if it's decent enough cables you should not worry about it. every decent cable has good shield and is braided to prevent crosstalking and interference so you should be more then fine with your mono-price cables. i used and made tons of rca cables and there really is no benefits unless your doing something like greater then 30ft or so and then is where you would want to balance the cable with a dedicated ground(negative,positive,ground. rca jacks can be balanced like any other plug. balancing is just separating the negative/cold and positive/hot with a dedicated ground for each channel).

only way better cable might work is if your amp's power supply is not doing a very good job and is not properly grounded or the filtering power supply caps are not doing their job. can be possible house power is dirty but that's only an issue if the house is like over 100 years old and never been redone at all, but even so a rarity. if it was house then simple surge protector with 20db noise attenuation will get the job done and clean up the signal if it was really problem with wall socket. overall though with that said you defiantly shouldn't worry too much and you'll be fine with your current rca jacks. i never even had issues with rca jacks more then 30 years old that came from old stereos i would collect.