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Electronics on the Floor: Testing $1 LM386 audio amplifier modules
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- čas přidán 7. 08. 2024
- In this video I test and try to blow up a cheap LM386 audio amplifier module through overdriving. Do I succeed? Watch and find out!
Contents
0:00 Introduction
0:21 Testing with crystal set
0:31 Testing with Walkman
0:50 Testing with microphone
1:23 Testing with Walkman again
1:32 Turning up the gain & overdriving
2:20 Conclusion
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I bought some and they're awesome. Instantly amplify signals even make the smallest guitar amplifier that's plenty loud and can be driven into distortion.
when i was a boy, this was one of the 1st electronics projects i ever did! using the '386 audio amp
That could be a great audio amplifier for such a low price. Sure if one is going to construct his own circuit buying individual components, it could be way costly. Thanks for nice upload.
Hi... Thanks for the the video. As a newbie to electronics, I request you please let me know where to connect the DC power+ and -, and where to connect the audio inputs. Thanks for your help!
I had the same question
Yep it seems to work and for the price can't complain.
I have a boat load of them, I can get enough sound out of one in my homebrew superhet. I even built a common emitter amplifier to drive it, still barely hear stations.
i used pam8403 module with 0.5watt speaker audio quality is poor like in the video. i need clear audio quailty like song playing in mobile phone. can any one please help me ?
Thank you for testing this circuit. I will have to buy one to try on my amp circuit. I am sure with lower in put it should be much cleaner. The question is will I have to initial a load resistor on the out put of it circuit to keep the LM386 from blowing up. As my audio amp circuit requires around 30Mw to750Mw to drive it. The rating output 0.25Mw to 1 watts according to spec. Thank you.
I would. This 'amplifier' is driven right off the op amp. It isn't designed to drive loads like that. I use these modules to adjust the line level, and they work perfectly for that. However, they feed into a power amp which drives the speakers.
Seven years later and still available, for about the same price if you look. I opted for a more expensive version with better VCC filtering, a full size pot and some additional signal conditioning. And, it's still an LM386 🙄 handy but not HiFi.
What voltage was applied?
cn you show us how to plug it one by one
wow that thing is tough, you can add a heatsink on that for better robustness
Everywhere I've seen this board discussed, the pot is referred to as a volume control. I've looked at pictures and I can't trace the actual circuit from the photos.
So my question is: Is that potentiometer what it looks like... A simple input-level control? Or is it the op-amp's actual gain pot for controlling the feedback loop?
My current guess is: They mean what they say -- it's just volume. And to get actual gain control it wants another pot jumping the output back to the inverted input.
If you know for sure, please do tell!
It's just across the input.
Plz provide complete connection with Bluetooth MP3 decoder receiver!
That's a nice earrape amplifier
How did you wire the pins, I've ordered one to use as a microphone amp... Many thanks..
The pins are labelled on the board. There's basically audio input, supply, ground plus the two screw connectors (one of them ground) for the speaker/audio output.
Cool, I didn't know that.. I did find a wiring diagram off the net, need to workout how to wire it up within the handheld microphone using that circuit with the amp board...
I am thinking of adding this amplifier within the Pixie kit to boost the volume/gain for CW without having to use an external speaker. Have you thought of or used it in this manner?
Haven't used it that way but should work.
@@vk3ye Thank you sir. I will let you know 73 KI5IUF
Thank you.
can you send the connections picture?
I have used this for reamping the output of passive preamps, and they work perferctly fine. Don't use the pot as a volume knob, but as a limiter. Turn it up to distortion, then back it off a quarter turn. I wouldn't recommend these for amping speakers, but they work amazing for adjusting the line level.
Thankyou, this is why I wanted one.
Hello, the review was good. But one thing I can't understand that can I use it as a 1st stage guitar amp?
I'd imagine it should work - though normally first stages in amps are opamps or discrete transistors.
vk3ye
Hi, thanks for your reply.
I couldn't find this module in my local market. So I bought a amp module which has PAM8304 chip in it.
My plan is, I'll use my acoustic guitar (has a piezo pickup) as input in the module I bought then I'll use the modules output in my 2:1 microlab speaker as input. Should I do that?
It will be really helpful if you answer my question, thank you.
This is nothing but an opamp anyway. I wouldn't call it a complete 'amplifier'. It will work fine as a preamp though, but I would not drive speakers right off the op amp, like what is going on here.
The 386 is technically a power amp,not an op amp.
Is it posable to use one as a mic amp on a UHF data transmitter module
Possibly.
vk3ye my idea is to try one as a voice beacon, see how far I can hear it
Basically want build a voice beacon out of eBay parts, UHF transmitter module, some kind of mic/audio amp and a 10sec digital voice recorder
Nice distortion sound for guitar amp
Im thinking Am series modulators here Peter,pin 5 is approx half what ever main VCC is,so 12VCC is 6V on pin 5 audio o/p
Before the decoupling cap on pin 5,these have enough power and drive the collector on a RF PA like a QRP rig for Am modulation.
You may need to add a RFC inline to collector on RF PA circuit,but it should give nice clean AM as a series modulator.
As you tested it on a microphone it could make a good AM modulator at $1 a shot.
I have tried it this on much higher power Audio chips and it works great as AM modulator and good thing is if on batteries the VCC tracks with pin 5 DC output so 9V=4.5V half VCC which is perfect as a use for series AM modulator.
Great Vid Peter as usual 73's
Rob
Definitely works. Used it on this little 160m rig. czcams.com/video/8L16-AUVPW8/video.html
THanks Peter 73's Rob
How do u connect the mic in this circuit show the making of this
Depends on the microphone. A dynamic microphone can be connected directly (maybe via a 1 to 10 uF capacitor). An electret microphone also requires a DC bias voltage delivered via a resistor of about 10k. Search circuits on the web for ideas.
@@vk3ye if i want to connect a condenser mic how do i connect?
Hi what is its output wattage
Don't know. Maybe a few hundred mW.
So you can use a microphone as the audio input?
Depends on its output level and whether the impedance matches. Many microphones would require a 1 transistor preamp.
@@vk3ye Thanks for the reply. I'll wait for mine to come in and test the mics I have. So a 1 transistor preamp. I'll try to look for more information on that.
it's not designed to drive 4 ohm speakers
32 ohm is the lowest I would attempt to drive off of this... it's just an op amp... LM386's will cook themselves, in spite of their meager thermal protection.
then what designed is sutitable to drive 4 ohm speakers
Yes it is designed to drive 4 ohm speakers. It says so right in TI's datasheet for the LM386:
www.ti.com/lit/ds/symlink/lm386.pdf
@@rich1051414 i use the DIP version of LM386N-4 it will drive 8 Ohm speakers for YEARS I've had a circuit with it that uses a radio shack mic into a TL081 Preamp then driving the 8 Ohm speaker in my House, the mic and circuit is in a box on my privacy fence gate at my driveway. I then have a reverse of the same circuit with the mic in the house and speaker at the box at the gate with a push button that connects to a relay that interrupts the indoor speaker so that I use these two circuits as an intercom.
I first put the circuit in in 2007 and its been operating continuously for many many years with the LM386 baking outside in the heat and freezing in the winters, with lots of loud wind, rain, and loud vehicles driving by.
It still works and like I said since 2007 its now 2022 that's 15 years worth of service!!! Nice little chip!
When I buy this this will be look like this from sh op
Asu
ASU TOO!
I bought this module but it is not nearly as good as it is said in this video. I got better results with two transistors and this IC has about 9 transistors.. At 200 gain it is barely audible. I connected it to a radio Super-regenerative FM, with a single transistor.. If I can directly connect the headphones, which do not have more than 12 ohms and I can hear the radio, with this module I should have room filling volume, but it is barely audible... And it is very noisy .Maybe it's my bad quality module... I'm extremely disappointed with these modules..