jacc1234
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[size=medium]
Friday 3/20 UPDATE[/size]
One month ago I decided to take the plunge into audio DIY by building Tangents Cmoy. Thanks to all of the information on these forums I was able to acquire the skills necessary to complete the project. After this small success I began researching my next project and decided on AMB Labs Mini³. This build is currently ongoing and I will be updating the thread as I go along.
My goal for this build log is to act somewhat as a step by step guide that will be helpful to others who are new to DIY or the Mini³ project. I would also like any feedback on my work because this is only my second project and I am still learning everything from proper multimeter usage to basic soldering skills.
All the pictures were taken with my Nikon D40 and Tokina 100mm f/2.8 Macro. I will be trying to closely follow the order stated in the instructions on the AMB Labs site. Enjoy!
[size=medium]Mini³ The Beginning[/size]
Here is the unpopulated Mini³ PCB that I purchased from AMB Labs:
The opamps I chose are for the "high performace" edition. U4 is the OPA690ID and U5 is AD8397ARDZ. These are the only surface mount components on this build and the instructions state they should be installed first.
Here are the locations where both Opamps will be installed starting with U5:
Optionally the instructions recommend using a small amount of thermal paste under the opamps to better transfer heat during usage. This is especially recommended for the AD8397ARDZ.
I have decided to use a small tweezer to scoop up some thermal compound.
Then I just wiped it on the metal pad where the opamp will sit:
After spreading out the paste I also fluxed the pads to prepare them for soldering:
[size=medium]Start Heating the Iron[/size]
Here is the AD8397ARDZ in position on U5, note the bevel designating pin 1 on the top left pin. If you have the board oriented correctly with the Mini³ logo at the top, pin 1 will be at your bottom left.
This was my first shot at surface mount soldering and it was not as bad as I thought. I fluxed the legs and pads then applied a small drop of solder to the tip of my iron. Holding the chip down with the tip of my tweezers I quickly dragged the iron tip down one leg. This worked perfectly! Once one leg was stuck down I made sure the opamp was still positioned correctly then soldered the leg diagonally across from the first. This made sure it would not move when I soldered the rest. Sadly with only two hands I was unable to get any pictures of this process.
With the first opamp down and my confidence soaring I prepared to solder the second one. I carefully positioned it then fluxed the legs and pads.
Here the second opamp is perfectly positioned and ready for soldering. There is only one issue that I wouldn't noticed till a few hours later....its upside down.
This is a nice shot of the second opamp after being fully soldered. Sadly, I still had not noticed that it was upside down at this point.
[size=medium]Putting Up a Resistance[/size]
After the opamps are in place the next step is to install the resistors. They are all through hole which means it should be easy. Sadly due to some sloppy technique I got some solder on some of the holes around my opamps. This made the process just a little bit harder.
First off I insert the resistors in the appropriate holes, bend the legs and then trim off the excess:
Make sure to start from the center and then work you way to the outside. Also always go from smallest to biggest:
This is how the board looks with all of the resistors installed. I also fixed the upside down opamp which was a pain once the resistors were in place. I ended up having to clip the legs off and install a new chip.
[size=medium]Time to Diode[/size]
Up next, diodes:
The process is basically the same as resistors, the main difference being that diodes are directional. Make sure to align the diode correctly.
Notice how the striped side of the diode is always oriented with the pointy side of the triangle:
After getting all of the diodes in the next step is to install the small ceramic capacitors. They are non-polar and very easy to install.
The next components to install are the Voltage Regulators. U1 is the LM317L chip and has three legs. You simply need to orient the flat side to match the silkscreen and bend the center leg a bit to line up correctly.
U2 is slightly more difficult to install. The TLE2426CLP chips legs are a bit more stiff and need to be bent down at a 90 degree angle. Remember to make sure the metal side of the chip faces down. Also you should apply a small amount of thermal paste to the board.
You want to make sure the outline of the chip matches the outline of the board. The chip is held in place with a screw and you want the holes to match. I had to bend the legs as the beginning of the fatter part for it to fit correctly. Also due to the thickness of the legs I found it easier to use a needle nose pliers instead of tweezers.
Next the Rail Splitter "U3" is installed in the same manner as U1. Here you can see it in place next to the OPAMP:
The Ferrite Beads are installed next. The only thing to keep in mind is to make sure they have at least 3mm of clearance from the PCB. I think the two beads in the front are a bit low but I am not sure what effect if any it will have on the amp. To be safe I would give them bit more clearance in the future.
Next to install are the Electrolytic capacitor. These are polar so care should be taken to make sure they are oriented correctly.
Here you can see were the C5 capacitors go as well as the + sign designating the positive side:
I continued installing the rest of my capacitors making sure to pay attention to polarity. After they were all installed this is how my board looked:
[size=medium]The Last Stretch[/size]
With all of the caps done there were only a few things left to do to get the amp finished.
All of the next parts simply click into place on the PCB and should hold firm enough to stay in place when the board is flipped. If not you will just need to hold it while you solder one leg.
First up is the potentiometer:
I then installed the DC power jack:
The 3.5mm jacks are now installed, make sure to fill through holes with solder:
The battery contacts ended up causing me more problems then anything else. I did not trim them down and because of that my battery was too tall to fit in the case. I ended up having to cut them apart to remove them because I could not de-solder them in one piece. Luckily I had a second pair for my other board but the moral is to trim off about 2mm of metal from all sides. You will also need to trim down the legs so they will go in deeper. Before you solder in the contacts connect them to a dead 9v and put them in place then try to insert it in the case. It might take a bit of force but just make sure you can get it all the way in and out.
Here is an image of the contacts:
I seem to have reached my post limit. I will add images of the complete board and my horrible casework in a new post. I hope you enjoyed it as much as I did.
Jacc1234
Friday 3/20 UPDATE[/size]
One month ago I decided to take the plunge into audio DIY by building Tangents Cmoy. Thanks to all of the information on these forums I was able to acquire the skills necessary to complete the project. After this small success I began researching my next project and decided on AMB Labs Mini³. This build is currently ongoing and I will be updating the thread as I go along.
My goal for this build log is to act somewhat as a step by step guide that will be helpful to others who are new to DIY or the Mini³ project. I would also like any feedback on my work because this is only my second project and I am still learning everything from proper multimeter usage to basic soldering skills.
All the pictures were taken with my Nikon D40 and Tokina 100mm f/2.8 Macro. I will be trying to closely follow the order stated in the instructions on the AMB Labs site. Enjoy!
[size=medium]Mini³ The Beginning[/size]
Here is the unpopulated Mini³ PCB that I purchased from AMB Labs:
The opamps I chose are for the "high performace" edition. U4 is the OPA690ID and U5 is AD8397ARDZ. These are the only surface mount components on this build and the instructions state they should be installed first.
Here are the locations where both Opamps will be installed starting with U5:
Optionally the instructions recommend using a small amount of thermal paste under the opamps to better transfer heat during usage. This is especially recommended for the AD8397ARDZ.
I have decided to use a small tweezer to scoop up some thermal compound.
Then I just wiped it on the metal pad where the opamp will sit:
After spreading out the paste I also fluxed the pads to prepare them for soldering:
[size=medium]Start Heating the Iron[/size]
Here is the AD8397ARDZ in position on U5, note the bevel designating pin 1 on the top left pin. If you have the board oriented correctly with the Mini³ logo at the top, pin 1 will be at your bottom left.
This was my first shot at surface mount soldering and it was not as bad as I thought. I fluxed the legs and pads then applied a small drop of solder to the tip of my iron. Holding the chip down with the tip of my tweezers I quickly dragged the iron tip down one leg. This worked perfectly! Once one leg was stuck down I made sure the opamp was still positioned correctly then soldered the leg diagonally across from the first. This made sure it would not move when I soldered the rest. Sadly with only two hands I was unable to get any pictures of this process.
With the first opamp down and my confidence soaring I prepared to solder the second one. I carefully positioned it then fluxed the legs and pads.
Here the second opamp is perfectly positioned and ready for soldering. There is only one issue that I wouldn't noticed till a few hours later....its upside down.
This is a nice shot of the second opamp after being fully soldered. Sadly, I still had not noticed that it was upside down at this point.
[size=medium]Putting Up a Resistance[/size]
After the opamps are in place the next step is to install the resistors. They are all through hole which means it should be easy. Sadly due to some sloppy technique I got some solder on some of the holes around my opamps. This made the process just a little bit harder.
First off I insert the resistors in the appropriate holes, bend the legs and then trim off the excess:
Make sure to start from the center and then work you way to the outside. Also always go from smallest to biggest:
This is how the board looks with all of the resistors installed. I also fixed the upside down opamp which was a pain once the resistors were in place. I ended up having to clip the legs off and install a new chip.
[size=medium]Time to Diode[/size]
Up next, diodes:
The process is basically the same as resistors, the main difference being that diodes are directional. Make sure to align the diode correctly.
Notice how the striped side of the diode is always oriented with the pointy side of the triangle:
After getting all of the diodes in the next step is to install the small ceramic capacitors. They are non-polar and very easy to install.
The next components to install are the Voltage Regulators. U1 is the LM317L chip and has three legs. You simply need to orient the flat side to match the silkscreen and bend the center leg a bit to line up correctly.
U2 is slightly more difficult to install. The TLE2426CLP chips legs are a bit more stiff and need to be bent down at a 90 degree angle. Remember to make sure the metal side of the chip faces down. Also you should apply a small amount of thermal paste to the board.
You want to make sure the outline of the chip matches the outline of the board. The chip is held in place with a screw and you want the holes to match. I had to bend the legs as the beginning of the fatter part for it to fit correctly. Also due to the thickness of the legs I found it easier to use a needle nose pliers instead of tweezers.
Next the Rail Splitter "U3" is installed in the same manner as U1. Here you can see it in place next to the OPAMP:
The Ferrite Beads are installed next. The only thing to keep in mind is to make sure they have at least 3mm of clearance from the PCB. I think the two beads in the front are a bit low but I am not sure what effect if any it will have on the amp. To be safe I would give them bit more clearance in the future.
Next to install are the Electrolytic capacitor. These are polar so care should be taken to make sure they are oriented correctly.
Here you can see were the C5 capacitors go as well as the + sign designating the positive side:
I continued installing the rest of my capacitors making sure to pay attention to polarity. After they were all installed this is how my board looked:
[size=medium]The Last Stretch[/size]
With all of the caps done there were only a few things left to do to get the amp finished.
All of the next parts simply click into place on the PCB and should hold firm enough to stay in place when the board is flipped. If not you will just need to hold it while you solder one leg.
First up is the potentiometer:
I then installed the DC power jack:
The 3.5mm jacks are now installed, make sure to fill through holes with solder:
The battery contacts ended up causing me more problems then anything else. I did not trim them down and because of that my battery was too tall to fit in the case. I ended up having to cut them apart to remove them because I could not de-solder them in one piece. Luckily I had a second pair for my other board but the moral is to trim off about 2mm of metal from all sides. You will also need to trim down the legs so they will go in deeper. Before you solder in the contacts connect them to a dead 9v and put them in place then try to insert it in the case. It might take a bit of force but just make sure you can get it all the way in and out.
Here is an image of the contacts:
I seem to have reached my post limit. I will add images of the complete board and my horrible casework in a new post. I hope you enjoyed it as much as I did.
Jacc1234
