I have a B-77 Sansui amp and on certain songs some tracks are extremely low. So far it has only happened on McCartney's voice on the bridge to You Never Give Me Your Money, Lennon's voice and the lead guitar on the title track of Sergeant Pepper's Lonely Hearts Club Band, and this morning I noticed it on the guitar break on Whole Lotta Love. Everything else sounds fine. I've switched out the speakers and got the same result. I've played the songs through itunes and my turntable and got the same result. On someone's advice i ran some pink noise through the speakers and used an RTA analyzer. The signals were fairly flat but it didn't seem out of whack. I have considered buying an equalizer and seeing if I can balance it out, but don't want to spend the money if it's something else. Anyone have any ideas?