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Is there an alternative?
Well, the circuit works like a charm now that I've got the bootstrap cap properly wired to the output junction. I've been fiddling with it all morning with various guitars and mics (by re-amping) and the performance is stellar. The bossman came by and proclaimed the circuit fidelity is 'almost too high' for his project.
Thanks a million for the help guys, I'll post my final results when the mail comes in.
I gave up using solderless breadboard years ago when the many rows of contacts and wires all over the place picked up interference or caused oscillation and the intermittent contacts caused many problems.
I use stripboard instead. The copper strips are cut to length with a drill bit so that a strip can have a few parts of a circuit making the circuit board compact then the strips and a few jumper wires form half of a pcb and the parts form the other half. Everything is soldered. Here is a sound level indicator project I designed and made on stripboard:
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Hey again, so I've designed just about all the circuits discussed in this thread and I've landed on this guy:
First off, the audio this circuit produces is SO LOUD! It's crazy I love it. However I've a few questions as it works but, barely. It sounds like the input is gated and must reach about 200mV before the amp produces any audio. Second, the audio is very distorted... and gated...
As for '? 2', does this actually belong? When connected, the circuit just hums and the audio just barely squeaks through (distorted). When disconnected, the audio is heavily distorted but works (still gated though), albeit very distorted, it's very loud.
This is by far the loudest circuit I've played around with and will, for sure, be the circuit I want to build.
Heading into the shop now, going to rebuild it and check for mistakes. I'll check back soon.
EDIT: Here's the error in my simulation..
First off, the audio this circuit produces is SO LOUD! It's crazy I love it. However I've a few questions as it works but, barely. It sounds like the input is gated and must reach about 200mV before the amp produces any audio. Second, the audio is very distorted... and gated...
As for '? 2', does this actually belong? When connected, the circuit just hums and the audio just barely squeaks through (distorted). When disconnected, the audio is heavily distorted but works (still gated though), albeit very distorted, it's very loud.
This is by far the loudest circuit I've played around with and will, for sure, be the circuit I want to build.
Heading into the shop now, going to rebuild it and check for mistakes. I'll check back soon.
EDIT: Here's the error in my simulation..
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The amplifier sounds awful because you forgot what I said in my post #38: "R5 TURNS OFF Q3!". Only very loud inputs turn on Q3 a little on the peaks. If R5 is removed then you do not need the first transistor but without the bootstrap capacitor there will be severe distortion as I showed in my post #56.
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what duke said ... you SHOULDNT have +V going down to C1
I simulated it with the puny little low power 2N2222 and 2N2907 output transistors. The output level is less because the top of the output waveform is squashed causing distortion. I reduced the 160k to 100k for the bias resistor of Q3 and the bottom of the output waveform became clipped causing the output power low.
Here is yours without the short and mine:
Here is yours without the short and mine:
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I know I have heard of diode biasing, and its great if you want to control the system, but this is a raw power amp, the longer it loops....the higher the output.
so use a 9v...wow thats a lot of power man! so if you loop it say... 5 times... thats like 45v! so you want some monsters in there... nothing under 50v will do if you want lots of sound. now about that 8ohm speaker.... even a 7 watt system sounds better with 8ohm speakers, most are only 2ohms. but with 9v... well you get the picture.so take that 10% rule and don't mess with the output. Because.. you aren't system matching, your pumping out the jams. get fets!!! and think 2 phase..
My solution to building amps was to think like an egyptian... they built 4 sided pyramids(the true pyramid has 3 sides) Where you might connect an input with a small cap you really don't need it and at the output, the power must be enough to drive the speaker. not enough power and you won't have an amp you will have a compressor of sorts. The idea is... load a slow cap with a charge, and while its loading, load a transistor with the same charge. When the cap fires, it triggers the transisitor, and drives the combined charge(double the signal) onto the next phase, which loops the current with the help of some resistors.... when the resistors can't resist anymore, they drive the speaker. raw power use is very very shocking sometimes!
so use a 9v...wow thats a lot of power man! so if you loop it say... 5 times... thats like 45v! so you want some monsters in there... nothing under 50v will do if you want lots of sound. now about that 8ohm speaker.... even a 7 watt system sounds better with 8ohm speakers, most are only 2ohms. but with 9v... well you get the picture.so take that 10% rule and don't mess with the output. Because.. you aren't system matching, your pumping out the jams. get fets!!! and think 2 phase..
My solution to building amps was to think like an egyptian... they built 4 sided pyramids(the true pyramid has 3 sides) Where you might connect an input with a small cap you really don't need it and at the output, the power must be enough to drive the speaker. not enough power and you won't have an amp you will have a compressor of sorts. The idea is... load a slow cap with a charge, and while its loading, load a transistor with the same charge. When the cap fires, it triggers the transisitor, and drives the combined charge(double the signal) onto the next phase, which loops the current with the help of some resistors.... when the resistors can't resist anymore, they drive the speaker. raw power use is very very shocking sometimes!
Tedstruck, you do not make any electronics sense.
The battery in a car is only about 13.8V so they do not use 8 ohm speakers to get only 1.8W. They use 4 ohm speakers and bridged amplifiers. A bridged amplifier has one amplifier driving one wire of a speaker and another out-of-phase amplifier driving the other wire of the speaker so the voltage swing is almost doubled and the power output is about 14W. My car used bridged amplifiers driving 2 ohm speakers for 22W output. 5 amplifier/speakers produced a total of 110W. This is real low distortion continuous power, not Mickey Mouse very distorted momentary "Music power".
The battery in a car is only about 13.8V so they do not use 8 ohm speakers to get only 1.8W. They use 4 ohm speakers and bridged amplifiers. A bridged amplifier has one amplifier driving one wire of a speaker and another out-of-phase amplifier driving the other wire of the speaker so the voltage swing is almost doubled and the power output is about 14W. My car used bridged amplifiers driving 2 ohm speakers for 22W output. 5 amplifier/speakers produced a total of 110W. This is real low distortion continuous power, not Mickey Mouse very distorted momentary "Music power".
I've made 3 small guitar amps for personal use, ruby, little gem & noisy cricket, all use lm386.
From memory all 3 are freely available & ok to replicate for sale with caveat that originator be credited.
Didn't miss not. Curious about not. Existing solutions can be sold, was alerting OP to this.
you didn't give any alternative existing solutions
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