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This topic has been discussed before by several individuals. So now it’s my turn to offer a solution that I have not seen discussed yet. Please feel free to comment if my search skills are lacking.
By happenstance, I’ve got 2 BM5500s in my shop, sitting and waiting for a second life. The shortcomings that I can immediately spot in the design are the lack of Powerlink ports, and a dedicated AUX port. Signals for both of these features appear to be readily available utilizing a series of cables/extra equipment/internal modifications/etc, and there have been a few threads over the years by users who have prescribed various solutions. I thought I’d take a stab at it myself, and see if I can make my own companion plug-and-play “super dongle”.
Looks to me like almost all the information I’d need lies within the available external ports on the BM5500. I have L&R, Power On (via the sensor, I think!), DL80, DL86, and Ground available.
TP2 & AUX : Using a tiny Arduino controller reading DL86 updates, I can monitor for source changes, and mux Tape2 and Aux inputs into the BM via a relay. That effectively creates 2 independent ports from the single TP2/AUX. TP2 will carry the DL80 signal from pin 7, and AUX will carry the DL86 channel from pin 6.
Powerlink: I’ve got most everything I need, but I may also need to rely on DL86 to poll for the Mute bit to trigger speaker-on, and if the Sensor hack doesn’t suffice for “Power On”, then I’ll need to monitor DL86 for “Zone on” as well. I’m also not sure how “overload” is implemented, so there’s some research required there. DL86 comes again from the TP2/AUX pin 6, and it looks like I’ll snatch L&R output as well.
I’ve already written the code to decipher and send DL86, so much of the work is in the circuit design. Alas, I’m not a competent circuit designer, so this project may ultimately be added to the long line of incomplete projects I seem to embark on until I get distracted by something else. Hopefully an enthusiast with downtime out there can be inspired to assist me. Any takers?
This sounds intriguing, exciting and a really worthwhile project.
But also way beyond my level of experience or expertise 😵💫I hope you find a suitable partner in project-crime.
Location: Kent, UK
Favourite Product: Beosystem 6500
My B&O Icons:
Nice project to look into. I have e few inputs to your Powerlink thoughtsI’m also not sure how “overload” is implemented, so there’s some research required there.
Not sure it was ever used in many powerlink speakers. Looking at the schematics for Beolab Penta and Beolab 3000/5000 it seems that pin 8 is not conencted to anything other than the two DIN connectors in the speakers.
and it looks like I’ll snatch L&R output as well.
But is that volume regulated?
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