How to Buy a Power Amplifier

A power amplifier combined with a separate pre-amplifier generally provides the best possible sound quality in a stereo system, and the separate components provide a flexible upgrade path.

Difficulty: Moderately challenging

Instructions

Things You'll Need:

• Cables
• Power Amplifiers
• Pre-amplifiers

1. Listen to both tube and solid-state amplifiers and become familiar with the difference in sound quality before researching specific models.

2. Check your speaker manual to determine minimum and maximum power requirements.

3. Check the nominal impedance specification for your speakers.

4. Consider only models that will be compatible with your current speakers.

5. Read reviews in audiophile magazines.

6. Take some of your favorite albums when you audition amplifiers. Play pieces that will challenge the bass and treble, imaging and soundstaging, and dynamic range capabilities of the equipment.

7. Listen to recordings of music you've heard performed live, if possible.

8. Arrange to listen to the amplifier at home through your own system.

9. Compare at least two or three models before making a decision.

10. Base your final choice on the sound quality in your current system, price, manufacturer's warranty, and dealer service before and after the sale.

Tips & Warnings

• Other than how it affects sound quality, power is rarely a consideration for solid-state amps.
• If you have low-impedance speakers, make sure the amplifier power is a match for your speakers. If your speakers require a significant amount of power or are rated below 4 ohms, stay away from tube amplifiers.
• Budget between $70 and $800 each for interconnects and speaker cables. Expect to spend at least $300 on cables to get value out of your investment in a good power amplifier.
• If your pre-amplifier has balanced outputs and your power amplifier has balanced inputs, buy a pair of balanced cables for a significant increase in fidelity.
• Avoid tubed products if you don't want the hassle of finding and replacing tubes.
• Rule out high-powered amplifiers and pairs of mono amplifiers if you don't have air-conditioning in the room where you will use them.

on 6/30/2006 An amplifier's quality is roughly based on its THD (Total Harmonics Distortion). A tube has THDs typically about 1% (there are better ones). A solid state amplifier can be as good as 0.01% (100 times).

A tube amplifier sounds good because it produces 2nd and 3rd harmonics. The surround like sound can be duplicated by a surround preamp to a solid state amplifier too. The problem is the price tag of an elegant tube amplifier. At the very high price, we could buy an award winning home theater.

on 11/22/2005 If your amp is over 500 watts and the headlights dim, buy a lighting cap. It helps the lights and extends the life of the alternator.