I highly suspect that it's oscillating. RF oscillation gets reflected back down into audio as a heterodyne or as an "angry" sounding hiss.
How's your wiring? Grounding? Is there a 0.1uF ceramic from V+ to V- on every opamp package?
This is my schematic:
I'm saying this for your education, not to be snotty - a schematic is a dramatic simplification of a circuit. It by no means puts all of the information about the circuit on paper. The actual wiring and layout may be *critical* to getting good results.
I don't see any 0.1uF ceramic from the original schematic. I am using a dual opamp instead of two tl072.
Also since this is a single supply version so it is not supposed to have v-
The original schematic may well not have power decoupling caps on it. That does not mean that they should not be there. And in single supply circuits, ground is connected to the V- pin of the opamps. The opamps are not smart enough to know the difference. It is good practice to put a 0.1uF or 0.01uF ceramic cap from the V+ pin to the V- pin on every opamp package. Sometimes, even most times, you can get away without this. But it's never bad practice to do it.
It is possible RF/ultrasonic oscillation is not the cause of your issue, as I'm only guessing. But it's a problem that has happened to me before. Other possible causes are:
- a mistake in the schematic
- a mistake in wiring the schematic into real parts
- poor layout; getting the wrong thing too close to the wrong thing, or running wires where they shouldn't go
As an aside, is this on a PCB? Stripboard? Perfboard? Chances for the board itself causing issues increase in that order. One screaming advantage of PCBs is that they are VERY consistent. Stripboard is less consistent, and perfboard is a handicraft, each one being different.
- construction problems, such as incorrect part values, connections to the wrong pins, broken parts, soldering issues, and so on.
