My Mixer (Behringer MX2004) emits a quite loud hum for about
a minute before it warms up. After it warms up it's fairly
good (the only noise is hiss). It's not 60Hz, it's more like
the semitone between Bb and B below middle C. Highly annoying.
I'm tempted to buy another Behringer mixer, but, I wonder if
they all do this? And are they all this hissy?
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