Do not attempt modifications unless you have been trained to work safely with high voltages. The amplifiers described here work with AC line voltages and with DC voltages approaching 500 volts - either of which is lethal!
Even if you do not get shocked yourself, an improperly modified amplifier can cause a fire that burns down your home.
You should also be aware that modifications to any amplifier will likely void your manufacturer's warranty.
This information is intended only for those who are qualified to do the work safely. For the rest of you, find a qualified person to do this work for you. The best amp in the world isn't worth killing yourself over!
Use at your own risk!