Howdy from the deep south.
Just a thought - what about a solid state like the Audio-gd NFB 15.32 (I have it's former iteration - the NFB-12).
I've owned the K701, Q701 and currently own the K702. All of the AKG's need current - not voltage. So the ideal amp for them is either a tube hybrid or straight solid state (ideally with less than 7 ohms on the headphone out, and a good current output).
I also own a LD MKIV OTL - and much prefer the K702 out of my NFB-12 than the LD. Switching to an OTL (IMO) is just adding extra voltage that you can't utilise, and also adding a bad impedance mismatch as well.
The NFB-12 and NFB-15 are both based on dual Wolfson WM8741s for the DAC stage - and to me are very full bodied (good bottom end and great fullness) - ideally suited to the AKGs.
Otherwise - consider switching to a different headphone - I'd suggest the HD600 for a start.