questions on Class B audio amplifier

Oct 21, 2008 31 Replies

Sure, there's only one way to build an amp, has been for 30 or 40 years, and nobody should dare do anything different.

John

Pure class B will have some crossover distortion, because the opamps can't slew through the deadband infinitely fast.

Replacing the right-most 0.22 uF cap with a resistor *can* kill the crossover distortion.

Yes.

Yes, but uses a lot more parts. Some people like that.

John

For starters, the pot can be set to infinite gain, making the amp output go to the rail and take out the speaker due to amp offsets. There is no current limiting, hence will blow up pretty much as soon as wiring it up to a speaker is attempted.

The schematic is truly a non starter.

Kevin Aylward

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Shirley you mean knowledge challenged?

Kevin Aylward

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Now, see, that\'s what _Graham_ should have said. JF

Seems like you could get rid of the 1st amp... it just buffers the 10k pot. You could make the 2nd amp non inverting and feed the input pot wiper into the + input.

Would you two please take your personal piss-fest elsewhere? This is sci.electronics.basics, where there is no such thing as a dumb quetion; all newbies are welcome here. Remember, we were all beginners once.

Thanks, Rich

Well, stupid is as stupid does. ;-)

Cheers! Rich

Gain problem could be fixed with two Sziklai pairs of transistors, right?

Michael

For those who want to impress with More Parts... this Class D chip amp is for you... page 12 :

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Michael

"Kevin Aylward"

** Err - not true.

The output current is limited by the Hfe of the TIP41/42s to about 700 - 800 mA peak, since the TL082 has internal limiting at about +/-15mA.

** Not true at all.

..... Phil

Ok... the gain aint infinite...whatever....

Kevin Aylward

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- SuperSpice

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