Hello, does anyone find that the atlas magnum amp produces a hum through the speakers when paired with the kt120s? I just put these tubes in my titan atlas magnum and there is a hum through the speakers even with nothing else plugged in. I didn't notice it with the kt90s. I use a fairly cheap power strip with audioquest power and speaker cables and dynaudio excite x16s. When the preamp is also plugged in the hum does not fluctuate with volume control. Is this a ground loop or noise from the amp? Can it be quieted? Thanks.