[sdiy] Voltage Feedback Resistors and Circuit Stability

[Michael E Caloroso]

Oberheim OBX voice summing circuit.

As you add more voices beyond voice#4, the background noise increases
on the entire unit.  By 7 or 8 voices the noise is REALLY noticeable.

Oberheim rectified the circuit in OBXa and succeeding models by
lowering the feedback/input resistors on the summing opamps.

MC

On 11/14/20, Bernard Arthur Hutchins, Jr <bah13 at cornell.edu> wrote:
>  AWKWARD Questions
>
> (1)   In a synthesizer with standard signal levels of +/- 5, has anyone even
> HEARD Johnson noises, let alone been able to attribute it to a particular
> resistance?
>
> (2)   Given a 100k resistor, how does one (specific circuit/methodology
> please) observe/hear its Johnson noise as compared to a 10k?
>
> -Bernie
>