It is possible - I'd need you to remove the bottom cover & send me some clear photographs of the interior in order to judge that... The issues I found were (1) the variable feedback circuit has some errors in it (2) there is insufficient power supply storage on the input and driver stages (3) the driver stage is poorly balanced phase-to-phase.
TAD1000 Modifications - interested?
I recently bought a pair of these based on the great reviews I found on the internet & found them to sound quite old fashioned (wooly bass and rolled off treble). After my initial disappointment I looked at the circuit and made some changes. They are now sounding really great - in fact they sound like different amps. If anyone is interested, I will provide details of the changes. There are some design defects that are quite easily corrected.