This is certainly a question that develops in many people's minds, no need to be apologetic.
I don't know why somebody would spend $100 on rodium jacks and not touch anything else. Granted, the nicer jacks will make a difference, but that would be a strange choice on its own.
I'd shy away from the silver if possible, instead opting for OCC if you can afford it. Yes, it is worth the price.
The stepped attenuator vs. Alps Blue debate at Bottlehead HQ results in the Apls Blue winning out most of the time. I came up with a new attenuator design that sounds a little better, but it requires at least 2 switches and some serious chassis space.
The Kiwame resistors are the same as a certain KOA Speer resistor available from Mouser for less $. On the Speedball PC boards, you would want to replace the R1 resistors (237 and 31.6 ohms). These values are very specific, the 237 ohm can vary by a couple of ohms, the 31.6 could vary by an ohm or two, with 33 ohms running slightly less current than stock, but still functioning just fine.
For power supply caps, yes, film caps will sound better. For a headphone amp, however, the size and ESR of these capacitors was chosen specifically to knock down the ripple in the power supply to an extent where you can't hear it in your headphones. If you were interested in going to something like 100uF @ 250V film power supply caps, you would want to drop in a power supply choke to assist these caps in accomplishing the goal. The Triad C-7X at Allied Electronics will do the job nicely without destroying your parts budget.
For coupling caps, we do indeed like the film output caps in place of the electrolytics, but boy are they large, heavy, and expensive. If you have the space, go for it!
-PB
