Quick question... I have a couple of the LM386-N3 chips, rated at I believe 0.7w@8ohm. I was looking at the LM386-N4 because rated for 1w, then realized it says 32ohm, not 8ohm... why they don't list at the same ohms for comparison sake, I have no idea.
Still learning this stuff, so I know it's a newbie question but... what would 1w @32ohm equal if 8ohm? ... or does it not work that way.
I have a few small 1w speakers, and a few 2w and 3w as well... all 8ohm. Was going to use them for small Little Gem/Ruby guitar amps, and had a couple chips for myself and my nephew, but few friends want one as well, was going to buy a couple more, and thought I'd go for which ever was loudest, which I assume is the N4, since the N3 is louder than the N2/N1... but not sure how going from 32ohm to 8ohm affects things.
Still learning this stuff, so I know it's a newbie question but... what would 1w @32ohm equal if 8ohm? ... or does it not work that way.
I have a few small 1w speakers, and a few 2w and 3w as well... all 8ohm. Was going to use them for small Little Gem/Ruby guitar amps, and had a couple chips for myself and my nephew, but few friends want one as well, was going to buy a couple more, and thought I'd go for which ever was loudest, which I assume is the N4, since the N3 is louder than the N2/N1... but not sure how going from 32ohm to 8ohm affects things.
Let me tie some stuff together for you here. The N4 version is optimized for a higher voltage power supply than the N1 or N3. The N1 and N3 are made to run off something like a 9V battery. The N4 is made to run off 12V or 15 V. You can run a N4 off a 9V battery, and it will do the same as the N3 as far as power output and headroom.
Running a N4 off a larger voltage supply nets you a few volts of headroom. If the amp can drive a speaker cleanly at higher voltage or not depends on the speaker impedance in ohms. with your example, an 8 ohm speaker only needs 2.8V rms to be driven to 1 W rms. A 32 ohm speaker needs twice that, or 5.6 V rms. A 9V battery cannot provide enough power supply headroom to drive a 32 ohm speaker to 1 W rms. OTOH, trying to eke more power out of the chip by increasing the power supply voltage and trying to drive an 8 ohm speaker is just going to heat up the chip and let out magic smoke. The chip will die trying to source 4 W rms to the 8 ohm (over)load in this example.
Running a N4 off a larger voltage supply nets you a few volts of headroom. If the amp can drive a speaker cleanly at higher voltage or not depends on the speaker impedance in ohms. with your example, an 8 ohm speaker only needs 2.8V rms to be driven to 1 W rms. A 32 ohm speaker needs twice that, or 5.6 V rms. A 9V battery cannot provide enough power supply headroom to drive a 32 ohm speaker to 1 W rms. OTOH, trying to eke more power out of the chip by increasing the power supply voltage and trying to drive an 8 ohm speaker is just going to heat up the chip and let out magic smoke. The chip will die trying to source 4 W rms to the 8 ohm (over)load in this example.
The original '386 was specced for 16 Ohms to get decent life out of a cheap 9V battery.
The die size allows about 1/2 Amp peak current. It won't do more, and if you force it to try it may die. (No over-heat shutdown.)
0.5A peak in 8 Ohms is 4V peak, 8V peak-to-peak, so a good fit for a 9V battery.
The originals were rated MAX 15V? The -4 is rated Max 22V. If we assume 10V and 0.5A peak we want a 20 Ohm load and hope for nearly 2 Watts. This would probably melt the chip.
If you only got 8 Ohm speakers, stick to 9V supply and take what you get. OR look at other chips.
The die size allows about 1/2 Amp peak current. It won't do more, and if you force it to try it may die. (No over-heat shutdown.)
0.5A peak in 8 Ohms is 4V peak, 8V peak-to-peak, so a good fit for a 9V battery.
The originals were rated MAX 15V? The -4 is rated Max 22V. If we assume 10V and 0.5A peak we want a 20 Ohm load and hope for nearly 2 Watts. This would probably melt the chip.
If you only got 8 Ohm speakers, stick to 9V supply and take what you get. OR look at other chips.
I'm just starting out so, right now just doing what the diagram says.
So... on a 9v battery, volume wise an N4 won't do anything more than the N3 then?
Which is fine, N3's are easier to find and cheaper on the sites I'm using. 😀
So... on a 9v battery, volume wise an N4 won't do anything more than the N3 then?
Which is fine, N3's are easier to find and cheaper on the sites I'm using. 😀
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