Tiny amp kit

[kiyotei[TK]]

Edit March 7, 2009] I think adding a small heat sink to the amp would be a good idea, especially if you are driving two speakers in parallel as most of us are (much higher amp draw). Its hard to find one that small and so a small aluminum block could be used. Make sure you attach it with heat sink adhesive.

 

[Edit March 1, 2009] You can buy the amp from this link. They also have many other neat kits including voice changers. I have not used any other their other kits, just this amp.

 

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[Edit Feb 28, 2009] After some use with this amp and my throat mic, I think that the amp is clipping the signal at high volumes. I need the high volumes so you can hear me. I think I will have to add a secondary amp to boost the signal so I can reduce the output of the first amp and stop the clipping. Unfortunately the next sized amp chip I could use with this board requires too much voltage (around 18v) and I cannot provide that much power in my helmet.

 

I recently built this kit for my TK helmet. I replaced the LM386-1 amp that comes with it with a LM386-3 amp. It has more output power. The -1 amp is not powerful enough. Using the -3 amp it works really well and is much smaller then the Radio Shack amp. It comes with all the parts you need except for input, output, and power lines. You decide how you want to wire those. For instance I ran wires to 2.5mm panel mount jacks for both the input and output lines. I ran wires from my helmet battery pack to the board for power. You can power it with a 9 volt battery. It has a red LED power indicator but its optional. You don't have to add it if you don't want to (conserve power). Its easy to solder together. I bought the LM386-3 amp from Digi-Key.

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Here is a photo showing the Radio Shack amp (on left) and this new amp on the right.

 

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Edited March 24, 2022 by gmrhodes13
link removed no longer working

[kiyotei[TK]]

You can buy the amp from this link. They also have many other neat kits including voice changers. I have not used any other their other kits, just this amp.

 

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Edited March 24, 2022 by gmrhodes13
link removed no longer working

[kiyotei[TK]]

I think adding a small heat sink to the amp would be a good idea, especially if you are driving two speakers in parallel as most of us are (much higher amp draw). Its hard to find one that small and so a small aluminum block could be used. Make sure you attach it with heat sink adhesive.

 

I've also doubled up the amps. I now have two of these amps in serial. I run the output of the first amp into the input of the second. This helps boost the overall volume with out having to over drive the amps. They will shut down if you over drive them and get hot. The heat sink should help with that as well, though I have not yet added them. With the heat sinks I might be able to go back to just one amp. I'll keep ya posted. I really like this amp setup. Its cheap, each kit is $15 plus shipping, and very easy to build.

 

I think the lack of volume is due to the tinny speakers in the hovi's. They just don't get that loud. Now when you test the helmet in a normal sized room with few people around it sounds fine, but in a large room full of people, volume becomes a problem.