Noise Feedback Instrument – Prototype
This prototype is a two-channel mixer designed for no-input feedback operation, where internally routed signals form the primary sound source. The core circuit consists of three cascaded op-amp gain stages arranged with non-linear feedback paths to promote instability, saturation, and self-oscillation.

Input 1 and Input 2 are left floating when unconnected, effectively acting as high-impedance nodes that can pick up and influence internal feedback signals. Both channels are summed via the Blend control, which determines their relative contribution to the mixed signal before routing to the Master Output stage.

Each channel provides an independent send output (Send 1 and Send 2), enabling external feedback loops or signal injection points. The first feedback path (Feedback 1) typically produces low-frequency pulsing and intermittent oscillation due to its gain structure and phase response. The second feedback path (Feedback 2) exerts a stronger effect on spectral content, introducing broadband distortion and shaping the overall timbral complexity.