Dear All, I have just received my Sansui AU-101 today in really good cosmetic condition (well chuffed), and fired it up with Wharfedale Denton 80th Anniversary addition speakers (6 ohm suitable for 20w - 100w amps per manufacturers recommendation). However, with loudness turned on, if I turn the bass dial beyond 0 or turn the volume up beyond level 4, it creates that high-pitched sound as if when your mic is too closed to your speakers, like a loud boom in the room. Could someone help me out what could be the case, is it the speakers being too heavy or are we talking something wrong with the amp? With loudness on, it produces sweet warm sound till up to volume level 4, and with loudness off, I can turn it up more. With loudness on, if I turn the bass all the way to + same boom / high-pitched noise starts again. Many thanks in advance for your help.