Greetings again, for the skeletons that still dwell here at ToyotaMinis

Recently I've noticed that the past two months or so while using my tape player, it seems there's an electrical hum in the background of whatever music I have playing thru it that correlates to engine speed; i.e. while accelerating and playing some Pantera, I'll notice a whine that follows in suit with increasing or decreasing engine speed in the background also playing through the speakers. Very noticeable in first through third gears. The one thing I can think of is my tape adapter which runs though my phone, as I haven't used any tapes themselves recently.

I find this quite an odd characteristic that came somewhat recently; symptom of a failing alternator maybe? A ground somewhere got loose? Never experienced something like this before...