adding noise. Plug a smartphone into a stereo with the volume maxed out and you'll likely get a lot of distortion. A preamp adds that volume without the noise. The need for a preamp bounces back and forth between audiophiles. Some prefer not to introduce an extra step between the music's source and the speakers, but others find it helps create a "warmer" sound. What does this mean for your cheap setup? You can skip it from the outset because most modern receivers handle this fine. Cables: It can be tempting to try justifying the purchase of expensive Monster cables for speakers or other components, but when it comes down to true sound quality, it doesn't matter. As a general rule of thumb, don't buy cables that look like junk and have cheap-looking insulation. Even speaker wire purchased at home hardware stores work fine. Michael Fremer is an advocate for quality cables but suggests, "A good audio store will let you use a credit card to take home cables to try. If you don't hear an improvement, you can just return them." Photo by MIKI Yoshihito . So what does this mean for your stereo? I talked with Ethan Winer, audiophile and author of the upcoming book The Audio Expert , about what components matter. He had this to say: The most important components to own are the source (CD and Blu-ray player), a receiver of some sort and good speakers. Buying a separate preamp and power amp gains nothing,