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Category: making things

AMB Mini³

Published June 18, 2009

Today the PCB and other parts that I ordered from from the AMB audio shop arrived, so this evening I assembled an AMB Mini³. This is a rechargable battery powered, credit card sized headphone amp does a great job of driving my Sennheiser HD570 headphones.

While I didn’t take any photos of the assembly or inside of the enclosure (I just wasn’t in the mood tonight, for some reason), the assembly went very smoothly. Part of the assembly suggested that one put thermal grease on the underside of the AD8397ARDZ op-amp to help transfer heat from the chip to the PCB. Wanting to wash the PCB I didn’t want to do this, and I instead found that scraping a bit of solder mask from the heatsink trace allowed me to reflow the underside of the chip without much difficulty. After that SMT pads themselves went nicely, and everything else was through-hole. I had a few problems with battery clearance in the case, but adjusting the battery contacts slightly made everything fit comfortably snugly.

Everything was built as-specified for the high-performance version, except that I used a different knob and LEDs. The knob is a Kilo International OEJL-75-4-7 (Digi-Key p/n 226-4094-ND), which was the only 6mm shaft knob that I had laying around the house. The power LED (LED2) is green in place of the standard blue, and the rear (LED1) is a red, and matches the power LED brightness-wise. The LEDs are Mouser part numbers 630-HLMP-1790 and 630-HLMP-1790 and 630-HLMP-1700, respectively. To properly fit the LEDs, R6 and R7 were changed, using 5.1K Ω (Mouser 270-5.1K-RC) and 7.5K Ω (Mouser 270-7.5K-RC) resistors, respectively. I’m happy with the LEDs as they are visible in a normal room, but not particularly bright, even in complete darkness.

Using the iPod dock to 3.5mm (1/8″) cable that I made last week I connected my iPod to the amp and gave it a go. In short, I’m really happy with it. My headphones finally sound as they should with the iPod. Right now it’s charging on the kitchen counter, and tomorrow I’ll give it a full go at work.

Abnormal for me, I didn’t take very many photos during the assembly of the Mini³. For some reason I just wasn’t in the mood to document it as I normally do, so I only took the following three photos:

· AMB Mini³, from the front, fitted with a slightly non-standard knob and a green LED instead of the standard blue.
· AMB Mini³, from the rear.
· AMB Mini³ connected to my 5G iPod Video.

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Impromptu Cheese Spread

Published June 13, 2009

This is what happens when I’m cleaning the fridge and decide to turn the leftover (and rather old) stubs of high quality cheese into cheese spread. Taking the general idea from this Good Eats recipe I took about six ounces of cheese, 1.5 Tbsp of butter, one clove of garlic, and a pinch of (inadvertantly) refrigerator dried parsley and processed it all together. The resulting spread is very good, but quite salty. I think it’ll work best as a potato or corn topping, or maybe a sandwich spread to compliment something else.

The cheeses used were very dried pieces of Montgomery Cheddar, Stitchelton, Raw Milk Clothbound Cheddar, and Caerphilly which were grated on a Microplane to near the rind. These grated cheeses were then padded out to roughly six ounces with about two ounces of Tillamook Vintage White Extra Sharp Cheddar which is waiting around for me to use in more macaroni and cheese.

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USPS Click-N-Ship

Published May 11, 2009

After hearing from I decided to give USPS Click-N-Ship a try for both domestic and international packages. In short, it worked great, and didn’t require me to hand-fill any customs forms. Additionally, the postage costs a good bit cheaper than visiting the Post Office in person.

Now I just have to figure out the best way to handle adhering the labels / address forms to the packages. For today’s shipment (as shown above) I just printed the labels on plain paper and stuck them on with rubber cement. In the future I may consider self-adhesive full sheet labels, but that’s also a bit wasteful if I’m not printing at least two labels with each go.

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Customs Declarations

Published May 4, 2009

Filling out customs declarations is a real big hassle. Because of their odd size they must all be hand-written. Additionally, when I dropped all of these international SDrive NUXX orders off at the Post Office, the person working at the counter admonished me for sticking the declarations to the back of the packages. This bothers me because there isn’t enough room to fit them on the front of most small packages, the directions do not indicate that one should apply them to any particular area of the package, and I’ve historically had no problem with them stuck to the back.

Ah well, at least all the international shipments are set. Now I just need to sell a few more so that I break even on the project and everything will be set. Oh, and prep the CAD and artwork files for release…

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Functional / Safe Rear Wheel

Published May 2, 2009

After getting home from Danielle’s house (and listening to one episode of This American Life each direction) I spent some time finishing off my rear wheel. Once it was dished to my satisfaction, trued, and reassembled I fitted it to my bike and went for a series of test rides. The tire was the Continental TravelContact at 55psi, which is what was on the bike when the last two nipples broke.

The first was a rather uneventful jaunt around the neighborhood using the Winwood Decksters, so then I decided to go for a bit longer ride. After donning a headlight I took off on the ~15 mile local loop, up to (and through) River Bends, back down 21 Mile, through a neighborhood, then over to my house. Along this entire route I made a point of keeping my weight over the rear wheel as much as possible, especially when going up sidewalk aprons, over large cracks in the pavement, roots, sticks, etc. Basically, I was trying to put a bit more than normal (for me) force on the wheels.

Half-way through the ride, in River Bends, a quick check showed that the wheel was just as true as when I’d left the house. Even better, I wasn’t hearing any of the occasional spoke-twang sounds from that wheel. They were still occasionally there from the front (especially when cornering hard), but the rear was spot-on.

I’ll definitely be rebuilding the front wheel in the same way quite soon. Hopefully that will be the last time I touch them.

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Nipples: Replaced

Published May 2, 2009

One of the Wheelpro-design feeler gauges and stand being used to true a rear wheel which had its nipples replaced.

After four and a half hours (or so) of work, all of the alloy nipples in my geared bike’s rear wheel have been replaced. While the wheel is pretty true (maybe 0.5mm out at the largest spot) the dishing is still about 5mm off, so I’ll have to do more playing another day.

Also, that image above shows one of the feeler gauges recommended in the Wheelpro Book. It seems to work pretty well, although I do need to get better at using it. I imagine that will take quite some time.

(I also must fix the damned Park SW-40 spoke wrench. Its got a nice head on it, but the curved handle part bends too far over the head, so when the spoke comes off of the nipple at a slight angle the tool gets stuck in place.)

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Plastic Bottles from Sally Beauty Supply

Published May 1, 2009

Plastic bottles purchased from Sally Beauty Supply for applying boiled linseed oil to bicycle wheel parts.

At lunch today I purchased these two plastic bottles from Sally Beauty Supply to be used in applying boiled linseed oil to the spokes and nipples when rebuilding my bicycle wheels. I think I’ll give this a go after work today, as I’ve got a bit of time this evening and I could use a nice, focused, new project like this.

I’m just hoping that the hole on the tip of the larger bottle is small enough to allow for one drop at a time. It’s about 1mm, so I think it should be sufficient. If not, I guess I’ll just go to a dollar store, buy some cheap eye drops, empty the bottle, then use it. I think this will be all right, though.

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Sixteen Assembled SDrive NUXXs

Published April 28, 2009

Sixteen assembled SDrive NUXXs, with 2GB Kingston SD cards, ready for final testing.

Here’s one more SDrive NUXX photo for tonight: sixteen fully assembled devices with 2GB SD cards in the slots, awaiting final testing. Here’s a few more photos, which I’ll just link directly to:

· 16 front and rear end panels snapped into 32 bezels, ready for final assembly to begin.
· Rear panels fitted to the cases. Note that the plastic is left on the panels to protect them.
· PCB slid into an enclosure with the rear panel fitted, showing the front edge components.
· Front panel fitted on an SDrive NUXX showing the nice alignment of the tactile switches, LEDs, toggle switch, etc.
· Rear panel of an assembled SDrive NUXX showing how the DIP switches, reset button, and SIO connector align with the panel.
· SDrive NUXXs with panels and PCBs fitted, waiting for the installation of rubber feet and switch caps.
· Detail of the SDrive NUXX end panels, shown with the protective plastic film still in place.

I hope to have these, and all the other related orders (PCBs, uCs, kits, etc) ready to ship by the end of the weekend so that I can get them out on Monday.

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