Make the PERFECT LM386 audio amplifier?
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- čas přidán 5. 07. 2024
- I use good design practice to make a decent performing LM386 amplifier. Schematic, layout, parts list and tips included in the video.
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Email: johnaudiotech@gmail.com
Thank You! - Věda a technologie
Never seen or heard a 386 perform this well. Always excited to see people getting the most from cheap and readily available components.
The LM386 is EOL'd by TI, perhaps will be by other manufacturers at some point, since class D chips are readily available for this power level.
@@MarkTillotson - and there are numerous benefits of Class D for low power amps. The LM386 is so old, there's not really any reason to use such a device now days.
@@johncoops6897 Could you be specific with what part number would be preferable to the LM386? I am guessing that many other chips might be out there now... any which could drive 4 Ohm speakers?
@@BruceNitroxpro - One of my favorites is the PAM8403, which can be purchased as a complete STEREO module for less than $1 on eBay, etc
Supply Voltage range / typical
* LM386N-3 supply 4V to 12V / typ. 9V
* PAM8403 supply 2.5V to 5.5V / typ. 5V
Output @ Volts, Ohms @ 10% THD / Typical THD
* LM386N-3 @ 9V 8 Ohm = 1 x 0.7W (max) / typ. 0.2% THD
* PAM8403 @ 5V 4 Ohm = 2x3.2W @10%, 2x2.5W @ 1% / typ 0.15%
So the PAM has heaps more power, uses a "easier" voltage (5V USB), can drive 4 Ohm loads, has lower distortion, massively higher efficiency (better battery life), is dual channel so far smaller PCB, and about the same price.
Agreed. Sounds pretty nice.
This is absolutely the best video I have even seen on using the LM386 the best way possible. Thanks very much for posting this !
I really appreciate how you explain what individual components do. I'm an absolute beginner and that really helps me.
Your channel deserve millions subscribers dude I'm impressed by your hard work for your viewers
This was my first amp I ever buillt back in the 1990's :)
Same here.
great video! I built one for a small 4" 8ohm dayton speakers (1 amp per speaker) and love it! I really appreciate you explaining the different cap options etc...and really appreciate you taking the time to do this...
That music sample was frickin' fantastic !!! WOW !!! I have to try this build. Great job and thanks so much for posting.
After struggling to get good sound out of my LM386 I found this video. Nicely done and thank you! I'm a subscriber now.
Thank you for the explanation behind this circuit! Alot of channels just say put this together and it works. Again thank you!
I remember building LM386 amplifiers as a kid on radioshack breadboards, I drove moms pair of Pioneer CS-203/CS-303 speakers with it. It actually sounded fairly well, and had a bit of bass. Man, brings back memories! Thanks for the nostalgia trip. Then I moved on to TDA2003 amps, (which is fun to use in a solderless breadboard), and LM380, etc... Eventually wound up making a super tiny little LM3886 amp which was very powerful.
have you ever connected this LM386 to the early "STEREO FM" (SONY or PHILLIPS)? Oh boy.. that was fun..I added 1000MFD capacitor connected pin 1 to pin 8. Even better. What a nostalgic trip indeed....
This is EXCELLENT !
I am currently using a 386 amp to add power to my 1.5v powered alarm (piezo) to turn on a 1.5v relay. Thank u for doing this.
Hi John, never seen the 386 perform so well!
Great build. I like the cap on the grounded input to get better symmetrical clipping - clever design.
Have watched your vids for some time and finally subscribed. Have time to experiment and play. Good vid and good explanation. Much appreciated. Thank you.
It sounds so good. Fantastic work.
I use these amps in my transceiver circuits. Nice video and I will incorporate your tips in my builds.
Beautiful. Thanks John.
Dude that's so nice I've never seen this performance of lm386 before
thanks for a great vid, you filled in a couple of missing pieces of the puzzle for me.
I think that is the best design. Never heard an LM386 amplifier like this.
I tried to make it many times but I never was able to make it sound clear like this.
Honestly impressive I've learned a lot watching this
Thanks! Works great as a mic pre-amp for condenser/electet mic to line level input. I added a 1kOhm resistor from 9V to mic-in to power the mic. My mics have 900-1000 Ohm static impedance. Needed the optional 10 uF capacitor between pins 1 and 8 for gain. I only used 220 uF capacitor at the output. On the breadboard, there was lots of noise pickup but on a compact circuit (one shown is good) it only picked up radio. Probably could use a low-pass filter on it (I was getting good response up to 160 kHz and very slow falloff from there). I found that encasing in a metal cage eliminated the interference so I'd done that and I use without a filter.
Breadboard done and sounds FANTASTIC !!! I wound up connecting the 47pF ceramic between pins 3 and 4. Now I'm going to build two circuits side-by-side for stereo. I'm sure it'll sound even better built (if that's possible). Volume is perfect for my use as is, no need for any volume control other than my source, the headphone jack on an old Sandisk Sansa I had laying in a drawer. I'm powering it with a couple of 18650's and it's only drawing around 35 mA with the music I'm playing, Joni Mitchell. This is my first amplifier, but now I'm hooked, and I'm sure it won't be my last. THANK YOU, John !!
Make a video of that sweet amp, i wanna see.
@@analogaudiorules1724 I just followed John's excellent instructions exactly.
Ive used the LM386 since the early 80's in mostly radio project but its also found itself in most every project Ive made that needed a small audio amp. Ive never given it much thought about making it run any better then the circuits in the data sheet. I would pull them out of old PC modems (US robotics) that where being scrapped years ago so I have quite a few in my parts bin. Like others stated Ive never heard one sound as good as your circuit.
I read & followed Radio Shack book..then connected to the early "STEREO FM" gadget. It was fun back then..
Nice explanation of the LM386, thanks
Thats the right way to Design a good running preamp, thank you for the Video! Your Video save my Time to Explain how to do it.These Old school Method is much more Precise than the CAD Way.Thank you, God bless you.
Now i Subscribe, because you are very clever.
Great tip for perf. board and 0.1'' graph paper.
I used to make headphone boosters with them. The only difference from your circuit was instead of a 470uf decoupling capacitor, I used 2,200uf for a better bass response. Also seemed to drive into 16 ohm loads better. Ran alright off a 9 volt battery with two lm386 chips
Nicely done!
The tda7052 is a great chip that's similar to the LM386 but it is more stable, doesn't require the decoupling capacitor, and puts out more power on less voltage.
1 amp to rule them all!
It worked perfectly, thank you!
It sounds really good!
John,
Thank You Very Much for your videos. I learn something new every time, and your discussion helps me a great deal on what to look for and things I should consider when I'm working with electronics. Wishing You and Snickers the very best.
Thanks for the kind comment!
You´re the best! I can´t believe you got that quality from that ¨thing¨
Thank you for your clear explanation of well designed release. Also for your teaching sharing of your study free of charge.
I will duplicate your circuit for my hobby s.w. radio.
Thanks for this video love it keep up the great information
the sound was incredible for a few dollars worth of parts - best I have heard from a 386.
Great video as always, just watched this again, having made a couple of your lm386 circuits. These are so instructive and clear, thank you.
Just one query...was that music by a band I used to listen to called Gryphon?
I just built this great little project! It's great! Now, I will be building a MP3 player.
Nice sound Lm386 👍🏻
Great video John!! A bridge with two devices would be an awesome follow up!
Bridging doubles the current each amp sees, so it isn't a good idea with the LM386.
@@JohnAudioTech could you please make an attempt to bridge this chip even though it doesn't make much sense like you explained, I think it would be interesting. Great video by the way !
@@BlackopTN Why don't you do it?
beautiful design and performance , speaker also counted for this
Thanks for taking the time to explain the capacitor on the negative input of the LM386. I've seen it done before, but as a relative noob to electronics, it wasn't really clear why.
To short out the noise due to the internal 50k resistor - both Johnson noise and flicker noise(*), and reflected current noise from the transistor base due to the 50k.
(*) integrated resistors are not metal film, not the best performing resistors.
3
About 3 years ago i build my own circuit like this,with lm386 Chip,all on my own so it played very well therr wasnt like a pot on for volume but i used a aux cable through phone so it played very nice,also the cap that i use give more bass
For the gain regulation, I find you can get the widest span in amplification factor with a 10k pot, so your overall resistance will be 909 ohms when the pot is in maximum resistance. This will give you roughly 25 to 200 times amplification, instead of the 50 - 200 that you'd get with a 1k pot.
Great video - Thanks! Can you also do a video (or some) about balanced audio input/output drivers?
Unbelievable. I never thought LM386 sounds so great !
Thanks very much for sharing your expertise. Everything you said made good sense to me. One area where I’d very much appreciate your comments regards the choice of capacitor types; specifically why the one ceramic cap and why the two mylar caps? Thanks!
How did you calculate the values of capacitor?
Thank you so much for posting this! I have tried several of these circuits and come away disappointed. This one is promising for a project I am working on. I really appreciate your explanations. I am assuming uF for each that don't specfically say p for pF. Is that right?
Have built loads of LM386 amplifiers, usually for 🎸 practice amps. I didn't know about dumping - input via capacitor rather than a short to ground, much better. For guitar use, I often use a one stage BC549C preamp to get a bit more welly and use high pass filtering as the sub harmonics from a standard guitar has a lot of bass. LM386 withstands abuse, well. I use a 12 volt supply into 3 ohms. It's been working like that for years but isn't a good idea. Helpful upload, thank you.
much better than my LM386. great !
may be i should redo mine.
Dont use the chinese diagrams to build it and you will have something worth using.
Hello John as you know there are 3 different versions of the 386 each with different max output levels, which version are you using here ?
wow! dude your a Pro for sure
Very nice video thanks!
Hey John, Question if I can; Where is the high frequency filtered by the 470 cap coming from? could it be filter best on the input, or in the power rail? I ask because i think that, if removed (instead of filtered on the output) it would yield a cooler and more efficient chip.
I've just built this amp on breadboard using your cap values, it sounds excellent, thanks! Stay away from Amazon and the cheap "lm386's" they have... they're fake. Sounded terrible when I was swapping them in and out. I used real Ti one's in the end.
Hi John - Thank you for this helpful video. I am puzzled by one thing. You added a .27 cap from the inverting input to ground to balance the circuit. However you then add the 47p cap from the non-inverting input to ground. Doesn’t this unbalance things? - Jim
thank you very much. I updated by Archer engineer's mini notebook ref 279-5011 by Forrest M. Mims the 3rd I bought at Radioshack last century.
CaptainDangeax I have that book. Still wanna wanna build that diode cascade multiplier that goes on for days
My first audio amplifier is using LA4440 12years ago.. Above half Volume and boom.. Too much noise and now i love TDA for low profile 2.1 Speaker setup
Could you do a similar video for the TBA820? I haven't had any good luck using them in builds.
I just thought of something, can we use a 12v power rail + 16-ohms transformer on the output with an 8/4-ohms secondary to connect the speaker can that boost the output power / sound ???
What an amazing explanation! But why did you connect bypass capacitor at dc 9v?
5:47 These damn LM386s made these days are real pains in the rear. The last circuit I made with them (Little Gem Mk II) required me to use a 10uf across Pins 1 & 8, and it had to be connected literally right at the pins or it would motorboat. When I used older chips (like 15 years old) I had no problem, but the newer ones are nothing but trouble.
Dave Smith - Could maybe be why
Adding the 10uf capacitor across pins 2 and 7 quietens the sound a bit, but playing the audio through a azotom stereo speaker the sound is pretty good thanks
The frequency sweep shows a hint of crossover distortion appearing above about 10kHz, a combination of inadequate bias on the output (to give low quiescent current) and starting to run out of open loop gain. As you mentioned, configuring these little amps for high gain makes performance worse in pretty much every respect and should be avoided for any application were reasonable audio quality is desired.
Always recomend supply decoupling capacitor approx 10uf near to the chip as possible.
brilliant video! How will this amplifier work on 150 ohm headphones?
I need to Make one it's pretty easy when you think about it not a complex circuit
Do you happen to have one of those cheap china tiny dc boost converters on hand? I wonder if there would be interference running it alongside using a 18650 as the power source as a portable amp.
Good n very detail...nice video
i used a 5v split supply and eliminated the output cap slightly adjusted the bias and got 3v into 8 ohms flat down to 10Hz
Thank you for the explanations, dear John, but I got a doubt: near 17:00min. you change something until the wave get round, not clipped. I'm too amateur to have an ocilloscope.And as I'm lookin for a good - not excessive but not poor - gain for a diy reusing of a pair of very small laptop speakers (but yet a 8ohm speakers), I'd like to know how to get a decent gain.
Are you using that 10uF capacitor between pins 1 and 8? If so, which resistance is used to get no distortion?
I'd like you to excuse me if you said that in the video but I'm not too fluent listener in English. Well... actualy, as you can see, not a fluent writer-speaker too.
Thank you.
How would this circuit work if powered by 5v via a usb cord?
Great explanation of this circuit, I've a couple of those 386 chips and I've done this circuit similar to yours(minus a few caps), and I use it for my guitar. I got a tube driver adaptor that plugs direct to the guitar and then I put the 386 amp on after that, where I connected with the phono male and female then out to the speaker. Your guide has solved a bit of puzzle why I couldn't directly connect the 386 amp into the guitar and then to the speaker ie. it needs a load for it to work(I think). I've used a dimmer switch for a push on and off, and another switch for the 200 gain, with a pot to adjust the loudness and it's powered by a 9v battery and it lasts for ages. Thanks a lot for this and I subbed :)
Hi Nick Sparks;
I would like to ask you something. As far as I am concerned you used the LM386 to make a guitar amplifier. Does this circuit usefull for a guitar amplifier ? If it is not is there any modifications that I can make on this circuit to make it usefull? I am looking forward to hear from you. Have a nice day.
Nice to see someone make a decent circuit on a prototyping pc board with the LM-386. So many knock this chip because they have no idea how to properly build the circuit in the schematic. They think they can build a high gain circuit on a plug in proto bread board (what you call socket board) using hook up wire and have no clue about mutual induction between wires and stray inductance and capacitive coupling between all the busses on a "socket board". LS Short, don't let any of the output signal get back into the input.
To do that effectively you have to use twisted pair at the least, like you have here on the input and output and keep all leads as short as possible and to get the most performance out of the chip, use SHIELDED audio cable on the input and output with the center lead as short as possible and connected to good ground. Build the circuit on a etched double sided PC board with the input and output separated by a large ground plane as the chip was intended to be put on by the designer of the chip, International Semiconductor.
Electronics Engineers like myself and knowledgeable techs like you can get away with a good circuit mounted on a proto board like we've both done with a few tricks.
I have a two way intercom between my living room and outside privacy fence gate using the LM 386N-4 driven by a TL-082 OpAmp fed to a Radio Shack Mic that has been working since 2008. I love this combo and I can pick up sounds from blocks away.
I've thought about making a vid on how to properly build an audio amp with this chip for a long time. It's amazing how loud and clean this little device will drive an 8 Ohm speaker and will fill a whole room with sound.
Very interesting what you say. It would be nice if you want and have the time to do it, to show how you do it in order to cover all the points you mention. I have problems with the smokey amp, and I am quite curious about what I am doing wrong to get that squeals and horrible noises, while the original ones do perform good or very good.
This worked amzing! I have built many mini amplifiers using the lm386 and none of them have even come close to the pure disturbance free audio, this circuit and layout gave me.
Can you use a mic with this, say, with a parabolic reflector?
Hi John I have a vintage Fidelity HF19 1961 tube amp in a record player. I want to change the mono high output ceramic cartridge for a modern stereo pickup so it won't damage my records. Do you think this little amp would be ok as a preamp to power the single UL84 tube amplifier?
Perfect for a headphone amplifier of course 1/channel., I also like using it as a preamp, so it doesn't need a dual power supply, relatively simple
Your quit knowledgeable bud ty.
If I am not adding volume control , where can I connect the load resistor ? Before the input capacitor or after it & what should be the resistor value ?
John, in your opinion, would a tda2822m bridge would make a good mini guitar amp? i don't have many LM386 if any, but I do have many many many... tda2822m
how feasible is using a 50k pointomiter in series with the gain adjust cap? i'm thinking of the guitar amp, "little gem" type thing using the pot to control gain
Could you not use that chip to drive the CV input on the second half of a NE556 which drives a high power Inverter output stage based on 2x BD131 transistors +1N4007 +560R resistor with feedback to the drive amp.
Thanks very informative 👍
I have seen in some amplifier circuits like lm386, tda2822, tba820 etc that the Input coupling capacitor is connected before the potentiometer (if a potentiometer is to be used) and if the input capacitor is connected after the potentiometer that's between the potentiometer wiper pin and the amp input pin, the amplifier starts oscillating when the power is switched on and even without any audio signal connected. What's the reason behind this ?
But in some audio chips like Tda2003, the Input capacitor is connected after the potentiometer (between the wiper pin and input of the amplifier). So what's the difference between the two connections ?
The best results I've had with these LM386 designs were the ones using a FET as a buffer for the input -- the Ruby from runoffgroove mainly. I recall using a J201 to best effect, but apparently the through-hole package for those are out of official production now? I also liked a bigger output capacitor than most of the LM386 designs (they usually called for a 220uf), I think I usually went 470uf like you're using here, or 680uf, especially for guitar use. I remember finding a 10k volume pot to cut too much high end for HiFi audio, and a 50k audio taper working best for me there. I'm not an engineer though, I just made semi-blind substitutions. I remember socketing the transistors and the gain resistors to try different things. Thank for this design, it's simple and compact and if I get back into it I'll try it out for HiFi. But I still have a stereo buffered LM386 board I never bothered to put into a box and use yet, lol.
so, you can amplify the signal before the ic amplifies it?
I'd like to use this amp, but I want to add a volume control, a reverb circuit and an overdrive circuit to control them with pots as well.
Can you direct me to site where I can learn that?
Thanks 👍
if you want more power or ability to use other loads you would have to graduate from the LM series to the TDA branded chips especially if you want a few watts in stereo unless you want to pile on LM chips on a PCB..
Holy Moly wonder why they don't show that capacitor configuration in the datasheet? Maybe it's got potential for oscillation?
(Anybody that comments on here, with this knowledge, is welcome to answer my question)
John, I just found your youtube channel. Excellent video! That LM386 amp sounds clean with plenty of volume.
I'm currently looking at building an FM radio using the RDA5807 FM Radio Tuner IC. I'm looking at a plan that I found on Instructables.
The amp being used, for that build, is a PAM8403 audio amp module. I'm wondering if the LM386 is a better choice for the amp
and also how do these two amps compare with each other?
Thanks!
Gary
could I build that amp but add a buffer like the jat half bake amp ?
Can u make vid about guitar amp. How are they made which amps are better
I built it with SMD components on double sided PCB and it's small. Works great! Question - can I put a capacitor with 10kOhm pot in series between pin 1 and 8 to control gain?
i have always wanted to try that, pity no answer yet
Wow! Liked and subbed.
18:03 This is a balanced differential input, so if you have different circuitry causing a different DC level on the inverting input than you have on the non-inverting input you will create an offset. So when you strayed from the data sheet and added a capacitor to the non-inverting input, of course you need to do the same for the inverting input so that they will both be at the same DC level. Not a big surprise. Unless you really understand the circuit and calculate and simulate to confirm changes, following the data sheet, which is based on good design practices and design reviews, will give the best results.
@ Dana Olson = I am not an EE, so I am a bit confused by the way your reply is written... John placed a 0.27uF cap on the non-inverting input, to clean up the signal input. He then added a 0.27uF cap to the inverting input. I take it that this evened out the offset and that your statement simply explained how the offset occurred in the first place; correct? You are not suggesting that another cap is needed on the non-inverting input, are you? If so, exactly where should it be placed in the circuit? I'm sorry to create confusion, but it is always better to ask a question... Thanks.
I have just built this, I have bought a 8.2 ohm non inductive 20w resistor.
How do you get your test signal?
I have a signal generator dds still clipping with 100mv 1khz sine wave going in? ( can’t get a smaller signal)
I can't wait to build this. I was planning on using it as a small guitar amp. In regards to the pin 1 and 8 gain stage could I use 1k pot in series with the 10mf cap to adjust the gain? And if so, what order should I have the components?
Better use 10k