Any Love for the LM386?

[Box_Stuffer]

I got some cheap LM386N-1 ICs and I have been messing around with them. I like that you can run them without a voltage divider. I am working on a pretty good sounding distortion based around one. I also rigged up an Acapulco Gold fuzz on the breadboard - which uses 2 of them in series - and it sounded pretty good.

I was wondering if it is worth paying more for them from a reputable seller. They are 90 cents each on StompBoxParts.com right now. I can get 10 for around $7 on ebay or walmart.com. StompBoxParts only has N-3 and N-4. How much more powerful is an N-4 vs N-1? Is it audibly much louder and does it affect the rest of the circuit if you swapped them out?

What are some of your favorite circuits using the LM386?

[Electron Tornado]

I've used the 386 for a distortion pedal, but not a fuzz. I tried the N-1 and N-4 versions, and the decay on the N-1 was always added fizziness that I never liked, while the N-4 decay was much more natural. Search "LM386" on here and you should find a few schematics.

Not sure what the chip should go for, but shop around. There are many reputable places where it can be had.

[antonis]

What are some of your favorite circuits using the LM386?

Any low voltage CLEAN signal power audio circuit..

[duck_arse]

What are some of your favorite circuits using the LM386?

Any low voltage CLEAN signal power audio circuit..

nevermind clean - uglyface.

[antonis]

IMHO, there are cheaper and more implementation-convenient chips for such kind of fuzz-distortion circuits..

[Clint Eastwood]

A while ago in another thread I posted this:

https://postimg.cc/8s4xyB9w

It is basically an overdrive circuit to wich you can connect a speaker.

[Fancy Lime]

Two circuits that are not getting the attention they deserve, imo:
Fuzzhugger Phantom Octave:
http://effectslayouts.blogspot.com/2015/12/fuzzhugger-fx-phantom-octave.html?m=1

And the Frantone Peach Fuzz:
http://effectslayouts.blogspot.com/2015/08/frantone-peach-fuzz.html?m=1

[Box_Stuffer]

What are some of your favorite circuits using the LM386?

Any low voltage CLEAN signal power audio circuit..

I am working on a distortion that is based on a video I saw on Youtube by some Indian guys. They called it a "blues distortion". You go into the inverting input and you can use hard clipping diodes on the output  It was not great when done as they prescribed, but I tweaked it a bit and now it sounds surprisingly good.

What similar chips do you prefer? I am just starting out and I have only tried a handful of ICs so far.

[Box_Stuffer]

Also I found this cool optical tremolo on Youtube that uses an LM386 to boost the signal. I guess you could just as easily use a transistor. I rigged it up on the breadboard and it works pretty good.

[Ripthorn]

This is a circuit I designed that is a combination of my FET-2B and the sonic titan with a couple twists. Great preamp, of I say so myself. https://scientificguitarist.wixsite.com/home/torivor

[antonis]

What similar chips do you prefer?

I presume you got me wrong..

Never said one can't get decent results in a distorion circuit with LM386..
(just it should be an overkill from particular IC implementation viewpoint..)

[drdn0]

Acapulco Gold's were one of the first PCB's I made. I did a bit of experimenting and found the following works pretty well over the stock setup:

• ditch the 10uf cap between pin 1/8 on the first IC (setting gain to 20)
• connect bypass pin (7) to ground through a 10uf cap on both IC's
• decent sized filtering caps to avoid sag (works better with a decent pedal power supply than a battery too)
• decouple both IC's as physically close to the pin 6 as possible
• use N4 variants over N1
• use 1uf or smaller MKT's instead of polarised electro's between stages

Gets rid of a lot of the fizziness and sounds much better with a bigger range of guitars IMO.

[Box_Stuffer]

I got some LM386N-4s and they are MUCH louder than the N-1s that I was using before.

What is the best way to attenuate down the output without changing the EQ? I added a 100k resistor inline at the end of the circuit and it got the volume down to a user - friendly range, but it also changed the sound a little.

[duck_arse]

attenuate the input to the lm386.

[brett]

Lot's of love for the LM 386 from me.
Plenty of power for a home amp.
About 88dB with a sensitive speaker.  It's not easy to convey loudness, but a food processor is 85dB to 90dB.
Some observations:
The inputs are low impedance, so a guitar needs a buffer before it.
The inputs have a low voltage limit (just 0. 4 peak) so signal reduction is needed to avoid input distortion.
The Class AB output gives nice distortion when it runs out of headroom.
You need a 1000uF output cap to get solid bass out to a 4 ohm or 8 ohm speaker.

Things that need exploring:
1. Using two to "push pull" a little output transformer. 
2. Improved use of feedback from the output to either pin 1, pin 8 or the inverting input. See the "bass boost" schematic in the datasheet.  It works great.
3. Power supply considerations.  The internal resistance of carbon 9V batteries and even alkaline batteries limts the output. This can be a good thing, increasing crunch.  Adding a big power filter capacitor increases output.  Maybe not such a good thing for tone?
4. How much capacitance on Pin 7?  I use 0.1 uF, but maybe that's too much?
5.  Is a film cap needed in parallel with the big output electrolytic? To provide a low resistance pathway for high frequencies?

I'm just putting together a pcb for a mini amp.  Battery powered, gain and volume controls and a "bass boost" switch.  First, I made it for minimum footprint (25mm x 40mm) but it was too tight and fiddly.  Now it's 30mm x 50mm.  Much better!

Keep exploring.
Cheers!

[Box_Stuffer]

I made this distortion with the LM386 and it is based on elements of several different schematics that I have seen.  They usually have some sort of capacitor or resistor set up at the power input. Some run a resistor in series, most with capacitor in series, some with resistor and/or capacitor bridged to ground. I wasn't sure what to do so I just plugged the power right in.

The circuit works, but after a few minutes it starts to get sputtery and fizzy and the level kind of fades in and out. What can I do to improve this and make it stable? Thanks.

[GibsonGM]

Why don't you post one with resistor and cap on the power so we can see.  That may well have something to do with your 'instability'.    386s drive me nuts because of those issues.

[Box_Stuffer]

Why don't you post one with resistor and cap on the power so we can see.  That may well have something to do with your 'instability'.    386s drive me nuts because of those issues.

These are the ones that I have found or seen on Youtube that I sketched out. The one that says "amp w/ gain" is straight off of the datasheet and it shows the power going straight in, so that's why I tried it that way. My circuit is based more on the one right below that one, but I added the additional gain loop. I originally had the cap and resistor like they have it, but it still fizzled out.

[Ripthorn]

Do you have the cap off of pin 7? In some designs it ends up being critical.

[Clint Eastwood]

With LEDs in the gain loop like that, I can confirm oscillation tendencies. Try putting 1k or 470 ohm in series with the LED pair, that worked for me.