So from eBay I got a pair of Kef Corelli (type SP1051) speakers for the grand sum of £12.50. It was sold as spares or repair with one of the tweeters being mentioned as suspect.

I started a chat with Geoff (walpurgis) over on the ebay bargains thread which basically starts here. Geoff essentially gave me some tips on testing the drivers (e.g. coil resistance to roughly 5/6 ohms etc).

Since those posts I have plugged the speakers into my system and to my surprise it sounds wonderful. Nice and open with lots of detail and, as expected, quite laid back with warmth. Very 70s sound.

However, there is quite a lot of distortion on one of the tweeters. Initially it was fine but then playing different music it became very evident. Playing one of my reference albums (Fiesta) which without fail always shows up the strengths and weaknesses of systems (esp. speakers) the Kef tweeter failed miserably. Amp being used here is a 60w EL34 PP.

When I lightly touch the suspect tweeter dome the distortion largely goes away - but of course the upper range dies as well.

The seller mentioned that about two years ago he replaced the tweeters with standard T27 Kef units and that worked for about a year then developed same fault. So he suspects it is the crossover.

I have not done any testing or swapping over yet. But I thought I would open up this thread to see if anyone has any ideas as to what may be going on.

I'll try grab some time tomorrow to open up the speakers, see what is there and perhaps swap the tweeters over.

I got these speakers as a fun project only. Perhaps will recap the crossovers. I need some desoldering and soldering practice after all. I've already found a schematic for the xover - I guess I will have to first learn to understand what a schematic is.