Injectr

Instrument Preamp Injectr’s high-impedance instrument input, INST IN, feeds straight into a variable gain circuit which can produce a range of tonal responses, from clean to heavily overdriven. The smooth character of the DRIVE parameter is made possible by a soft-clipping topology using a classic 4558 op amp and four diodes, two silicon and two germanium. A post-drive LEVEL control is provided to trim the output of the preamp stage, which is accompanied by a RED LED, indicating that the signal is reaching the typical eurorack audio level of 10 Vpp. Because stringed instruments tend to have strong transients, it is suggested to adjust the LEVEL control so that the LED is illuminated with moderate to heavy playing. CV Extractor Buffered directly from the instrument input is a responsive envelope follower circuit, which produces a control voltage signal at the ENV output jack based upon the input’s volume dynamics. The ENVELOPE parameter adjusts the sensitivity of the circuit, depend