KEF 104ab B200 SP1039 woofer

[Benjib]

I am in the process of auditioning a pair of KEF 104 that have had the ab crossover upgrade. Super sounding speakers. I have already planned to upgrade the caps but now I’m wondering if I should invest at all in these speakers. As great at they sound, the woofers rubber surrounds are suffering from flattening/shrinking/deforming. They aren’t totally flat but they have lost maybe 50% of their shape. I don’t know how much this might be affecting sound quality and I don’t know how quickly this flattening might progress, if at all. I have been giving them a good listen (using a Pioneer SA-8800) and I hear no defects, even at higher volume. These speakers are priced to factor in mediocre cosmetics but I’m wondering if those surrounds are serious cause for concern. I’m looking for a high quality late 70s speaker system that I can enjoy for a long time to come. Should I recap and work on the cabinets even considering the deforming rubber surround?

 

[sqlsavior]

Have you rotated the woofers 180 degrees? If the deformation is caused by sagging suspension, that might help. Or maybe they were rotated before you got them and are still acclimating to their new position.

If you are looking for an investment, maybe pass. If you are listening for great sound, you've already found it, apparently.

 

[orsen]

i would buy
i have 104/2 and 105/2 in my living room

 

[Benjib]

Have you rotated the woofers 180 degrees? If the deformation is caused by sagging suspension, that might help. Or maybe they were rotated before you got them and are still acclimating to their new position.

If you are looking for an investment, maybe pass. If you are listening for great sound, you've already found it, apparently.

I will absolutely rotate the drivers if I decide to keep them. The deformation seems rather uniform. I got these from the original owner and he didn’t even notice the surrounds had changed when I pointed it out. Yes, they certainly sound wonderful, I am just worried they’ll degrade and won’t hold their valued, sonically or otherwise.

Update, decided to rotate the drivers. Needs to be done regardless. Wholly heck these magnets are heavy!

 

[sax6]

As it is uniform.... I would put the grill on and forget... but still, keep an eye on a 1039 replacement.

Are both woofers surround suffering the same bloating ? No VC rubbing ?

Rotating, in my most humble opinion, as no link to this issue.

 

[SaSi]

Yes, the SP1039 seem to suffer from this surround flattening. No other KEF drivers from that era, despite using similar looking surround material, seem to show this problem.

It is more a visual thing than a functional issue. It does affect max excursion but only slightly. It doesn't affect their performance unless you really push them hard, and then, the effect is minimal.

It must have something to do with how they were stored or where they were located. I have seen several SP1039 drivers for sale that show the surrounds to be in perfect shape and they were not replaced. So, you could look out for a pair of drivers if you like. I did get a replacement pair for mine and have the old drivers stored in case I decide to replace those surrounds.

I would certainly replace the capacitors. Just go for non-polarized electrolytics of 5% tolerance, you don't have to go crazy with them. Falcon acoustics must have a recap kit for those for sale.

 

[crdm6]

I just looked at my Calinda woofers which are B200 SP1054. The surrounds also seem a little flat. I also looked at my B200 SP1014s and they have a "normal" arched shape. Do we know for a fact that the big magnet versions had the same surrounds as the "little" magnet versions?

The Falcon cap kits are effectively "original" equipment as the caps are made by the original people. I got the Calinda kit. Sounds great!

 

[Benjib]

As it is uniform.... I would put the grill on and forget... but still, keep an eye on a 1039 replacement.

Are both woofers surround suffering the same bloating ? No VC rubbing ?

Rotating, in my most humble opinion, as no link to this issue.

The are very similar. The photos I included are each of the two. No VC rubbing. Several folks in other forums have also noted rotating as helpful, but I suspect their drivers were sagging in such a way this was an apparent course of action. I could detect no visible sag one way or another, just the uniform flattening of the rubber surround. Definitely going to keep my eyes out for fresher SP1039s.

 

[Benjib]

Yes, the SP1039 seem to suffer from this surround flattening. No other KEF drivers from that era, despite using similar looking surround material, seem to show this problem.

It is more a visual thing than a functional issue. It does affect max excursion but only slightly. It doesn't affect their performance unless you really push them hard, and then, the effect is minimal.

It must have something to do with how they were stored or where they were located. I have seen several SP1039 drivers for sale that show the surrounds to be in perfect shape and they were not replaced. So, you could look out for a pair of drivers if you like. I did get a replacement pair for mine and have the old drivers stored in case I decide to replace those surrounds.

I would certainly replace the capacitors. Just go for non-polarized electrolytics of 5% tolerance, you don't have to go crazy with them. Falcon acoustics must have a recap kit for those for sale.

Thank you for your thoughts. I have have a pair of Monitor Audio MA5 with the lighter SP1014 and its surround is pleasantly perky. Wish it was the big-magnet driver and I could just swap ‘em!

Seems Falcon is out of stock on the kit but I was able to find the individual caps in their catalog, price is the same so I’ve ordered them. Read lots of good things about Falcon.

 

[Benjib]

I just looked at my Calinda woofers which are B200 SP1054. The surrounds also seem a little flat. I also looked at my B200 SP1014s and they have a "normal" arched shape. Do we know for a fact that the big magnet versions had the same surrounds as the "little" magnet versions?

The Falcon cap kits are effectively "original" equipment as the caps are made by the original people. I got the Calinda kit. Sounds great!

My SP1014s are fine as well. I wonder too if the big magnet drivers have a different surrounds.

Caps are ordered This will be my first recapping job. I’ve don’t a fair bit of research and am a generally handy guy. My refoam jobs have gone well, hope this does too!

Guess I’ve made my decision!