Question about Linn Upgrade route

Love my LK140 even strapped onto the lowly but lovely classik the system seems to have more breath and control. So I wonder what should be my next moves. Do I change the source or the pre. What is Activ? and looking at a couple of threads in the speaker sections would the Katans be a good match? This is to addictive, does it ever stop. Im smiling everytime I listen to a track now, how does it get better is it subtle changes or will evrything be a huge difference?

If you've got external amplification, the Katans would make an excellent match. They're good passive, but a whole other level when active. Active means using a separate amplifier channel for each driver (mid-bass & tweeter), with the cross-over before the amplification, instead of inside the speaker, after the amplification. This means that not only is each speaker driver getting an uncompromised channel of amplification to itself, but there is no cross-over circuitry filtering the amplified signal, so the result is a much cleaner, clearer, more dynamic sound.

I used active Katans for a while, from a Classik Movie Di, powered by an AV5125 amplifier - 2 channels for each speaker and one for the sub. You need to put active cross-over cards into the amp, one stereo treble card and one stereo bass card, so a Linn 4+ channel amp is recommended. You can pick up Katans and AV5125s relatively cheap second hand or ex-dem. You also need to reconfigure the Katans to disable the internal cross-over. This is just a matter of moving a couple of link plates on the rear terminals - a simple and clever solution.

Going active from a passive Katan configuration is a real eye-opener, so if the budget is tight, starting with passive Katans provides a very good upgrade path.

Im guessing then that you can only go Activ on a speaker if its a speaker that has been built to allow Activ (ie Linns own only)

Yes, the speaker must be designed so that you can disable its internal crossover and it must provide terminals to connect each driver independently. Most high-end speakers allow this, not just Linn. You can get some speakers (often studio monitors) that have active amplification built-in - such as the AVI ADM9's.