Look what I picked up today.

It is just what I need and I did not even know it existed

It allows 5 speaker sources to be switched to any 1 of 8 sets of speakers.

Furthermore, it appears that in switching the speaker source you implicitly switch a single line input to one of 5 outputs.

That is funky!

So, apparently you can connect five amplifiers, and the mixing console kind of thingy allows you the level the levels, so to speak?

The typography suggests that it would be from the early '70s...

Well sort of.

There are eight sliders which suggest that they allow the output to the speakers to be balanced and that is what the person that sold it to me suggested they do.

What I can tell you is that it has an offical B&O sticker on the back:

Beocomparator Series 02

The part numbers are 8802033 & 8802029.

And it is number 0729 which suggest there are a few more out there waiting to be discovered.

Before connecting any of my Beomasters I will take the back off and try to work out how it all works.

Richard

WTF?

richtoy:

Beocomparator Series 02

The part numbers are 8802033 & 8802029.

Used for blind tests of loudspeakers and/or amps ?

I HAVE TO HAVE ONE!

Great find! Do tell us more as you dig into it!

Well today I had the boxes in bits to clean and work out how they work.  I have photos but whenever I try to upload the server appears to freeze

Anyway, there are 26 relays (13 in each box), the line in is simultaneously connected to all 5 line out via an attenuator/amplifier that is controlled by the 8 sliders.  That means the a slider will only control the output volume at a given speaker if the source of the selected amplifier is being fed by one of the line-out sockets.

It was nice to fine a little sealed brown package inside one of the boxes with 2 spare fuses and the circuit diagram.

The problem now is working out which 5 pieces of my collection to connect...

1) BM8000

2) BM4400

3) BM3400

4) ?

5) ?

The speaker choice is not so difficult:

1) Pentas

2) S60s on trumpet stands

the other 6 are spare....

Hi, in case you didn't know: this is a dealer demo box, to listen to different amps (BM's) onto different speakers.

I used to have one but traded it for some other old B&O toy :).

As far as i know, you basically connect the BM's with the TAPE in/out (din) to the box and the speaker outputs.

There should be more of those around because about every dealer should have had one in the 70's but than again some B&O things seem to just dissapear....or pop up for that matter.

Similar thing seems to happen now to B&O  measuring gear: there should be some around still, never ever saw it offered all these years and now it seems to pop up....maybe with the crisis peole clean their attics ?? :)

Congratulations Richard with your very nice chrtismas present.

Yep, I saw it too, but obviously you were a litle faster.

This is a graet accessory to connect and switch between your Beomasters and speakers.

 I can remember when I saw one for the first time.

I guess it was some 30 years ago in a B&O shop in Turnhout.

I have been searching for a long time ...... and you don't see these very often.

Thanks Rudy

As soon as I saw it I emailed and telephoned with the asking price.  It was only 50km away too...

I spent another 50 euro yesterday on din plugs and cable and that is just to connect the 5 amplifiers and the 5 line-outs 

Once today's Grand Prix is over I think I will have a bit of soldering to do

Richard

As promised, here are the pictures of the internals and scans of the circuit diagram.  There is black tube shaped device in the second picture (Phillips RPY13).

You can read about it here http://www.tubecollector.org/rpy13.htm

Enjoy

That is one confusing circuit! Apparently the RPY13 is there just to avoid using dual slider potentiometers?

Or, just to make do with a single buffer stage in the Beomaster selector... dubious savings if they only ever built one per dealer!

EDIT: Now I get it! It's of course because the control unit can be a long distance from the switching box. This way the level adjustment only carries a DC signal, not the actual audio back & forth.

You are absolutely right Mika

What you don't see from the pictures is the 10m of cable that connect the two units together and you would not want line level signals travelling 20m...

I am not sure if it is the right place but the only one entry I found about Beocomparator is this.

So I found this device a short while ago (Beocomparator-3) and I would know what can it be?

Obviously it enables different sources to be switched to different sets of speakers. Unfortunately the second unit is missing :-(

Does anybothy have a picture of this device/set?

I would be grateful for any information.

Thx

It's beautiful! And I don't have a freaking clue what it is!

Well yes, it's obviously the remote control panel for something similar to what we saw earlier in the thread... Sources on the top row, speakers on the bottom, perhaps? The looks with the piano keys à la the quad system would date this one to the late 70s I guess.

This is the controll unit for BeoComperator III. It should be connected to a connectionunit on which the BeoMasters and BeoVox speakers can be connected. It is for comparing speakers. With BeoComperator III also small lights could be connected which could be placed on top of the speakers so you could see to which speakers you were listening. And I have a complete set.....

Hey Blackrix!

Can you post any fotos here?

If would be interesting to see the second connection unit, please...

Do you know how many pieces were made?

Dr.Google cann't find anything about Beocomparator-3. It is very rare I think...

I think it will be challenge to find the other part of it....

This Beocomparator-3 looks like something that have been used in the B&O factory only (in their testing rooms?).

Did they ever have this in any shops..? I've never seen it - and I've been in a few shops all over Denmark through the years...

It was used in stores, but that is also the reason why there are not that many around, and not every dealer had one. But I know there are more!