Choose a soft source
Begin with piano or triangle-like material rather than the brightest synth preset.
Listen for: A clear note without a large buzzy top end.
Open PS-10 and try it →Start clean, then add softness, wobble and a restrained room around it.
A familiar keyboard voice with softened edges and gently unstable pitch.
Begin with piano or triangle-like material rather than the brightest synth preset.
Lower tone until the attack sits inside the track instead of in front of it.
Use a small amount of vibrato. Tape character is convincing when you notice it after a few seconds, not on every cycle.
Add only enough shared effect to put the keys somewhere. Long bright reverb undoes the worn, close feeling.