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A mix of cs-9 and pl301
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gforse
Junior Contributor 20+


Joined: 25 Jan 2010
Posts: 24

PostPosted: Tue Feb 02, 2010 7:04 pm    Post subject: Reply with quote

there is a 105/2 Build end 80s for sale. its has some scratches, also the owner had left a candle on the tops and have a few burning holes in the top.

he whats €475 for it thats about 415.079 GBP and 663.032 USD

here´s some picture´s

http://link.marktplaats.nl/316424543

what do you guys think its worth??
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Lee in Montreal
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Joined: 22 Aug 2009
Posts: 203

PostPosted: Tue Feb 02, 2010 7:10 pm    Post subject: Reply with quote

Not a bargain. And there are always surprises. Cabinets seem to have been dyed too. Offer 25% less, and keep that money to redo the crossovers.

Lee

PS before buying them, have the owner remove the woofers just to check if the real filters are actually still there...
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Kef Calinda - since 1979
Kef Cantata - since 2009
Kef 105/2 - since 2009
Evo 105/2 - in the build
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gforse
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Joined: 25 Jan 2010
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PostPosted: Tue Feb 02, 2010 9:40 pm    Post subject: Reply with quote

that a smart thing to do with the filter! i didnt thought of that.

I offerd him 25% less. and he whent a little mad en said that i have to wait 2 weeks. bud one week later nobody has offer something...

theres at the moment a 105/4 for sale on ebay! very nice one in england.
http://cgi.ebay.nl/Stunning-Kef-Reference-105-4-Monitor-Speakers-SP1120_W0QQitemZ280457429057QQcmdZViewItemQQptZUK_AudioVideoElectronics_HomeAudioHiFi_HiFiSpeakers?hash=item414c90c041

for the one ho like''s one!

Is there more things i sould look for when i buy them?
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Lee in Montreal
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Joined: 22 Aug 2009
Posts: 203

PostPosted: Tue Feb 02, 2010 10:27 pm    Post subject: Reply with quote

Not a big fan of the 105.4

Not the same tweeter. And not the B300 anymore. Stick to 105/2 or 107

104/2 can be great but most of them need a lot of love... Damn foan surrounds.
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Kef Calinda - since 1979
Kef Cantata - since 2009
Kef 105/2 - since 2009
Evo 105/2 - in the build
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gforse
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Joined: 25 Jan 2010
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PostPosted: Tue Feb 02, 2010 10:33 pm    Post subject: Reply with quote

i would stick to the 105/2


Is there more things i sould look for when i buy them?
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Lee in Montreal
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Joined: 22 Aug 2009
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PostPosted: Tue Feb 02, 2010 10:56 pm    Post subject: Reply with quote

Push the B300's diaphragm. Sometimes they sag and you get coil rub. The B300 will benefit from being rotated by 120° every year.
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Kef Calinda - since 1979
Kef Cantata - since 2009
Kef 105/2 - since 2009
Evo 105/2 - in the build
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SaSi
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Joined: 24 Aug 2008
Posts: 223

PostPosted: Tue Feb 02, 2010 11:32 pm    Post subject: Reply with quote

Lee in Montreal wrote:
The B300 is designed to fit a 70-90 litre enclosure in sealed form. If you increase the size, you are loosing in output.

As for designing the bracing, invent your own process.

Here's what B&W did with the Matrix serie



Hi Lee,
that looks almost as good as the bracing in your EVO 105s. Good for B&W...

BTW, what's a B330? First time I hear of it. I thought the pics showed B300 SP1060.

BTW, the crossovers shown in gforse's pics appear to be the ones from the original 105s, so they are a better match (perhaps) than what the SP1071 would be. Although my first attempt at measuring T/S parameters on a driver showed that the SP1060 appears to be identical to the SP1071.

Gforse, you have significantly less than what you need to realistically build 105s. The bass unit could be replicated and the heads as well - but they need higher woodworking skills - and they also need some way of mounting on the bass units. On the original 105s the heads rest on adjustable metal bases that allow them to turn and swing up or down. That would be a challenge to recreate.

The crossovers you have are optimized for the enclosure and the geometry of the 105s.

I think that you need to decide if you will wait for the remaining drivers to be found or proceed on a different route.

I am currently restoring a pair of 105s and the first unit is ready and assembled. It plays fine but I consider the T27 a better tweeter than the T52. My pair of T52s are fully working (I think) but the ferrofluid in these tweeters gives them a finite lifespan. Theoretically all existing T52s of the '70s are way past their useful lives. OTOH, all T27s I've listened to appear to be in excellent health.

Since you are keen on experimenting with bass enclosures and you have two B300s, I recommend you experiment building a 180 lt enclosure and use the two B300s in isobaric configuration and vent the enclosure tuned at 19Hz. This is exactly what I am experimenting with. The WinISD simulation was very promising and a mock up trial with a box that was not treated inside (no bracing, no dampening) was very very exciting (both for me and the box).

If you ever get remaining drivers to build complete systems you can re-use the B300s there. Until then you can have an interesting subwoofer (in desperate need of more than 350W @4Ohms to sing.
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gforse
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PostPosted: Wed Feb 03, 2010 11:09 am    Post subject: Reply with quote

i´m planning to wait with the design until i have a pair of 105/2. the b300 and the b300b are identical accept the bracing. kef made the 3 point bracing for less contact and there fore less vibration.

i was thinking about a plan to make a box with the b300 inside and the b300B outside the box. there fore creates more and deeper bass. bud I don't now if it will work!

i have now the b300 in a 185L cabinet. at is loses a lot of output! it go´s very deep but with little output.

let me show you what I mean.
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SaSi
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Joined: 24 Aug 2008
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PostPosted: Wed Feb 03, 2010 12:28 pm    Post subject: Reply with quote

Take design 6, make the Vb 185lt and change the enclosure type to vented and tune that to 18Hz.

The 185lt enclosure will need to have such a large front baffle that you don't really need 4 vents. A single vent of adequate cross section is enough.

That should give you a f3 of about 18Hz, max SPL of about 108dB and an excursion of less than 14mm down to 15Hz with 350W power to both drivers (in parallel).

The large volume (huge considering the compound mounting) provides a good group delay performance with values <10msec down to ~30Hz.
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gforse
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PostPosted: Wed Feb 03, 2010 1:40 pm    Post subject: Reply with quote

something like this?


and what would this idea do ? Both are B300 one in the front and one faced down
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SaSi
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PostPosted: Wed Feb 03, 2010 2:36 pm    Post subject: Reply with quote

The Bassbox simulation appears to agree with the one from WinISD.

However, your drawing on compound driver mounting is incorrect. The two drivers are mounted either face to face on the front baffle (in which case one of the two drivers operates with the magnet facing on the outside - not the most attractive mounting) or they are mounted back to back (in opposite electrical phase) on a small sub-enclosure. This subenclosure is like the one made for midrange drivers. Only in this case the second B300 is mounted at the back of that enclosure.

They can also be mounted as BassBox suggest, in the same orientation and in electrical phase.

What the compound configuration achieves is halving the Vas effectively making the 185lt enclosure with these two drivers equivalent to a 360lt enclosure if a single driver was used.

Additionally, the compound configuration has several other benefits as well as drawbacks of which the most important is double the number of drivers and the power needed.
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gforse
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PostPosted: Wed Feb 03, 2010 4:50 pm    Post subject: Reply with quote

the drawing i made was an example of my idea i was wondering if it will work?

and is still don't get it... one single driver in an 360L enclosure has almost no output. also i think that two of them will give some problems. what if one a bit out of phase? than you get an ugly sound! and never that you're going to achieve 18hz with a woofer that can go 25hz or am i wrong about it?

also the group delay doesn't look good. to me
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SaSi
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PostPosted: Wed Feb 03, 2010 10:39 pm    Post subject: Reply with quote

gforse wrote:
...
and is still don't get it... one single driver in an 360L enclosure has almost no output. also i think that two of them will give some problems. what if one a bit out of phase? than you get an ugly sound! and never that you're going to achieve 18hz with a woofer that can go 25hz or am i wrong about it?

also the group delay doesn't look good. to me

I don't understand why you say that. Increasing the enclosure volume doesn't cause output to be reduced. To the contrary, it improves transient response (by decreasing group delay). With sealed enclosures cone excursion increases as volume increases but vented enclosures have much smaller excursions down to the tuning frequency. The large enclosure allows a more favourable tuning lower (18~19Hz), below the useful output and music content, thus reducing the need to control the sub-tuning large excursion of the driver.

The group delay plots for vented and passive radiator enclosures are worse than sealed enclosures, however the large volume (i.e. alignment) plus the low tuning frequency improve the group delay plot in the audible spectrum.

In an isobaric configuration the two drivers are never out of phase. To the contrary the small enclosure has constant pressure as the two cones move in sync.

If you want to understand this in an easier way, try modelling a 360lt vented enclosure with the same (single) driver, tuned to 18Hz. Using two drivers in isobaric mode simply reduces the enclosure volume in half, making the box a bit more manageable.
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gforse
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PostPosted: Wed Feb 03, 2010 10:50 pm    Post subject: Reply with quote

i understand the the meaning of it. but when i now listing to the b300 in a 185L box there's not much output. from one-2 meters it sounds nice and go`s very deep bud if i step 2 meters back there`s no bass left. it is not my room that's not acoustic. because when i place a different sub or a different loudspeaker at that place is sounds very good also on a distance!

and if the b300 is tuned at 25 Hz how can it go to 18~19 Hz?
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Lee in Montreal
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PostPosted: Wed Feb 03, 2010 11:14 pm    Post subject: Reply with quote

If I had two B300s, I would build a bass cabinet like the 104/2 or the 107. In any case, each B300 has a small enclosure, and they face each other in a common area. The 107 then has a long duct going up acting like a natural filter.

Using a smallish enclosure for each B300 will limit the cone excursion, and probaly allow higher sound level. Total volume would be small.

And guess what? I would look for another pair of B300s to end up with two bass cabinets...


_________________
Kef Calinda - since 1979
Kef Cantata - since 2009
Kef 105/2 - since 2009
Evo 105/2 - in the build
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