@@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.
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.
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.
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.
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!
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.
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.
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.
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.
Ah I finally got this IC to work! so many poor circuit diagrams and instructions out there and no explanation of which part is filtering / doing what - thankyou!
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
After four years, this is still one of my favorite projects! I have just reworked the board files and ordered another round of boards. Thank you, John, for having shared this great little circuit!
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....
Excellent! So many LM386 (and other IC amp) projects misuse them. You not only talked about why, but showed what happens. Another thing to consider is that a volume pot on the input side should have a cap between the wiper arm and the amplifier input, because bias currents through a wiper arm can cause extra noise.
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.
Nope, at least not when loaded with 8 Ohms. As explained in the video @8:00 the amp can hardly provide any more current. The increased load would lead to a significant voltage drop at each output stage, only causing more distortion.
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
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.
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 !!
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.
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.
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?
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?
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.
John, I would be glad to share my KiCad files. However, YT will not let viewers post links (or even talk about them,) unless the channel's author grants the viewer some sort of "trusted viewer status." If you can arrange that, I'll set up the link. Let me know what you would like for me to do. Thanks.
posted 3 years ago ... thanks for the effort but I can't believe how someone put so much time and effort in the video but couldn't just make the schematic at least in paint , and provide the list in text format...
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...
Hey, Could you give me some feedback on this circuit imgur.com/vySepZm I want to know if i got the Resistor/Capacitor 's values right. Microphone is an electret microphone with magnet speaker. Single-suppy LM324, 9V.
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?
Hi, John. I thought it might be rewarding for you to see your project built by others. I made a tiny, SMD board and had it manufactured, to play with the design. I don’t use DropBox, much, so I hope it works... www.dropbox.com/sh/6dfkydg0q80y6sa/AACFIeph0lK8ZrKxgY0aLhEGa?dl=0 Dollar Bill Photo: The boards are only the size of your thumb. The LM386 is not in its socket and the 9v barrel jack is not installed, yet, but you can get an idea of the scale of things. They are installed in the video. I saved a lot of space, by piggybacking the smoothing cap on the back of the unit. The huge, solid-core input and output wires are just for fooling around. KiCad PCB Photo: Shows the compact layout. Video: Shows it working. Thanks for the education and the inspiration!
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 👍
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?
It’s a shame that todays replacement (The Pam 8403 amp) cant be configured for headphone boosting as its a simpler amplifier with more output and at a cheaper price
Hi, John. Please tell me what type of capacitor you actually used for the 47pF input cap, across the LM386's two input pins, pins 2 and 3. I watched the video, again, to catch this detail. I thought that you had commented on it, but, if so, I did not catch it, this time. Around 14+ minutes, there is a quick glimpse of the component. It sort of looks like a yellow ceramic, but I am just not sure. Teachable Moment = In addition to telling me what you actually used, please comment on what would be the best type of cap to use for this application and why so. Also, what might be substituted, in a pinch... Such as, maybe what appears to be a common ceramic is actually a Tantalum? This is very much the audio signal, so I was expecting some type of a film cap. I checked at Mouser on 47pF film caps and they only seem to be available in really high voltages. I have a nice 47pF/1KVDC-250VAC/Polypropylene/AC and Pulse Film cap on hand. And, I that you taught me that, if the cap voltage rating greatly exceeds the signals voltage, the cap will not form up correctly and the rated capacitance will not be achieved? Thanks, again... I have learned so much from you!
The capacitor is a NPO ceramic type. It is a low pass filter to help keep RF out of the amplifier. Ceramic is fine for this duty. Value can be changed depending on needs.
@@JohnAudioTech "NPO" = I haven't heard that one. Common ceramic - DIP, gum drop, etc. I know of these. I take it that a common ceramic will do. Thanks for the reply and the information. Cheers!
Ha! Me too! The LM380 was a bit of a blunderbuss, but hey... The one I MISS was my OTHER little project the headphone amp - I just used 741's! I thought it was SO neat, lol - if only I'd known lol (Hi Z stereo phones, so I got away with it - imagine the distortion, but it didnt actually sound so bad)
The chip is still available on the internet. I was thinking of putting together the lm380 amp just to keep it "alive". If it ain't broke don't fix it!😂
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.
Hello John, a few years ago I've built a tribute to the LM386 using your superb teachings. hackaday.io/project/166669-lm386-stereo-audio-amplifier After this first one the end result was better than i expected, no noise, excellent sound, low power consumption, no problems, so did a few more with other recycled audio chip's, also all other components are taken from scrap electronics. Thank you for all your dedication and sharing.
I have a better idea use from 100nf to 470nf or 1uf capacitor connected from pin 1 to pin 8 instead of the 10uf gain capacitor the result lm386 will give a very clear high frequency crystal sound without hum to reduce the highs as you like use from 100ohm to 1k resistor connected in series with the capacitor or use a 1k trimmer to adjust the highs, i used 220ohm resistor
Ceramic capacitors are notorious for they lack of stability, they also shift capacitance with vibration. That's why you avoid using them in anything here value stability is more important that lower ESR.
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.
Ever since I tried this little amp when I got it from Radio Shack in 1986 it was such a disappointment I never tried it again. Your circuit surprised me!
I'm having a good time with this little chip ^^ I used it to make my practice little guitar amp and I'm trying to improve the circuit, hence why I'm here :) For guitar amps the distortion the chip can produce is VERY nice, it's almost a fuzz type of distortion and it's very simple to do. However I can not get clean tones from the amp, for clean tones they are pretty bad, at least for guitars :(
Am I right in thinking, even though this chip is very low power output,, it has a really good frequency response? Because, I was always under the impression that that the usual 8 pin, or even 16 pin amp chips were seriously lacking in FR.
It does a good job as long as you are staying under a half a watt, at that point the frequency response really goes tits up. It has a niche driving transistors in audio circuits, where you need more current than highly accurate op amps, but not so much the 386 needs more than a half a watt. They are also good enough for driving headphones.
Frequency response depends mainly on the coupling capacitors used on the input and output (and feedback in some cases). The chip itself will have a response from DC to several tens of kilo Hertz.
Lm386 N-1 has 325 mw @ 6V 8 ohm, N-3 has 700 mw @ 9V 8 ohms and N-4 has 1Watts @ 15V 16 ohms according to datasheet. So which of these flavors we are actually getting now in the open market as there is nothing printed after Lm386 on the chips ?
Regards from Ukraine) Could You please tell me if there is any solution with my situation. I am making portable 8 bit game console. I use NES clone with onboard opamplifer, and its output distorted sound. Its sounds not good on TVset but acsepteble. But when I try it with PAM module or this LM386 schematic amplifer and small dynamics its sounds terreble. I find it at the wery late stage - I doned so much work with case and other parts of project. The internal opamplifer do not have any outer components to change, all in one chip. Is audio signal can be filtered, can You help me with advice?
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?
Ive had so many problems with this chip, sometimes i plug it in, it sounds clean and produces fair volume, and then in less than a minute without changing anything all of a sudden it has extreme distortion and low output. Must be because im doing it on a breadboard.
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)
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..
Hello buddy. Iam trying to build an amplifier using TDA7265 amplifier chip with single supply design. The music is playing but don't know why the volume is so low. I have put input volume on full. For the circuit diagram, you can check the datasheet. Iam using fig 2, single supply design.
18:55 The harmonics you see at clipping are the reason why you blow your tweeter during clipping. This is why "underpowering" is a common cause of breaking your speakers.
@H A R Yes it can. When the amplifier starts clipping you get tons of harmonics and those harmonics are unexpected HF that can stress your tweeter and damage it (probably the main reason of tweeter failure). See : jblpro.com/en-asia/site_elements/danger-low-power This can happen if you clip any stage of the audio signal.
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.
