I'm currently using an RA-1 with my GS1000i headphones and would like some opinions regarding the HPA-1.
From what I have gathered, generally, the HPA-1 has "less grain" than the RA-1.
From pictures I have seen of both amps, the HPA-1 appears to be better built even though it contains "the same circuit" as the RA-1. The HPA-1 seems too use 4 capacitors instead of 2, like the RA-1. Are the additional caps used to bypass the PS? I also notice two small caps in parallel with the output. I'm assuming these form a low pass filter on the output.
Basically, is it worth trying to find an HPA-1 to replace my RA-1?