[nagaokasan]

In your experience, if you need to run a 15ft cables, is better to run the speaker cable or RCA between pre and power amp and please let me know why.
Thanks in advance 

[nagaokasan]

Fogot to add that Im talking about low wattage power amp and full range speakers

[Tyson]

Better to have long speaker cables than long interconnects.  Because the signal is so low with interconnects, greater chances of losses.

[Digi-G]

I agree with Tyson.

Way back in the early 1990s I had my first surround system.  I had a dedicated 2-channel amp for the back speakers.  I decided it would be really cool to have that amp closer to the rear speakers, so I moved it from the front to the back and extended my interconnects.  Now granted, the interconnects weren't fancy or high end but my god, the noise they picked up - I couldn't believe it.  And it wasn't subtle.  They were noisy with no music playing and any music was so distorted...  I moved my amp back immediately.  I learned a good lesson if nothing else.

[mick wolfe]

Agree with Tyson as well. FWIW, I'll add that I've never heard an advantage of a 4' speaker cable vs. an 8' speaker cable of the same model and manufacture. In fact over time, I preferred the 8 footer.

[nagaokasan]

There seems to be consensus, thanks for your input

[JLM]

Long balanced cables (XLR) and short speaker cables would be ideal.