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 

Ref 101

 
Post new topic   Reply to topic    SpeakerTalk Forum Index -> KEF Speakers from the 1970s
View previous topic :: View next topic  
Author Message
iso
Senior Contributor 200+


Joined: 29 Aug 2011
Posts: 215
Location: Finland

PostPosted: Fri May 18, 2012 10:57 am    Post subject: Ref 101 Reply with quote

Is Reference 101 crossover exactly similar, without overload protection unit, that is used CS1.

101 and CS1 cabinet dimensions seems to differ slightly. Is there reason for this and does this have any effect on B110/SP1057 notch filter.

I have also wondered if 220ohm resistor value in T27 crossover is correct on CS1 bulletin?

Best Regards,

Kimmo
Back to top
View user's profile Send private message
ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Fri May 18, 2012 1:38 pm    Post subject: Reply with quote

No.

All components were "matched" to a required selection criteria.

R4 is 2R2 cf 3R.

Inductors are iron dust not ferrite.

The professionally made box dimensions remained the same, but it lost it's false bottom along with the crocodile clip input.

220R is correct.

So don't bother trying to make a clone Ref 101 you won't be able to, BUT you can make a nice CS1 which will have 99% of the characteristics which you desire.
_________________
This post or any other information supplied to this website or any other by myself is not available for any form of commercial purpose i.e. to hi-fi magazines or as sales and marketing material for sleezeBay or Audiodogging pimps and the like.
Back to top
View user's profile Send private message
iso
Senior Contributor 200+


Joined: 29 Aug 2011
Posts: 215
Location: Finland

PostPosted: Mon May 21, 2012 12:22 am    Post subject: component matching Reply with quote

Basic 101 crossover was probably for target spec B110:s and T27:s. Do you have any idea which components were used to adjust crossover for off target spec drive units?

Best Regards,

Kimmo
Back to top
View user's profile Send private message
speakerguru
VIP Contributor 750+


Joined: 18 Nov 2005
Posts: 958
Location: Green Hut, Tovil

PostPosted: Mon May 21, 2012 5:04 pm    Post subject: Re: component matching Reply with quote

iso wrote:
Do you have any idea which components were used to adjust crossover for off target spec drive units?

None. Woofers and tweeters were matched for sensitivity and that's all. High or low sensitivity pairs resulted.

There were no crossover/eq components used to compensate for deviations in frequency response "shape".


Last edited by speakerguru on Tue May 22, 2012 10:46 am; edited 1 time in total
Back to top
View user's profile Send private message
iso
Senior Contributor 200+


Joined: 29 Aug 2011
Posts: 215
Location: Finland

PostPosted: Tue May 22, 2012 9:17 am    Post subject: 101 clone Reply with quote

Colin mentioned that inductors were iron dust cored.

As far as I remember, iron dust cores have better distortion characteristics near overloading. However if my memory is functioning correctly... ferrite cores do have less distortion when overload is no concern. If this is true, would it make sense to use iron dust cored inductors in series to woofer and ferrite cored inductor in tweeter circuit.

Best Regards,

Kimmo
Back to top
View user's profile Send private message
speakerguru
VIP Contributor 750+


Joined: 18 Nov 2005
Posts: 958
Location: Green Hut, Tovil

PostPosted: Tue May 22, 2012 10:40 am    Post subject: Reply with quote

KEF used to buy Stackpole ferrite cores from the USA in the 70s. These had much superior characteristics for audio use than what was then generally available in the UK. Later when there were increasing problems with supplies from the USA, they worked with Neosid in the UK to develop a similar core.

At the same time, iron dust cores (I forget who made those) were found to saturate at much higher level than any ferrite as well as being low distortion at low levels. They were thereafter spec'ed for use in Reference Series.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    SpeakerTalk Forum Index -> KEF Speakers from the 1970s 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