Are DIY Cables Worth It?

Fellas,
I am in the same boat, trying to find the answer to GOOD, QUALITY interconnects and speaker cables. Lately there is a "air" hiss from my Avalon Eclipses when I play LPs. It is not obvious while a track is playing, but between tracks and between LPs it is certainly there.
This concerns me more because I am considering a long interconnect run from BAT 3i preamp to Primaluna 7 mono amps (approx 30 ft) and short (1-2 meter) biwire speaker cables.
I have been using video cable i.e., 75 ohm shielded RG6, with Canare RCAs all DIY terminated. One poster said that "interconnects are supposed to be 50 ohms, not 75 ohms. I was not aware of such a difference, or that this may be a non desirable effect???
Should I replace my DIY interconnects?
IS my proposed 30 ft interconnect- pre tp amp, and short speaker cable- a good idea? Or is a long speaker cable, short interconnect, better?
BTW, Heyitsmedusty, I am not trying to hijack your thread, but this may influence your decision and shed some light on your decision especially if there is a particular ohm rating which must be considered with regards to interconnects.

Gregm,

When you say return you obviously mean the ground or the part of the rca that connects to the outter part of the female?

Yup, that's correct freemand -- the "neutral" part of the equation:)

I've experimented with doubling up and using heavier gauge for the return run of speaker cables and it's interesting how it impacts the sonic characteristics.

I still need to try the Home Depot extension cord speaker cable project, heheh.

Since speakers run on AC through the wires, how does one determine which is the 'return' run of the cables on which to use the double run? And how can that make a difference since the current direction changes up to 20000times a second?