New OB-6 keyboard, is this normal?

[Tristanmac72]

Hi All,

I just bought a new OB-6 Keyboard, and after a few days Ive noticed this not so random noise.
I updated to 1.8, and calibrated / tuned etc etc

The sound is an initialized patch with frequency turned down so you can hear it, its like every 5-6 notes it makes a subtle hiss sound... Its like a hiss then low hiss each time

I just added a 2nd WAV to show the sound when I lift off the note
the 3rd WAV file shows that every 6 notes it makes a hiss??

Please do let me know if I should return it.