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Can temperature fluctuations affect audio gear?

Don't know about this...some owner's manuals say that you should allow equipment and tubes to warm to room temperature before using them, but this is different. My audio room is upstairs, isolated from the thermostat. Have to keep the door closed so the dogs don't venture in there and create havoc. Hence, in summer, the temperature in the room regularly goes to 85 degrees or so. In winter (like now), it will easily drop below 60 degrees. No need to worry about equilibration, since the gear is always in there, but should I worry about the temp fluctuations? Could get a baby gate to keep the dogs out, then it would stay 70-72, but otherwise, in winter a space heater is the only option.
afc
magfan
1,583 posts
 
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.


hifihvn
943 posts
 
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.
magfan
1,583 posts
 
HiFi,
Let me give this a try.....Big, check and see if we're getting this.

The semiconductor will, under use simply go to some temp above ambient and stay there, depending on load. The device HAS to be warmer than the heatsink.
I don't know...If you chill the sink to 30f while the device is at 90f? The device will first cool, than begin pumping heat back into the system raising its temp.

HERE:: READ THIS.....
I'm going to go thru it. I already see it makes sense of this and the math part isn't too bad.
http://homepages.which.net/~paul.hills/Heatsinks/HeatsinksBody.html

BigBucks. Please read above link and see if it meets your approval. It seems straightforward explained this way.

One further question, however.......and that deals with maximum power dissipation of semiconductor devices as well as the maximum junction temp allowed.....all apparently related back to ambient temp and the thermal resistance of the system.....

cheers........
magfan
1,583 posts
 
Hifi,
You can always run something out of spec and blow it up.
Read the link I provided.

I have no idea of the speed of propagation from the junction, thru all the various interfaces and to the air.

Maybe you COULD 'shock' it.

C or F? just a conversion. The US is probably the ONLY country left in the world who uses the English metrology system. Darn French.
hifihvn
943 posts
 
Everything in engineering is most likely C.
Another example would be heat and A/C.

If room temp is 70F and blows through a/c coil @ 40F great transfer.

If room temp is 70F and blows through a/c coil @ 60F little
transfer.

If room temp is 70F and blows through a/c coil @ 70F no transfer.

If room temp is 70F and blows through heat coil @ 120F high transfer.

If room temp is 70F and blows through heat coil @ 70F no transfer.

When transferring from more extremes,the transfer rate increase.This must be true,or our Heat A/C systems wouldn't work right,or at all.
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