This is the bigger/faster/more/better quality we humans are born to seek. You mustn't let it get out of hand. I recommend you commit to being happy. Pursue it directly. It sounds to me your hobby is now to the point where it is bringing you more sadness than happiness. This can happen in a relationship with anything, and it means you must alter the relationship if your goal is happiness. Read "The Art of Happiness" by the Dalai Lama...excellent book.
If you don't deal with the problem at its root (which I believe to be about happiness), you may stop buying stereo equipment, but this problem will likely manifest somewhere else in your life.
If you don't deal with the problem at its root (which I believe to be about happiness), you may stop buying stereo equipment, but this problem will likely manifest somewhere else in your life.