I came across this at the audioreview.com site under KLF-20:
**** "A quick look at it shows that the parts are ALL VERY LOW GRADE ! Which means that there is a lot of room for improvement.
So if you can solder, here is a quick-and-dirty recipe (please, if you don't know, don't take the risk, and don't blame me):
- replace the yellow caps in the middle (2 are 2.86 uF 200V 15% in series, 1 is 1.25 uF 250V 15%) with high grade polyprop like Audyn Caps, Hovland Musicaps or Auricaps.
- replace the long ferrite self (1.75 mH) with a very large self of the same value from Jantzen audio for ex. (1.7 mH www.jantzen.com), and the smaller self of 0.175mH with a larger one of a close value (0.17 mH).
Replace the resistors from T+ (tweeter) by two Philips PR 02 or PR 03 of the same value.
Replace the caps in the black box by Elna Silmic II (same or smaller tolerance) for example. " ******
Does a cross-over upgrade exist and would it make much of a difference?