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I recently came to own an iPod Classic, which I had wanted for a while for its large storage compared to newer iPods and its clever Genius feature, which randomly generates a playlist with a little more cohesion than straight shuffle mode. I have been since enjoying everything from AC/DC to Zero 7 on my way to work.

In fact it turns out that AC/DC is more relevant than first seems, because I also recently came to acquire - rather cheaply - a Bose SoundDock. The reason it was rather cheap was the fact it came into my possession without a power adapter nor a remote control. I was not worried about the remote control; The SoundDock has buttons I could press to control volume, and I can control skipping tracks though the iPod. And although power adapters are not usually a big problem - one simply finds the a replacement of the correct voltage and adequate current rating - the SoundDock presented a problem. Firstly, and mainly, the cost; A proper replacement would set me back ~£40 - second hand - due to Bose tax.

Secondly the power supplies I had lying around would not work. The immediate problem was the fact that the connection was one I had never seen before. I later discovered it was a Molex Micro-Fit™ 3.0 connection, and buying leads with ends of this type - a 4x4 block - is particularly hard and expensive.

Normal Power Supply with ConnectorMolex Micro-Fit™ 3.0 4x4 Connector

Another problem is that all of the power supplies I own are AC/DC converters that transform the 250VAC supply into varying voltages of DC - a 0V line and an 9V line, for example. Searching for how the SoundDock's power is wired up lead me to an iFixit page, informing me that the SoundDock requires both a +18V and -18V line in addition to the 0V ground, at 1A each. I would need some way of generating both a positive and negative voltage of direct current.

Through more frantic googling, two solutions were presented to me.
The free solution: Find two power supplies lying around of 18V and with a current rating of at least 1A. The voltage generated by these two supplies would be floating, so there is a method to wire them together to produce -18V and 18V, along with a ground. Then solder wires providing the current to the correct locations on the SoundDock PCB board.

The free solution's downside would be the fact that two power supplies would have to be turned on at the same time to actually run the SoundDock at all. In addition if, by accident, I left one power supply off while the other was on I was assured Bad Things™ would happen and damage the SoundDock.

I opted for the correct solution, which was to use a single to dual supply converter. I was able to pick up from eBay at a reasonable price. I could then use a power supply which provided 36V at 2A and convert it into a dual -18V and 18V supply at 1A each. DC Single Supply to Dual Supply Converter

Unfortunately I didn't have a 36V power adapter lying around. Luckily however I know there are eBay shops that sell recycled supplies. I was able to find a very reasonably priced - and good quality - supply that had powered a Kodak printer in a previous life. 36V. 2.05A. Wonderful!

The Recycled Power Supply

I hooked up the supply to the DC/DC converter board and checked the result with my multimeter. The result was a steady +18V and -18V. At this point I could have soldered the wires directly to the SoundDock but I had decided I was going to do the job properly and ordered 5 wires with the correct Micro-Fit™ socket. The result was perfection. The SoundDock works beautifully.

I had always believed the main reason for Bose's reputation of quality is the placebo effect caused by paying for expensive equipment and playing music a little louder. I will gladly admit I was wrong. The quality of the sound from a machine of this size is incredible.
Then again perhaps it's a placebo effect caused by not paying a lot of money for it.

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Teggers Blog

Stuff I do when bored.

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