It's been done. Not to 100W, but...
http://www.diyaudio.com/forums/chip-amps/174540-doug-selfs-ne5532-power-amp-thoughts-anyone-7.html
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http://www.diyaudio.com/forums/chip-amps/174540-doug-selfs-ne5532-power-amp-thoughts-anyone-7.html
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There are a couple of other threads on the subject but I haven't been able to find them using the search facility. I don't recall anyone actually having heard one, but the measurements were extremely clean.
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The highest common/cheap opamp voltage supply is 42V (=+-21Vdc).
This will allow maximum output voltage of ~ 18Vpk into a load.
Now parallel sufficient opamps to deliver the peak current that a speaker could demand from 18Vpk transients.
8ohms could be ~220 30mA opamps giving an effective output power of ~ 20W into 8r0.
Speakers seem to be a non starter. Medium or high impedance headphones would be a more suitable load.
Oh, before you ask you could bridge your opamp amplifiers for ~80W into 8r0 but this would require ~ 900 opamps each capable of delivering undistorted 30mApk (not the short circuit limit)
This will allow maximum output voltage of ~ 18Vpk into a load.
Now parallel sufficient opamps to deliver the peak current that a speaker could demand from 18Vpk transients.
8ohms could be ~220 30mA opamps giving an effective output power of ~ 20W into 8r0.
Speakers seem to be a non starter. Medium or high impedance headphones would be a more suitable load.
Oh, before you ask you could bridge your opamp amplifiers for ~80W into 8r0 but this would require ~ 900 opamps each capable of delivering undistorted 30mApk (not the short circuit limit)
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As advantage i realy can't think of anything... At least keeping in mind the amount of op-amps you would need.
load sharing will more than probably not going to be equal so you can run into -more or less- n-1 problems, where n is the number of opamps You need to use.
Maybe if You need to, You might find a decent opamp that has enough current capacity and output voltage to paralell a quad opamp for a headphone.
or drive a piezzo tweeter (whatever is benefical in that, but who em i to know.. realy)
Actualy if You ask me, for those power levels it may not be usefull at all.
You might be better of just adding output transistors on some high supply/output voltage opamp. Not a clever solution but who knows, might actualy work out well.
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