Tweeter replacement for WAD KLS3 MkII

[Richard]

Many thanks to Greg. for the following;

I am a long term user of KLS3 MkI, and continue to be very happy with the performance. Several years ago I built for my son, a pair of KLS3 MkII which used the Audax gold dome HD-3P tweeter. After a few years, which commonly happened, these tweeters failed with the dome surface crinkling and there being no output. My son passed his speakers back to me. The HD-3P is no longer available so I set about looking for a replacement.

In June 2008, Peter Comeau carried out a repair on a pair of KLS3 MkII owned by Guy Pettigrew who is a member here. Peter replaced the HD-3P's with a pair of Seas T25CF002 Millennium Tweeters. He also introduced some other modifications to the whole crossover network. I know the Millennium tweeter well and it certainly has a lovely clear and transparent sound. The downside is it is very expensive at over £190 each! With the other component changes Peter introduced, the overall repair cost would be around £500 which is a price too steep for me. Furthermore my speakers have bevelled baffle edges and with the Seas face plate being 10mm larger, there was insufficient baffle and cabinet space to incorporate them.

The KLS3 MkI uses the Audax TW025M1 tweeter which is a fine performer although admittedly not quite as refined as the Seas but nevertheless good and affordable at around £41. It is well matched to the other Audax drivers used in KLS3 so I asked my friend, Scott Lindgren of Woden Designs and Reiver Acoustic to redesign the MkII crossover to incorporate the TW025M1 as I think the later MkII crossover has a better balance than the MkI version. He came up with this.

Total cost of the tweeters and crossover components is under £120. I bought all the parts from Falcon Acoustics and carried out the conversion which was pretty straight forward. The tweeter is more or less a drop on replacement. The cabinet hole needs a little opening up to accommodate the tweeter terminals and the four mounting holes may need a little opening up as I found the original holes were slightly out of alignment. It was easy to remove the old treble filter section from the crossover board and replace with Scott's design. Note that tweeter terminal polarity is reversed from that used with HD-3P.

I found the new filter blended the tweeter in well with the midrange and conclude this conversion a success with the KLS3 now appearing to look like a MkI, but actually having the refinement (tighter bass control and more revealing midrange) of the better MkII crossover.

I hope this is useful for any KLS3 MkII owners needing to replace their gold dome tweeters.