I'm trying to locate a schematic for a circuit that allows a sustained resonance of guitar or instrument strings. There is already such a device called an Ebow, found here:
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However, this unit doesn't allow the oscillator to be varied, and I'd like to vary the string frequency this way.
If anyone knows where I could locate a circuit schematic or plans for either the above device or something similar, please share it if you would.
Thanks, Sam