I am searching for some data from some old KEF speakers I want to design. These are the tweeter T33-SP1210 and the woofer B160-SP1222. KEF doesn´t sell anymore and it´s very hard to find data. If anyone has a link or data it would be very helpfull. Thanks in advance.
I have datasheets for all the KEF drive units that were available to the DIY market. Send me an email and I'll copy the T33B SP1210 details to you. The B160 SP1222 will be more of a problem as, so far as I am aware, it was never sold as a DIY product and so the datasheet wasn't available from KEF.
Geoff many thanks, I got your email and I allready printed it )))).
Nisbeth I can try that and see if I get a reply, but from telephone I tried once I couldnt get something usefull. Anyway...
Lohk that´s wonderfull. I can transfer that somewhere and print it. If it is possible to scan your data it would be ideal.
Thanks again to everyone so far.
This sounds interesting. I am the (still!) happy owner of some KEF 104/2 loudspeakers. Does anyone know what drivers were used in this model (purchased in the early to mid 1980s) and where I could get specs on the drivers? I think about redoing the crossover: measuring the drivers' characteristics, tweaking the crossover board with better quality, tighter tolerance parts with values chosen to match the particular drivers, but I hear stories of such difficulty getting to the crossover. Call me chicken... I just say if the KEFs are down, I'd need more than my DT990 headcans
Please email me your actual (german?) postal adress, so that I can send you photocopies of KEF160 data and applications. A letter is ready and wainting to be sent. I have no access to a scanner right now.
Drivers in the KEF104/2:
This is/was a five loudspeaker / three way design.
2 x KEF160 inside in a three chamber bandpass bass-reflex system in the main case (a big sized port in front), and outside a separate MTM assembly with special drivers (slightly similar in size to 2 x KEFB110 and 1 x KEFT33, but with different cones, different compliancy etc.). The assembly is only detachable as a whole, single mid and high drivers cannot be removed or changed alone. The crossover was inside the small box too, I think.
A genuine 4 Ohm design.
Redoing the crossover of a 104/2 will be a VERY tricky task, I would rather let it if you are satisfied with your loudspeaker.
And be careful: There are probably no more spares available, and if something happens you would have to change many expensive chassis at the same time anyway.
There was also a KEF104ab, which was different model from the early eighties. This was a 35l so called three way design with a BD139A (the legendary oval chassis as a passive resonator), a B200-Sp1039 (Qts 0.45) and the T27A (also known from the LS3/5). This loudspeaker had a contour control for the 1.5khz midrange.
The B300 was only used in the KEF105/2 (the B&W 801 counterpart, a 70l/8.5l three-box design), together with a B110B and a T52B.
There was also an earlier version called 105.4 (a 40l/8.5l three-box design) with 2 x B200G-SP1075, B110B and T33A.
I actually should know everything much better, because I was selling the 104/2s in the mid-eighties, when I was working with a hifi-company in Vienna. I will browse through old magazines to get it right if necessary.
I have almost all data of KEF DIY loudspeaker chassis, at least from this time, but only a few crossover schematics.
Michael, Klaus is correct about the driver complement in the 104/2, except that the bass drivers in the coupled cavity were 8 inch. It was the 103/4 that used 6 inch drivers along with a UNI-Q mid/tweeter. The crossover in the 104/2 is very complex. It incorporates full conjugation for the drivers and the overall impedance, in order to produce a pure 4 ohm input impedance, +/- 0.5 ohms over the whole frequency band. This was done in order to reduce the interaction with the cable resistance and amplifier output impedance, and to minimise heat dissipation in the amplifier. A further complication is that ALL components in the crossover are mixed and matched to gaurantee minimum departure from the reference response. This was done by measuring every capacitor, inductor and resistor and then sorting them into 1% tolerence bands. Then, for every deviation from nominal , we would re-calculate the crossover response on the computer and adjust the other components to compensate for this deviation. We built up extensive "build charts" that then allowed full utilization of the components we had measured. So although the marked value on a capacitor might be 10uF, it could deviate from this by up to 10%, and yet by proper selection of the tolerence deviation of some of the other components the crossover would still measure within 0.1 to 0.2dB of the reference. If you start replacing these components with "nominal" values, the response of the crossover will deviate from the reference. Sure it will sound different, but not neccessarily for the reason that the component quality is "higher". I would advise to leave well alone.
The midrange section was unusual in that the 5" drivers were assembled directly to the midrange enclosure without any chassis. The enclosure itself was lined with a thermosetting rubber to damp the panel resonances. Midrange unit replacement was not possible in the field, it was neccessary to return the complete assembly. I don't know whether KEF still offer repair services on this model, another reason not to fiddle with the crossover!
As for getting to the cossover, from (my dim) memory it is in one of two places, either fastened to the removable bottom plate of the bass cabinet, or to the inside surface of a removable plate hidden behind the midrange enclosure.
If you choose to go looking for it, be very carefull not to damage the seals when you remove the panels. The correct performance of coupled cavities is critically dependant on sealing the cavities correctly.
Whatever your course of action, enjoy yourself!
Thanks for your input! I found out more than I expected. Andrew, it sounds like what I wanted to do has already been done, so I will simply continue to enjoy them. I had to change tweeters this year (one failed, I bought a matched pair of replacements and put them in). It sounds like you worked for KEF?
After all these years (and the many homebrew amps, preamps, etc.), I still really like 'em.
Of course, I drool over my friend's Sound Labs, but that's another story
Michael, Klaus is correct about the driver complement in the 104/2, except that the bass drivers in the coupled cavity were 8 inch. It was the 103/4 that used 6 .......
Whatever your course of action, enjoy yourself!