Hi,
"Boat Audio" and "Robot forum"... How off-topic can we get?
I'd recommend taking audio related questions to a site like DIY Audio or similar, where all members have a keen interest in the subject (most of them wouldn't know the first thing about 'bot's though).
I am working on an audio amplifier for a rowing shell. I will need to power more than three 8 ohm speakers in parallel. The main factors that will determain what chip and design I will use are
1. Battery Life.
2. At least 15 W output
3. long part life
4. audio quality
This tells me that you...
A) Don't row for the peace and quiet on the sea
B) Either have a substantial hearing loss, very inefficient speakers, or no clue about SPL.
C) Need to read up on amplifier classes.
D) Think that integrated circuits are build to fail(?)
I have researched Class D amps for a couple of days. They offer high efficiency when compared to classical amplifiers. My question is has anyone had experience with a certain chip that fit the criteria above?
Not with chipped Class-D amplifiers, only discrete designs, but unless you have "Golden Ears", which the above doesn't point towards, I'd assume them to sound fairly equal withing a certain range of output powers.
Good amplifiers do sound equal - all the rubbish about eg warm or colored sound are just nitwits way of describing distortion of the original signal. A really good amplifier pass the signal without adding or subtracting anything (sadly they are few and far apart).
Class-D amps will have the best efficiency.
Class-C have the same efficiency, but is only used for stuff like power stages in radio transmitters, robots and such like, as it would sound ghastly (you could see Class-C as "half" a Class-D).
Class-B is still the most used "class", but it has the inherent cross-over distortion problem that needs carefull design.
Class-A, the cleanest sound, but with a constant high power drain, whether the input is going full blast or silent.
Your options are thus Class-B or Class-D. While I have no experience with the integrated ones (a quick search turned up a 1W chip and a 3.2W chip). They seems easy enough to use, if you can find one that accepts an impedance of 2.7 Ohm and gives you the output power you think you need.
The lifetime of an IC is mainly determined by the design it's used for, temperature extremes and physical vibration. With a sensible design and a little care, it may out-live you (electrolytic capacitors on the other hand...)
Class-D amplifiers will have the same power drain for the same power output - their own drain is negligible compared to the output.
A well designed loudspeaker box with sensitive units don't need much power for an adequate SPL - You can get very unpleasant sound levels from a 5W amp with the right box. And sticking to a lower output power equals a longer battery life.
Personally, I really enjoy the silence, on the rare occasions I get
