Hi everyone, just thought you might like to know that I've found an answer to the ABR (Auxiliary Bass Radiator) foam surrounds rotting in the original RedLine 60 speakers.  B&O still sell a conversion kit (about £60 in the UK) to allow you to replace the ABR with the bass reflex port used in the later RL60.2 and RL6000 models.  I bought a pair of RedLines on eBay and found the ABRs to be completely missing!  The replacement ports from B&O (big thanks to the staff at the Nottingham Store who located and ordered these for me) include a steel plate to completely cover the hole where the ABR went.

However, I didn't think to check the two woofers (didn't want to disturb them), so I was wondering if anyone knows whether these are liable to suffer from foam rot as well?  I think these are 6.25 inches in diameter, but can't be certain.  Can anyone advise me please, to save me having to strip the speakers down again?

Thanks,

Steve.

 

I'm not 100% sure but I think the RL60.2's have rubber surrounds as opposed to the foam surrounds of the earlier RL60's so rot shouldn't be an issue here.

EDIT: - I've just re-read your post and it seems you have the RL60's so yes they do suffer foam rot unfortunately

 

Chris.

Thanks Chris,

I'll strip down the speakers tonight and check the woofers for the dreaded foam rot!  If I find out anything that could be useful to others on the forum, I'll post an update later on.

Cheers,

Steve.

Hi Steve,

            if you've refoamed drivers before then ignore this, but if you want any help with this feel free to drop me a line as I've done more than my fair share. Since you've managed to actually sort out the original problem I'm sure you are a pretty handy chap with a screwdriver, crowbar, pot of glue & a soldering iron - pretty much like a fair few of us on here.

BTW if the foam surrounds are intact but tacky to the touch then they're on their last legs anyway so you may as well do them whilst the cabinets are split.

Anything helpful that you think worth posting would be more than welcome in the "workbench" section of the forum where it won't get so buried in the huge amount of traffic that we get on the general forum.

 

Chris.

Hi Chris,

Thanks for the advice, I've stripped down the speakers again and found that the woofers have rubber surrounds, not foam (HURRAY!)  I will try to find the "Workbench" section of the forum and post a quick update so that people with original RL60s can benefit.

Steve.

Chris, or anyone else.
 Is there any particular ambience that causes foam rot in the first place?
Is it coz they don't like central heating or the opposite?
Is it too humid or not humid enough?
Why do some speakers fare worse than others of the same model?
Is it bacterial or merely a chemical transition?
This problem has been known for years, Why haven't manufacturers sorted it.
My Pentas are from 1993 and I have never had the covers off. They still sound great but how would I know if they're suffering?

Andy T.

The only real way of checking properly is to take the covers off and look. However, it is possible to shine a bright light on the fret and see through it but the view is not that good.

Could be I'm going blind or something, but has anyone mentioned where the replacement rubber surrounds are available from?  (RL140 woofer foam surrounds in tatters). I'd quite like to try it myself, being a practical sort of bloke. 

Thanks in advance

Fran

okay okay. Just read Dillen's reply in another thread regarding tolerances in RL140's. I think I'll send them in for professional repair (Recone Lab), unless there are other thoughts on this.

Fran

Hi Fran

Just had my surrounds on the four mid bass drivers in my RL140's done at Recone Labs,  speak to Mark Noble, who is both helpful and informative. I am also upgrading the capacitors on the crossovers.

Does anybody have experience of recovering the speakers to ensure the cloth reveals the Bang & Olufsen logo which is in relief on the Redlines?

 

 

Kind regards

 

Dave 

Beowulf:

Hi Fran

Just had my surrounds on the four mid bass drivers in my RL140's done at Recone Labs,  speak to Mark Noble, who is both helpful and informative. I am also upgrading the capacitors on the crossovers.

Does anybody have experience of recovering the speakers to ensure the cloth reveals the Bang & Olufsen logo which is in relief on the Redlines?

 

 

Kind regards

 

Dave 

See here, but I imagine the process is the same. - already mentioned in the Workbench section, albeit for RL6000's, thanks to stevem for the link and Beomuse for the info.

Thanks Dave, all packed and ready to go. They seem quite chuffed at getting a steady flow of work from here. Capacitors I hadn't thought about, but fabric yes: it's finding something with that same amount of stretch that I'm having trouble with ...and then the colour! I thought a nice subtle tiger stripe ... :O

Best 

Fran

stevem:

Hi everyone, just thought you might like to know that I've found an answer to the ABR (Auxiliary Bass Radiator) foam surrounds rotting in the original RedLine 60 speakers.  B&O still sell a conversion kit (about £60 in the UK) to allow you to replace the ABR with the bass reflex port used in the later RL60.2 and RL6000 models. 

 

Steve,

Do you have a part number for these, I contacted B&O technical recently and they said they were no longer available.  I could really do with any information you have.

jandyt:

Chris, or anyone else.
 Is there any particular ambience that causes foam rot in the first place?
Is it coz they don't like central heating or the opposite?
Is it too humid or not humid enough?
Why do some speakers fare worse than others of the same model?
Is it bacterial or merely a chemical transition?
This problem has been known for years, Why haven't manufacturers sorted it.
My Pentas are from 1993 and I have never had the covers off. They still sound great but how would I know if they're suffering?

Andy T.

My personal opinion is that it is chemical transition. I've seen foam rot in speakers that have been kept in similar condition to ones which have been totally unaffected.

Having spent the best part of 20 years working in the chemical industry (manufacturing azo, dyes) I understand how variations in very small amounts of a certain chemical can mean the difference between an extremely expensive leather dye, something to be sold as fence paint or 3,000kgs of tar in the bottom of a reactor vessel

There are many variables that will affect a chemical reaction and ultimately the longevity of the final product. Other than the obvious quantities & qualities of raw materials used - time of additions, temparature & pH values during certain stages of reaction are but a few. It's extremely complicated and no 2 batches of dye we produced were ever identical and ALWAYS required some blending at some stage to attain the correct colour. I cannot see why the production of foam or its constituent materials should be any different.

Chris.

Cheers Chris for that quick reply
You know, I only live about 6 miles from a firm called Caligen foam. Maybe next time I'm down there in deepest Accrington I could call in and speak to someone from the lab and get a detailed explanation to share with everyone.

Andy T.

It would be interesting, Andy, if only to find out if they are even aware of it, because it isn't just the foam on these speakers that is affected.  I recently had an urge to use some film, after 10 years of digital (I'm a photographer).  Digging out my old darkroom equipment, I opened up an old Paterson contact printer with a foam backing, dating from late '60s / early '70s.  That had gone to dust and I'm not aware if it went through a sticky phase.  As a by the way, that had never seen sunlight, but had lived (mainly) in a badly insulated but dry attic, in a cardboard box. 

Fran

...it's not just the contact printing frame you need to worry about - the light traps on a lot of 70's cameras is disintegrating, too! Minolta & -even, dare I say Leica R's are affected, though my 1937 Contax III is too old to have used such new-fangled materials!

Material Science is just that - a science! Who'd have thought that components would have lasted, and still be sought after, 20 - 30years after their sale!

Maybe (hopefully) now they know better.

I don't believe that the B&O conversion is obselete - I bought the same radiator to port conversion from my dealer (Durham) this very year for a pair of RL 60's

I listen to a pair regularly and I still have a set of parts in my loft if anyone cares to make me an offer!!.

I contacted B&O directly via their website a couple of weeks ago. At first they denied the conversion kit ever existed, but then they came back later saying the kit did exist but was no longer available - at least not from them directly. They couldn't tell me which dealers might have it.

Does anyone here have a contact at a specific B&O dealer I could get in touch with, to see if they can get it for me?