June 2016 – The Quad Oscillator below is a common beginner project, with surprising nuances depending on parts and configuration.
In this case, I bought a kit online from GetLoFi.com. The kit arrived quickly, but was plagued by a few issues. First, my kit didn’t include the SPDT switch that was listed on the packing list. In fact, several other parts, while present, were completely different from what was pictured online or on the packing list. Most notable was the output jack – pictured as stereo, but mono was included instead. The battery clip was also completely different.
Included with the kit was a slip of paper noting a resistor substitution compared with the online instructions, apparently to allow the LED to shine brighter. Due to the poor online photos, this simple kit turned out to be way more complicated than necessary. There’s only three resistors, so how hard can this be, right? (I contacted the seller, and they quickly responded, but I never got the missing part.)
Despite all this, I assembled the kit and got audio out of it, but the LED got very hot (due largely to the resistor value modification). Later I took this to my dad for some troubleshooting, and to drill holes for the case (a holiday candy tin from Big Lots). We ultimately put the resistors back in the original configuration, and removed the 100 Ohm resistor on the output, otherwise we didn’t get audio.
The Quad Osc is good for drones, though I’ve had mixed results connecting it directly to my recording rig or submixer. Seems to be some impedance mismatching or something because it sounds way better plugged into an amp first. Still, it’s a lot of fun.
Here’s some samples: