James Perrett wrote:
ef37a wrote:Given how complex a good class D amplifier needs to be and that it needs to be partnered with a nearly as complex regulated* and protected PSU it is a wonder to me that they are a popular as they are?
They use lots of cheap parts instead of a few expensive parts.
A proper professional amplifier will have a mains input rating that is higher than its output rating. As an example: the Quad 405 which is rated for 200W total output has a specified mains input power of 30-350W depending on signal level.
Well yes James, a bit but the most expensive part of any amplifier (apart from maybe the casing) is the mains transformer which you would not fit in a class D amp as you don't want a 50/60 Hz supply.
In any case in a "500W" D power amp I doubt the high speed,high power output MOSFETs are cheap? Class D has made great inroads in even top end monitors.
I'll say again, I reckon the 80W is just for 'legal' reasons. Also, although I have THE GREATEST respect for Acoustical's products, didn't the 405 have a problem in a review with meeting the 'pre heating' temperature rise test? That would to me dismiss it as a "professional" amplifier since such a device should be able to run at full power indefinitely. I don't say the Quad would fail, like "POOF!" but I think it would shut down.