Altoids Tin Speaker

Step 5 Soldering Parts to PCB

There are numerous resources on the Internet that describe the process of soldering electronic components to PCBs. See, for example the soldering tutorial at ladyada.net. The order in which you install components doesn't really matter, although I have found working from smallest to largest them easiest. I assemble the board in the following order.

Jumpers
I use jumpers (small pieces of wire) in a few places instead of having a double sided board. There a several places in this design where I could not figure out a simple way of getting a wire from one place to another without crossing a second wire. Jumpers were my solution.

Note that the schematic calls for a second diode (D2) where power enters the LM386 chip. This was necessary when the circuit only consisted of the amplifier portion; I don't think it is necessary any more and I replace it with a jumper.

Chip holders
I put the chip holders in next. The two provide a relatively stable surface on which to balance the board upside down for future soldering. The orientation of the chip holders matters -- make sure the notched end is located as illustrated so that the chips are oriented correctly when inserted.

Small capacitors
The four small capacitors go in next.

Resistor
The resistor is positioned vertically

Diode
The holes for the diode should be 3/64. The spacing between holes is a little small so care must be taken fitting the diode in place. More important, however, is getting the orientation of the diode correct.

Large capacitors and inductor
These go in easily and form a sort of wall to support the battery holder. Care must be taken to ensure the correct orientation of the electrolytic capacitors. Note the location of the white strip on each capacitor. The orientation of the inductor does not matter.

Check your work
Be careful to orient the components properly. The orientation of the chip holders, the electrolytic capacitors and the diode matter. Check the layout diagram and the schematic or just make sure things match up with the pictures!

Comments

[Motts]

Would it be possible to add to and modify this into a sort of mini amp with a headphones jack?

[matth3w]

The ATS is mono which would cut down on its usefulness with headphones. I imagine that you could replace the speaker with a second jack (there would be lots of room without the speaker) for headphone output. To get stereo input and output you would have to put in a second amplifier chip or use one designed for two channels. Better to look into something like the CMoy Pocket Amplifier which is designed as a headphone amplifier, has stereo output, volume control, and is built using perfboard rather than an etched circuit board.

[Motts]

right, good plan. I have dozens of these tins anyway, no point in trying to conserve one. Thanks for the link!

[buiocchi]

why are there chip holders? just wondering what purpose they serve

[narcoduck]

When soldering, your using quite a high temperature. The miniature cicuitry in an IC chip can be damaged by this intense heating, and so most people use chip-holders, which are unaffected as they are only bits of metal and plastic. If you use one, but leave the chip in it while soldering, why even buy one in the first place? It's just a quick and simple way of avoiding damage to an expensive chip, as some 8 pin chips can cost up to 300 times the cost of a holder.

[matth3w]

The cost of the MAX756 chip justifies the use of the much cheaper chip holder. The chip holder makes it easy to remove and reuse the chip if you abandon a project and it is much safer to solder a chip holder than to directly solder a chip.