Amp heats up and shuts off - Help!!

[E-Stat]

When ever i push up the volume of the amp to anywhere beyond 40% mark on the volume control - its protection circuitry just cuts in and pushes it to stand by mode. I assume this should be due to overheating or overloading - as per the amp literature.

It is quite possible that there are no problems at all in your system, other than an unintentional case of overdriving the amplifier. Since your subwoofers are powered units, that would likely rule out the difficult load scenario that some have speculated upon. I believe you may simply be unaware of the relative nature of the gain (volume) control. Full output of most amplifiers usually occurs far earlier than at the maximum position.

Basically, all audio systems are composed of multiple amplifiers, each driving the next one in the signal chain. Engineers will usually build in some extra capability in each stage in order to cover variations in other components. In your system, there are three output stages: one in the DVD player (or tuner), one in the preamplifier section of your integrated amp, and one in the power amplier section of your integrated. Most CD/DVD players put out somewhere around 2 volts. In some cases, even more. Your integrated amplifier, however, is likely designed to operate with far less. For example, my NAD 320 BEE integrated can be driven to full output with a .22 volt input. That is roughly one tenth the amount that is being sent to it by the player. Since I'm not exactly sure what you mean by 40%, I will use the clockface as an alternative way to visualize the setting of the gain control. With my Pioneer CDP, I get full output on the NAD at about 10:00 with most content. Moving it further simply pushes it into overload, called clipping. The sound becomes noticeably distorted. Persistent clipping will usually result in the protective circuitry of an amplifier to intercede.

In another system of mine, I take advantage of this situation and simply eliminate the middle stage. The CD player drives the amplifiers directly. In this system, full gain occurs at just below the 2:00 position. In both systems, I am getting the full output of the amplifier being driven, albeit at very different settings on the gain control.

rw