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Step 6Build the PCB
So, have your boxes from Mouser and Digikey arrived, packed with goodies? Yeah, they cost you a bit but it'll be worth it.
Print out the component layout and parts list and set them out in front of you. The parts list will tell you what part in that big box corresponds to each designation, and the component layout will tell you where to put it.
I tried very hard to make as few top-side solder joints as possible. If you are using a pro-manufactured board this isn't an issue, but if you made your own board some of those joints will be tricky. You can place components in whatever order you wish, but in general it will be easier to install the potentiometers first, then work from smallest to largest where possible. For each component make sure you solder both top side and bottom side connections, since some traces rely on this top-to-bottom connection for continuity.
Also make sure that every component is installed in the right direction. The component layout drawing will show you how polarized components (like the big capacitors, ICs and diodes) are meant to be installed.
There are a few pads and traces that are very close together. Again, I tried to minimize traces passing between pins, but I couldn't eliminate all of them. This isn't as much of a problem on pro boards, but be sure that you don't make any solder bridges. Shorts like this can be harmless, or they can make stuff blow up. Be careful.
Finally, a note on the tiny temperature compensated resistor. Thomas' original design used an ordinary through-hole component, but I was unable to get one in a reasonable amount of time. By all means, if you can get a 2kohm 3500ppm through-hole tempco resistor, use it! Otherwise you'll have to rig up a surface mount part like I did.
When everything is soldered in place, inspect your work for mistakes and soldering errors. Now inspect again. And again.
***Please note that your board won't look exactly like my pictures. The pictures below are of the "alpha" PCB, which has since undergone heavy modification. The files I provided are all up-to-date.***
Print out the component layout and parts list and set them out in front of you. The parts list will tell you what part in that big box corresponds to each designation, and the component layout will tell you where to put it.
I tried very hard to make as few top-side solder joints as possible. If you are using a pro-manufactured board this isn't an issue, but if you made your own board some of those joints will be tricky. You can place components in whatever order you wish, but in general it will be easier to install the potentiometers first, then work from smallest to largest where possible. For each component make sure you solder both top side and bottom side connections, since some traces rely on this top-to-bottom connection for continuity.
Also make sure that every component is installed in the right direction. The component layout drawing will show you how polarized components (like the big capacitors, ICs and diodes) are meant to be installed.
There are a few pads and traces that are very close together. Again, I tried to minimize traces passing between pins, but I couldn't eliminate all of them. This isn't as much of a problem on pro boards, but be sure that you don't make any solder bridges. Shorts like this can be harmless, or they can make stuff blow up. Be careful.
Finally, a note on the tiny temperature compensated resistor. Thomas' original design used an ordinary through-hole component, but I was unable to get one in a reasonable amount of time. By all means, if you can get a 2kohm 3500ppm through-hole tempco resistor, use it! Otherwise you'll have to rig up a surface mount part like I did.
When everything is soldered in place, inspect your work for mistakes and soldering errors. Now inspect again. And again.
***Please note that your board won't look exactly like my pictures. The pictures below are of the "alpha" PCB, which has since undergone heavy modification. The files I provided are all up-to-date.***
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There are a few other tricks that you can use, like applying flux to the connection, a tiny blob of solder on the iron, and touching the tip to the joint.
But in general, a quality fine tip soldering iron is the key. It doesn't have to be expensive, either. I used a $30 Weller iron for this project.