I'm new to this forum and am (at least I was) pretty good when it comes to stereo equipment.
I have a Yamaha RX-V592 stereo receiver that up to a few months ago was sounding great. I won't go into the details of everything I have connected to it but the problem is this: Regardless of what input I have selected, the audio starts off very muffled, like lacking "treble". If I raise the volume enough, the 'treble' kicks in and everything sounds great. After a few minutes, the sounds goes muffled again, I increase the volume, and all is ok. This repeats for at least 20 - 30 minutes, maybe more, and eventually will continue to sound OK. It used to do it sometimes but now it is every time I use the receiver. It is 17+years old and obviously there is an audio circuit problem. Is this fixable without spending hundreds of dollars? The receiver has and continues to work flawlessly EXCEPT for this issue.
Thanks for any help you can provide.