Vortex Sound Research

Hi all! So I've just taken the plunge and bought my first synth, an MS2000, which so far I've been over the moon playing around with. However, it seems to be humming a bit. The hum doesn't get any louder or quieter if I turn the volume knob up or down, but is just kind of always there. Here's an audio clip of it, with the volume knob set to around 11 o'clock (and some chords for reference, so watch your ears!): https://drive.google.com/file/d/1SV38aza6co9qINJHSJ3C1EgGcnEyY_kq/view?usp=sharing

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Hoping some of you can help me figure out what's wrong with this thing as I'd hate to have to return it or spend a fortune getting it fixed. Please say if you need additional info. Thanks!