Hello ,I got a new bass yesterday its a Peavey Milestone pluged into a little Peavey practice amp. It sounds great but when ever I turn the Pick-up blend control knob up the amp with start buzzing unless I'm touch the strings. If i touch the strings it will sound perfectly fine and if the pick-up blend knob is turned all the way down it also sounds fine. Would the problem be the amp? The amp is much older than the bass, i would of thought that there would be no problems in a brand new instrument.