I need help building an amplifier for my mp3

[jbatts29]

I recently built a portable speaker box for my mp3 player.(nothing technical, just two speakers and a wire to plug it in.) the problem is is that is not very loud so i wanted to build an amplifier for it.i went online and found plenty of plans for one, but i am using parts taken from other electronics so my choices are limited.I'm pretty sure i can build the curcuit but i am confused when it comes to connecting it to my setup. The plans i am following use one speaker and i have two. when i built the speaker box i tried connecting both speakers together to give me mono sound but the sound would cut out periodically. so i connected them separately.(one positive wire to each speaker and a common ground) all the plans use one input and one output. if i connect both red wires from the mp3 to the amp and then run both speakers off of the one output will i still have the same problem? also i was hoping to use the headphone socket from a stereo to connect it but that appears to have seven pins to connect to and at most i would have 4 wires.(2 red and 2 black) so i don't know what to do.
does anyone have any input on this subject? please keep it simple, I am still new at this.

 

[davenn]

Hi and welcome to the forums

most hobby electronics stores have kitset amplifiers
With outputs anything from 1 Watt to several 100 Watts

do some googling on kitset audio amplifier sales

Dave

 

[CocaCola]

Do you want to build one yourself, do a kit or just buy one?

This is an excellent little amplifier module...

http://dx.com/p/y148-audio-amplifier-module-93121

There are dozens of DIY kits if you google, some better than others...

Be mindful of the kit you choose, the module I linked is a digital amplifier so it produced very little heat, other analog amplifiers can run very hot and require large heat sinks that can complicate the design...

 

[jbatts29]

i'm trying to build this from old parts because i have no money to buy a kit

 

[CocaCola]

Well if you don't have $10 to purchase parts, what kind of inventory do you have on hand, because if you don't have everything you need you will need to spend money and $10 will go poof real quick...

 

[jbatts29]

i have all the parts to make the actual circuit. resistors, capacitors, the amp chip, everything but my headphone socket has 7 pins on the back and the tutorial does show me how to connect that.

 

[CocaCola]

Well maybe you could start with the obvious that would help us out with helping you? Pictures of the parts, the schematic and the part numbers of the components would be a great place to start... And maybe said tutorial...

Basically give us a hint, the crystal ball we used to share was broken last week...

 

[jbatts29]

here is the plan. i have all the components shown except the mono phone jack
http://blog.makezine.com/projects/small-amp/

 

[CocaCola]

The communal crystal ball is still broken, your question is?

If it's about the 7 pin socket, we need info picture, part number? You really need to help us before we can help you...

 

[jbatts29]

i dont have that. i'm pulling it pout of a stereo. and there was a first question. what do i do about the sound cutting out when i connect the two red wires together and will it happen with an amp

 

[CocaCola]

i dont have that. i'm pulling it pout of a stereo. and there was a first question.

Then we can't help you with that...

what do i do about the sound cutting out when i connect the two red wires together and will it happen with an amp

Don't connect those two wires together seems the logical solution...

 

[jbatts29]

but i have one output from the amp and two speakers. so how do avoid connecting them

 

[CocaCola]

As I said we need more info, you appear reluctant to actually help us by providing any info that I have requested to help you yet you continue to expect us to read your mind and know what you have in front of you... Spill the beans, tell us everything about what is in front of you, take pictures, lots of them describe your problems, basically paint an entire picture we can see...

There comes a point when you just have to toss in the towel, and I'm there... Until and when you are actually willing to help us and do your part in supplying the requested info I'm going to stop responding as there is no point to the secret charades game you are playing...

 

[BobK]

If you have stereo output from the MP3 player and want to run it into a mono amp, connect a 1K resistor from each MP3 output to the single amp input.

Also, an LM386 has a minimal gain of 20db or 10X. This is too much for an MP3 output. You might have to hook another resistor (something like 100 to 500 Ohms) from the amp input to ground to avoid serious distortion when the MP3 player is turned up.

Bob

 

[jbatts29]

thank you bobk. apparently your crystal ball isn't broken

 

[BobK]

thank you bobk. apparently your crystal ball isn't broken

Well, I read your original post and, though not entirely clear, I was able to make a good guess at what you were doing.

Bob