Some stuff from ICEPower200ASC manuals relating to heat:
Even with the high efficiency of the ICEpower200ASC module, proper thermal design is very important.
When doing the thermal design and tests it is important to note that the amplifiers are to be used for
music signal reproduction. Thorough investigations have shown that the RMS level of any music signal
does not normally exceed 1/8th of the peak value. Consequently, pink noise with an RMS level corresponding
to 1/8th of the rated maximum power should be used as the worst-case signal along with various music signals.
The ICEpower200ASC module has full onboard thermal protection for both the power supply and amplifier section.
This protection circuitry shuts down the module if the temperature reaches critical levels.
Please note that in case of thermal shutdown the module must be reset by disconnecting the mains.
And:
Thermal design is generally a great challenge in power amplifier systems. Linear amplifier designs operating
in class A or AB are normally very inefficient and therefore equipped with extensive heat sinking to keep the
transistor junction temperature low. The ICEpower200ASC is based on highly efficient ICEpower switching technology
providing high overall efficiency characteristics at all levels of operation.
Part of the “component” philosophy of the ASC–series is to provide a self-cooled component thus eliminating the
need for special attention to thermal design.
The ICEpower200ASC module is designed for music reproduction, which means that the output power of the amplifier
will never be continuous. If the average power exceeds 40W @ 4Ω (typical) for a long time at 25°C ambient temperature,
the module will reach its maximum allowable temperature and the temperature protection will be activated. At 50°C ambient
temperature more than 25W @ 4Ω (typical) average power will activate the temperature protection.
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25 Celsius = 77 Fahrenheit
50 Celsius = 122 Fahrenheit
//========================================================
I only have a crude understanding of Class D amplification.
Amplification occurs ONLY when their is a signal at the input. Amplification=heat.
Class A the amplification is always occurring whether or not a signal is present.
Class A/B the amplification about half of a class A.
The ICEPower200ASC does not contain a heat sink.
Larger ICEPower amplifiers (500,1000) do contain built in heat sinks and contain plenty of thermal
testing / warnings in their manuals along with suggestions for fans under 'severe' conditions and additional heat sinks.
So, to be honest, I have no idea what any of this means in the real world!
To bad Whippinpost does not have a thermal probe he could insert into his cabinet which would allow
him to produce a log of ambient temperature / time for us!