The Quest for The KEF… Reference 107!

[canuckaudiog]

Yeah I really think it might be the crappy banana plugs I'm using. I'm going to try removing them to see if that makes a difference.

If you hear it again play around with that and your other components, see if you can narrow it down.

Is it specific to one side? Or is it both sides?

Edit: Just read it's the left side.. shoulda read a little more closely

Swap the speaker wire around and see if it stays with the speakers or follows the swap.

 

[steve59]

I am interested how the bass cabinet of the 107 is, my 105/3 has 2 8" woofers both facing up each having it's own sealed enclosure at the top and bottom coupled by a steel rod firing into middle of the box with a port facing the listener, Kef called it infinite baffle and the bass is amazing. when I look at the 107 design it looks more like a push-pull design with 1 woofer loading the other woofer that fires into the upper chamber before being vented to the outside? what am I missing?

 

[SimplySound]

I am interested how the bass cabinet of the 107 is, my 105/3 has 2 8" woofers both facing up each having it's own sealed enclosure at the top and bottom coupled by a steel rod firing into middle of the box with a port facing the listener, Kef called it infinite baffle and the bass is amazing. when I look at the 107 design it looks more like a push-pull design with 1 woofer loading the other woofer that fires into the upper chamber before being vented to the outside? what am I missing?

Well technically it is all the same... the 107 uses a "Coupled Cavity Design" as well. The 104.2 and your 105.3 are also "push pull" configurations and that is where the KUBE comes in, controlling that feedback loop.

The big difference as you note is that the 104/105's vent in the middle towards the listener. The 107 was designed to vent straight up through the top of the cabinet in front of the "Mid/High Head".

Now we could probably get into quite the discussion of how that works, but I for one believe there is a real interaction between the "Bass Wave" emitting in front of the Heads and how that gets dispersed into the room. I believe it was KEF's first attempt at trying to develop a "Single Point Source".

Did it work? I believe it worked incredibly well, but was far too expensive to develop further (those Heads are were the cost is)! So they took the Bass design and applied it to the Uni-Q in the 105 and the D'Appolito Design in the 104.

The 107 was truly a unique speaker the likes of which we shall probably never see again. Not that it is the best speaker ever, but it truly was a great speaker. As I like to call it; "an LS3/5a on Steroids, married to the best Sub-Woofer ever!"

That's basically the difference in my book. :yes:

 

[SimplySound]

Now this is interesting. I just swept through the Museum and this is what is stated...

Specification: Model 107
System Type: Three-way, floor standing
Enclosure type: Coupled cavity
Size: 1165 x 330 x 448mm (45.9 x 13 x 17.6 inches)
Weight: 45kg (99 lb)
Frequency response: 20Hz to 20kHz +/-2dB at 2m on reference axis

Specification: Model 105/3
System Type: Four-way, floor standing
Enclosure type: Coupled cavity
Size: 1104 x 280 x 405mm (43.5 x 11 x 16 inches)
Weight: 42kg (92.5 lb)
Frequency response: 49Hz to 20kHz +/-2.5dB at 2m on reference axis (-6dB at 20Hz when used with KUBE 200)

Specification: Model 104/2
System Type: Three-way, floor standing
Enclosure type: Coupled cavity
Size: 900 x 280 x 415mm (35.5 x 11 x 16.5 inches)
Weight: 32kg (70.5 lb)
Frequency response (standard): 55-20,000Hz +/-2dB at 2m on design axis

I guess the cabinet design really did change things up from a Frequency Response standpoint. I wonder how much of a role the weight and size had on the resonance of the cabinet and how well it could go low? :scratch2:

 

[Reed Felton]

Very much enjoyed the Kef 107 thread. I currently own the Kef 104.2's that I bought new in 1988 which I have since "hot rodded". I also had the 107's for a few years. They are wonderful speakers. Smooth, uncolored and pretty soulful. By all means...enjoy the journey. The Kefs are wonderful companions.

 

[steve59]

I was going to give my 105/3's one last listen before selling them in favor of the 107/2's that was the plan anyhow. With this new setup Anthem225I up top and the kube to B&K 4420 down low kube 200 for the 105/3, 107/2 has it's own kube. why can't the 107/2 just destroy the 105's an make life simple again? The upside is I opened all 4 boxes up inspected the surrounds, mounting, filler, and pulled out the multimeter to check the crossover components, took pics along the way if anyone wants to see. all 8 woofers had replaced outer surrounds and all 8 had the inner donuts removed. As far as crossover values all I can say is they looked good and values were pretty close comparing 1 unit to the other. Both are very well built however the foam in the 107/2 is custom cut to fill the bass bin tightly the 105/3 uses an off the shelf padding.

 

[steve59]

there's 1 that looks a little burnt but it's value was 6.1 ohms the identical part on the other board was 6.2 since kef matches their reference speakers individually for matched pairs the value is probably in spec.
These aren't the 107, but maybe we can leave them here for reference SN 1232 l&r 105/3.

 

[steve59]

here's the 107/2 base the head units sound great and i'm going to need to hear some degridation to open them up. even though the 107/2's are newer the crossover look older, I wonder if kef used original 107 crossovers for the bass? only updating the heads.

 

[SimplySound]

...all 8 had the inner donuts removed.

Steve, you'll want to get the "inner donuts" on there!!! It makes a big difference!!! :yes:

Think of it this way, what creates the Sound Pressure Level (SPL) is moving air with the piston motion of the speaker. With the center open like that you are letting air slip by and reducing the output SPL.

I believe many people that repaired these left those out because they weren't available. I believe it's only been in the last 5-6 years that the center foam elements were manufactured.

Get the donuts!!! :thmbsp:

 

[steve59]

that explains why 2 different shops repaired them the same way.

 

[canuckaudiog]

Steve, you'll want to get the "inner donuts" on there!!! It makes a big difference!!! :yes:

Think of it this way, what creates the Sound Pressure Level (SPL) is moving air with the piston motion of the speaker. With the center open like that you are letting air slip by and reducing the output SPL.

I believe many people that repaired these left those out because they weren't available. I believe it's only been in the last 5-6 years that the center foam elements were manufactured.

Get the donuts!!! :thmbsp:

Yes, definitely replace the donuts. You're missing out on some bass as a result - they won't sound proper until these are done.

 

[Hawkeye83]

Hmm...now I'm thinking I don't have the donuts on mine either. I'll have to post a pic. I'm not super familiar with re-foaming but from the pics of the donuts that I see on ebay, it looks like mine don't have them?! You mean these speakers can sound better?!

 

[SaSi]

Hmm...now I'm thinking I don't have the donuts on mine either. I'll have to post a pic. I'm not super familiar with re-foaming but from the pics of the donuts that I see on ebay, it looks like mine don't have them?! You mean these speakers can sound better?!

Considering how well my "lookalikes" sound using B200SP1014 and no KUBE, I suppose the real 107 with properly repaired drivers and a KUBE must sound fabulous.

 

[Hawkeye83]

 

[canuckaudiog]

Nope.. no donuts there.

Your bass is currently diminished as a result. Get those donuts in there, pronto! If they haven't been already, I would refoam them as well.

 

[Hawkeye83]

These are Thundermud's old speakers...completely worked over already...he must have just forgot the donuts or didn't know about them. Actually, this is an old picture from when he still owned them...so there may be donuts in there now. I'll have to check this weekend. I had the bottom off of one speaker and don't remember seeing donuts, but we'll see. Actually I've been meaning to take one speaker apart anyway...it still has the loose terminal connector...when using them for HT when there's a lot of bass, I get some crackling...I assume from the connection vibrating because it's not tight. When I use a vice grip and spin the terminal from the outside to tighten it, the static goes away. Kind of annoying! At least it's only with HT (not music)...and it hasn't happened for a month or so...it's kind of intermittent...the connection must be good right now.

I think the bass is already pretty outstanding. I don't expect to hear much difference with the donuts, but we'll see I guess!

 

[canuckaudiog]

Ahh right. He probably did replace them but in case he hasn't then you will want to.

I thought much the same that it wouldn't make an improvement, but it does. The bass quality doesn't improve but the frequencies at which you hear the bass do improve. It will sound fuller afterwards, basically.


Sent from my iPhone using Tapatalk

 

[Thundermud]

Heyyy its me! Have not been on AK in a while but just stopped by and stumbled on this post, cosmic timing? How are my old babies doing? If memory serves me correctly the donuts were not included in the re-foam kit. I have been busy with our new baby (6months) and work. I have done some major upgrades to my system I've been wanting to share with everyone, soon! Hope everyone is well!

 

[Hawkeye83]

Good to see you here, T-Mud. They're doing great. Just that intermittent crackling with heavy bass (HT only). No other issues with them whatsoever! They are definitely heavily used and loved. Been trying to wax them at least once a month to keep the wood in good shape. At some point I will take them apart and fix that speaker terminal issue and probably put the donuts on at that time as well. So far I've just been hesitant to do much disassembly, since they're mostly working well. It's mostly the connecting rod I'm worry about...need to look into it more, how that comes apart and if there's anything I need to be careful about. Luckily there should be lots of good info here. Considering at least 2 or 3 of you have been through re-builds.

I'm sure you are busy with the baby! We are having another...we're actually finding out the gender today. Our oldest daughter will be 3 in August.

Can't wait to hear about your system and hopefully see some pics...you've got a lot of pieces that I'd like to have myself! Particularly the Juicy Blueberry and the MC60's!

 

[Thundermud]

Congrats!! Very exciting! I thought the donut was the "dust cap"? If so, you should not need to mess with the tightening rod, just glue the dustccap over the rod area. That damn rattle from the speaker terminal was a pain for me too! I reached in there several times to tighten it. Maybe ask around if there is a glue of some sort that will stop the rattling without interfering with signal connection. Or maybe you may only need new washers?