Resistive Ladder Volume Control

preamp

[jefffolly] published some straight forward plans for a passive volume control. It uses a resistive ladder built across the contacts of 12W rotary switches. Each resistor provides a 5dB difference, and he recommends using 0.1% tolerance resistors to maintain accuracy. The use of discrete resistors instead of volume pots means that the output is much more predictable. All of the RCA sockets were connected using oxygen-free copper wire.

Passively Cooled Computer

This came in on the tipline: [Ville ‘Willek’ Kyrö] wanted to build a fully passively cooled computer. That means no fans at all. He started with scrap aluminum heatsinks, ripped apart a cpu heatsink to get the copper heat pipes, and began surrounding the boards with heatsinks to form a case. Cooling down the powersupply was the hardest part, as it did not lend itself to the flat surfaces of heatsinks. Any passive case with powerful components will inevitably be huge and heavy; this one weighs over 20 kg. He says, “It might not have been worth it, but it sure was weird watching the computer boot up with no sound at all”.