Nice review, the quality control issue is concerning although it only seems that a small minority has been effected. Quite a few people have this amp and nearly all don't have an issue with the volume control. The most common issue the supposed grinding on the volume knob is easily fixed as its caused by the volume knob being pushed in whilst in transit against the chassis. If the knob is loosened and slid forward slightly with an alan key it fixes this issue. I have a hunch that the rod on yours was warped as a result of this same reason as it was punched in hard whilst in transit causing it to warp. More of an issue with packaging I think.