ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hi,
sharing some experience on this topic. I had some spare Beolabs so I decided to change to surround.
I considered getting a BV, Almando or another HDMI ARC to Preout gadget. But I ended up with this <100$ solution. I bought a secondhand AV Receiver with preout.
Setup:
Rear: Beolab 4000
Front: Beolab 4000
Center: Beovision 7 stand with Beolab 7.2
TV: Sony Bravia 55" with custom frame of hardwood
Receiver: Harman Kardon AVR 255
Control: Beo4 supported by Lintronic
Preout / PowerLink
The receiver has preout but I don't want to use the line input of the speakers. I decided to build a RCA to Powerlink box with trigger signal injected via USB. The center RCA input delivers the same signal to Powerlink L/R channel. There are two Powerlink sockets for both front and rear allowing to use one cable per speaker or only one cable if they are looped through a speaker with two sockets.
The result:
Problems and solutions:
I soldered PIN 2 (audio ground) to PIN 7 (data ground) but still had hum in the speakers. The root cause was the USB trigger cable which was connected to a USB socket of the TV. The amplifier has a power socket which turns on/off with the amp. I moved the trigger cable to a phone charger connected to the amp power socket. Problem solved.
Integration & ToDo's
LinTronic TT455-RT-238 is programmed to control Sony TV and Harman Kardon. No downsides.
I did consider using BL3's as front speakers but for pure esthetic reasons I selected the BL4000. Just looks great that front and rear are identical.
Considering adding a sub. I will probably build it myself to allow it fitting under a sofa.
Will post some more pictures.... but there is still some cable management to do
^ Great project and the end result looks very professional! I like such cost effective solutions to B&O connectivity
One question: For the centre channel, is it safe/advisable to effectively bridge the L/R inputs of the BeoLab 7.2 - I am no expert but doesn't this cause problems with input impedance? However, if you are using some kind of auto calibration for the surround amp, perhaps this is cancelled out once the amp automatically adjusts the level of the signal sent to the centre channel.
Regarding the center channel.
I see no risk to provide the left and right channel with the same input. It is the 'mono' pre-out output from the AVR center channel which is splittet and connected to both left and right channel in the powerlink socket. It allows me to connect any BL7 range speaker.
I set the speaker distance, dB gain and crossover manually in the AVR. Very pleased with the result.
"You think we can slap some oak on this thing?"
Thanks... If you want the files of the 3D printed RCA/Powelink case, then just let me know. I made the case in Fusion 360 but can export to other formats as well.
Ha ha .... That can be arranged as well .... I'll create a schematic as well .... Will post it in the near future.
This is the "inside" of the RCA to PowerLink box I made.
All my speakers are connected via MKIII cables.
Full spec of PowerLink socket can be found here: BeoTech :: BeoWorld Technical
If someone knows in which scenarios it is needed to shorten PIN 2 and 7 I would like to know.
I did it because I read in a different post that it is needed to avoid humming in the speakers. But is that the case for both AB amps and D (IcePower) amps ?
I am not 100% certain, but i believe that the ground must be shorted, no matter whether the amps are class AB or D. I use a prepro from Emotiva with a trigger out, so no noisy USB connection needed. Not sure if your AVR has that port.
Lab2 moved in.
5.0 is now 5.1
:-)
@Ravsted: Oh my god, what a beautiful solution! I want such a box soooooo badly!!!
Not sure if I can make this myself (I have a 3d-printer at work and I can hold a soldering iron...), do you also sell/make them?
If I have such a wonderfull box, I could look for a small form factor AV preamp, like a Canton Smart Connect 5.1I can't use a full AV-receiver (with unnecessary power amplifiers) because they are too big to place under my self made TV wall/floating shelf) (see attached photo).
I have a beolab 7.1 and two beolab 8000 mk2's. I've connected the to a B&O Playmaker. So this is only stereo sound. In fact, this give 'double stereo' sound (left beolab 8000+left side beolab 7.1 and right beolab 8000 + right side beolab 7.1). Of course this does not sound optimal and I would like real 3.0 (or in future 5.0 or 5.1) sound.
Your box, with the centre channel internally connected (so it is connected to both the left and right channel, because I want to use it on a beolab 7.1) would open up possibilities for me!
Small form factor all-in-one AV pre-amplifier and streamer (I could hide this underneath my floating shelf. The same way as I installed my PlayStation 4). Hoping The USB port (only for 'service) on this device is providing 5v when device is on and 0v when device is switched of, so I can use this for the usb-triggering on your box):
no... I don't sell the box. It's too labor intensive and I would not take the risk of making a bad soldering causing trouble for you.
But here you have the files for printing. I printed in PLA with 100% infill and no support. You can print in other materials as well (e.g., PETG)
Part 1
Part 2
The files are an updated version with sockets for 5.1 setup.
I used these DIN/RCA connectors:
Elextra, DIN 8 270 degrees for cabinet
Ebay, RCA gold plated
Everything is held together with plate screws 3,5 x 9,5 mm. (or shorter)
The LFE/SW channel is soldered the same way as the center channel.
I screw all the DIN connectors upside/down to a piece of wood while soldering.
Good luck
Regards
Ravsted
Edit: double post
Ravsted has helped me very well and extensively by email. I will soon be working on the construction of this rca> powerlink converter.
Maybe I'm not going to replace my 7.1 and 8000's for a Stage or Sonos Arc soundbar after all...Instead buying extra rears, like the beolab 3 or 4's
Received The av pre-amp. Ordered the DIN, plugs, RCA plugs and 24awg 6 color wiring.Going to print the STL files, received from Ravsted.Hoping to solder everything correctly.I'll keep you updated.
Hi tuttivini,
How did this work out? I am also looking for a way to gain surround sound on my LG CX with BeoLab speakers.
Does the Canton Smart Connect 5.1 come with its own remote control or are you stuck with an app only like Almando?
Thanks BeoMedia
Hi
As mentioned above I use a Lintronic (tt455-rt-238 fw 5.1) along with Beo4.
It preserves the B&O integrated feeling. Everything is controlled via Beo4 - no compromises.
I don't know if you can achieve that via B&Os "BeoRemote1 app" for the LG TV combined with an amp connected via HDMI (ARC/CEC) ?
When you use the remote from your television does it then control the volume of the Canton Smart Connect? I'm thinking HDMI eARC could provide such integration?