I think you have something wired wrong, the circuit should be able to power an external speaker, so long as its impedance is suitable, ie no less than 4 ohms, however if you plugged a 1w amp into a big pa stack it might not do much, very long leads might also cause issues.
If you want more power then you'll probably need a different amp chip, maybe a tda2030 if you can still get them.
But you'll need something other than a pp3 battery as it couldnt power a larger amp, maybe some 18650's or a drill battery.
With a 6 Ohm speaker it would just be a little quieter but it would still work. I think you have the wiring to the loudspeaker socket wrong. When shown as a layout plan it isn't easy to see which pins on the socket are which. You should connect one side of the loudspeaker (black on the diagram) permanently to ground and only interrupt the red wire with the output socket. If you look closely at the socket as you insert a plug you will see the contacts bend back slightly, the ones that are in contact with the plug are the ones to go to the external loudspeaker and the red one to the internal speaker should be visibly disconnected as the contact to it opens.
Again, make sure you use a mono socket and a mono plug.
The small 9V battery will barely be able to supply enough to produce full output power, remember that to get power to the loudspeaker it has to come from somewhere so if you get 0.5W out you are drawing more than 0.5W in as some power is lost in the internal circuitry. I note you also have '100 Ohm' as the resistor value in series with the LED. This wastes quite a lot of battery power, about 70mA which is more than the LM386 consumes! I would increase its value to 1K ohms, it won't be quite as bright but it will make the battery last much longer and probably help to make the amp louder.
Brian.
Is the Full Fat stripboard circuit your new kit? It has some differences and errors:
1) Why does it have a 470 ohm rheostat in series with the speaker and speaker jack?
2) Why is there a switch and a 47nF capacitor connected from pin5 to pin7 of the 386 amplifier?
Please post its schematic because some of the parts block where they are connected.
Increase the power? Sure, replace the low power 386 amplifier with a more powerful one and maybe a higher voltage and higher current battery.
No. An opamp produces a very low output power and cannot drive a speaker. You need a power amp chip instead.I've been reading that, to get more power I should try different Op amp chips.
The PAM8403 amplifier IC already has the output of each channel "bridged" which is why it produces 3W per channel into 4 ohms when its supply is only 5V.3 Watts per channel Stereo (the board, not my finger). The only drawback is you can't operate it in bridge mode to get 9W but you can link the L and R inputs together and drive two separate loudspeakers at 3W each or just ground one input and ignore its output for a single 3W amplifier.
I wonder if the rheostat is there so you can overdrive the amp into distortion but keep the sound level down so's not to annoy next door.
I have a coupleof those pam switching amps, they are not so bad for what they are/cost, but I suggest you get a 10w or so amplifier if the little '386 isnt loud enough.
I spose the thing to do is find if the noise is something up with the speaker, or the amps just run out of power, a little '386 cant raise the roof.
If the amp is clipping theres not much you can do 'cept go for a bigger amp, you can tell clipping by playing a note without effects, crahnk up the volume at the onset of clipping other notes will appear, 3 octaves higher and above.
The lm384 makes 5w, its a bit like the '386 but has more pins, a pp3 9v battery will not power it though, you'd need a stack of AA's.
A speakerphone is designed to play voices when it is close and directly in front of you. Then its power in the speaker is only 0.1W for the loudest peaks.
So it has a cheap speaker that works poorly above 0.1W which is not much power.
Guess why a guitar speaker is not a cheap one from a phone?
The Ruby amplifier produces almost 0.5W into an 8 ohm speaker when the battery is brand new.
A speaker needs to be mounted in an enclosure designed for it to prevent bad sounds.
Have you tried using a computer desktop speaker? My computer speakers sound pretty good and play about 2W each. They are properly enclosed.
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