SpeakerTalk Forum Index SpeakerTalk
This forum has been set up to facilitate discussion of 1970s KEF speakers and drive units. The owner of the Forum has no connection with KEF Audio.
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

KEF T-27 tweeter replacement advice needed

 
Post new topic   Reply to topic    SpeakerTalk Forum Index -> DIY with KEF drive units
View previous topic :: View next topic  
Author Message
Gary
Senior Contributor 200+


Joined: 07 Nov 2004
Posts: 275
Location: Toronto, Canada

PostPosted: Tue Sep 13, 2005 1:35 am    Post subject: KEF T-27 tweeter replacement advice needed Reply with quote

Perhaps not the right forum - or topic - but here goes!

I have a pair of (relatively obscure) Tangent RS6's. They have two Audex drivers, Tangent crossovers and KEF T-27 tweeters.

I am looking for replacement T-27 tweeters. I have KEF T-27 tweeters in other KEF speakers but why should I ruin perfectly good KEF speakers?

My problem is that I don't know the first thing about slopes, matching, etc. I have no intention of changing capacitors - that's too scary. And it would take a speaker builder to figure out what to do or change!

I was thinking of installing a set of Audax TW025A0 tweeters which I have purchased from a kind member of this board. But I have no idea if they would match. I guess I could try the "hit and miss" method.....

Can anyone sugggest a replacement tweeter other than the Audax? Or will Audax be a good match?

Please note - titamium or other metallic tweeters are not an option - they sound very harsh to my ears!

Can anyone help?

Thank you!
_________________
Sometimes I lie awake at night, and I ask, "Where have I gone wrong?" Then a voice says to me, "This is going to take more than one night."
-- Charles M. Schulz (as Charlie Brown)
Back to top
View user's profile Send private message
ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Tue Sep 13, 2005 12:40 pm    Post subject: Reply with quote

Very Happy Horrible logical technical reply.

History - the T33 was the replacement for the T27.

Technical - the T33 has a slightly higher sensitivity.

The Concord IV uses a T33.

The later Concord III uses an Audax HD100D25 - 89dB/1W/1m sensitivity.

The Concord IV & III have identical crossover circuits.

The Audax TW025A0 is the progeny of the HD100D25 -90dB/1W/1m sensitivity.

So Tangent RS6 - T27 + Audax TW025A0 = a silghtly brighter speaker!

No poncing about with frequency responses or crossover frequencies btw as they are of similar orders, so go for it Very Happy .
Back to top
View user's profile Send private message
Gary
Senior Contributor 200+


Joined: 07 Nov 2004
Posts: 275
Location: Toronto, Canada

PostPosted: Wed Sep 14, 2005 12:22 am    Post subject: Reply with quote

Has anyone told you that you are brilliant?

Seriously.

Thank you very much!

And you've saved another KEF from being dismantled (not that this was ever a serious possibility, mind you. Smile )
_________________
Sometimes I lie awake at night, and I ask, "Where have I gone wrong?" Then a voice says to me, "This is going to take more than one night."
-- Charles M. Schulz (as Charlie Brown)
Back to top
View user's profile Send private message
ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Wed Sep 14, 2005 12:21 pm    Post subject: Reply with quote

If the speaker is too bright pop a 2.2 Ohm 17 Watt resistor between the unit's input terminal and the speaker's wiring.
Back to top
View user's profile Send private message
Gary
Senior Contributor 200+


Joined: 07 Nov 2004
Posts: 275
Location: Toronto, Canada

PostPosted: Thu Sep 15, 2005 1:05 am    Post subject: Reply with quote

Thanks!

And if they're not too bright, I may have a pair of fuzzy (slight distortion) T-27's up for grabs. I might be able to get them fixed locally or pehaps there is a "fix it" expert on this forum who would love to give it a whirl! Smile
_________________
Sometimes I lie awake at night, and I ask, "Where have I gone wrong?" Then a voice says to me, "This is going to take more than one night."
-- Charles M. Schulz (as Charlie Brown)
Back to top
View user's profile Send private message
ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Thu Sep 15, 2005 11:50 am    Post subject: Reply with quote

If the dc resistance of the voice coil is outside the range of 7.4 Ohm +/- 5%, the following will be of no help - the tweeter's knackered.

Fuzzy sounding T27's sometimes have scorched voice coils, where the lacquer has been fried so you're getting metal to metal contact.

Find my old post which deals with playing with sharp and palette knives and T27/T52 domes.

Once you've got the dome off, hopefully without damaging the yellow double sided tape too badly.

Pinch your wife/girl friend's clear nail varnish and do a light paint job on and around the affected part - the coil should be shinier where it's lost the lacquer.

Carefully press things back together - the locating pins are there for a reason.

The yellow tape on the dome should provide sufficient adhesion, unless you've knackered it.

I've no recommendations for glues if you do mess up.

Note

You must be alone, sober, have steady hands and good eyesight to attempt this.

If at all possible, practice on a dud unit to get your eye in.

The knife goes in near to a locating pin first, then twist to open up the gap, then use the palette knife to release the rest of the dome.
Back to top
View user's profile Send private message
Gary
Senior Contributor 200+


Joined: 07 Nov 2004
Posts: 275
Location: Toronto, Canada

PostPosted: Tue Sep 20, 2005 12:00 am    Post subject: Reply with quote

Interesting tip!

Some used stereo stores I know have a "pushed in dust cap" problem. I've seen a guy pop a T27 back out.

Quote:
You must be alone, sober, have steady hands and good eyesight to attempt this.


You forgot to mention: Lots of light!

Very Happy
_________________
Sometimes I lie awake at night, and I ask, "Where have I gone wrong?" Then a voice says to me, "This is going to take more than one night."
-- Charles M. Schulz (as Charlie Brown)
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    SpeakerTalk Forum Index -> DIY with KEF drive units All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group