I love the LM All that is needed to build an audio amp are a few external components most of which are decoupling capacitors. It is well suited to low power applications and runs just fine on a 9 volt battery or any voltage supply from volts.
The gain is internally set to 20 but the addition of an external resistor and capacitor between pins 1 and 8 will increase the gain to any value from 20 to An increase in bass frequency can be facilitated by adding a 10K resistor and.
The parts list for this build is pretty minimal: 1 — Enclosure of your choice 1 — LM Audio Amplifier 8 pin DIP 1 — 10 ohm resistor 1 — 10K potentiometer 1- uf polarized capacitor 1 — uf polarized capacitor 1- 10 uf polarized capacitor 1 —. I suggest building the circuit on a bread board first.
The 1/2 watt LM386 Audio Amplifier
You can leave the audio jacks off the output and install some small binding posts or just two wires with alligator clips on them for connection to an external speaker. You could also put the whole circuit in a larger enclosure and install the speaker for an all in one portable amp. Have fun building your amp and keep on hackin!
Those tins look great for small projects. Perhaps they offer good for RF shielding for certain applications? I really like this application of the LM! My goal is to implement a two-channel version with a switch to activate bass-boost. Any ideas on how to implement volume control on two of these while using only one control knob — maybe I could do some trickery with a series resistance in the gain circuit?
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Also, have you had any trouble with distortion resulting from hitting the power supply rails? Thank you for this simple but effective schematic! My little sister wants to build one for her bass guitar next weekend, and I am really looking forward to that. Again, thank you very much for taking the time to make a video, draw the schematic, and share it with the world at large.
I do have a couple of questions, as a complete newb: Is it ok to solder right to the chip? Is this a chip that I would need to worry about that?For new electronic enthusiasts, though, making tiny versions of bigger circuits mostly becomes more intriguing and amusing. Amplifier circuits with smaller outputs may look insignificant, but are in fact more popular and find wider applications in many electronic gadgets like radios, iPods, telephones, transmitters, etc.
Moreover these configurations are simpler to understand, constructing them at home becomes easier, and the circuit therefore can be even attempted and completed by school students. One such simple audio circuit is proposed here using the IC LM, which requires very few other external passive components for functioning. The IC LM is a power amplifier used for amplifying small audio signals with low supply voltages.
Though the gain of this IC is set at 20 internally, it can be raised almost 10 times higher - that is up tojust by introducing a resistor and a capacitor across its pin 1 and 8.
How to Build Small, Simple Audio Amplifiers Using IC LM386
The inputs of the IC operate with respect to the ground, while the output is automatically biased to half the supply voltage.
The IC is available with four versions, viz: LM N-1, N-2, N-3 which typically show very low distortion characteristics and function well with voltages ranging from 4 to 12 volts DC. The fourth type, the LM N-4, is specified with working voltages from 5 to 18 VDC, these being the final safe thresholds beyond which either the devices stop working or become too hot and get damaged.
The quiescent current drain current consumption when the IC is in the idle mode is around 4 mA only. The circuit below shows the basic format of wiring up the IC as an amplifier. Here, as discussed in the previous section, the gain of the circuit is restricted to 20 by keeping the pins 1 and 8 open.
The internal connection of a 1. The output is connected to a loudspeaker via a filter capacitor, which is normally witnessed in all linear IC amplifier circuits. The pot VR1 at the input functions as the volume control for enabling the output to be adjusted to the desired levels. The second circuit shows how the gain of the above fundamental design may be boosted to almost by adding a capacitor across pin 1 and 8 of the IC.
The gain can be made adjustable from 20 to by including a variable resistor of 4K7 in series with the above capacitor.
Excess offset conditions may be reduced by engaging the unused input to a resistor from the ground. However all offset issues are cancelled-OFF if the active input is coupled through a capacitor. With the circuit set at a gain ofit becomes essential to bypass the unused pin 7 via a 0. Other than audio amplifiers many different small circuits can also be built using this versatile chip; the following datasheet will provide you with more added information. LM Datasheet - biltek.
Page content.This is a really simple portable guitar amp project you can complete in an afternoon ; with the parts you need at hand. I used an old surround sound speaker as my enclosure, and used the speaker. The unit also has 5 tone settings to allow you to go from clean to gritty.
It sounds much better. The diagram below explains this build in detail. If you want 5-mode distortion, then you simply use the dip switch in place of the SPST switch on the 2. Remember that the speaker you use will make all of the difference in how clean your new portable guitar amp sounds.
Mine sounds pretty clean, I achieve this by isolating jacks and components from each other, and I hot glue the audio lines and PCB wiring to avoid leakage. Parts List: Enclosure: I used an old surround sound speaker as my enclosure.
You could make this unit into a box and use as a 'head' for speakers in mini-cabinets too. Follow my wiring diagram photo 2 to put it all together. A 'Supercap' battery is another idea -- DIY 9v rechargeable or some other rechargeable battery as this device runs up to 15v.
You can build this into anything, but I decided an old surround sound speaker enclosure would work best for being dropped, etc. Reply 3 years ago. Reply 5 years ago on Introduction. C4 filters input audio signals and C2 filters output signals.
And C3 filters the Vcc coming from battery. Great tut, but why use a switch between pins 1 and 8??? A pot works much better and provides more tonal flavors. For added distortion, use clipping diodes. These can be strategically inserted and still use the switch to give different clipping options. Also, a simple tone stack works great in the Little Gem. You new guys should start with the BMP stack Reply 6 years ago on Introduction.LM386 Guitar Overdrive Test
Look at the schematic. If you can't read schematics--go to runoffgroove dot com for the perfboard layout.Only problem is your amp. Or maybe you want to warm your fingers backstage when your stack is already on stage.
Well, build yourself a battery powered practice amp that you can take with you anywhere. On the other hand, a simple preamp would make the amp much more versatile, but also it will increase cost and complexity a little bit. A simple preamp would just be your favorite distortion effect pcb mounted in the same housing with the amp.
Or you could make a two channel opamp preamp so you could have a separate clean and distortion channels. Len Galasso has a nice design called PracticeMan. There are many different type tone controls. You can have a simple one band tone control circuit like explained in the Design Your Own Distortion -article. A practice amp can drive a pair of headphones or a few watt speaker. Any way you want it. If you want to practice without disturbing others, choosing headphone operation might be an ideal choice.
Battery life is long and the amplifier will be cheap and can be fitted into a small housing like a cigar box. If you want to play along with others, you might want to have a little speaker mounted in your amp. Remember that the bigger speakers you drive the shorter the battery life will be. There are several options for a practice man power amp. You can use LM with headphones and a small speaker. Drives nicely even a little bigger speaker.
Kills batteries, but ok with wall wart supply. About Us Acknowledgements. Tone Controls There are many different type tone controls. Speaker or Headphones A practice amp can drive a pair of headphones or a few watt speaker. The Power Amp There are several options for a practice man power amp. Related Schematics Headphone Amp Simple headphone amp. LM Power Amp A half watt power amp to use with headphones or small speaker.
LM Power Amp 8 watt power amp for driving a bigger speaker. Electra Preamp Electra variation combined with the Big Muff tone control. Simple and Cheap.Powers a 1x10 cab up through a 4x12 cab? Ultra-low wattage so you can rip out the shred while the baby sleeps? This simple chip offers good performance, minimal support parts and is available in a range of version, some which can handle up to 18 volts DC and put out over a watt of power.
This great chip has spawned the commercial Smokey amp, and various great practice amp projects from runoffgroove. More about my Ruby builds here. It was quite easy to build and I was amazed that a 9v battery into a chip could easily power a 4x12 guitar cab.
But as always, there were mods to be tried. After a many evenings of experimenting, I ended up with the Noisy Cricket Mark 1. Built into a simple Hammond enclosure, the Noisy Cricket added a simple tone control, and grit mod for getting just a bit more sizzle. I built quite a few Noisy Crickets for folks who wanted one. But I met even more people who wanted to build their own. So several DIY versions have been available. Here's the first prototype build of the Noisy Cricket with the just the Grit boost switch: This pedal is now in the collection of Richard Guy at www.
The first run sold out in one day. I was surprised and pretty stoked at the same time. Having shown the one of the production units to some local dealers, and based on emails from folks about missing out on the first run, I decided to do a second production run.
I did about 20 of these.
How to Build Small, Simple Audio Amplifiers Using IC LM386
Here's the prototype for production run The indomitable Adam at Swankbox has provide me with a set of beautifully painted enclosures. A run of ten of those will also be part of production run 2. The following pictures don't do justice to these boxes--they are simply fantastic. For this version, I wanted to leave the circuit intact, but work with a custom PCB and board-mount parts. The result, is this:.
I found some great enclosures from Boxenclosures. The Mark II was fun to build and there are probably about or so units out there. Ok, so here we have the interesting bits. How to build your own. Schematics, layouts, all that good stuff. So here's a handy build guide showing the info you need to build your own cricket without etching boards.
PDF Version. Ruby Amp from runoffgroove.Mine did. Until I plugged in the wrong power supply. Now it's dead. Lesson: always add a protection diode to the power connector.
Hi Ralph, congratulations on this project; the cab looks amazing.
How does the amp sound like? I've just started to build the amp and I'm out of ideas. I think it's better to have a metal plate rather than mounting the pots on the wood more work ; any ideias?
You should get alumin i um sheets at your DIY store. They make great noisy cricket panels. Or cut a piece out of a food can preferably empty. Fold it for extra strength. Only a few more coats of Tru-Oil, and then assembly, wiring, stringing, tuning and intonation are necessary. Oh, wait What I really meant to say is that I want a small guitar amp that I can take anywhere.
It is a simple amplifier running off of a 9V supply wall wart or battery and consisting of a handful of components around a LM audio amplifier chip.
You can find various veroboard designs for a Noisy Cricket on the intertubes, but I chose a small protoboard to build mine. Here's a picture of the component layout. I usually do small layouts in Microsoft PowerPoint. No, I'm fine.
It only takes a minute to sign up. I soldered all the components on but no sound comes out when I play.
Because of the different layout of the universal PCB, the circuit's grounds are connected differently than they were on the breadboard, so maybe that's the potential problem since its the only difference I think there is.
Sadly I don't remember what it looked like on the breadboard and I didn't take any pics. Heres the layout of the circuit on the universal PCB:. Heres something I don't understand, when I measure the potential between the output and the ground with a voltmeter, it corresponds nicely to the signal from the guitar, it seems like it should work. But when I measure the potential between the wires going into the speaker which are connected to the output and the ground I get zero volts between them always.
Why is that and how can it be fixed? Also sometimes when I poke around with the voltmeter at different spots on the ground and output it will randomly start working and sound will come out. I can't really notice any pattern when doing so though.
Once again I'm very new so I'm sure I'm making a ton of embarrassing mistakes and that my soldering is terrible lol. One quick thing to check is the wires that are soldered to the board. I've had this issue a lot when I first started making my own circuits.
Although they will seem like they are soldered, sometimes they don't have a good connection and will cause issues like this. I would reflow all the solder joints and see if that works. I also recommend tinning the wires prior to soldering them into the board. This will help get a good connection. Sign up to join this community. The best answers are voted up and rise to the top.
Home Questions Tags Users Unanswered. LM guitar practice amp circuit not working, need help finding mistake Ask Question. Asked 2 years, 6 months ago. Active 17 days ago. Viewed times. Heres the layout of the circuit on the universal PCB: Heres something I don't understand, when I measure the potential between the output and the ground with a voltmeter, it corresponds nicely to the signal from the guitar, it seems like it should work.
Heres the pin layout for the LM operational amplifier: Once again I'm very new so I'm sure I'm making a ton of embarrassing mistakes and that my soldering is terrible lol. Niteesh Shanbog 6 6 silver badges 19 19 bronze badges. TwoheadedFetus TwoheadedFetus 1 1 silver badge 8 8 bronze badges. Then you have an intermittent connection: a very careful visual inspection may find it. Look for poor solder joints, or cold-soldered joints.