Hello, I'm new here so if this isn't the right place to post this, I apologise in advance.

I own a Technics SA-160L which serves as secondary amplifier for when I listen to music at my desk, like as I post this for example, however very recently (over the past 2 or 3 weeks) it appears to have lost a large portion of it's sound, the bass is considerably duller and the only cure for this is to sit literally on top of the speakers, or raise the volume to that which is too loud for others in the building, is the amplifier nearing the end of its life? If not how can I remedy this problem?