Ref75 bias

[2fastdriving]

I was sitting here, listening to my new ref5 and ref75, trying to get this break in process moving faster, when I had a thought. It was sounding pretty shrill and thin to me, which I just chalked up to breaking in. But I thought I should check the tube bias, since that is so easy to do. Well guess what...all four kt120's were way low on the bias voltage! I dialed them in, and most of the shrillness is gone, and bass has improved! At least it sure seems that way to me. Anyone have a similar experience with tube bias that was wrong from the factory? Is it just my houses power that might be a volt off or something?