Adding a LM386L Amp to an APC

[Mojohammer]

I was breadboarding a Atari Punk Console and was able to get it working (first attempt at this), and figured I would add a LM386L Amp to the same board to boost the sound coming out the speaker. Unfortunately, when I have the LM386L amp hooked up, the sound level either remains the same or decreases.

I tried both using a single 9 V, two 9 Vs on the same circuit, and also separating the power.

Is this purely a grounding issue?

When I googled Amp and APC, it looks like most or all people put the two elements in two separate containers with their own power supplies and run the output from the APC to the Amp.

I have another breadboard coming in the mail and am going to separate them when it gets in, however, I would like to keep them on the same board, as the strip board I have, has room for both.

While I am typing this I realize, I have not tested the LM386L amp separately, I will do that tomorrow.

[Uncle Krunkus]

Also, what kind of speaker is on the 386?

[Mojohammer]

I changed out the not very good radioshack speaker for a decent 50mm 8ohm speaker. Sounds much better.

I could not test amp circuit, as I was having trouble connecting up the leads from a stripped headphone wire.

I will just build the APC as a stand alone unit. I was able to find a little speaker with a male 3.5mm plug and built-in amp on ebay that was supposed to fit on the bottom of an MP3 player. That will work for now I guess.

[JingleJoe]

If I am right in remembering the atari punk device uses a 555 timer and they can output 200mA, which is enough for most small speakers. You could just put your speaker in series with a capacitor (about 1uF) and a resistor to increase the overall resistance to a value which only draws 200mA at your operating voltage. (Remember too, I=V/R, ohms law )

[bubzy]

to electro-music mojohammer!

it might help if you can show the schematics you are following. if the output is the same with both the lm386 and the apc, you may have just wired something up wrong, or you may have the lm386 wired in a low gain configuration, the APC itself is quite loud and doesnt normally require amplification.
but a schematic of what you have built would certainly be advantageous

[Mojohammer]

Thanks for your your input. I have pulled the amplifier off for right now. Tried making a APC on a strip board. I can say one thing, I need to practice my soldering. Good thing I bought a bunch of strip boards

[JingleJoe]

If I may offer a soldering tip: it's all about heat transfer, hold your iron on the board and the component for 2 or 3 seconds, then touch the solder to them and it should flow nicely on to them both if they are hot enough.

[Mojohammer]

Thanks for the advice,

I practiced a ton the other day on my messedup strip board. I also understand you have to make sure the tip is tinned properly also. I can make consistent "blobs" around the holes and wires, or at leaset what I consider consistent and clean.

[SineHacker]

I've been using and learning about the LM386 lately, it's usually very loud and it's difficult to stop it self-oscillating! so I would second that you might have misplaced a lead somewhere. I have just been following schematics from the datasheet.

Also I have found that if you use it with other chips and just use one battery, it does tend to misbehave - I haven't found a way around this yet so I usually end up with separate circuits. I would like to figure out how to fix this though!

[JingleJoe]