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The Mute Audio GrubDAC

Construction Preparation
Note: Some pics show the BantamDAC, but the principles are identical!

Proper preparation in soldering an SMD PCB can't be over-emphasized. Find a good day, a good time of day, and try to relax. This can contribute to steady hands and a clear focus. It can mean the difference between having fun in doing this or creating loads of frustration. At right, you'll see the table I use at home to build projects. There are many methods of organization and this setup makes no particular claim at being ideal. However, it should be able to give you an idea for your own setup. With these ideas you should be able to organize your own workplace and ensure your chances of success in building the GrubDAC.
 
 

On the right side of the table, you'll see a trusty Hakko soldering station. Note that nothing else is on the right side of the small building board (a simple 1 x 10 piece of white pine), save for a lamp and a brass wool pad.. This gives unfettered access with the soldering iron. The brass wool pad is inexpensive, keeps the tip hot, and makes it last longer - highly recommended.

As mentioned, the building board is a simple piece of 1x10 white pine, with a mouse pad underneath to keep it from sliding across the table. The Helping Hands will be discussed in detail below.


 
At left, you'll see collection of tools. From bottom, left to right:
  • Cutter/Strippers (red handle)
  • Smooth-jaw needle-nose pliers
  • Flush Cutters
  • ESD-safe curved tip tweezers
  • Scissors
From top, left to right:
  • Electrical tape
  • Leatherman knife
  • De-soldering braid
  • Flux pen
  • Solder
The cutter/strippers were purchased at Lowes, the smooth-jaw needle-nose pliers from Harbor Freight for $1.99, and the scissors came from a first-aid kit. However, don't scrimp on the flush cutters. Those pictured are a quality pair that were purchased at Mouser. As mentioned in the GrubDAC overview, the tweezers are the single most important item in assembling an SMD board. These are ESD-safe and use curved tips.

The electrical tape comes in handy for protecting the edges of the board from the Helping Hands alligator clips. The de-soldering braid helps to clean up mistakes. The flux pen may be the second most important tool for assembling SMD - it allows you to put a very sticky, liquid flux right where it's needed. The flux is so sticky that it can actually help to hold the parts in place while soldering. The solder is a 63-37 eutectic, rosin-core solder that's 0.025" in diameter. That's almost too big, but smaller solder will break easily. The Leatherman knife is optional, of course, but seems to be a most handy tool. It keeps the table uncluttered with knifes, scredrivers, files, etc. that might be used only once - if used at all.

 

Another helpful idea is to utilize the parts bag labeling feature at Mouser and DigiKey when you order parts. This one is labeled "B-DAC C1 - C6". If you do this correctly, almost all you need to do is reference the parts bags with the silkscreen to populate the board.

Highly recommended.

 

Here is a set of helping hands - again, not very expensive: about $1.99 when on sale at Harbor Freight. Note the pieces of electrical tape to protect the edges of the board from scratches from the alligator clips.

These helping hands come with a magnifying glass, which comes in handy for inspecting the pins of the PCM chip. However, in this instance, the odd position of the magnifying glass is actually functioning as an additional support for the GrubDAC board. You want to make sure that the helping hands is holding the board so that you can apply a reasonable amount of force without tipping over.

 
file last changed:Monday, December 21, 2009 6:00:00 AM
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