Undervolting correctly my keyboard

[dok]

Hi,
I own a Yamaha PS3. I noticed accidentally that its sound was great when running on old batteries : a delicious distortion appears ! Thus, I was thinking about adding an undervolting option on the keyboard, with a potentiometer.
What would be the best solution ? A voltage divider right after the voltage input ? If so, what values for the resistor and potentiometer ?
Any thoughts welcome !


edit : okay, the search with "undervolting" did not give anything but there was this subject on first page : http://www.circuitbenders.co.uk/forum/index.php/topic,1269.0.html

edit2 : really sorry guys, there is allready some infos on the site :http://www.circuitbenders.co.uk/tips2.html] [url]http://www.circuitbenders.co.uk/tips2.html[/url]

[Tyler1144]

I wonder what would happen if rather than resisting power, what if you just built a 555 pulse modulation circuit? constantly starving it of 50% of its power 100 times a second might make some cool effects too