Pa150

[Nate805]

So... I have been doing some thinking, and looking throughout this site and National Semiconductor's lm3886 & the coresponding application notes, and I want to build either a pa150, pa100, or bpa200. Basically I'm strapped for cash, and I want to build a stereo amp with power ranging from 100-200watts into a 4ohm load. I'm not really clear on the limitations of the chips and the way output impedances are changed in either bridged or paralell contexts. The main factor that has me trying to cut costs is the toroidal PSU. I'm wondering if any of these National designs can feasably be built with a single toriod in the 100$ range. Avel has a few, but i think the voltages are too high (i need like 800VA for like 200watts right?). Well lots of questions for u pros . Also from reading the application notes i'm wondering if i can build a PA150 w/o all the servo op-amp ciructry (keeping it simple) by just using trimmer resistors and closely matched resistors to keep the gain between the amps equal. Lastly, can a simple no extra servo crap or anything pa150 (3xlm3886) drive a 4 ohm load with around 150w power???? Thanks so much everyone. Sure is a great site you guys have made

 

[AndrewT]

If you're strapped for cash, then build to suit your budget.
Try a 60W into 4ohm chipamp and keep it simple. It will play pretty well if all the filters and PSU components are chosen correctly.
BTW,
the case and hardware will probably take 40% of your budget, the transformer and PSU will absorb about 30% and the "amplifier" another 30%.
A big beefy amp will increase the cost of all these components for little benefit.