Speaker noises

Hi,

I am a newbie in HiFi and HT, and I just bought some used speakers, pre-amp and amp to build my first HT.

I tested my system for the audio part and wanted to know why there are very obvious noises from the speakers. Anyone can hear this kind of noise even in a room that is not so quite and when you are 5-10 feet away from the speakers.
Currently I only have front speakers (Revel F32), a center speaker (Revel voice) and a sub (JL Audio F112).

Below is my configuration. I am using some cheap cables because that's what I have in my hands right now, and the main goal of my testing was to show that the items work (otherwise I will contact the seller for a solution).

1. Laptop playing CD, connected to Pre-amp (Marantz AV7005) using RCA audio cables (like this cable but a cheaper version: http://www.radioshack.com/product/index.jsp?productId=2290564)
2. RCA audio cable from pre-amp unbalanced audio pre-out to Theta Dreadnaught single ended jack. (FL, FR and center signals are connected).
3. audio cable (Gauge 24 bare wire) from Dreadnaught to FL, FR and center speakers).

When I turn the volume down to 0 in the pre-amp, I can hear very obvious noises from all 3 speakers, and the noises basically remain constant when I turn the volume up in the pre-amp. Since all speakers have the same noise, it doesn't look like speakers' problem.
And I also tried a different pre-amp (a much cheaper one), and still get the same amount of noise, so this basically rules out the pre-amp's problem.

One thing I have to let you know is that I am using 24 gauge speaker cables connecting the Dreadnaught to the speakers. Revel F32's user manual has a table listing the recommended max speaker cable length when connecting to this speaker, the max cable length varies depending on the gauge of the cable. The table listed all the way to gauge 18, so gauge 24 wire is not included in the table.

I can understand speaker cables can affect the sound quality, and eventually I will buy some better wires/cables. Now I just use what I have in my hand for some basic testing. But I am not sure if it is going to cause this much noise. I am new to the HiFi and fancy home theater thing, so I am asking for experts' opinion on this forum.

Thank you very much!