Thursday, 8 January 2015

FRANKENKEILIDHS - Zombie Speakers Rise Up: PART 2

A brief introduction to the project is contained at PART 1 here.

So what are the main challenges with bringing a set of empty speakers back to life?

Well, for many speakers it could be straightforward - spend some time on ebay, Google, Wilmslow Audio (I'm sure other good driver vendors are available too), find either the original drivers or something very close, buy them up and bolt them in.  Or find something with really rough cabinets and transfer all the bits into your better, but empty, cabinets.

So here's the challenge with the Linn Keilidhs, a speaker I believe to have been Linn's best selling speaker ever with around 25,000 units shipped.  Available for most of the 1990s with a few tweaks over the years, such as the addition of an optional wide footprint heavy polymer stand, 2 variations of mid/bass drivers (013/2 and 013/4) 3 variations on the tweeter (numbered 015/1, 015/2 and, wait for it, 015/3) and a move from a painted front baffle to a veneered version.  Possibly there was a 015/5 tweeter, but maybe not.

Some information here about the Keilidh history and specifications:

Owners' Manual

Lots Of Images

A Review

Some Data On Versions

Musings' Own Keilidhs (when being used active with Rotel power amps, since sold on)

Whilst the Keilidhs have 3 drive units (1x tweeter, 2x mid-bass) per speaker, they're actually a 2-way design.  The 2x mid-bass drivers are fed by the same information from the crossover and they share the same cavity inside the cabinets.  You can drive these speakers passively with a single amplifier, bi-amplify them passively or active or you can go for 3 amplifiers in active mode.  Passive means using the crossovers inside the speaker cabinets, active means using an external (much more accurate) crossover which then feeds a single to one power amp directly connected to the tweeter and one or two power amps connected to the mid-bass drivers.  In the 20 years I had the Keilidhs in my system, I went through all of these steps, finishing with them driven tri-actively with Rotel amps and later Linn amps (we'll skip over the 10 days or so going down the wrong turn labelled "Cyrus").

Today Keilidh's sell for 200 to 350 GBP depending on age, finish, condition, location etc.  They're great value for money and sound very good when equipped with Linn's later 038/2 tweeter from the Katan / Ninka era.  Early Keilidhs which still have the 015/1 to 015/3 tweeters sound a little uncultured in comparison, but still play a tune well.

Tweeters are shared with the contemporary Keltik, which was Linn's top of the range floor stander, later versions of the Kaber mid-range floorstander and the Tukan - a small standmount speaker.  So there are lots of opportunities for finding the tweeters, although they usually fetch a reasonable price.  But curiously, the mid-bass drivers rarely come up for sale, and a quite highly priced for something that might have already seen 20 years of use, and is a reasonably straightforward design.  The mid-bass is also an unusual diameter at 6.5" / 165-170mm in the home audio world, more frequently seen in the car audio world.

So here are the challenges:

- genuine mid-bass drivers quite rare and pricey
- genuine crossovers probably just as rare, if not more so
- choice of replacement mid-bass drivers is limited, and those that are from established speaker component sellers are priced reasonably, but 4 of those would quickly come to more than the price of a complete set of secondhand speakers
- mid-bass chassis diameter is unusual (thanks Linn!)
- tweeter faceplate diameter is unusual (thanks Linn!)

So, off to t'Interweb to research some options.




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