Help needed :)

[nikmak]

Hope this is in the right place!

Here goes; I have acquired a set of Bang & Olufsen BEOVOX 5702 speakers as part of a job lot at auction. Was bidding on the other item and didn't really know much about these speakers. I instantly stuck them for sale on gumtree and got a couple of hits straight away requesting details on the condition. I opened them up and the bass cones were rotted away. On opening I obviously found out they have the Celestion HF2000 and the MD500 tweeters inside.

I am guessing the owner of these originally was a serious collector as the reel2reel I got was in mint condition and the exterior of these cabs isn't too bad. So well looked after.

I have taken these out with the view to getting rid of them on ebay but need to test them. (I have a multimeter) I am a little unsure of what I am doing though. So any advice or what to look out for is appreciated. I did try already but got less than 8ohms on the HF2000's and around 9 ohms on the MD500s. This is presuming I am testing these correctly...

On a different note, in my cupboard I have a ditton 25 and a ditton 44 (unpaired). Maybe I should just make a hybrid speaker out of the parts somehow? Or maybe get shot of the lot and reclaim the space!

Any words of wisdom gratefully received!

Cheers
P.S Also acquired was the 3702's

[walpurgis]

The 5702 is a very good speaker and well worth resurrecting if possible. They are a close relative of the Celestion Ditton 66. Your measurements for the drivers sound about right. What is wrong with the bass drivers exactly and are the passive ABRs OK? Do you have photos?

[nikmak]

The 5702 is a very good speaker and well worth resurrecting if possible. They are a close relative of the Celestion Ditton 66. Your measurements for the drivers sound about right. What is wrong with the bass drivers exactly and are the passive ABRs OK? Do you have photos?

The foam on the bass drivers has rotted away. I'm not sure what passive ABR'S are but Im guessing the other area beside the bass driver. That had also rotted away. Way beyond repair from what I can tell?

The HF tweeters measured about 7 ohms. Is that not odd if they are the 8 ohm tweeters.? I think I'll need to take them for someone else to test.

[struth]

yes, good drivers...youve got them wrong way round i think the 2000 is the tweeter; the other the mid... ohms check is good.. can certainly be fixedI guess if you can find new foam kit

[walpurgis]

The foam on the bass drivers has rotted away. I'm not sure what passive ABR'S are but Im guessing the other area beside the bass driver. That had also rotted away. Way beyond repair from what I can tell?

The HF tweeters measured about 7 ohms. Is that not odd if they are the 8 ohm tweeters.? I think I'll need to take them for someone else to test.

Any driver can be repaired or replaced. Cone surrounds are not really hard to replace. Spare parts for these speakers do appear on eBay.

The 8 ohm rating for drive units is the impedance, not the resistance. Impedance is calculated under dynamic conditions and is an average of the varying load confronting the amplifier. The average 8 ohm rated driver can have a resistance (not impedance) of anywhere between 4 ohms and 8 ohms. It depends on what the manufacturer deems right and this varies.

Some photos could be useful.

[nikmak]

http://postimg.org/image/nuv2g1nn7/

http://postimg.org/image/ndb4cwsbh/

The mesh for the tweeter was inside the speaker btw.

Cheers for the help so far. Every day is a school day!!

[Light Dependant Resistor]

Try to move away from foam as you can be sure it will perish again and again. Rubber is a good
much longer term material.

[walpurgis]

Looking at the pictures I can see that the dust cap on the Philips bass units has perished. These are easy and cheap to replace and available on eBay and the drive unit is likely to be OK otherwise. The lower unit with the rotted surround is a KEF BD139 passive radiator and can be replaced with later units with rubber surrounds that don't perish. These too are available from eBay (I've bought two pairs myself). I hope you have both MD500 midrange units.

The B&O 5702 is a serious monitor quality speaker and capable of excellent sound.

[nikmak]

Looking at the pictures I can see that the dust cap on the Philips bass units has perished. These are easy and cheap to replace and available on eBay and the drive unit is likely to be OK otherwise. The lower unit with the rotted surround is a KEF BD139 passive radiator and can be replaced with later units with rubber surrounds that don't perish. These too are available from eBay (I've bought two pairs myself). I hope you have both MD500 midrange units.

The B&O 5702 is a serious monitor quality speaker and capable of excellent sound.

Yes have both MD500 mid range units. I had started stripping everything out. Top advice, cheers.

If I was to replace the drivers and renovate the speakers, what do you suggest for the speaker connection terminals? They seem very dated? Better to leave as is or upgrade/modify?

[walpurgis]

Yes. Updated terminals would be good. Can you show a picture of yours? I can't recall what they were like on those speakers. It'll give me an idea of what modern replacement may suit.

You don't need to replace the Philips bass drivers, just replace the dustcaps!

You are in luck. There's a late pair of KEF BD139 units with rubber surrounds on eBay now at a sensible £29.99.

http://www.ebay.co.uk/itm/Pair-of-Ke...MAAOSw3ydVibdo

They look slightly different, but will fit and work fine.