DIY: Low Cost Gakken Tube Amplifier Kit
By James Grahame
Japanese kit builder Gakken sells a stunningly affordable Vacuum Tube Amplifier kit. It retails for about $125, including a set of four surplus Chinese vacuum tubes (2 x 2P3 and 2 x 1B2). The kit comes with a pre-built circuit board, so no soldering is required. All you have to do is screw the various parts together, plug in the vacuum tubes and enjoy your new toy. The kit even includes a pin straightener to ensure you don't accidentally bend a pin while inserting a tube.
I suspect that the audio output is extremely low, since the unit is powered by a couple of D-Cell batteries. My first mod would be the addition of a power jack on the back panel for a regulated 3V wall wart. My second "mod" would be to substitute some slightly higher quality speakers. The plastic horns included with the kit look really cool, but I doubt they sound anything but awful. Also, you should be warned that the instructions are in Japanese only, but there are lots of detailed pictures for illiterate westerners like me.
Purchasing one of these could be a bit of a problem for those of us in North America. Engadget featured it this morning with a link to a Korean online retailer, but the product page isn't in English. The same goes for the official Japanese Gakken site. Luckily, there seem to be a a few of these on eBay at very reasonable prices.