I replaced the filter cap can in my old PANaramic 1210 (distant cousin of the Magnatone 213 Troubadour) last night and encountered a puzzling rectifier circuit. Can someone explain this to me please. Here's a photo. I've added the diode symbol for the small, black diode. It's clearly marked but you can't see it in the photo. The larger "top hat" diode is not marked w/respect to polarity, but my understanding is that the cylindrical part is on the cathode side and the "brim" part is the annode side--so it is oriented in the opposite direction of the other diode. So this diagram represents my interpretation: I'm more familiar with this kind of rectification scheme, when two diodes are involved: So what's going on here?