High Power Chip Amp

[Eva]

I have not read the entire thread, but if you are discussing how to get chip-amp "simplicity" at higher powers (more than +/-40V rails and +/-10A output), class D is the way to go.

What star882 is trying to explain is that with two TO-220 output MOSFET, a driver IC, a comparator IC, the LC output filter and some more parts you can get close to 1KW at 4 ohm (+/-90V rails). No bulky heatsinks, no heavy power supplies (class AB wastes more power than what it delivers to the speakers), no dozens of expensive output devices and the chore of mounting them.

Incidentally, all my amplifiers are either chip amps or class D. I don't keep any of my class AB discrete prototypes, they use too many parts for what they achieve.

[Eva]

Originally Posted by AndrewT

which chipamp are you recommending that has these MOSFETs or IGBTs integrated into them?

Above 100V and 10A you can't expect the output devices t come in the same package as the small signal stuff, the fabrication processes are quite different. Also, PCB layout and thermal considerations and package parasitics prevent everything to be in the same chip.

For example take a look at IRS2092:
http://www.irf.com/product-info/data...ta/irs2092.pdf

It contains a simple class D modulator, rudimentary current limiting and gate drivers, it only requires an output stage and a LC filter. It can be considered a high power class D chip amp.

[danielwritesbac]

Originally Posted by Eva

. . . class AB wastes more power than what it delivers to the speakers. . .

That happens at three configurations.
1), like the gainclone, large caps locally, is a bit like driving the car in one gear too low. For the amp, its a way to level the frequency response--technically an inappropriate method, but it does work. There are other ways to change the speed: HDOA - High Dynamics Op Amp
2), the "fireball" amp (not a gainclone type) operates as a dynamics expander for a more-live presentation--Class D will emit a great deal of green smoke instead (unless the voltage is decreased).
3), over-reliance on noise filtering at the amplifier board instead of using noise filtering at the power supply--the great tolerances of Class AB are often exploited to decrease power circuit expense at the cost of efficiency, wheras, the smaller tolerances of Class D usually force one to do a good job on the power circuit design.

I really do like the sound of Class D. The chopped signal reminds me of Blackgate or the classic Red Cerafine+Polyester combo. This can make a lovely clarity. Unfortunately, the supersonic pilot tone of Class D is audible to me. After many hours of exposure, I get stuffy ears and it takes about 3 days to recover. One day, I'll explore using Class D in an active 3-way system for bass and midrange.

Its possible for the efficiency of Class AB to match Class D at scales up to 70 watts (run the same little TO220 size heatsink nearly cold), but I don't have personal experience with comparisons beyond that point, so I couldn't tell you about efficiencies on a larger scale amplifier.

[Eva]

I design class D amplifiers for a living, now I'm working in a commercial product with nearly 400 parts in it, smaller than a shoe box and capable of over 4kw on 2 ohms, and I admit that I fail completely to understand what you are talking about.

So sorry for disturbing if you were talking about metaphysics, I thought it was about electronics and acoustics (science)

[danielwritesbac]

Originally Posted by Eva

I design class D amplifiers for a living, now I'm working in a commercial product with nearly 400 parts in it, smaller than a shoe box and capable of over 4kw on 2 ohms, and I admit that I fail completely to understand what you are talking about.

So sorry for disturbing if you were talking about metaphysics, I thought it was about electronics and acoustics (science)

Do you also include audiology? If so, that would be impressively efficient.

[authlxl]

Originally Posted by Mark Allen

Is there a design here for a high power Chip Amp? Say three or four chips in parallel. The single chip amps just doesn't quite cut it for me or my Dynaudios... I have seen several from Asia on E-Bay but am extremely hesitant to order from China because of all the rights infringement going on over there.

Thanks for any suggestions,

Mark

Look here
Class D Audio, Who are these guys?