Konstant Lab Active Stereo Piezo Pickup

These preamps were originally designed for wooden tongue drum builders. They produce excellent sound and are a great choice for DIY music instrument makers.

Manufacturer's description

The Active Contact Stereo Piezo Pickup is ideal for capturing a wide range of acoustic musical instruments in both traditional and experimental music settings. It includes a high-quality pair of piezo sensing elements that can be placed anywhere on the resonating instrument, and active electronics powered by a 9V battery that amplify, correct, and impedance-match the output signal from the piezo elements to a level suitable for further processing in your audio chain.

The pickup allows for high-quality, low-noise reproduction of the instrument's sound thanks to the use of high-quality components and a well-tuned electrical circuit. Additionally, its capabilities create a full stereo sound image, providing new and previously unknown possibilities for amplifying your musical instrument. The pickup is also suitable for field recording applications.

The active stereo preamp itself features a precise high-impedance input based on discrete JFET transistors, ensuring very high-quality reproduction of the signal captured by the piezo pickup across the full frequency range, from the deepest lows to the sparkling high harmonics of your instrument.

With an input impedance of Rz=10MQ, this preamp (after desoldering the piezo pickups) allows the connection of other pickups and instruments that require a high-quality shielded high-impedance input, such as various electric guitars and bass guitars, electro-acoustic pianos, experimental musical instruments, and others using electromagnetic or piezoelectric sound capture principles. It can also be used as a high-quality impedance converter from HiZ input to LoZ output. The possibilities are endless.

The internal circuits provide an overall voltage gain of 6B (which is equivalent to doubling the voltage from input to output). The stereo preamp offers the ability to balance the relative gain of each channel so that the combined output voltage is placed precisely in the center of the stereo field (Balance function). Additionally, the output audio signal can be frequency-corrected by adding bass or treble components using the DIP switch section, providing additional sound options when capturing your instrument.

The preamp allows for both stereo and monophonic operation (selectable by a small switch under the battery), enabling the mixing of both stereo channels into a single mono channel and using a standard 6.3mm guitar jack for further signal processing with common guitar effects or amplifiers. The 9V battery connection to the stereo preamp is activated automatically when the output jack is connected. You don't need to worry about the battery status, as a blinking purple LED will indicate low battery when it reaches the end of its life.

The stereo preamp is constructed as a printed circuit board attached to a 9V battery holder with a connected pair of piezo elements and a 6.3mm stereo jack output. It can be mounted directly into a musical instrument or an enclosure that you can make yourself.