Power efficiency is a good reason to use class-D amps instead of class A-B amps. Class-D amps dissipates much less heat than class A-B amps, and are returning power to the supply; this power can be stored temporarely in big filtering capacitors (in parallel with the supply output); if big enough, these capacitors can supply a lot of extra power for strong transient signals, reducing the requirement for a large power supply.
Reference: http://www.powerguru.org/class-d-audio-amplifier-matches-class-ab-with-higher-efficiency/ Look at the graphs at the end of the article; at low power, A-B amps are extremely inneficient; this is not a problem on systems with constant power supplies (like at home or in a running car). Class-D can generate RF noise from the cables and speakers, but it's not a big concern with small systems. So, for a "small, portable, low to medium power" system, I would use class-D amps with a switching power supply (or a car battery), and extra filtering capacitors. -- Marc On Sun, 1 Nov 2015 11:13:34 +0000 Dave Malham <dave.mal...@york.ac.uk> wrote: > To say nothing of peak currents of over 33 amps from the 12v supply > if you run at a full 8 x 50 watts - you are going to need some serious > cabling! > > Dave > > On 01/11/2015, David Pickett <d...@fugato.com> wrote: > > At 13:48 31-10-15, umashankar manthravadi wrote: > > >i should check the specs for the ic.it is a single chip and the > > >board looks well made - it says 50 watts per channel, but i would > > >be happy with about 18watts into 4 ohms per channel. (it should > > >be capable of that much - these are bridge outputs. > > > > http://pdf1.alldatasheet.com/datasheet-pdf/view/233388/STMICROELECTRONICS/TDA7850H.html > > > > Says 50W at 10% THD, 20W at 1% THD... > > > > I suppose there IS no such thing as a free lunch! > > > > David > > > > _______________________________________________ > > Sursound mailing list > > Sursound@music.vt.edu > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe > > here, edit account or options, view archives and so on. > > > > -- Marc "Il y a moins de cerveaux lumineux que de crânes éblouis" (Albert Brie) _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, edit account or options, view archives and so on.
