Showing posts from August, 2022

The humble vacuum tube, and why is it (not always) better than solid state

  vac·u·um tube /ˈvakyo͞om ˌt(y)o͞ob/ noun an electron tube containing a near-vacuum that allows the free passage of electric current. Ah yes, the humble vacuum tube, ancestor of the transistor. Also known as electron tube. Or tube. Or valve (for our British friends). As its name implies, the components are housed in a glass (or sometimes metal) envelope that is at high vacuum, where all the magic happens. Get ready, because we're going to say "tube" a lot in this article. Tubes: a (very) short history and (very) short explanation of how they work The simplest of tubes - and also the first practical application of the concept - dates back to 1904 and is called the Fleming Valve, invented by John Ambrose Fleming. It contains a single heated electron-emitting cathode and an anode. The current can only go in one direction: from the cathode to the anode. The current flowing between the cathode and anode can be controlled by adding grids and applying a voltage on them. Most tu

The Mother Of All Switchers, or switching multiple inputs between multiple outputs

  My latest purchases, which I will review once the instrument in question is back from the luthier, exposed a small problem for which I could not find a ready-made solution on the market and instead had to make my own. The Problem™ I have 2 amps. Both of them have an effects loop. I am lazy and I don't want to play "plug-unplug" whenever I want to switch between both amps. I could not find a 2-channel switcher let alone a 3-channel one. Since what I need is not sold, I had to make one. The Solution™ Behold, The MOAS (Mother Of All Switchers)! The circuit itself is super simple. It is entirely passive and does not require any power to function. The LEDs are purely for aesthetic reasons and do nothing except be shiny. The commons of the 4PDT toggle will receive the +9V from the DC jack (through a current-limitting resistor), the input from the instrument, the pedalboard in, and the pedalboard out. Each side of the 4PDT is connected to its own LED and respective jacks for t