SpeakerTalk

[proffski]

We have several grades of Ferrofluid here at the labs with varying viscosity levels.
How do you determine the correct one to use in an audio transducer as the effects will obviously be very different depending on the carrier…
_________________
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

[speakerguru]

Depends on the application and what you want the ff to do.

You can use a low viscosity ff to just improve cooling or you could economise on magnet strength, giving a high Q resonance and then use a high viscosity ff to bring the Q down mechanically.

If you use ff in a mid or woofer, you might go for a higher viscosity to reduce splashing at high excursions.

KEF tweeters of the 70s and 80s used a low viscosity (75 cp) grade of ff.

[proffski]

Thank you for the information.

Duly noted, but for those not in the know another variable...
I remember back in the distant past a service open to punters to have ff squirted into their drivers, sometimes with disastrous audio results.
_________________
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

[proffski]

These sites have some nice pointers...

http://www.ferrolabs.com/en/information/30/

http://www.ferrotec.com/products/ferrofluid/audio/

Blinking minefiefd if you do not know as to what you are doing!
_________________
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

[laro80]

i read all the thread about the "replace a T33 SP1191 with the SP1548 (or SP1548X)" and it seems that is not as good as the original T33, not as smoother as the T33...

What the options for the replacement of my T33?

I know Vifa Mg27....but discontinued
SP1548, but not as good as T33

so with all of my reading, i don't know what to do.

Help me please with those almost irreplacable tweeter,T33.

thanks and sorry for my bad english!
________
Matiz

[Ragnar]

Hi laro80,

The current KEF replacement is the SP1549X.

I have had it for a few months now and it sounds ok for me.

Immediately after the replacement i found it a bit busy to listen to, and not as easy as the original 20 year old SP1191.

With the new units you become aware of how loud you are playing, a matter that you not necessarily would notice withe original SP1191. On the other hand i find that the quality of the recorded material to be more critical with the new units. They reveal any weakness in the production of the music, as if they are more analytic in nature.

Se the following thread for dealer information.


Ragnar


http://www.hifiloudspeakers.info/speakertalk/posting.php?mode=editpost&p=3602
_________________
Record:
KEF C10's (1986-now)
KEF C80's (1987-2007)
KEF Reference 105's (2006-2006)
KEF Reference 104/2's (2006-2007)
KEF Reference 107's (2007-now)
KEF Reference Two (2007 -now)
KEF Reference Four (2010 -now)

[centaurus]

contact solen.ca

they still list the MG27-04 in their parts list:

http://www.solen.ca/v1/

they might be able to track down a pair.

yeah, it's sorta stupid that they don't make that tweeter anymore. it's a solid and affordable 4 ohm tweeter.

Robby

[Ragnar]

Picking up an old thread.

I did replace the T33's in my pair of R107's.

A few days ago (actually the day before christmas of all) I noticed that one speaker was dull and by closer listening, there was no sound from the tweeter replaced a few years back. What ?

The units I removed were SS1191. According to the KEF Museum the original units were SP1210. SP1191 were used on 104/2.

Either way: SP1191, SP1210 and all known replacements are history and not obtainable, as far as I know. If any of You know of anything else - Please share that knowledge.

Anyway, I have checked Ebay and similar sites now and then since that, and hoping for a replacement unit.

Today I found a pair of C42 speakers (with fresh SP1210 units) for £40.-, a pair of Reference 103/3 for £70.-, also with working SP1210's and a spare SP1210 unit, all within 20 miles of my office. 5 SP1210's !

And on top of that a pair of fully functional R107's. How likely is that ?

I secured the C42's and surgery is being planned. I know this may be controversal, but I want to save my 107's.
_________________
Record:
KEF C10's (1986-now)
KEF C80's (1987-2007)
KEF Reference 105's (2006-2006)
KEF Reference 104/2's (2006-2007)
KEF Reference 107's (2007-now)
KEF Reference Two (2007 -now)
KEF Reference Four (2010 -now)

[dublin78]

Hi
I have been doing a bit of research on current solutions to poorly performing SP1191 tweeters:

1. People seem to have had good success in cleaning out all of the dried up ferro fluid, and then replacing it with new. There is a You Tube video that demonstrates how to do this.

2. Midwest Audio now make a replacement. Search on Ebay for "KEF Copy Tweeter". They are $45 each and £36 postage to the UK. I have not heard any reports, but MWA should provide some feedback, no doubt.

3. Some people have replaced with the Morel MDT29. You need to remove the flange first, then it fits perfectly. The success of this swap seems to be one of personal taste. Some love it, and some do not. They appear to make the 104/2 a bit brighter, which may be a bonus to some.

[proffski]

Agreed on all counts, at my age a bit of extra HF is acceptable.
Also could mean the difference between keeping an old classic working or not!
_________________
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