Building a Piezo Pickup DIY: Understanding High Impedance and Capacitive Output

When working with piezoelectric pickups, it's essential to grasp the basics of their behavior, particularly when dealing with high impedance and capacitive output. In this article, we'll delve into the world of piezos and explore how they can be used in a DIY setup.

A key aspect of piezo pickups is their very high impedance, which allows them to function effectively even at low frequencies. This is due to the equation for voltage (V) holding true all the way down to bass frequencies. When no load or a light load is connected, the usual capacitor charge equation Q=CV applies, with the voltage across the capacitor being proportional to the amount of stress (bending, roughly speaking) applied to the piezo.

In essence, a piezo sensor physically behaves like a small capacitor – a thin insulating material with metallization on both surfaces. This makes it easy to understand how they can be used in a circuit. By recognizing how piezos behave and simulating their behavior in a circuit, we can create an effective DIY setup that takes advantage of their unique properties.

When using piezo sensors with capacitive output impedance, it's natural to wonder whether the mix pot will cause changes in frequency response. The answer lies in understanding how piezos behave when connected to a circuit. By recognizing these behavior patterns, we can design a system that effectively utilizes piezos in our DIY setup.

One popular approach is to use a 100k pot as a variable resistor, wired in series with the output of one pickup and the jack. This allows for adjustment of the level of each pickup independently. Another option is to wire the pot wiper to the output jack and insert a 100k pot between the two pickups on their hot side.

To further refine our setup, we can break the wire between the two pickups on their hot side just above the word 'passive' and dial down the overall level until it reaches the lower limit of what's useful for balance. Then, we can insert a 1M pot as a variable resistor in the signal line serially.

By understanding the behavior of piezo pickups and using these techniques, we can create an effective DIY setup that takes advantage of their unique properties. Whether you're looking to build your own pickup or enhance your existing one, this article provides valuable insights into the world of piezos and high impedance capacitive output.

Piezo pickup diy