Guide to keeping Amplifiers, AVR's, Integrateds alive - An EE's Perspective
Serendipity
Posts: 6,975
Just picked up an Onkyo 806 (thanks BlkynNupe!) and decided to write this as a guide to keeping your tunes going for as long as possible and avoid amplifier downtime. After all, who doesn't want their music playing after a hard day of work?
1. Outputs are low impedance and MUST be connected to high-impedance loads (your speakers). A low impedance load such as a direct short, speaker with voice coil damage, or mismatched load will severly shorten the life of your amplifier. The unit may go into a protection mode forcing the outputs into current-limit, or the unit may even turn off completely. On A/V Receivers, this is usually indicated by a flashing red 'Standby' light.
2. HEAT - heat is the enemy of any amplifier. Units that are run with components stacked directly on top run the risk of overheating and failing. As the temperature rises, the life of MOSFETs, capacitors, and IC's drops dramatically. A 20'C increase in temperature may shorten the life of some components by as much as 50%!
3. Voltage on speaker lines - this is very bad. Connecting an amplifier's output to another unit's output, or having voltage present on transmission lines is a surefire way to destroy many amps. So check your connections and make sure the power is OFF before connecting. A unit with its left and right speaker outputs shorted together may likely suffer damage on BOTH channels.
4. Mechanical damage or shock. Amplifiers that have been dropped should not be powered on as they may have internal damage. Usually circuit boards develop hairline cracks that are not always visible and applying power will most likely make the situation worse.
Note: the above is a general guide and an Engineer's perspective after seeing various failures in the field. Your results may vary. Cheers!
1. Outputs are low impedance and MUST be connected to high-impedance loads (your speakers). A low impedance load such as a direct short, speaker with voice coil damage, or mismatched load will severly shorten the life of your amplifier. The unit may go into a protection mode forcing the outputs into current-limit, or the unit may even turn off completely. On A/V Receivers, this is usually indicated by a flashing red 'Standby' light.
2. HEAT - heat is the enemy of any amplifier. Units that are run with components stacked directly on top run the risk of overheating and failing. As the temperature rises, the life of MOSFETs, capacitors, and IC's drops dramatically. A 20'C increase in temperature may shorten the life of some components by as much as 50%!
3. Voltage on speaker lines - this is very bad. Connecting an amplifier's output to another unit's output, or having voltage present on transmission lines is a surefire way to destroy many amps. So check your connections and make sure the power is OFF before connecting. A unit with its left and right speaker outputs shorted together may likely suffer damage on BOTH channels.
4. Mechanical damage or shock. Amplifiers that have been dropped should not be powered on as they may have internal damage. Usually circuit boards develop hairline cracks that are not always visible and applying power will most likely make the situation worse.
Note: the above is a general guide and an Engineer's perspective after seeing various failures in the field. Your results may vary. Cheers!
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polkaudio 255c-RT Inwalls
polkaudio DSWPro550WI
polkaudio XRT12 XM Tuner
polkaudio RM6750 5.1
Front projection, 2 channel, car audio... life is good!