Harbeth's are typically a warm sounding speaker ( nothing wrong with that, IMHO). Koetsu's are also a warm sounding cartridge. The Kleos is more resolving- and if set up correctly, more neutral than any Koetsu that I have heard.
I would think that for most the Koetsu/Harbeth match would be too warm and not resolved enough.
I would think that for most the Koetsu/Harbeth match would be too warm and not resolved enough.