Yeah, I just referenced them both for completeness, but I consider them to be basically the same.
Saw another thread with this schematic of the default audio output path of the NES:
What is all that circuitry for between the CPU pins and the mono audio output? Some kind of amplifier I guess. Would I get better output by feeding only one pin from the CPU into that circuit and the other into a separate replicated circuit?
It's worth noting that ben heck's method seems to tap the same places in the schematic as the other method even though they're on different physical places on the NES mainboard (opposite sides of the CPU).
Edit: Found a spare Motorola 74HCU04 laying around, so I'm playing with the idea of breadboarding a double amplifier circuit based on the NES schematic just for the heck of it. I'll put a couple of 10K pots on the input end of the breadboard to implement benheck's cross-mixing method. The hard part will be figuring out what I can use for the inductors, because I have no idea how to identify the inductance of any that I may have laying around, nor am I experienced enough to make one of my own. I also can't find the 39uH inductor on the NES itself to use as an example
Edit 2: Ah, I didn't know that blue and green resistor-like components can be inductors rather than resistors! The green component FC1 on the mainboard near the RF box is the 39uH inductor in the schematic. ...doesn't help any though, as I don't seem to have any resistor-coded inductors laying around unless I want to gut both NESes
All I have are some crude bare-winding ones with no way of identifying them, other than something over the top like using a step-down transformer AC power supply to make a crude signal generator. Maybe I'll just do the no-amplifier stereo hack