General Forum

Re: Solution to foam rot in RedLine 60 speakers

Colin — Wed, 10 Oct 2007 04:22:47 GMT

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?

Re: Solution to foam rot in RedLine 60 speakers

Puncher — Thu, 07 Jun 2007 17:47:22 GMT

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!!.

Re: Solution to foam rot in RedLine 60 speakers

Puncher — Thu, 07 Jun 2007 17:34:23 GMT

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.

Re: Solution to foam rot in RedLine 60 speakers

kimberley — Thu, 07 Jun 2007 16:18:11 GMT

...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!

Re: Solution to foam rot in RedLine 60 speakers

franE — Thu, 07 Jun 2007 13:55:50 GMT

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

Re: Solution to foam rot in RedLine 60 speakers

Jandyt — Thu, 07 Jun 2007 13:22:02 GMT

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.

Re: Solution to foam rot in RedLine 60 speakers

Medogsfat — Thu, 07 Jun 2007 09:29:20 GMT

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.

Re: Solution to foam rot in RedLine 60 speakers

meandmyshadow — Thu, 07 Jun 2007 07:41:12 GMT

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.

Re: Solution to foam rot in RedLine 60 speakers

franE — Thu, 07 Jun 2007 04:23:14 GMT

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

Re: Solution to foam rot in RedLine 60 speakers

Puncher — Wed, 06 Jun 2007 15:37:56 GMT

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.

Re: Solution to foam rot in RedLine 60 speakers

Beowulf — Wed, 06 Jun 2007 15:17:18 GMT

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

Re: Solution to foam rot in RedLine 60 speakers

franE — Wed, 06 Jun 2007 08:31:41 GMT

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

Re: Solution to foam rot in RedLine 60 speakers

franE — Wed, 06 Jun 2007 07:34:11 GMT

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

Re: Solution to foam rot in RedLine 60 speakers

joeyboygolf — Sat, 19 May 2007 01:42:13 GMT

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.

Re: Solution to foam rot in RedLine 60 speakers

Jandyt — Fri, 18 May 2007 16:15:07 GMT

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.