I love the clean channel of the KH but the Lead channel is horrible imo but I think something like the Komet Concorde preamp could be an improvement.
Let's take a look at the schematics:

The tone stack of the KH is behind the last gainstage, so it has to be replaced.
Is there any chance to leave the TS where it is without changing the sound drastically?
Here's my schematic that I would follow if the tone stack has to be moved.
Is there to much gain going on, if I bypass the cathode R with a diode?

Thanks