Looking for a good audiophile grade 15-20 foot 1/8" to stereo RCA cable for running the audio out on my soundcard / pc to a reciever . . . who / where ?

When I connect my p.c.'s soundcard audio out (analog-1/8" output) to my headphone amp/DAC's line-level input connection, I'm hearing a real high pitched whine/noise (I can pretty much hear it in the p.c. speakers too...) It's real noticeable and annoying and ear-fatiguing ...) Why would I...

I'm new to Head-Fi . Love the enthusiasm on here for all things hi fi and headphone ...(and in general, y'all are a fired up bunch.) Just kinda overwhelmed however, with the crazy degree of opinions being flung about ... And you know, like they say, opinions are like ********...

Hello... I'm new to this forum/site ... I began searching / browsing headphone amps on Ebay and was impressed with the specs/etc. of the Yulong Audio DAH/Mark II headphone amp/DAC unit ... A few others look good too for the similar amount of cash (Zero and StyleAudio...