[attachmentid=4204]
Heres the schematic,so you will know whats required.
Audio
-all three opamps take input from one source, from the mini jack input.
-three volume controls, each with amplifier capable of delivering enough power to headphones, or use as a pre-amp for speakers.
-optional bass-boost. for no bassboost, just short output to r4, hence the switch.
-use ic sockets, so user can change opamps, take note some opamps cannot run under 5v from usb.
Power Supply
- technically usb supplies 5v @ 500ma, more like 300ma in real life, still its enough to power the amp.
-three TLE2426CLP, one for each amp, basically its a separate buffered powersupply for each opamp.
-1000uf is quite enough, to save costs u can go down to about 470uf, the more capacitance the merrier.
-0.1uf decoupling capacitors, important to maintain stability of opamp.
Pre_amp.bmp
