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LM386 Alternative (Simple but slightly more power?)

TheLaw

Sep 27, 2010
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Hi,

I'm trying to build a tiny portable speaker system. I was considering an LM386 but that seems so generic and the chip itself is so old...Essentially I'm looking for a low voltage, (2V-9V or close), amplifier that can do 1W-2W. I've seen TDA2822M around. I was hoping for a little bit more? It should be efficient too...

I'm not good with IC names so perhaps some of you know. Also, I'd prefer it is not obsolete.

Thanks.
 

davenn

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Sep 5, 2009
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The LM386 is a mono amplifier chip, the TDA2822 is a stereo chip

what style do you need ? :)

Dave
 

TheLaw

Sep 27, 2010
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Actually, after looking around for a while, I'm liking the LM380.

One question I have about the mono-stereo thing. If I have a stereo source, how do i hook it up to a mono amp? As in...Can I incorporate the two stereo channels into one 'mono' signal. I'll only be using one speaker but can the amp be configured that the two channels get "merged"?

Thanks.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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If I have a stereo source, how do i hook it up to a mono amp? As in...Can I incorporate the two stereo channels into one 'mono' signal. I'll only be using one speaker but can the amp be configured that the two channels get "merged"?

Yeah, sure.

One way is to simply connect the left and right channels together. As long as the output impedance if the source is high enough, you won't break anything.

A far better option is to place a resistor in series with the outputs and then join these resistors and connect this to your input. The resistor can have a fairly high value, I'd pick something close to the input impedance of your amplifier (if you have a volume control -- use resistors the same value as that)
 

TheLaw

Sep 27, 2010
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Yeah, sure.

One way is to simply connect the left and right channels together. As long as the output impedance if the source is high enough, you won't break anything.

A far better option is to place a resistor in series with the outputs and then join these resistors and connect this to your input. The resistor can have a fairly high value, I'd pick something close to the input impedance of your amplifier (if you have a volume control -- use resistors the same value as that)

The outputs of source, right? (As in the CD player, iPod, etc). So two wires, one from each channel and then when you join them together with a 10K resistor? My potentiometer would be 10K. So one 10k resistor in line with each channel and then these two resistors get joined into one "wire" and that wire is the signal?

What does this effectively do? Sounds intelligent and almost obvious but what is it doing compared to simply just joining the wires?

Thanks!
 

davenn

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yes they would work just wired together, but it means you are trying to pump signal from one outlet directly into the output of the other channel and visa versa.
The resistors provide a bit of buffering and impedance matching. makes it a better situation for the outputs of the 2 channels

Dave
 

TheLaw

Sep 27, 2010
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Thanks guys. After I finish this giant LM3886 amp, I'll try this. Yeah this was just out of curiosity as I wait for the parts to arrive on the amp I haven't even started yet.

Thanks!
 

Lm386

Feb 28, 2020
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With the lm386 ic I must recommend from 4 to 6v don't use 12v or more because it can caused damage I've try 12v for my lm386 mini Amp it so very cheap at first the sounds good by and by you can't hear anything sounds only noise very noise then I tried to touch the ic it so very hot
 

Lm386

Feb 28, 2020
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bertus

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Nov 8, 2019
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Hello,

When making an amplifier with the LM386, the 10 Ohms resistor and 0.05 uF on the output are a must:

LM386_typical_applications.png

For the 0.05 uF capacitor an 47 nF capacitor can be used.
Without the resistor and the capacitor on the output, the LM386 might oscillate and get hot.

Bertus
 

Lm386

Feb 28, 2020
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Hello,

When making an amplifier with the LM386, the 10 Ohms resistor and 0.05 uF on the output are a must:

View attachment 47181

For the 0.05 uF capacitor an 47 nF capacitor can be used.
Without the resistor and the capacitor on the output, the LM386 might oscillate and get hot.

Bertus


Hopefully my lm386 has 100 uF capacitor but still my ic it's getting hot
 
Last edited by a moderator:

PETERDECO

Dec 19, 2019
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Personally I prefer LM4862. However in recent years it is available only in SMT.
 

bertus

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Hello,

Did you undertand my statement?

LM386_typical_applications_annotated.png

The 100 uF will only give a little less basses.

Bertus
 

Audioguru

Sep 24, 2016
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With a 9V supply and an 8 ohm load, the LM380 and LM386 produce the same 6Vp-p at clipping which is 0.56W. They produce a maximum of only 0.45W at low distortion. Lhe LM380 has more pins for cooling so its supply can be higher then its maximum output power is higher.

With a 9V supply and an 8 ohm speaker, the datasheet of the LM386 shows heating of 0.52W which makes it fairly hot.

The peak current is high so use a 220uF or more supply bypass capacitor and a battery much larger than a little 9V.
 

Audioguru

Sep 24, 2016
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The PAM8406 stereo amplifier IC has an absolute maximum allowed supply of 5.5V so you cannot use four AA alkaline cells producing 6V.
It is rated to produce 5 Whats into 2 ohms with horrible 10% of clipping distortion. Each output will produce about 1.3 watts into 8 ohms with low distortion when the supply is 5V. It can be switched between normal class-AB or high efficiency class-D.

I do not know if the very cheeep (!) ebay Chinese amplifiers use a real IC or a cheap Chinese copy. I do not know if the ebay Chinese amplifiers produce good bass sounds.
 

dave9

Mar 5, 2017
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^ I'm confused. Are you suggesting an attempt at "hi-fi" with slapped-together <9V setup? It's a recipe for low fi, a project to "get sound" out of it.

Frankly, I don't see any point in the project at all. Tech changes, as must DIY efforts if it is to be a useful end result rather than a learning exercise. Learning exercises have their place but better still if the rest solves a problem.

However, some spec the PAM8406 as 6V max, but regardless, it depends on the purpose. I wouldn't try to build a low powered "tiny portable speaker system". The driver size matters much.
 

Audioguru

Sep 24, 2016
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I never liked the sound from expensive little Bose "one note bass" boom boxes until I saw and heard a little portable one at Cosco.
It sounded fantastic but it was small and was priced $200.00. I told my son and he went to see and hear it then he searched online for a similar one and bought two cheeep Chinese ones from ebay and gave me one. It sounded bad and was not loud enough.

Parts Express sell some 3" little woofers that can be EQ'd to sound good.
 

dave9

Mar 5, 2017
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^ Sure, I was assuming tiny meant smaller than a pair of 3" drivers + enclosure, like less than 400 cm^3

Sometimes finding (or making) a nice enclosure is the larger part of a project like this.
 
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