Are there any drawbacks to having a tightly regulated PSU for a car audio power amplifier ?
I want to build my own audio power amp powered from a 12V car battery, boosted with a switched-mode power supply. I've designed and built several power amps as well as a few SMPS'es in the past, but most of the amps were mains-powered with unregulated supplies and the SMPS'es were for other applications. Is there any advantage to using an open-loop DC-DC converter ?
Thanks in advance.
Mostly just extra cost and weight.
In my head an audio amp is a voltage-controlled power supply anyway. Preregulation is not particularly necessary.
Preregulation can hurt if it limits peak current output under max signal levels or odd nonlinear loads.
Preregulation can help efficiency in some circumstances if you lower the rails to the real amp when signal levels are low and thus lower power dissipation (but there's a gotcha when the content fools you and you aren't ready for a big peak level). This was hot stuff in the 80's and early 90's with all sorts of new "classes" invented but I'm not sure anyone really cares much anymore outside of battery-powered portable stuff where battery life is paramount.
Tim.
I would say preregulation has less cost and weight. The linear output stages will run much better with lower rails.
greg
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