an home assistant integration so I could use music assistant, which I currently use with google chromecast audios. Thought the ML Interface the ESP should be able to select input and set volume. ESP would use the data pins to send so called “telegram” commends to the speaker. These commands are in a hex format. Although a voltage regulator is needed to take the ESPs 5v to 15v, which is the ML trigger voltage. The actual audio is sent analog. The ESP should be able to provide a high enough audio quality. For me this sound like the best option to “modernize” the speaker and others.

Also when searching using Gemini, I found out that the trigger volts with MCL should be 7v and not 5v. Don’t know if others have tried that.

I have seen these Almando device, but never tried them, maybe one day. But good to know that the TIMER function was what Almando used, if i go down the ESP32 route.

[Madskp]

Kristian Buckhøj wrote:

Also when searching using Gemini, I found out that the trigger volts with MCL should be 7v and not 5v. Don’t know if others have tried that.

I do not belive there is a trigger voltage on MCL. The 7V is for powering the MCL2A boxes since they do not have a separate power supply. On the Beolab 3500 however the 7V is not connected to anything. The Triggering TK is talking about is in form of data commands on the DATA wire which is in 5V pulses.

Location: Denmark

[TK]

My understanding is the same as @Madskp – there is no “on-off” single voltage signal as there is on a Powerlink system.

If I have time tomorrow I’ll check and see if the 3500 will respond to a few commands sent via Datalink.  I’m now wondering if I mis-remembered activating it using Datalink, or a Beo4, and then just mistaking the data as being a relay of Beo4 commands from the 3500 over MCL2.  The talk about needing the timer to be active makes me think it is not programmed to respond to all generic MCL2 commands via the Datalink pin.

That said, since the 3500’s IR channel is also MCL2, if my experiment fails, there’s probably a way to inject incoming Datalink signals via the IR gateway – without scouring over a schematic, Id imagine thats probably more trouble to engineer than it’s worth.

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