Hi all, I'm new, so bear with me ;) I have a Beomaster 1000 receiver that has been in my family since first purchased in 1968-1970. Last year, I bought a Beogram 1000 turntable, and Beovox 1000 speakers, to complete the original system. All have sounded good until recently.  Now, when I start a record on the turntable, the first 20-30 mins. sound great.  Then, the sound gets muddy in both channels, like there is big distortion.  I do clean my records and stylus frequently, and have found that this does not make a difference to this change of behaviour.  I get tired of the noise, so shut it all down; then it sounds good again, next time I get it going. Any thoughts about this phenomenon? Thanks, Drew