Reparing KEF t27s
Phil Allison wrote:
"jasee"
Actually I was rewinding the voice coil. (I've done this succesfully
before, but not with this tweeter). It seems that the enamelled
copper wire that was used was not standard enamelled copper wire as
the total length of the dual layer coil was about 2.84metres which
in 40SWG gives a dc resistance of about 3.7ohms. However the
original which appears to be the same gauge measures about 7ohms. So
that is that, unfortunately, as far as I can see. :-(
** KEF's data on the T27 says that the voice coil is rated for
continuous operation at 130 C.
It also says that it can withstand 220C for 5 seconds.
Suggests that the enamelled wire is not low temp ( self fluxing)
grade.
Thanks for your reply.
The standard stuff I've got has a 'rating of 155C'.
I wasn't aware that there were any other grades!
Having had a quick look around, there are loads of types! Colour is no guide
(you can have any colour you want!) I must have been just lucky the first
time!
SWG in standard enamelled wire seems to define an overall diameter and a
depth of insulation. The measured diameter was the same. If it is standard
copper then it would have to be significantly thinnner to make the dc
resistance (which it doesn't appear to be). So, still a bit puzzled.
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