Renovating OA-116, starting next week :) some advice please?

[dsmudger]

Hi everyone, been on the forum for some time now reading via Google translate, the newsletters as well, but not everything comes across so I was wondering if I could ask for some advice.

So after wanting some Sonab speakers for many years now, I finally managed to buy a pair of OA-116 in fairly bad condition, and they're due to arrive next week and I'd like to start ordering parts, preparing everything I need to bring them back to life

They've never been renovated, so have all the usual problems: the foam surrounds have rotted; there's some damage to the wood veneer; not sure about the tweeters and/or whether they are the MT24 or MT20.

My question really, is which of the parts mentioned on the carlssonplanet renovations page are really worth doing? Should I replace the internal wires, the capacitors, do any filter adjustments, should I replace the connectors? I see there's a thread where someone did this on a 2212 and doesn't sound to happy with the result..

I've seen in a photo of the ones I bought that the dust caps have the Sonab logo on them, suggesting it's an older model in the 116 line - does this mean it might be better to replace all the speaker elements with some new B65-oa rather than re-foaming the existing ones? (and when they're released the new T22-oa tweeters?) Has anyone here had listening experience of renovated original elements vs. the B65-oa?

Overall the cost of some new B65-oa seems ok to me if there's a general consensus here that it improves the sound vs. re-foamed originals, but on the other hand a full set of T22 at the price suggested in the last newsletter makes me think twice

so fellow Sonab fans, if it was you, what would you do?

Thanks in advance!
Dan (London/UK)

[Jörgen]

Hi
Congratulations, nice catch, they certainly do get harder and harder to find in intouched condition. I would really like to get my hands on some myself. First, if it would be possible for You to post some pictures, some questions would be easier answered I think. If they are from the first model, maybe the renovating procedure would be a little different, than if they are from later ones, at least for me.
But in general my take would be to do as little as possible in a first step, just get them running, and then later You can decide more precisely what You want to do.
/jörgen

[dsmudger]

you know that sounds like good advice - reason I ask about all this stuff though, was mainly because I imagine that taking the speakers apart even to just re-edge the cones will probably be a fairly big job, and so possibly worth not having to do again too soon.. (e.g. as I understand it the rubber seal gets destroyed when you open them and needs to be replaced with some new material like neoprene o-ring tube - not sure if this would need to be done each time etc so that's one reason I'm wondering if there are any particular things things like wiring/capacitor changes that might be best done along with the new foam edges..) Then there's also the fact that it'll cost more if I re-foam now only to later replace the element altogether..

Then again, as you mentioned they are in as you might say original condition, so maybe from that point of view it's worth keeping them as much as possible like that at least for a while.. and so maybe for that reason it's just worth taking the hit on doing the extra work at least so I know exactly what difference each change makes to the sound (let's say even if it starts out being not that great with only the new edges)

Some photos (haven't arrived yet, these are just from the seller)
1,2,3,4,5,6,7,8,9,10

[Jörgen]

Nice pictures. They sure will be fine looking after some minor fixing.
As they have the MT24CT tweeter You don´t have to worry about changing these, they will be fine sounding. Also there is normally not any need to change any rubber seal, and if so it will only be at the bottom baffle, and it´s very easy.
For a start I would just refoam the midranges and woofers and maybe change some caps at the midrange high-pass filter and nothing more, just look at the spiders before doing that, so they are not totally collapsed. A little hanging spider on the midrange is no big deal, there is no particular moving of the cones anyway. Please post some pictures of the cross-overs after opening the speakers, the caps for the midrange are placed on the bottom baffle.
/jörgen

PS: When opening the bottom You will see a lot of cables attached to the cross-overs, be careful with these and make sure to mark them properly before removing them, You cannot fully remove the bottom before doing this.

[dsmudger]

yep will definitely post lots of pictures when I do the work - perhaps it will even help someone doing this in future (especially having a version in English ), to be honest though, the more I think about it, the more I think I should use new drivers if I can still get some of the 8/16 ohm B65-oa (i.e. as long as I don't have to mod the crossover to use a b65-oaII) - is there anyone here with listening experience who can say if the sound is better or different than re-foamed original SC165?

Main reasons are - it's less work in the beginning, and I kind of think there's a good chance I might 'upgrade' to the newer drivers at some time in the future anyway, in which case I might as well do it now.. Also a friend of mine with some experience refoaming/reconing speakers tells me it works but it's never perfect and sometimes they don't sound that great so better to replace if I can afford it?

I could even install some good quality gold plated terminals inside, so I can refoam the originals as a later project, and so more easily swap them over to compare the sound (terminals would also make changing the wiring easier and cleaner than de-soldering - but decided I shouldn't change wiring straight away just based on a 'change one thing at a time' principle). Whatever I decide of course I won't throw the originals away - they'll go for sale or exchange on the forum/send to SSC or something..

but either way, would be great to hear from someone who has heard both SC165 and B65-oa in any of the 1970s range of speakers?

[dsmudger]

So one of the speakers arrived the other day (other one is being held for import taxes unfortunately), I've had a look inside - everything is just push-on terminals (i.e. no soldering) so I don't know why the oa-116 page has all these scary warnings about how difficult it all is? Seems to me the difficulty is all in the re-foaming, but the speakers themselves seem very easy to open/change parts..

In any case, I've removed the mid range element and cleaned off most of the old foam, but some of the glue still remains (no hurry, I'm waiting for new surrounds to arrive).

Thing is, I'm no expert at this and quite worried I might do something wrong - even if only a little bit wrong, and end up with working speakers but not quite the sound it should be :\

There seems to be some warning about this in this thread: http://www.carlssonplanet.com/forum/vie ... nt&start=0

From the first post (translated through Google):

"Renovation of the foam edges is by far the most difficult at Carlsson renovation, so difficult for us to editorial page so far chosen not to post any info when many will not meet the work even with a detailed instruction. Will fitting the wrong speaker sounds bad - often without the owner recognizes the foam edge."

The post also mentions things like

"3. The various limtyper used in different series (requires different solvents)"

- but they don't give details, so which should I use for mine? acetone, isopropyl alcohol, paint thinner? also;

" 7. Important pre-treatment of foam edge"

- but again they don't say what this pre-treatment is?

I'm not sure if I've understood it right but I think in this next bit (which shows some of the difficulties working with Google translate ) they're saying that the answers to these questions are being compiled into a document - does anyone know what happened to this? (post was made in 2004 so I assume it's finished now?)

"We are preparing now Carlsson plane skimmed the edge of official documents with all necessary information when it is clearly teaches sold for a dog ring. It will be a substantial document with unique Carlsson knowledge that previously only existed in a few hands. The creation of the instruction will take time, so we may come back on when it is ready. But as I previously wrote on the forum:
Quality of foam edge transfer may be important effects on the entire speaker, therefore, must all recognize the importance of accuracy in this. To a lot Carlsson Owner regret on their dyrgripar because of the noise after felmonterade foam edges would be the greatest disservice we could do Stig Carlsson in which he strictly looking at us from the sky!"

Anyway, all these questions I have probably indicate I have not much idea of what I'm doing, and so perhaps quite likely I'm one of those who 'will not meet the work even with a detailed instruction'? At any rate, without a detailed instruction I probably stand no chance and I certainly don't want to waste two good pairs of SC-165 elements! :\

As an alternative approach, I tried emailing a shop that lists the B65-oa for sale but they haven't replied (maybe because I wrote in English..) and likewise it seems to be quite hard to get a reply from the SSC team about renovation/upgrade instructions (or even the limited quantities of restored elements that are sometimes available) - I've just tried again, but if I don't hear back would someone here perhaps write to them for me in Swedish? Overall I will do the renovation if I really have to, but after reading that thread (especially the last part I quoted above) I just wonder if it might be a mistake, and perhaps more respectful to these excellent speakers (and Stig strictly looking at us from the sky!) to just pay a bit more and buy new b65-oa or a professionally restored element, and then send these ones to someone who can restore them properly?

[Martin Dellstig]

Hi

Firstly I think you should decide on how much money you are willing to put in to the speakers.

I think that starting of with as little work as possible to get them playing is the first proper step.
Then upgrading bit by bit to what ever your desired end-result is.

As a starter I myself would try to get the units re-foamed and changing the capacitors (at least the round ones) in the filters.

After that I would focus on the look of the speakers whilw using them so to get aquainted with the sound of them.
Then I would decide what to do next, if anything needs be done.

Regarding new drivers there are only 8 Ohms drivers available so using these will require some modifications of the filters.
There are also new cone-tweeters, developed for Carlsson-speakers, that should be available in a few weeks.

These units will be available via www.hifikit.se in a few weeks, the speak english and send stuff abroad.

Best regards

Martin

[dsmudger]

So I've done the re-foaming via the battery method - seemed easier than I thought, but as it turned out I ended up getting two of them a bit wrong (I think they started off centered just right, but the way I left them to dry with some pressure on top the foam must have moved a bit). Used the method of pulling the cone away from the direction where it rubs in the air gap to try to fix it (in one case with the glue still setting, the other I basically had to stretch the foam a bit), it's sort of worked in that there's no more scraping, but one side does seem to be generating distinctly less bass than the other (and the bass element in that side was the one where I had to stretch the foam, so I think what they say about lower efficiency if it's not perfectly centred may just be true..)

For now I think I'll just listen to them for a bit, just because it's taken quite a long time to get to this stage, but seems likely I'll be ordering another kit at some point.

Also have what seems to be two blown tweeters - this is just by trying to listen with my ear up against each one - quite difficult to be sure unfortunately. EDIT: checked more carefully with some pink noise - one is definitely not making any sound, but the same one on the opposite speaker seems quieter than the others - does anyone know if the two closest to the listening position (pointing towards the wall between the speakers) are supposed to be quieter? I checked the DC resistance but it seems they're all between 2.7 and 3.2 ohms / not really sure what's the next step?

Overall I got the impression 'yes this is clearly in a different league to my previous speakers' (some small Wharefedale Diamonds), in one word: 'smooth', but to be honest I can't quite feel that Sonab magic I got from my friend's OA-5 II - could be the tweeters, could be the misalignment of one or more of the cones, could be room placement (I'll have to have a play around with that, for now I just made sure a minimum 1.5m from the corners), could be the amp - NAD 7020e (think it's the same as the 3020 but with a built in radio).. maybe I'll ask my friend come round for a listen and bring his (really nice sounding with the OA5) Phillips amp

[andy_hudson]

Hi Dan and other owner restorers,

I've started to follow your progress with some interest as I have just bought a pair of 2212's from Germany which are in much the same condition as your 116's but twice the problem!

I am expecting them to arrive late this week and have contacted Speakerbits in Australia to order the new foam surrounds. (Is this the best supplier?)

I have owned 3 pairs of OA 14's and 1 a pair of OA 12's since 1974 when I bought a new pair. What I distinctly remember was that the movement of the cones was at times quite extreme when playing music with a lot of base on the original pair. All the other pairs had re-foamed drivers and although they sounded fine I always felt that they were stiffer and not as rich sounding as the originals had been. (comments please)

In any event I am currently using a pair of OA5 mk 2's which, although perhaps not as punchy in the bass, seem more mellow and revealing in other ways.

As others have suggested, I will be taking my time and will start with the restoration of the drivers and see what they sound like afterwards.

I assume that the battery method refered to involves connecting a battery across the speaker terminals. Please could you tell me exactly how this is carried out as I can't find the original posts.

To Dan - good luck mate we are going to need it!

[Jörgen]

Hi
I would recommened either of two methods. Use a power supply where it´s possible to adjust the voltage needed to position the cone, or cut the dustcap and use shims. Personally I prefer the second method, then you know you have the right space between the coil and the pole piece.
Always glue the surround to the cone first and let the glue dry, then glue to the speaker metal.
/jörgen