Hello everyone,
Perhaps you recall my previous thread on my quest to make a decent portable LM386 amp. Well, I finished up everything earlier today, and I am very happy with the results.
I'm giving this one away as a gift to a close friend. It'll be hard for me to part with it, after many hours of work, but it's going to a good cause.
Specifications:
Amplifier Chip: LM386N-3 (National Semiconductor)
Gain: Default (20)
Power: 1x 9V Battery
Driver: 3 x 5" 8ohm Panasonic
Cabinet: 4.5" L x 4.5" W x 6.5" H
Amp Component Selection:
Electrolytics: Panasonic FM
Films: Wima MKP4
Resistors: Dale CMF55
Pot: Bourns PTD901
Jack: Neutrik 1/4"
Switch: NKK DPST
Onto some pictures:
I used 24AWG solid wire, which explains the rigidity of the wires, and how it looks a bit messy. I would have used stranded if I had it, but I don't have any thin stranded.
This genuine Panasonic speaker is a factory buyout from Parts Express. It is listed as $1.50 as of 7/7/2011. Shipping is going to cost you around $6, but still relatively cheap in the end.
That's about it. Really happy with this build.
Perhaps you recall my previous thread on my quest to make a decent portable LM386 amp. Well, I finished up everything earlier today, and I am very happy with the results.
I'm giving this one away as a gift to a close friend. It'll be hard for me to part with it, after many hours of work, but it's going to a good cause.
Specifications:
Amplifier Chip: LM386N-3 (National Semiconductor)
Gain: Default (20)
Power: 1x 9V Battery
Driver: 3 x 5" 8ohm Panasonic
Cabinet: 4.5" L x 4.5" W x 6.5" H
Amp Component Selection:
Electrolytics: Panasonic FM
Films: Wima MKP4
Resistors: Dale CMF55
Pot: Bourns PTD901
Jack: Neutrik 1/4"
Switch: NKK DPST
Onto some pictures:
I used 24AWG solid wire, which explains the rigidity of the wires, and how it looks a bit messy. I would have used stranded if I had it, but I don't have any thin stranded.
This genuine Panasonic speaker is a factory buyout from Parts Express. It is listed as $1.50 as of 7/7/2011. Shipping is going to cost you around $6, but still relatively cheap in the end.
That's about it. Really happy with this build.
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Well "normal listening volume" is sort of subjective. What do you think is "normal"?
I think about 1/2-2/3 volume on this is about "normal". 2/3 volume is about the max that I find to be "comfortable". From 2/3 volume to 100%, it will easily cover a conversation you are trying to have.
Here's my measurements. Using an Amprobe meter, so I THINK it should be accurate. The measurements varied A LOT, depending on the song I was playing, so I'll give sort of a range. I determined that playing a lot of techno seriously increases power consumption, and I'm not sure exactly sure why. "All I Ever Wanted" by Basshunter, on 3/4 volume, I got around 70mA draw. Meanwhile, playing "Little Wing" by Jimi Hendrix, I got around 40mA average....So again, it's really hard to say.
1/4 volume: 7 - 10mA
1/2 volume: 15 - 22mA
2/3 volume: 30-60mA
3/4 volume: 35-70mA
100% volume: 40 - 80mA
I guess "normal volume" could be anywhere between 15 and 60mA. Quite a range...
So, it's really hard for me to say. It's very inconsistent, but that's the best I can do. Battery was measuring at about 8V if that matters. Source is my computer via iTunes. Source is on maximum volume. Volume adjustment was done via potentiometer.
If you listen to mostly classic rock, and that type of music, it seems that you will get much better battery life than if you listen to some more "club-like" music present in today's music scene. Maybe I'm wrong, but there is a bit of truth to it, going by my results.
I think about 1/2-2/3 volume on this is about "normal". 2/3 volume is about the max that I find to be "comfortable". From 2/3 volume to 100%, it will easily cover a conversation you are trying to have.
Here's my measurements. Using an Amprobe meter, so I THINK it should be accurate. The measurements varied A LOT, depending on the song I was playing, so I'll give sort of a range. I determined that playing a lot of techno seriously increases power consumption, and I'm not sure exactly sure why. "All I Ever Wanted" by Basshunter, on 3/4 volume, I got around 70mA draw. Meanwhile, playing "Little Wing" by Jimi Hendrix, I got around 40mA average....So again, it's really hard to say.
1/4 volume: 7 - 10mA
1/2 volume: 15 - 22mA
2/3 volume: 30-60mA
3/4 volume: 35-70mA
100% volume: 40 - 80mA
I guess "normal volume" could be anywhere between 15 and 60mA. Quite a range...
So, it's really hard for me to say. It's very inconsistent, but that's the best I can do. Battery was measuring at about 8V if that matters. Source is my computer via iTunes. Source is on maximum volume. Volume adjustment was done via potentiometer.
If you listen to mostly classic rock, and that type of music, it seems that you will get much better battery life than if you listen to some more "club-like" music present in today's music scene. Maybe I'm wrong, but there is a bit of truth to it, going by my results.
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bass uses a lot more power(club music), will cause it to clip easily at this power range.
i agree that's a very subjective question, but
the 386-3 at full rated output (0.5 watt) running from a 9v source draws 78ma, assuming an efficiency of 60 percent.
offhand guess 50ma at normal output, of course it always varies, but we need a guesstimate. a duracell 9v alkaline battery is rated at 565mah, so in 11 hours of total use it's essentially dead (550ma taken).
the 50ma loading of the 9v battery is probably within it's normal intended range so official guess is,
11 to 12 hours with consumer 9v alkaline batteries.
i agree that's a very subjective question, but
the 386-3 at full rated output (0.5 watt) running from a 9v source draws 78ma, assuming an efficiency of 60 percent.
offhand guess 50ma at normal output, of course it always varies, but we need a guesstimate. a duracell 9v alkaline battery is rated at 565mah, so in 11 hours of total use it's essentially dead (550ma taken).
the 50ma loading of the 9v battery is probably within it's normal intended range so official guess is,
11 to 12 hours with consumer 9v alkaline batteries.
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Hi,
If you want it to sound far better for peanuts read on :
Google "baffle step compensation", understand it, work out the baffle step
frequency. Modify the power amps feedback loop to have an inverse function.
This will make a huge difference in the apparent richness and accuracy.
rgds, sreten.
If you want it to sound far better for peanuts read on :
Google "baffle step compensation", understand it, work out the baffle step
frequency. Modify the power amps feedback loop to have an inverse function.
This will make a huge difference in the apparent richness and accuracy.
rgds, sreten.
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11 hours isnt too bad. The LM386 can run down to a very low voltage, so battery life will be good, however sound quality might get a little messy towards the end of it's life.
LM386N-3 has a 0.75W output at 9V with a 8ohm speaker...which is what I have...so battery life might be a bit less, (if at max volume).
A rechargeable 9V would probably be ideal, and though it probably wont last as long, it will save you money in the end.
Uh yeah no offense guys. It's an LM386. xD. I tried my best with the National schematic. I used above average quality components and did my best with layout. It sounds good to me! I already gave it away by the way.
Off topic: Speaking of 9Vs, I was in Lowe's today and they have a crapton of batteries at the front. Just being curious, I wanted to see where Energizer's 9Vs were made. And I'll be darned, they're actually made in the US! What a shock.
LM386N-3 has a 0.75W output at 9V with a 8ohm speaker...which is what I have...so battery life might be a bit less, (if at max volume).
A rechargeable 9V would probably be ideal, and though it probably wont last as long, it will save you money in the end.
Uh yeah no offense guys. It's an LM386. xD. I tried my best with the National schematic. I used above average quality components and did my best with layout. It sounds good to me! I already gave it away by the way.
Off topic: Speaking of 9Vs, I was in Lowe's today and they have a crapton of batteries at the front. Just being curious, I wanted to see where Energizer's 9Vs were made. And I'll be darned, they're actually made in the US! What a shock.
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Hi, No. Incorporating dirt cheap accepted acoustic practice is a good idea, rgds, sreten.
The modification is an RC in parallel with the higher feedback resistor. No hard and fast rules.
Best to double its value, add a cap and the same value R series RC in parallel. Simple voicing.
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Ahh, the LM386, one of my good old FAVORITES!!!! I've built many projects with this, not only for speakers, but also for a high powered microphone portable bug (listen through windows and in quiet places for conversation, worked great in high school HEHE!) that was using a condenser mic, an op-amp preamp, 10K volume control, and LM386 Amp driving headphones (LOUD ) I still have it even though I don't use it, just because it was a fun project.
GREAT JOB on the project!!! I liked how you used an oval speaker (more efficient and louder) for that size box. The 9V is a great power supply that is simple and provides loud enough output without stressing the chip. Even better, you used 8 ohms which won't overload the chip, and get better sound with less distortion than 4 ohms.
I also have much DIY Respect for anyone that uses the LM386, because you learn and make a simple amp with this, that works good, and later on, you move up to building the bigger amps as you go along, instead of trying to build a big 100W+ amp as your first amp like many do and struggle getting it to work for a long time if ever, while INSTEAD, you can be jamming out to some music on your little LM386 while taking the time to better learn how to build the next amp! (or in this case your friend will be jamming out to it, and you had fun building it for him)
I still have lots of the LM386 chips saved even though I build high power discrete amps now, the LM386 is great if you just need to easily feed a speaker with some power.
The 9V battery works really well for you. If you want to add battery life, you could add another snap on holder for an additional 9V battery to double the battery life, then you will get 24 hrs of play. (or add 3 or 4 9-volt snaps to have a row of batteries and give him the option for more battery life, but you can still use just one if you want to.)
) I still have it even though I don't use it, just because it was a fun project.GREAT JOB on the project!!! I liked how you used an oval speaker (more efficient and louder) for that size box. The 9V is a great power supply that is simple and provides loud enough output without stressing the chip. Even better, you used 8 ohms which won't overload the chip, and get better sound with less distortion than 4 ohms.
I also have much DIY Respect for anyone that uses the LM386, because you learn and make a simple amp with this, that works good, and later on, you move up to building the bigger amps as you go along, instead of trying to build a big 100W+ amp as your first amp like many do and struggle getting it to work for a long time if ever, while INSTEAD, you can be jamming out to some music on your little LM386 while taking the time to better learn how to build the next amp!
(or in this case your friend will be jamming out to it, and you had fun building it for him)I still have lots of the LM386 chips saved even though I build high power discrete amps now, the LM386 is great if you just need to easily feed a speaker with some power.
The 9V battery works really well for you. If you want to add battery life, you could add another snap on holder for an additional 9V battery to double the battery life, then you will get 24 hrs of play. (or add 3 or 4 9-volt snaps to have a row of batteries and give him the option for more battery life, but you can still use just one if you want to.)
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The project is (was) finished. To suggest this now is to suggest disassembling the whole thing, hoping to have the spare parts lying around in the correct values to make an audible improvement, "IF" there is one to be had with an LM386 powering a $1.50 speaker in a cabinet with unknown acoustics, implementing this suggestion, sealing up the parts in the cabinet again to test the sound change, then repeating all the above over and over until the correct value is found IF there is one that makes a noticable improvement... in the end it's hours of work, possibly not even having the parts, to end up with a 700mW mono amp.
I can't feel that it's a good idea, unless you happen to have a suggestion for parts values that should be best in this particular project and FenderBender11 happens to have the parts and the desire to do the work... when in the end the beauty of the project was simplicity, a quick easy way to drive a speaker from a source.
Ahh, the LM386, one of my good old FAVORITES!!!! I've built many projects with this, not only for speakers, but also for a high powered microphone portable bug (listen through windows and in quiet places for conversation, worked great in high school HEHE!) that was using a condenser mic, an op-amp preamp, 10K volume control, and LM386 Amp driving headphones (LOUD
GREAT JOB on the project!!! I liked how you used an oval speaker (more efficient and louder) for that size box. The 9V is a great power supply that is simple and provides loud enough output without stressing the chip. Even better, you used 8 ohms which won't overload the chip, and get better sound with less distortion than 4 ohms.
I also have much DIY Respect for anyone that uses the LM386, because you learn and make a simple amp with this, that works good, and later on, you move up to building the bigger amps as you go along, instead of trying to build a big 100W+ amp as your first amp like many do and struggle getting it to work for a long time if ever, while INSTEAD, you can be jamming out to some music on your little LM386 while taking the time to better learn how to build the next amp!
I still have lots of the LM386 chips saved even though I build high power discrete amps now, the LM386 is great if you just need to easily feed a speaker with some power.
The 9V battery works really well for you. If you want to add battery life, you could add another snap on holder for an additional 9V battery to double the battery life, then you will get 24 hrs of play. (or add 3 or 4 9-volt snaps to have a row of batteries and give him the option for more battery life, but you can still use just one if you want to.)
Thank you! I was very fortunate to find a very good driver for a very good price. $1.50 + shipping. SPL of 89.6db/1W, 8ohm, not too big, and decent quality/manufacturer.
Perfectly met what National Semiconductor had down as the ideal setup for the LM386N-3 chip.
Yes. I've learned a lot from this, and about PCB layout, and how it affects sound quality etc. The only real problem I encountered was cutting the 3 x 5 hole with my jigsaw, but otherwise, went well.
Thanks for your comments.
I built a nice LM386 amp as a first project in the 1980's. I had it for about 15 years and sold it on ebay. Hopefully its new user still has it going today. If implemented properly, I find that any chip amp will sound very good if kept out of clipping.
The OP can buy one of those 6AA battery carriers that will connect right on to the 9v battery snap and provide long listening hours.
I don't use the LM386 anymore for small amp projects because there are better ICs available today that can provide a higher output swing and drive 4 ohm loads with ease.
The OP can buy one of those 6AA battery carriers that will connect right on to the 9v battery snap and provide long listening hours.
I don't use the LM386 anymore for small amp projects because there are better ICs available today that can provide a higher output swing and drive 4 ohm loads with ease.
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