Amplifier build in LTspice

Mooly sir how to calculate amp output watt in ltspice?

You can do it as @steveu suggests 🙂

I normally set the output to just below clipping and holding CTRL I left click the output trace expression to see the RMS voltage and just quickly calculate it manually.

So 7.5 volts rms and an 8 ohm load is 7 watts.

You can also calculate the theoretical max output you are aiming for using the supply rails while accounting for some voltage loss due to losses across output and driver transistors. For example and amplifier running on -/+38 volt rails might reasonably be expected to deliver lets say -/+32 volts into an 8 ohm load and that is around 64 watts rms into an 8 ohm load.

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What you suggest is possible with a fully complementary output NPN+PNP
I managed to get a result with complementary devices - this was just curiosity and to get LTspice onto my laptop and see if I could make it do anything 🙂
I don't know if it would sound any good and it needs a bit more voltage swing, but I like the local feedback - get the drivers in line with the local(ish) feedback then a couple of followers push and pull the speaker 🙂
Probably a better VAS stage and darlington followers might do, but at least it does something !

I see the drawback of the quasi approach, the top transistor seems to be a follower but the bottom one is current amplifier, so there's something slightly unholy about it LOL.

Thanks to the OP for the thread start, apologies for polluting it a bit, It's years since I had SPICE on the laptop so this is useful - cheers all!
 

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Easyamp ?? Actually - 32ppm with 35V rails/20Khz full power. An easy "Badger".
Same as most above amps , but really performs. Has proper decoupling , proven Vbe (thermal).
Use BCxxx / 2Nxxxx / anything will work @35V. Runs at 50V with proper devices.

OS
 

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