Modern or Vintage Kef's

[RDSChicago]

I am just getting into 2-channel listening and am agonizing whether to go new vs.vintage. A pair of Kef 107's are available in my neighborhood. I am not at all handy and naturally concerned about condition, how much restoration would be needed, etc. A Kef dealer would give me a very nice discount on the R700's which have reviewed so highly. What do you think? How would you compare the two? If it helps, I am deaf in one ear and tend to listen to my music at a fairly high volume. Thanks in advance.

 

[cpp]

I am just getting into 2-channel listening and am agonizing whether to go new vs.vintage. A pair of Kef 107's are available in my neighborhood. I am not at all handy and naturally concerned about condition, how much restoration would be needed, etc. A Kef dealer would give me a very nice discount on the R700's which have reviewed so highly. What do you think? How would you compare the two? If it helps, I am deaf in one ear and tend to listen to my music at a fairly high volume. Thanks in advance.

I say it depends on the price and the conditions of the drivers. I still have ( tried to sell them) a pair of kef 104/2 and still like their sound..Here's some history KEF R107 loudspeaker | Stereophile.com

 

[RDSChicago]

Thanks. They are $1,400. I have 103.2's and have heard the 104/2's. They sound great.

 

[TLS Guy]

I am just getting into 2-channel listening and am agonizing whether to go new vs.vintage. A pair of Kef 107's are available in my neighborhood. I am not at all handy and naturally concerned about condition, how much restoration would be needed, etc. A Kef dealer would give me a very nice discount on the R700's which have reviewed so highly. What do you think? How would you compare the two? If it helps, I am deaf in one ear and tend to listen to my music at a fairly high volume. Thanks in advance.

The KEF 107 is a fine speaker, but there are installation issues you need to be aware of. You won't need a sub with this speaker, it is truly full range, it gets to 20 Hz with no sweat.

However, the speaker uses a coupled cavity bass system, that requires and an active equalizer, known as the KEF Kube. This has to be connected in the tape monitor loop, or between a preamp and power amp. Modern equipment does not have a tape monitor loop, so unless you plan on using a vintage receiver, which I don't recommend for those speakers, the you need separates. You can not use those speakers with a modern AV receiver. Use of the Kube active equalizer is mandatory for those speakers. You need to make sure that item is included and working, or the speakers are useless.

Like most coupled cavity designs they are not sensitive or efficient, and KEF recommend a power amp in the 300 watt per channel class.

If you have the funds and ability to set those speakers up properly, you will not go wrong.

Those speakers were made when KEF were at the top of their game and not owned by and outfit from Hong Kong.

The only other caveat, is that the drivers use Bextrene cones. Sometimes this material can crack with age. Bextrene is no longer made in the world, and the drive units can not be repaired if a cone cracks.

 

[RDSChicago]

Wow. Great explanation. Thanks. I have a Pioneer SX-939 receiver. Sounds like this is insufficient in terms of power requirements. How would a Pioneer M90 work with the 107's? Alternatively, could I add a power amp to the 939 receiver to drive the speakers effectively?

 

[TLS Guy]

Wow. Great explanation. Thanks. I have a Pioneer SX-939 receiver. Sounds like this is insufficient in terms of power requirements. How would a Pioneer M90 work with the 107's? Alternatively, could I add a power amp to the 939 receiver to drive the speakers effectively?

You could certainly use your SX-939 as a preamp and add a power amp. You just take out the loop connectors between the preouts and the power in. You connect the input of the Kef Kube to the preouts of the SX-939 and the the outputs of the Kube to the inputs of your amp. Or you can put the Kube in the tape monitor loop of the SX-939.

I would think an amp of 250 to 300 watts into four ohms will do the trick fine. Make sure you get an amp that will deliver that much power into four ohms or less.

Do not try and drive those speakers with the power amps of that receiver, the impedance of those speakers will pretty much spell death to any receiver amps.

 

[-Stan-]

I have a pair of KEF 107/2's with a KUBE and then bought a Denon 4311. I actually think Audyssey XT32 does a better job than the KUBE with these speakers. They are really a marvel to listen to and like TLS Guy say a sub isn't needed unless you're a real bass hog and want to go lower than 20Hz.

 

[Fomoco69]

Just bought a pair of KEF 203,SP 3001 from early 80s…waiting on delivery .any thoughts or expierienced on these

 

[TLS Guy]

They are an eighties bookshelf speaker, and actually a KEF "budget" speaker. The big problem with those is that with age those bextrene cones are prone to suddenly crack. Bextreen is a rigid but somewhat brittle plastic that has not been made for years.

So you need to keep your volumes very moderate, or you are likely to get a large crack suddenly appear in the bass driver.

 

[Fomoco69]

They are an eighties bookshelf speaker, and actually a KEF "budget" speaker. The big problem with those is that with age those bextrene cones are prone to suddenly crack. Bextreen is a rigid but somewhat brittle plastic that has not been made for years.

So you need to keep your volumes very moderate, or you are likely to get a large crack suddenly appear in the bass driver.

Ok, thanks good to know…

 

[Fomoco69]

Which model would you suggest without needing the cube….maybe 103.3

 

[TLS Guy]

Which model would you suggest without needing the cube….maybe 103.3

Not sure why you want to buy old speakers. The coupled cavity designs use the KUBE. However you can Eq the speakers with Audyssey.

Speakers have improved over the years, and I don't know why you want old ones, that risk driver deterioration.

 

[lovinthehd]

How much have Kef evolved their concentric designs?

 

[TLS Guy]

How much have Kef evolved their concentric designs?

Significantly.

 

[its phillip]

How much have Kef evolved their concentric designs?

Currently on the 12th generation design. https://us.kef.com/pages/uni-q

 

[Fomoco69]

When I receive my 203s this week as long as the woofers are in good shape & sound good is there any suggestions on treating the surrounds or cones from deteriorization?

 

[highfigh]

How much have Kef evolved their concentric designs?

The LS-50 is a small, potent speaker and the coaxial arrangement makes the sound very cohesive (I don't like most adjectives used for audio, but that works pretty well).

 

[lovinthehd]

Some day maybe I'll get to experience Kef (if I did in the past it was a very long time ago but don't think I did), they certainly get a lot of good comments from a variety of users....

 

[Eppie]

When I receive my 203s this week as long as the woofers are in good shape & sound good is there any suggestions on treating the surrounds or cones from deteriorization?

I would not add treatment to the surrounds or cones. The surrounds are not foam so they are not susceptible to foam rot. The bextrene cones are a form of plastic and I would be concerned that any treatment could make things worse.

I rebuilt a pair of 103.2 for my daughter and you can see from the photos that on one the cones the surface began to delaminate. I used automotive clear coat to patch the affected area and the patch has held up fine for the last three years. Best advice I can offer is not to play those speakers at very high volumes. They can still get moderately loud and I really love the warm sound that the 80's KEF speakers produce but you can't mistreat them or the cones may get damaged.

If they are all original, you may want to consider having the capacitors checked on the crossovers. Any old electrolytic caps may have gone out of spec over the years. KEF did use very high quality parts though. I read that for the 103 (and likely the 203 as well) they hand picked each crossover component to match each driver. Few manufacturers go to that level of detail.