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patch 16th September 2007 03:24 PM

KEF Driver Information TS1084 ?
2 Attachment(s)
Some years ago I traded a fellow for a pair of KEF drivers - he said they came out of a pair of small bookshelf speakers, didn't recall the model.

The code is TS1084. Its in that KEF shield shape, with three trianglular mounting points. Paper cone, approx 1 inch coil. Approximately 6.5 inch cone, indented rubber surround.

Not having luck with the KEF web links, I wonder if anyone here might know about these various models where these were used, and possibly even the specs and t/s parameters.

I intend to use them in an approx. 2 cubic foot revamped JBL cabinet with a ribbon - without the specs I'm not sure how to adjust the chamber volume, except for listening and reworking.

The old Carlton IIIs had an almost idential looking driver, but it was coated with plastic, and was used as the main driver. This one is gray paper. These are in my testing really for mid frequency, but I'll give them a try at a vented two-way. Attached is the KEF image.

Any help?

patch 19th September 2007 06:18 PM

Added pics of kef ts1084
2 Attachment(s)
Possibly this pic might help to identify specs for the speaker. Hope these post OK with this message.

pinkmouse 19th September 2007 07:21 PM

Ha, I've got a pair of those as well! I did run them through Speaker Workshop ages ago, but I'm not sure if I still have the data after the Great Motherboard Fire of '06.

IIRC, after measuring and a little simulating, I came to the conclusion that around 12l sealed worked best, but never actually built boxes to test them out.

patch 20th September 2007 10:45 PM

A little sealed box
Hey thank you. A sealed box I can do readily - and a small one too, yippee! I suppose these little throats can use all the backup support available.

Such interesting units these are, almost gnomes compared to others out there. In testing they have a dry middle-range belly in them. I'll see what some tight chambering will do. Thanks!


lcsaszar 23rd September 2007 06:16 PM

I believe this is a B200.G, here are the specs:

Net weight: 1.35 kg
Nominal impedance: 5 ohms
Typical enclosure volumes: Totally enclosed box 20-25 litres
Power handling: Continuous sine wave 28 V RMS
Programme: 150 W
Magnet: Flux density 1.1T (11,000 gauss)
Total flux 7.15 x 10-4 Wb (71500 Maxwells)
Voice coil: diameter 32.6 mm
Inductance: (N/A)
Max. continuous service temperature (30 min) 250 deg Celsius
Max. intermittent temperature (5 sec) 340 deg. Celsius
Nominal DC resistance, Rdc 4.7 ohms (tolerance +/-5%)
Minimum impedance (in nominal frequency range) 5.3 ohms @ 160 Hz
Diaphragm: effective areaƉ Sd 246 cm2
Effective moving mass Md 24.3 g
Max. linear excursion, Xd 6 mm peak-peak
Max. damage limited excursion 20 mm peak-peak
Free air resonance frequency, fs nominal 27 Hz
Total mechanical resistance of suspension, Rms 1.38 mech. ohms
Suspension compliance, Cms 1.4 x 10-3 m/N
Force factor, Bl 6.82 N/A
Damping: Mechanical Qm 3.03
Electrical: Qe 0.42
Total: Qt 0.37

These data come from KEF SP1075 spec sheet. For double checking if this is the same speaker as yours, here are the mechanical dimensions:

Mounting holes radius: 107.5 mm
Outer radius: 118 mm
Basket diameter (mounting hole) 183 mm
Depth: 95 mm

I calculated the efficiency, it is 0.552% and Vas is 119 litres


patch 25th September 2007 06:43 PM

That could be the series
Thank you very much oshifis for the specs and calculations.

The mechanical dimensions are on the mark with the B200s. The magnets on my units appear smaller than the smallest of the B200s I see in the web links. The weight one one of mine comes in at 1kg, or my scale is slightly off.

150w seems a little too hot for these....but what do I really know without actually testing? These may be a B200 variation from some small production run, or maybe for another speaker maker. I'll stop talking now and get to building.


pinkmouse 25th September 2007 07:59 PM

Sorry, but the B200 is a completely different driver, the TS1084 is a much more budget model.

patch 17th November 2007 05:55 PM

And now packed in their little sealed chambers, the TS1084 has that distinctive and nostalgic sound of aged cardboard. An OK sound really, esp. when compared to broad-market loudspeakers from the 1970s and 80s. The sound lines up with my memory of good tuna-boat tv/hi-fi consoles from the 1960s - all in-the-middle with a pleasant pinch and grit.

I mean these as complements: From my tests using a box of maybe 10 liters, with a nice beamy CTS paper cone tweeter and salvaged KEF filter, I find the 1084s ideal for presenting the (apparently intended) sound of early Beatles, early Joni Mitchell, any Grateful Dead, any Waylan Jennings. Possibly a best choice for sharing time with oldies that were aimed at listeners on a budget.


IG81 26th May 2009 03:34 PM


Sorry for resurecting an almost 2 year-old thread.

The KEF TS 1084 drive unit was used in at least the Coda II model in the early 80ies.

I have bought a pair of those in bad shape to restore for 10$ at local goodwill thinking it was a B200 unit in there, but it's a bit more budgety. Still sound nice though.

Just thought I's shed at least this much light on this little-known drive unit as there is still not much info on the web to be found.

I might measure it's T/S parameters one day for fun or if asked by someone in need.

Yeah, it's good to play the kind of music you described. Bass response it not that thight and a bit "slow/muddy", probably due to the small magnet size. I threw some Alice in Chains (Facelift) and Smashing Pumpkins at it with nice results too. Good for rock/pop, less so for critical/high-quality recordings.

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