SpeakerTalk

Burgerking · Introductory Contributor Joined: 01 Dec 2014 Posts: 9

I just bought a pair of Kef 105.4 Their midranges (Kef B110) aren´t working, there´s no sound at all. So, I changed them for another pair of Kef B110. Surprisingly there was no sound either.

What could be the reason the mids aren´t working? All 4 B110 mids I have seem to be just fine

Crossover problem?

willem-57 · Posted: Mon Dec 01, 2014 1:26 pm Post subject:

Yes, probably a X over problem. Most likely and hopefully it is only wiring that is not connected. Under you see the X over and i think that there is a problem with one of the wires that are attached on 1 of the 5 pins that you see in the middel right. They are market Gn, Bl, BK, etc.

by the way dutch?

Burgerking · Introductory Contributor Joined: 01 Dec 2014 Posts: 9

Hello,

yes, that´s what I also thought. So, I took a piece of new cable and connected directly to x over yellow and green point (which are as far as I know for the midrange) to my midrange. There was still no sound.

I took midrange and connected very carefully directly to my amp and it played well.

SO, probably one of the caps dried out?

Burgerking · Introductory Contributor Joined: 01 Dec 2014 Posts: 9

And yes I´m Dutch, also replied to your topic at htforum Smile

willem-57 · Posted: Mon Dec 01, 2014 1:47 pm Post subject:

Burgerking · Introductory Contributor Joined: 01 Dec 2014 Posts: 9

https://www.dropbox.com/s/blzlncys1l5vj0p/DSC_0649.JPG?dl=0

Burgerking · Introductory Contributor Joined: 01 Dec 2014 Posts: 9

Hello,

yes, those are the ones I bought. Tomorrow I´ll restore the housings of the woofers....

I don´t understand why both of them ain´t working, maybe I´ll just order new ALCAP caps

Burgerking · Introductory Contributor Joined: 01 Dec 2014 Posts: 9

Possibly the old ELCAP dried out? Don´t know thich ones are for the midrange?

I I know which caps are related to the midranges I can just order only them and see if it works

Is it true that the midrange wires are the green and yellow points on the x-over and from there the go directly to the midrange?

willem-57 · Posted: Mon Dec 01, 2014 2:00 pm Post subject:

Yes, they go directly from crossover to the midrange.
I believe that C6 is indeed for the midrange, the LL (LowLoss) are for the tweeter and the four big ones, C1-C2-C3 and C4 are for the woofers.

By the way, under your crossover there is a stamp with the fabrication date.

Burgerking · Introductory Contributor Joined: 01 Dec 2014 Posts: 9

I don´t see a stamp with a date on the back. If the LL ones are for the tweeter, than C5 C6 C8 C9 are for the midrange?

If so, going to try to order those first...

willem-57 · Posted: Thu Dec 25, 2014 8:46 am Post subject:

On the dutch HT forum the problems of burgerking have been resolved, it where indeed a couple of capacitators in the midrange section ( C6-C8 ) that where failing, replaced them with new ones from Falcon and has now a nice set of RR 105.4 's, end of story.

willem-57 · Last edited by willem-57 on Sat Apr 11, 2015 2:32 pm; edited 1 time in total

A specialist has made some drawings off the new bas cabinet for the 105.4 speakers. It will be made from 18 mm MDF and the internal volume will be about 5 liters more as the original cabinet. The damping will be better, carpened bitume on the panels and BAF in the middle. The real fabrication will be done by an profesional, speaker & co from Haarlem, Netherlands. And the cabinets will be black, that i can do myself, i also do things like the xo placement, cables etc. Total height will be about 110 cm, so 14 cm heigher as the standard 105.4, and it will have a slim, more modern look if you'll sitting before them.

Here some drawings:

speakerguru · Posted: Sat Feb 21, 2015 9:56 am Post subject:

Speaking as the designer of the original 105.4, and unfettered by production considerations, I would be inclined to give each B 200 it's own enclosure, i.e. put a divider shelf in the middle of the cabinets. Each woofer would then be loaded by the identical closed box compliance. Any box resonances would be raised where they are easier to damp and may even be above the pass band of the crossover. At high levels there would be less interaction between woofers due to any unequal non-linearities. The one complication would be sealing the inter woofer wiring.

willem-57 · Posted: Sat Feb 21, 2015 10:35 am Post subject:

Thank you for the advise Idea

I have already been in contact with the builder and he confirmed that you have a point there. Cosmetic it will be a little less beautiful because the 2 B200's have more distance from eachother. But sonicly it will be better indeed! So the new design will be with every B200G in it's own chamber. Very Happy

SaSi · Senior Contributor 200+ Joined: 24 Aug 2008 Posts: 256

The point where the two B200 "meet" will be the weakest of the front baffle. So it's better to make the spacing about 20mm and mount an internal chamber separator there.

You don't need to make the baffle space that much. You can use the flange widths for that - if you feel the drivers need to be that close to each other.

IMHO, the bass drivers don't really need to be that close together.