One of the simplest DIY builds, the AI Synthesis AI010 Switching Attenuator was also a test to see if I could find a better quality “tall trimmer” potentiometer.
But first, the build…
The panel and PCB are available for only $20. I got them from Modular Addict. I already had a stock of Thonkiconn sockets, and I went searching for the pots (more later).
Assembly entails soldering the pots and jacks to the board and affixing the panel. The board has convenient solder pads for the side supports of the pots, assuring mechanical sturdiness. You need to insure the pots are completely upright. I suggest first mounting the jacks to the board, attaching the panel temporarily, making sure the holes are aligned on center. Then solder the jacks. Remove the front panel and mount the pots. Use a small needlenose pliers to bend the pot feet around the board edge. Replace the panel and secure with jack nuts, keeping the panel centered. Then solder the pot feet, being careful to keep the pot vertical and centered in the panel hole. Finally, solder the pot wires.
Watch out for installing the panel upside down! (I did it, of course.) Fortunately, it’s easy to reverse. I put black nuts on the outputs with silver nuts going on the two inputs. It can be confusing, because the top input supplies the top two pots. The top input is also normalized to the bottom input, which make it possible to use the module as a three output passive multiple.
The Pots
Photo above shows Bourns PTV09A-4025U-B104 pots.
The Build Guide for this module lists the pot part as Tall 9mm Trimmer.
AI Synthesis sells these for $1.99 each, much higher than the typical price on Synthcube or Thonk. But I went looking for something better. I found Bourns PTV09A-4025U-B104 available on Digikey, for $8.64 for 10. These are a drop-in replacement for the typical blue 9mm ‘tall trimmer’.
The PVT09 series comes in a variety of mounting styles, shaft styles and lengths, and of course values. I scrutinized the technical data sheet and guessed (correctly) on the part number.
