SpeakerTalk

ColinR

Lifted from diyaudio.com with full acknowledgements.

http://www.diyaudio.com/forums/showthread.php?s=d40b5003a4a8f1ad90f849fa2a048a4d&threadid=39641&perpage=10&pagenumber=2

"KEF Replacement for SP1191 Post #13

Like a few of you who experienced the heartbreak of their KEF 104.2 tweeter going belly up, one of mine just died this past week. Doing web searches for a replacement to the SP1191 proved fruitless.

I called KEF just to see if there were any economical options and believe it or not KEF called me back today with a replacement for the SP1191. It is part number SP1548. KEF says it is physically smaller but sonically identical to the SP1191. They say it fits the 104.2 with no cabinet modifications. As of today (06/15/05) the price per SP1548 is $83.00 (USD) plus shipping. I ordered two.

KEF's phone number (as of June 2005): 732-683-9783."

I presume KEF UK and all other distributors will also be able to assist with this "replacement."

For faceplated varients I also presume individuals who can operate a cross-head screwdriver after removing the "dead bit" can also fix the SP1548 driver unit to the rear of the plastic.

marcod45 · Posted: Fri Jun 17, 2005 4:09 pm Post subject:

I got the same answer when I sent a query to KEF UK.

Dear Sir

We no longer have the original 104/2 tweeter, but we can supply a
substitute tweeter. These are different from the original tweeter,
therefore they would need to be replaced in pairs.

These can be ordered direct by contacting service@kef.com

The part No. is R1548X and the cost will be £15.77 per tweeter plus
carriage

Regards
Service Department Manager
KEF AUDIO (UK) Limited / Celestion Consumer Division

clem_o · Posted: Wed Jun 22, 2005 5:45 am Post subject:

Odd, it seems it was only a year ago I was able to purchase a 'true' replacement pair of tweeters for the 104/2 from KEF... I'm curious though - what was the failure of the original T33s of others reading this post? In my case (and my brother's as well), all three tweeter pairs of our 104/2s lost sensitivity. The voice coils and domes were all intact. When we opened up the units, we found the ferrofluid all dried up, and managed to get a *small* degree of restoration by carefully removing the "muck" left. Sensitivity never came up to the required levels though, so we wound up ordering (if I recall) at least two replacement pairs.

Appreciate any responses/insights others may have on this...

Cheers

Clem

proffski · Posted: Sat Jun 25, 2005 2:44 pm Post subject:

I have found this on other manufacturers tweeters as well.

The oil "carrier" for the Ferro particles dries up, especially if the units have had good use!

I am not sure if all use the same oils in their versions of “Ferrofluid”.
But it would be interesting to monitor, I salute anybody with the eye and steady hand enough to take on restoration jobs like these.

You can buy Ferrofluid quite cheaply now, but I know nothing of the specifications.

WARNING! It stains hands and clothes black, and is a pain to remove, you have been warned!
_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

clem_o · Posted: Wed Jun 29, 2005 2:59 am Post subject:

So where is ferrofluid available (in small quantities)? It would be great to try on a few old tweeters that dried out...

ColinR · Posted: Wed Jun 29, 2005 11:45 am Post subject:

General Information

http://www.ferrolabs.com/ff-info.php

A few sources after doing a Google

http://www.scuddlebutt3.co.uk/Ferrofluid.htm

http://www.speakerbits.com/net/catalogs/cat12.aspx

http://www.liquidsresearch.com/products/ferro_loud.asp

http://www.rare-earth-magnets.com/SearchResult.aspx?KeyWords=Ferrofluid&All=True

and one in China, which refused to talk to my Unix machine.

proffski · Posted: Wed Jun 29, 2005 6:50 pm Post subject:

Cheers Colin! I will add these to my data base.
_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

witort · Introductory Contributor Joined: 02 Aug 2005 Posts: 1

The part No. is R1548X and the cost will be £15.77 per tweeter plus
carriage

I made the same enquiry to KEF USA, and got this answer:

We have a replacement tweeter available part number sp1548x priced at $ 83.00 each plus shipping

I didn't know the dollar had fallen so far against the pound! Shocked

SoundAsAnOldEngineer · Posted: Thu Oct 06, 2005 9:46 am Post subject:

I have a pair of the R1548X on order, and will let you know if they sound OK in 104.2.

proffski

Any guess as to which speaker the "smaller" but identical driver was intended for?

SoundAsAnOldEngineer · Posted: Tue Oct 18, 2005 8:49 pm Post subject:

KEF told me that they were used in some more recent (but not current) reference series speakers. I don't know which.

The R1548X has an impregnated fabric dome that looks very similar to the T33. KEF told me that the voice coil diameter was a shade smaller, but it looks the same to me. However, the magnet assembly is quite tiny. In fact, at first I thought there was no magnet. I can only assume that they are using some rare earth magnets here.

The R1548X has a plain circular flange that fits exactly into the rebate inside the sub-baffle of the 104.2. It also has a threaded boss at the rear of the magnet assembly, and KEF have placed a screw into this such that the overall depth is roughly the same as the SP1191.

The small size and threaded boss may give you a clue as to which speaker this was taken from.

I fitted the R1548Xs quite easily and they seem to work OK. I don't have any SP1191s for comparison, but I'm not disappointed.

proffski · Posted: Tue Oct 18, 2005 10:02 pm Post subject:

Oh, I just love KEF mysteries!
None of the recent loudspeakers prior to the introduction of the Q series to my knowledge used the R1548. I am pleased that the KEF sound is still there and that it suits your applications well.
Neodymium magnets, I too was amazed at the tiny structures having taken apart a Q unit. Quite staggering, it looked more like a car tweeter!
Must do some more research...

Cheers!

clem_o · Posted: Wed Oct 19, 2005 1:46 am Post subject:

Sadly, the experience with the Neodymium magnet-based tweeters from KEF seem to indicate a drop in sensitivity over the long-term. Q and C series tweeters suffer from this; probably partly due to ferrofluid dry-up, however despite cleaning out the gunk the sensitivity remains pretty far from that of a 'fresh' unit. I certainly hope that the newer designs have fixed this problem (though the experience of a friend seems to indicate otherwise)...

Cheers!

Clem

proffski · Posted: Wed Oct 19, 2005 1:42 pm Post subject:

I have mistrusted ferrofluid from the day of its introduction to Hi Fi.

Bad enough playing with it in a laboratory environment! Crying or Very sad

If only the drivers were properly designed in the first place, in my most humble opinion ferrofluid is just a shortcut to cost cutting in the design...

oplancq · Intermediate Contributor 50+ Joined: 30 Apr 2003 Posts: 61