Hi Everyone,

 so i made this bargain on eBay (i guess at 50,- Sfr i can't really complain) and ofcourse the ABR's are history. I called a good dozzen or so B&O dealers, but they said they've either never heared of or couldn't get the conversion kit :-(
 

Now im wondering if anyone has ever bothered meassuring and or fotographing the plate before building it into the speaker cabinet? Are there actual bassreflex tunnels, or is it just a plate with holes? I mean, this should'nt exactly be rocket sience ... Can anyone help?

 

Thanx in advance, Oliver

 

If you still have the ABR frames and plate, they can be "re-foamed". The trick is finding a material of the right compliance such that the resonant frequency of the repaired ABR is correct.

Thanks Puncher, but that's exactly the Problem. I found a Dutch Onlineshop that sells foamcones etc, also for B&O, but only for speakers. My guess would be that the material is not that much of a problem, but i don't see how i could use a cone for a circular speaker on the rectangular ABR. Or is the material flexible enough? If yes, i could use a cone for a larger speaker, say maybe a 25 or 30 cm (what ever may fit)?

 

On the other hand, people seem pretty happy with the conversion. Didn't you say in an old thread you have a spare kit? I'm surely not the only one who'd be verry happy to have the specs, tho i'd never dare ask anyone to take the speaker apart and messure it.

A serious alternative could be the specs of the speakers, so someone could calculate the BR openings ... hmmmpf ... as a last resort i might just close the cabinet and get a subwoofer.
 

goodhifi.com is the dutch website. they are friendly but busy - worth a try though - they might be able to help

Thank you Nick,

i've already contacted goodhifi on the weekend but didn't get a reply yet. I'll give a heads up as soon as i have more info. 

Drop MArtin (Dillen) a PM as he can refoam the ABR's for you with correct spec material. Mine have been packed up ready for shipping to Denmark for him to do. Just not got round to sending them yet.

 

Craig

I'm making a conversion using two passive radiators in place of the metal plate ABR.

I'm putting up a new website and hope to have it online with next few days.  I've got the RL60 page almost finished, so when you see it, I will have the photos and test results posted with my new modification/conversion.  I made sure to complete this page first as I've got a lot of information I'll be adding as time goes on to the rest of the site  The new site is www.speakerhobby.com.

I don't want to spend the effort to refoam them only to have them fail within a couple of years, so I made a conversion to twin passive radiators in place of the ABR.  The cabinet tuning will be raised a few hz, but being used as my surrounds, they should work great.  These speakers are 96dB efficient....that's awesome...

Mike

I have my website www.speakerhobby.com up and running now with the first completed page being the Bang and Olufsen Redline 60 modifications if you want to see how I fixed mine.  They sound great, but I would try to find a passive radiator with a little more xmax.  They will be great for my applications as side surrounds in my home theater.

Thanks to all of those who have supplied me with info about the caps and resistors.

Great forum.....keep it cranking!!

Mike Cason

Update.......11-2-2008  The modified Redline 60s have been in the home theater as side surrounds paralleled with some Polk in ceiling RC 85-Is and these speakers have performed flawlessly.  The modification is a wonderful treatment for those failed ABRs!

I've got my modificaton to the RL60's failed ABR's finished along with the rebuild of the crossovers.

Stryke out my comment in my last post about seeking out passives with a higher xmax.  The new crossover upgrades fixed this issue.  The suspension of the Peerless Tymphany passives are stiffer than the drivers and are doing a great job.  Things are ratteling in my office now with only my first finished speaker hooked up.  I'm anxious to finish the xover in #2 and get them into my home theater!

If B & O still made the ABR's, I wouldn't buy them as my speakers sound fantastic with my modifications.  I know the factory ABR's would fail againl.

At 100 dB's at 3 feet away, I was pleasured to listen to  -0- distortion and extreme clarity in the speaker drivers.  The bass is much improved as well as the mids and highs.  I kept turning up my receiver until I pegged 100 db and stopped.  My Rotel will give me even better quality music from them.

For those of you who have been to my website's B & O modification page already, please go back to see the latest results and updated photographs that I have posted to help others out.

I've also have my "Main's" page finished and pics of my subwoofers posted.  I've got a lot more content and photos to add, but the rebuilding of the RL60's have consumed much of my time.  Thanks for visiting my site and join my forum to help me get some members as the site is brand new.

Mike Casoon

www.SpeakerHobby.com

 

Nice site! Just so you know, the RL60s cost £225 in 1985 - about $400  - and when discontinued as RL6000s in 1996 cost £450 or about $900. The later speakers had a reflex port rather than the ABR but were the same size and used similar drivers.

I appreciate that info...She must have been talking about her whole system cost.  I'll remove the price from my website..

She also told me that they worked great!  After I got them and started doing some research and purchased a second pair for the back up drivers, I found the plastic bands on the second pair.  The ones she gave me had the bands cut off of the hold down inserts on the back of the speakers, so she knew they were broken as someone attempted to work on them, but she didn't disclose that to me.  Oh well, the price was right and I don't have much money in the complete package with back up parts to boot. $400 bucks 20 years ago would probably be about a grand now....I appreciate the heads up.  These are sure some fine sounding and efficient speakers.  Like I said in my website, they are well suited for home theater surrounds.  I've got some $350 Polk RC85I's in the ceiling already, so I'll parallel them for even better surround with a 4 ohm presentation to my amplifiers....  In addition to my Rotel, I'm running 3 other amps.  I had to add 2 more electrical circuits.

 Very best regards, Mike

For those that haven't seen it before, here is a picture of the rear of the official B&O port conversion for the ABR of RL60's/40's.

 

Peter :

Nice site! Just so you know, the RL60s cost £225 in 1985 - about $400  - and when discontinued as RL6000s in 1996 cost £450 or about $900. The later speakers had a reflex port rather than the ABR but were the same size and used similar drivers.

Puncher has just posted a pic of the port.  That pipe came off of my old motorcycle!!....just kidding...

Peter you said the newer ones used "similar" drivers.  I would hesitate to use the port conversion with the original speaker that had the ABRs.  After pulling and examining my drivers, I think they would reach xmax before the peak RMS rating because they have such soft suspension and surrounds.  I would bet that the newer speakers that came with the ports had similar drivers, but with much stiffer suspensions.  With today's audio technology and the Dolby, DTS, & etc., the explosions in the movies that could hit them pretty hard.

Puncher.....thanks for the pic....I've been wondering how they did that!

I've got a company called the Speaker Surgeon located near me that is excited about me dropping off the ABRs to them to see if they can duplicate the surround.  They want the challenge.  I'm just going to give them to them.  If they can do it, that will be a good source for the USA folks to ship their failed units to them if they want.  They are light and shippping would be cheap.  I've got the Speaker Surgeon's website posted on my resources page.  I'm keeping mine as they are.  After finishing up the second one, I am very happy with my conversion.  Total cost, $125.00 for 4 passive radiators, new Solen caps, Mills resistors, and shipping.  Almost forgot, plus the $5.95 for the red automotive vinyl pinstriping....

Mike

I believe our own Dillen can refurbish failed ABR's with rubber rather than foam that has the same (or at least very similar) compliance to the originals. The rot problem would be no more. The reason I have the ports is that I repaired mine many years before Beoworld was invented and could only source the official parts. By the time I knew it was feasible to repair the ABR's I had long since lost the frames and the damping plates.

Thanks Puncher.....I'll pass on that info to my Speaker Surgeon...

I think foam ought to be used on coffee "to go" cups only....

Mike

mfishmike:

Thanks Puncher.....I'll pass on that info to my Speaker Surgeon...

I think foam ought to be used on coffee "to go" cups only....

Mike

The trick will be, when in the sealed enclosure of the speaker housing, to match the resonant frequency of the original part.

Puncher,

That was one of my concerns I had when I converted mine to passive radiators.  I knew the cabinet tuning frequency would be raised a few hz, but being used as surrounds and the sub taking over everything from 60 or 80hz and below, it wasn't an issue for me.  I will probably leave one of the spare RL 60's I have with them and the specs, and let them see what they can do  with it.  I'm getting a some driver protection from over excursion with my design, and so if the tuning is a bit higher, it won't affect my application as surrounds.

They like challenges and after visiting my site and seeing the ABR plates, it's a twist to their normal refoaming and speaker building so they want to see what they can do.

Thanks for the reminder..

Mike

mfishmike:

Puncher,

That was one of my concerns I had when I converted mine to passive radiators.  I knew the cabinet tuning frequency would be raised a few hz, but being used as surrounds and the sub taking over everything from 60 or 80hz and below, it wasn't an issue for me.  I will probably leave one of the spare RL 60's I have with them and the specs, and let them see what they can do  with it.  I'm getting a some driver protection from over excursion with my design, and so if the tuning is a bit higher, it won't affect my application as surrounds.

They like challenges and after visiting my site and seeing the ABR plates, it's a twist to their normal refoaming and speaker building so they want to see what they can do.

Thanks for the reminder..

Mike

No probs

Remember to keep us informed if your company manages to re-manufacture original spec ABR's!

I certainly will......

You guys have a great forum here! 

Mike

Wow ... you guys seem to have a lot of fun around here

 

i just wanted to let you guys know that the ppl at "Good-Hifi" are able to get replacement surrounds, though it may take 6 weeks for them to deliver and they can't give a price yet, though the estimate is around 25€ for each ring.

Also i identified the bass speaker as an ITT and some verry helpfull ppl at some other forum could provide the specs for the reflex tube.

With the diameter at 6,8 cm the length is 13,93 cm, however their actual advice was to close the box and try to reduce the volume by half to 8 / 9 Liters rather than repairing the ABR or converting to bassreflex, since the speakers are actually designed fore much smaller boxes.

 

Puncher, you really made my day. Thanx alot for the pic.  I'm sure the two guys from this other forum who helped me out would like to take a look at it. If it's OK with you i'd like to steal it and reupload it for them ??? Though i doubt it would produce any meassuerable traffic, i guess a deep-link would not be apreciated by the admins?

And can you verify the size with what they came up? Judging from the pic, the lenght could be ~14cm, but it does look thinner. 

Anyways, i've already spend more time researching and nagging around then i would have wanted to spend repairing the speakers, so i'm not really sure about what i'm going to do now ... especialy since i'm sitting in the middle of nowhere here in switzerland and DIY is an almost unknown phenomema in this part of the world. Like not beeing able to find a suplyier for caps ...

 

@mike:  Verry nice site and pic-tutorial !!!!!!!!!!!! 

oliver:

Wow ... you guys seem to have a lot of fun around here

 

i just wanted to let you guys know that the ppl at "Good-Hifi" are able to get replacement surrounds, though it may take 6 weeks for them to deliver and they can't give a price yet, though the estimate is around 25€ for each ring.

Also i identified the bass speaker as an ITT and some verry helpfull ppl at some other forum could provide the specs for the reflex tube.

With the diameter at 6,8 cm the length is 13,93 cm, however their actual advice was to close the box and try to reduce the volume by half to 8 / 9 Liters rather than repairing the ABR or converting to bassreflex, since the speakers are actually designed fore much smaller boxes.

 

Puncher, you really made my day. Thanx alot for the pic.  I'm sure the two guys from this other forum who helped me out would like to take a look at it. If it's OK with you i'd like to steal it and reupload it for them ??? Though i doubt it would produce any meassuerable traffic, i guess a deep-link would not be apreciated by the admins?

And can you verify the size with what they came up? Judging from the pic, the lenght could be ~14cm, but it does look thinner. 

Anyways, i've already spend more time researching and nagging around then i would have wanted to spend repairing the speakers, so i'm not really sure about what i'm going to do now ... especialy since i'm sitting in the middle of nowhere here in switzerland and DIY is an almost unknown phenomema in this part of the world. Like not beeing able to find a suplyier for caps ...

 

@mike:  Verry nice site and pic-tutorial !!!!!!!!!!!! 

Feel free to re-use the photo

The measurements you mention are certainly of the correct order however to get a better measure of the B&O solution (I didn't measure anything - sorry) you could measure then distance between the outer casing screw bosses shown in the photo and then use this as a scale to measure the port dimensions.

Find attached a pdf detailing the results from changing the crossover capacitors from my ~24 year old RL60's (apologies for the poor quality pictures but I compressed them right down to be able to load up in a single document).

What this shows is the equipment I used to measure before and after results for the capacitance (and their disapation factors) and before and after spectra of 10sec bursts of pink and white noise for speaker 1 (similar results for speaker 2 but omitted to maintain small file size).

I also recorded the same track (Song to the Siren - Tim Buckley) before and after. The net result was -

         I couldn't measure or hear any real differences during my audio tests. A few days later, when the removed capacitors were measured, the reason became obvious - the twenty four year old parts were as good as those I replaced them with.

I was so dejected - I had thought I was going to get the improvement mentioned many times here, the increased detail, the sharper focus and definition etc. - instead I got nothing. I'm just starting to get over it

This of course does not mean that replacing old caps in crossovers is not necessary - I'm amazed that my devices survived all this time unaffected, it certainly isn't typical of electrolytic parts. My recommendation would still be if your speakers are old then go ahead and renew the capacitors in the crossovers

Puncher,

That really suprises me!!!!

Electrolytic caps do fail and die over time, just like an electrolytic automobile battery.  I noticed a tremendous improvement when I went to the higher grade Solen capacitors & Mills resistors.  It was like the speakers woke up after a long nap! 

Did you go back with the 63 volt caps?  That could explain why you didn't notice a difference.  I would use a minimum of 250v to 400v replacements caps.  The Solens I used are 400v.

16 years ago, I purchased an absolutely beautiful Baldwin Organ with all of the bells and whistles on it from a wealthy doctor for $100.  It had a huge bank of amplifiers inside of it.  When you would power it up and push any note on the keyboard, it would squeal or wail and none of the notes were what they were suppposed to be.  I knew it was broken when I bought it. I  would estimate it's value new was 2 to 3 thousand dollars or more.  This was a full size organ with beautiful woodwork and all of the console switches and bass pedals..

I turned it around and  faced towards my living room wall, and I started removing all of the banks of amplifiers, one at a time.  There were 6 or 12 of them.  It's been a few years and the ole memory is what it used to be.  I went through every amplifier in the organ and replaced every electrolytic capacitor with new "Orange Sprague" capacitors, which was a very long project.  I had another couple of hundred bucks in parts not counting labor.  When I got the last amplifier finished and reinstalled, I turned it back around and powered it up.  It sounded as clean as it would have if it were brand new.  I ended up trading the organ for a dual axle 18' trailer to the man that bought my last house because I needed the trailer to move, and he wanted the organ for his girls.

I'm really surprised you didn't notice an improvement, and yes, I agree with you,  while it's open change them out!

Mike

Hi Mike,

 The voltage rating od the parts should not affect their performance, although the 63V parts in the RL60's are marginal (~ 40Vac rating with the Amp of the BM5000 having 40V rails). The replacements were 100V rated devices.

An aged electroytic will shows itself first by an increasing disapation factor (tan d) which is related to it's ESR. As you can see from the measurements on the individual parts the old ones are as good as the new.

No - it would just seem that these parts survived  24 years and still within original specification - remarkable!

Puncher,

I agree that the 100 volt should be plenty.  I chose the 400 volt Solen caps because of their build and audio quality.  I've used them in many audio applications with outstanding results.  They are a French company and also have a build house in Canada.

This goes back to what I tell a lot of folks about audio.....It doesn't have to be textbook to work and sound great, meaning that your caps should have died like mine did, but didn't.....I broke some box calculation textbook rules with my subwoofers but they perform better than what the size of my enclosure is recommended for them, probably due to the use of the passive radiators.

This is what keeps the DIY stuff so interesting....

Mike