I have built an amplifier based on the LM3886 reference design http://www.national.com/ds/LM/LM3886.pdf The amplifier requires a +v and a -v supply between 20v and 84v (35 seems good). I want to convert this amplifier to run from 12v dc car power. The only thing I've found so far is the LM2587-ADJ reference designs. I don't see a 68w-135w amplifier being able to operate at about 1 amp, which if I understand correctly is the theoretical limit that the LM2587 can output given my input voltage and output voltage. So, I need to build a power supply that can supply enough wattage to operate the amp. I understand I can use a switch-mode power supply for this? Are there any other ways? I would prefer a cheaper, compact or simpler solution. So far I've found this write-up about pretty much exactly what I need: http://sound.westhost.com/project89.htm If no other options exist than the smp, I need to learn as much about them as possible before I try to build one. My understanding is that the 12v input is put into a square wave generator to convert the 12v dc to ac? The AC is then stepped up through a center-tap transformer to the required voltages, rectified and filtered. What I don't understand is the purpose of the transistors and the gates and how that whole mess functions. Also, the schematic I found is a bit odd to me referring to the multiple +12v tabs...usually that is due to my lack of understanding of proper schematics... I am wanting to put the amplifier right next to the speaker in the door of the car because I don't want an amp in the trunk and run long wires through the car to pickup noise. Also, a single channel amp is just as expensive as a dual or some quad channel car amps, and they are bulky and have way more power than I need to drive the speakers (~50watt RMS, 180w max) and the head unit can't drive them at a sufficient volume, and I build circuits as a stress-reducing hobby (I'm an ME). Worst case is a dual channel amp under the dash, but that is a last resort. I also want to take the lesson learned to built a 12v to 19.5v 2.4a laptop car supply in the future. Any help is appreciated, suggestions welcome.