On the single-sided pcb, there are pads and a R1 designation. These are NOT on the layout for the double-sided pcb, nor is it listed in the parts list. and as far as my wine-drinking eyes can see, it's not even in the schematic. on the SS (single-sided) board, it is connected to the INPUT A, along with the input cap. typo on the board layout? anyone built the SS version and figured this out?