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Still require 105.4 bass driver details

 
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Parts
Senior Contributor 100+


Joined: 13 Jan 2006
Posts: 174
Location: Edinburgh

PostPosted: Sat Jun 13, 2009 11:36 pm    Post subject: Still require 105.4 bass driver details Reply with quote

I am still looking for a complete technical specification for the bass drivers from my Kef R105.4?

Anyone?
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speakerguru
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Joined: 18 Nov 2005
Posts: 1007
Location: Green Hut, Tovil

PostPosted: Tue Jun 16, 2009 7:40 am    Post subject: Reply with quote

Sorry no. I designed those units but I don't have any records of the paramers.

All I can remember is that the cone, chassis and magnet were the same as the 103|2 bass unit, the SP1075. The SP1075 had a "velbex" surround, more suitable for midrange damping. I used a more robust rubber surround in order to withstand the higher pressures in the 105|4 bass box . I also opted for 2 x 16 Ohm units in parallel rather than 2 X 4 Ohm units in series, because they were more stable when overdriven.

If you're designing from scratch, it's not that hard to build a test box, do some measurements and then move on to the final design from there.

Good luck
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ColinR
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PostPosted: Tue Jun 16, 2009 9:26 am    Post subject: Reply with quote

Quote:
I also opted for 2 x 16 Ohm units in parallel rather than 2 X 4 Ohm units in series, because they were more stable when overdriven


Interesting, I would have expected to have found a couple of 16 Ohm units in my pair of Ref. 105-4s but I found a pair of 4 Ohm SP1076 in series.

The surrounds are very similar (fingers & diy Hooke's Law) to those of SP1075s.

The cabinets were made ~Dec 1980 SNo. ~1300.
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speakerguru
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PostPosted: Wed Jun 17, 2009 7:29 am    Post subject: Reply with quote

ColinR wrote:
Interesting, I would have expected to have found a couple of 16 Ohm units in my pair of Ref. 105-4s but I found a pair of 4 Ohm SP1076 in series.


Oh dear, my memory is going then. Perhaps I was overruled for production or purchasing reasons and then chose to forget........................
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ColinR
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Location: Staffordshire

PostPosted: Wed Jun 17, 2009 9:15 am    Post subject: Reply with quote

speakerguru wrote:

Quote:
was overruled for production or purchasing



If the 1980 Hi-fi Choice book reviewers had opened the Ref. 105-4 boxes at the time to confirm what they were told by KEF.

For the review states "two less expensive 200mm units operating in parallel."

I imagine there might be a few (~200-500?) production models as designed by you out there.

Another speaker design to add to the collection Very Happy .
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