[suneohair]

Hello everyone! After some thought, I have decided to jump into the fray and build my first headphone amp. At first, I was looking at pre-builts, but coming from my DIY background in computers and other electronics, it was a no-brainer.

So, my first project is a Mini^3. All the parts have arrived, but I need to get some better soldering gear as the fatty tip iron from radio shack won't cut it.

My first question is this, the mini^3 instructions note the need to countersink the holes for the main securing screws. I got the Hammond case thinking I would need to do this, but it seems to be done already. See picture. I was thinking maybe this was based on an old design of the hammond or something. Not a big deal really.

Second question is: What type of bits are recommended for drilling the holes for the front and back panel?

I am sure I will have more questions, so I will use this thread. I will keep a detailed photo log as well for the other newbs! Thanks guys! I am really enjoying my time here and am hoping to get to the bigger designs later.

Oh yeah, please say sorry to my wallet!

 

[Pars]

You might do a search as there are lots of threads here on drill bits. The top choice is typically a Unibit (stepped drill bit). It doesn't hurt to have a set of normal hi speed bits as well.

 

[MisterX]

Quote:

My first question is this, the mini^3 instructions note the need to countersink the holes for the main securing screws. I got the Hammond case thinking I would need to do this, but it seems to be done already. See picture. I was thinking maybe this was based on an old design of the hammond or something. Not a big deal really.

I have never seen a Hammond cases that didn't have countersunk screw holes on the panel and as such I would be inclined to believe the portion of the instructions you are referring to is for those that wish to have custom panels fabricated "from" the dimensional information provided.


Quote:

What type of bits are recommended for drilling the holes for the front and back panel?

Just a cheapo drill index is enough for the panels on those hammond cases (the aluminum is pretty soft and the holes for a Mini3 are small enough that a stepped bit is overkill IMO)

Here is a random example from Amazon---->

Amazon.com: Grizzly G9753 TiN Coated Drill Set - 50 pc. Metric: Home Improvement

 

[Uncle Erik]

The drill bits are not the most important part of drilling.

You need one of these:

Cool Tool: Auto Center Punch

An auto-centering punch is an absolute must. It lets you drill where you want - a must if you want holes to line up and look neat. I got mine for $10 at Home Depot, but there are cheaper ones out there.

Next, you want a T-square. You can get them for a few dollars at Office Depot, Staples or a stationery shop. You'll be able to cleanly lay out your holes and where things go.

A scratch awl ($5-$10 at hardware stores) is also a good tool to lay out with the T-square before you use the auto-centering punch.

Finally, use paper, pencil, ruler, and T-square to lay out what you want to do before you do it. If it doesn't look right, keep at it. When you get it where you want it, use the tools to transfer your work onto your casing.

And be sure to post some photos when you're done!

 

[fordgtlover]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif The drill bits are not the most important part of drilling. You need one of these: Cool Tool: Auto Center Punch An auto-centering punch is an absolute must. It lets you drill where you want - a must if you want holes to line up and look neat. I got mine for $10 at Home Depot, but there are cheaper ones out there. Next, you want a T-square. You can get them for a few dollars at Office Depot, Staples or a stationery shop. You'll be able to cleanly lay out your holes and where things go. A scratch awl ($5-$10 at hardware stores) is also a good tool to lay out with the T-square before you use the auto-centering punch. Finally, use paper, pencil, ruler, and T-square to lay out what you want to do before you do it. If it doesn't look right, keep at it. When you get it where you want it, use the tools to transfer your work onto your casing. And be sure to post some photos when you're done!

This is great advice on how to work towards a tidy case.

 

[suneohair]

Ok, so I started today. I was moving along and then I realized I put the wrong part in D4. I got out the desolding braid but I screwed up pretty bad. I think I screwed the connections (pads) on the board. Attached is a picture. Can I salvage this?

Just a note, I can't seem to get the rest of the part out. I was heating the back and pulling up on the other side. Eventually the part snapped and I was left with pins. There is one pin left in on top.

This really sucks, I would really like to salvage this. Thanks for the help.

 

[Uncle Erik]

Heat up the pad and use a solder probe, clipped off lead, piece of solid core wire, or possibly a straightened paperclip to clear the hole. You will want to hold whatever you're using with a pair of needlenose pliers - it will get hot.

I usually keep clipped off leads (and other trimmings) in a bowl next to the PCB. For one, it keeps stuff with lead on it in one place, but I frequently use clipped leads to clean out holes. You'll need to pass a couple through the hole, but they'll pick up the solder on the way through and it'll come out clean.

Also, let the PCB cool off between passes. If you apply a bunch of heat to it for a few minutes, you might have a trace or pad lift.

Let us know how it goes.

 

[suneohair]

Well I got it going. However, I am not getting anything out of my multimeter. I turned it on and used it (I know I am not supposed to!) It sounds ok. Then again, it is connected to iPod headphones as mine haven't come in yet.

I am going to borrow a multimeter from a friend at work who does this stuff.

I am at the very least relieved that it does something. A lot of money down the drain otherwise. It looks like crap, but I don't mind. I have a second waiting to be built. It won't be touched until I completely get this one working optimially and learn from my mistakes

I will report back when I officially run it through its initial check. Thanks for the help!

 

[diredesire]

Doesn't look terrible, the solder pads LOOK to still be down, although you may have scratched up some solder mask (no big deal). If you've got any flux lying around, I'd give a little dab in that area and then re-heat the solder. If the part is snapped off from the other side, grab the lead with some pliers, and then warm up the joint. Gently lift out the lead, and then clean up with some solder braid. When you're removing a part, IMO it's better to have a little extra solder and flux to increase the solder flow rather than drain the joint with braid first.

HTH

 

[suneohair]

Ok, I have changed the battery in my multimeter and tested it on a battery. It seems to read fine. Any idea why I can't get anything out of the mini?

I don't even get anything on the dc jack joints. I know there is power coming into this thing....

EDIT: Ok, I am an idiot. I wasn't using the ground on the side of the board. I have some readings. Multimeter is still a piece however. Will update tomorrow.