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Two B110B drivers deteriorating at same time...audio source?
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speakerguru
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PostPosted: Sun Nov 29, 2009 10:14 am    Post subject: Reply with quote

The old one you have, has a separate magnet centre pole and backplate These have been staked together. It's the staking you can see at the back. All later speakers used a one piece forged pole/backplate. These were cheaper and has less magnetic loss. The back is plain except for the dimple.

I didn't remember that Meridian had un-labelled units though. Maybe the previous owner "cleaned them up".
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ColinR
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PostPosted: Sun Nov 29, 2009 11:51 am    Post subject: Reply with quote

Quote:
Meridian had un-labelled units though


As a M2 owner I would have expected to see at least the serial numbers on the back and some evidence of the KEF label around the magnet (I played with the image brightness), is there any supporting documentation?

So tread with care, they may or not be SP1057s as the last B110s came out as KEF as that, unidentified and unlabelled.

I've got a pair and I've no idea whether they're SP1057s or SP1003s Confused .
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SaSi
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PostPosted: Sun Nov 29, 2009 12:06 pm    Post subject: Reply with quote

These look like plain common SP1057 drivers for KEF loudspeakers. The constructor series have a "Constructor Series" adhesive around the magnet.

How do your drivers look like?

Colin, I think the "tell" between SP1003 and SP1057 is the dust cup. On the 1003s it's "rugged" and hard. On the 1057 (one and only one pair I've seen) it's softer, smoother and more "elegant".
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proffski
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PostPosted: Sun Nov 29, 2009 3:00 pm    Post subject: Reply with quote

Hmm, the mounting holes look butchered as well.
I have not seen a Dalesford unit for a heck of a long time, any chance it could be a Dalesford driver?
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lt2525
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PostPosted: Sun Nov 29, 2009 3:37 pm    Post subject: Reply with quote

SaSi wrote:
These look like plain common SP1057 drivers for KEF loudspeakers. The constructor series have a "Constructor Series" adhesive around the magnet.

How do your drivers look like?

Colin, I think the "tell" between SP1003 and SP1057 is the dust cup. On the 1003s it's "rugged" and hard. On the 1057 (one and only one pair I've seen) it's softer, smoother and more "elegant".


Here is what mine look like. Due to the damage it will be hard to compare Sad

[/img]
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proffski
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PostPosted: Sun Nov 29, 2009 3:49 pm    Post subject: Reply with quote

Picture of the Dalesford 110 here: http://sites.google.com/site/mpbarneyspeakers/friedbiispeakers

The job lot I bought in Cheltenham had no labels on gthe rear magnets, that was years after W.A.R. loudspekers went bust...
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speakerguru
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PostPosted: Mon Nov 30, 2009 9:56 am    Post subject: Reply with quote

SaSi wrote:
Colin, I think the "tell" between SP1003 and SP1057 is the dust cup. On the 1003s it's "rugged" and hard. On the 1057 (one and only one pair I've seen) it's softer, smoother and more "elegant".

No. The dust caps are the same on SP1003 and SP1057. The only difference is in the voice coil. The SP1003 has a nomex former and self-bonding wire. The SP1057 has an aluminium former and high temperature wire, wet-wound with high temperature epoxy. The SP1057 has a lower mechanical Q from the induced current losses in the former. You can measure this.

Later SP1057s had the mounting holes drilled out to accept soft grommet anti-vibration mounts. Later still, the holes were punched instead of being drilled.
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ColinR
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PostPosted: Thu Dec 03, 2009 7:46 pm    Post subject: Reply with quote

Quote:
Here is what mine look like. Due to the damage it will be hard to compare


I had some SP1003s that looked like that, do they still work?

If they do it's a couple of new dustcaps and a bit of PVA glue with a slight detour to a jewellers if you cannot get your paws on a two pan balance.

Old dust cap plus container = new dust cap plus container and PVA.

Gluing should be performed upsidedown using a roof beam or metal "workmate" so the glue ends up on the floor not in the voice coil.

My "unmarkerd" B110s are probably SP1057s having fed them with a small audio signal which caused a "real" SP1057 to make a small noise but not a squeak out of a "control" SP1003 Cool .
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RGBE
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PostPosted: Sat Dec 05, 2009 6:59 pm    Post subject: Reply with quote

The SP 1003 has a perfectly round surround, while the SP 1057 surround is round but somewhat flat. At least in the ones I have.
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speakerguru
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PostPosted: Sun Dec 06, 2009 10:25 am    Post subject: Reply with quote

RGBE wrote:
The SP 1003 has a perfectly round surround, while the SP 1057 surround is round but somewhat flat. At least in the ones I have.


Of course. Stupid of me to forget the obvious Rolling Eyes . The SP1003 had a moulded rubber semicircular section surround. The SP1057 has a vacuum formed Velbex compound curve surround.
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lt2525
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PostPosted: Wed Dec 09, 2009 11:33 pm    Post subject: Reply with quote

The drivers have arrived. They are labelled and definitely say KEF B110 SP1057, consecutive serial #'s.
Very Happy

There is a bit of a difference in the configuration of the magnet. The part where it couples to the basket is a sort of irregular octagon. While on the older units this is basically circular. As mentioned by a poster earlier, I put this down to simple evolution of manufacturing.




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speakerguru
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PostPosted: Thu Dec 10, 2009 9:29 am    Post subject: Reply with quote

lt2525 wrote:
The part where it couples to the basket is a sort of irregular octagon. While on the older units this is basically circular. As mentioned by a poster earlier, I put this down to simple evolution of manufacturing.


Evolution is right. The cropped circle saves quite a bit of steel and so is cheaper. It also reduces the magnetic leakage on the outside of the ring so the change in gap flux is barely measurable.
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