Can temperature fluctuations affect audio gear?

Al, computer cooling, certainly a 'side issue' here is related to hifi. The point being that 'heat kills'. Enough statistical data exists to support this.
I had a Motherboard which had an automatic overclock feature when the CPU was pushed. I kept it on the most conservative setting and ran one of the Zalman Cu/Al 'mushroom' shaped heat sinks with the fan on 'full'. I chose a conservative CPU and never pushed it. I never saw my 2.4gig CPU go above about 2.6 I kept the dust bunnies cleaned and the all the cooler fins de-linted.
Point is valid that 'heat kills'.

Processing temperatures for Silicon devices run from about 1150c for some of the Junction Drives down to very low temps like 200c or less, used for 'sinter' or 'anneal' processes...usually right at, or near the 'end of the line'. Nothing goes above about 425c after 'metalization' which is usually an aluminum alloy and deposited somewhere mid-line. I am not current on what is used in State of the Art CPUs. They may have gone to copper or some other metal. Very thing / narrow aluminum has some problems with reliability and electromigration.

The 'statistics' to which Paperw8 also refers to are valid. They are well understood and proven. That they are statistics means you are dealing with populations.....large numbers of a given object some of which will crap out immediately and others which will last.....seemingly forever. The 'take away' is that Al is also correct: MTBF is the most visible metric applied to this stuff. The object of manufacturing quality is to produce product in the middle of the spec. All 'excursions' are suspect.
Semiconductor plants, called 'fabs' spend a bundle on 'rel labs'....Reliability. Here they torture what they make in an 'accelerated' lifetime. Indeed, before a new product or process is released to production, parts must go thru what is called a '1000 hour burn-in'. Too many failures or parametric shifts during the test are grounds to deny the 'go ahead' for volume production. What went wrong? The innocent are usually than punished.

I worked at a company that had a 'Hi/Lo' group. Bad lots were investigated....what went wrong? Especially GOOD lots got the same treatment....what went right? Go Figger.

Now, if you go for the 'weakest link' line of thought, buying mil-spec stuff for part of your design and cheap-o commodity chips for other parts doesn't make sense. This is why good equipment is not only well designed...but well executed, too. One could probably build a Bryston Copy for a fraction the cost of the real thing but out of cheaper parts and NO warranty! It wouldn't surprise me to learn that companies like Bryston had 'thermal budget' folks on hand. Engineers to calculate and verify type and amount of heat sinking. Even those IR imagers to look for 'hot spots'. All sorts of cool, hi-tech lab gear.

Mil Spec parts are not necessarily different from those you can buy. I say necessarily because electrically they may be the same and even made in the same fab. The difference is that NO rework is allowed, so if a production 'lot' has a problem, it is immediately either scrapped or degraded to 'consumer'. Other rules apply and the factory audits are BRUTAL. A factory must EARN the right to build Mil-Spec parts and be so certified. Than periodically audited. The taxpayer picks up the bill. You'd use parts like that, too, if a repair call took you 200 miles into space.

Having no formal education on the subject,let me give my two cents anyway.Use F with these examples.

Semiconductor@90f mounted to heatsink @ 30f.High transfer

Semiconductor@90f mounted to heatsink @ 50f Good transfer

Semiconductor@90f mounted to haetsink @ 90f Any transfer?

Semiconductor@90f mounted to heatsink @ 91f Any transfer?
Or the reverse, absorption?

12-06-10: Bigbucks5
12-05-10: Magfan
It would seem that as the ambient temperature and temperature of the electronics got closer and closer, the amount of HEAT transferred would get less and less. It maybe that BigBucks is right, but I don't see it. The constant delta above ambient may work but I just see stuff getting hotter faster than the room it's in....especially if the room is externally heated...sunlight, hot day...etc. At some point, the junction temp of an output device would be nearing limits and be unable to dump enough heat.....thru all forms of shedding...radiation, conduction, convection....(others?) But would that be at a constant delta from ambient?
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From above:
"It would seem that as the ambient temperature and temperature of the electronics got closer and closer"

I forgot to put my two cents in response to this statement.

This is baffling. But I DO see what you mean. Since a device and its enclosure/ sinking can move only so much heat.....so fast.... the junction will be above ambient as its heat migrates away. And I see they should stay a set difference apart. As long as you can sink the whole system.

But what happens in an enclosed space? I've had gear in confined spaces where the heat evolved simply had no place to go. Would the temp difference continue until the device failed? I'm talking Very Hot.....like over 100c, air temp. perhaps.
What happens if you put a cold / off device into a warm environment? Does the device warm....than as its temp rises to the 'delta' temp, heat begins moving the 'right' way?

My 'd' amp is on the shelf below my small dish receiver. If I close the door overnight, even with everything off/ standby, the next morning it is pretty warm inside. Even the amp is warm to the touch.

I walked into a very small demo room at a video store. They had 4 plasma TVs in about a 10x10 foot room......and it was almost too hot to breath. I'm sure the electronics was way too hot for comfort.

I spent 25 years building semiconductors from wafers to die. Apparently I didn't spend enough time in probe or reliability.

If the internal temp rises faster than the case could dissipate it,I would think it would keep rising,until failure.Don't forget,semiconductors operate at Celsius ratings.Look at the temperatures Almarg gave earlier.