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Generic heat question

post #1 of 15
Thread Starter 
Most, if not all, modern AVR's have some sort of thermal protection, and most, if not all, manufactures recommend against putting their AVR in a cabinet.

If you had to put your new AVR in a cabinet, what would be a safe maximum temperature?

And, at what point would the typical thermal protection kick in?
post #2 of 15
Although I've seen a few posts where someone has used a thermal gun to read the temp above the unit (105-115 IIRC), as long as you have at least 3-4" clearance above the unit, you should be fine. If the unit does shut down in protection mode, you can simply add one or two small PC fans (eg. USB) to exhaust the heat away from the top of the unit to the rear of the unit. If the unit is in an enclosed cabinet, consider cutting a heat exhaust hole in the back to allow the heat to escape (or better yet, cut the hole to fit the fan and install the fan into the hole).

http://www.coolerguys.com/usbfans.html
post #3 of 15
Quote:
Originally Posted by ceh383 View Post

Most, if not all, modern AVR's have some sort of thermal protection, and most, if not all, manufactures recommend against putting their AVR in a cabinet.

If you had to put your new AVR in a cabinet, what would be a safe maximum temperature?

Since AVRs now contain quite a bit of digital circuitry for both the audio and the video, we probably need to treat them like computers.

In a computer a part operating at 50C (122F) is considered to be operating at too high of a temperature.

Some audio components such as power amplifier heat sinks and transformers are designed for higher operating temperatures, perhaps 60C (140F)
Quote:
And, at what point would the typical thermal protection kick in?

Probably no lower than 60C, might be as high as 80C (176F)

Here's the deal, While many components can stand higher temperatures for a while, in general higher operating temperatures above room temperature lead to reduced lifespan.
post #4 of 15
Thread Starter 
Quote:
Originally Posted by jdsmoothie View Post

Although I've seen a few posts where someone has used a thermal gun to read the temp above the unit (105-115 IIRC), as long as you have at least 3-4" clearance above the unit, you should be fine.l

My AVR is in a cabinet, and I can only get about 1.75" clearance above it. I was watching a movie last night at a moderate level, -20db and was wondering about heat. I used a contact thermometer on the top of the unit, it ran between 100 ~ 105F, Ambient room temp was 78F
Quote:
Originally Posted by arnyk View Post

Since AVRs now contain quite a bit of digital circuitry for both the audio and the video, we probably need to treat them like computers.

In a computer a part operating at 50C (122F) is considered to be operating at too high of a temperature.

In some respects they are computers, so this makes sense.
Quote:
And, at what point would the typical thermal protection kick in?
Quote:
Originally Posted by arnyk View Post

Probably no lower than 60C, might be as high as 80C (176F)

Given these temps, a unit that shuts down due to thermal protection,which mine has not, is in severe need of cooling.
Quote:
Originally Posted by arnyk View Post

Here's the deal, While many components can stand higher temperatures for a while, in general higher operating temperatures above room temperature lead to reduced lifespan.

I think I'll look into adding a second fan, possibly a third...

Thanks for the input...
post #5 of 15
Back about 4 years ago, I had an Onkyo 705. That thing ran extremely hot. It always read about 104 degrees, it had a built-in temperature monitor. It never had a problem when it was operating at that temp, but I got nervous and started using a small PC fan. Having just that little PC fan on top reduced the operating temperature down to about 88 degrees at all times.
post #6 of 15
Thread Starter 
Quote:
Originally Posted by MrEastSide View Post

Back about 4 years ago, I had an Onkyo 705. That thing ran extremely hot. It always read about 104 degrees, it had a built-in temperature monitor

At 105F I put my hand on it, it felt warm...Not what I would call hot, let alone extremely hot.
I am going to add a second fan, it can only help...
post #7 of 15
Quote:
Originally Posted by ceh383 View Post

Quote:
Originally Posted by jdsmoothie View Post

Although I've seen a few posts where someone has used a thermal gun to read the temp above the unit (105-115 IIRC), as long as you have at least 3-4" clearance above the unit, you should be fine.l

My AVR is in a cabinet, and I can only get about 1.75" clearance above it. I was watching a movie last night at a moderate level, -20db and was wondering about heat. I used a contact thermometer on the top of the unit, it ran between 100 ~ 105F, Ambient room temp was 78F

Is the back of the cabinet open?

I cut a 4" hole in the back behind the top shelf of mine, where it was blocked from view by a component, and it made a huge difference. I had a fan to install there, but the temperature dropped so much that I held off on it.
post #8 of 15
Thread Starter 
Quote:
Originally Posted by arnyk View Post

Is the back of the cabinet open?

I cut a 4" hole in the back behind the top shelf of mine, where it was blocked from view by a component, and it made a huge difference. I had a fan to install there, but the temperature dropped so much that I held off on it.

The cabinet is made for AV equipment, it has slots in each shelve and had two large openings in the back panel plus a large notch for cable routing.
My new AVR is deeper than the old one, so I cut the back panel, now the entire back of the AVR is exposed to outside air.

I've got a few computer fans laying around, I'll add another one...
post #9 of 15
Quote:
Originally Posted by ceh383 View Post

At 105F I put my hand on it, it felt warm...Not what I would call hot, let alone extremely hot.
I am going to add a second fan, it can only help...

Yeah, I think I'm probably remembering incorrectly. I'll bet it was actually higher than 104.
post #10 of 15
You are missing multiple crucial points..
Inadequate ventilation greatly decreases the component's life expectancy.

  • Measuring the temperature of the AVR's external cabinet is not the real temperature as internally it is significantly hotter..
  • Free-air clearance is also required for the L/R sides in addition to the top cover
  • Do not stack products on top of the AVR, this only makes things worse
  • Many AVRs actually pull air through the bottom cover as well, so it should be clear



Keep in mind...
Although individual manufacturer's specifications vary, the majority of electrical distribution and control equipment is designed to operate properly and achieve normal life expectancy under ambient air conditions ranging from 40°50°C [104°-122°F]. It is generally accepted that operating temperatures above this range reduce life expectancy: Every ten degree rise in temperature shortens the average reliability of electrical/electronic components by 50%.

Here is the link for more info..

http://www.kooltronic.com/component-lifespan-white-paper.aspx


Just my $0.02... 👍😉
post #11 of 15
Thread Starter 
Quote:
Originally Posted by M Code View Post

You are missing multiple crucial points..
Inadequate ventilation greatly decreases the component's life expectancy.
Hence the asking of the question.
Quote:
Originally Posted by M Code View Post

[*] Measuring the temperature of the AVR's external cabinet is not the real temperature as internally it is significantly hotter..
Without opening the AVR up and placing the temp sensor inside it, external temp is all I can do.
Quote:
Originally Posted by M Code View Post

[*] Free-air clearance is also required for the L/R sides in addition to the top cover
Some people, like me, have no choice but to put their AVR's in a cabinet with little clearance all around, making fans the only viable option for cooling.
Quote:
Originally Posted by M Code View Post

[*] Many AVRs actually pull air through the bottom cover as well, so it should be clear
My cabinet has ventilation slots under the AVR to help with this.
Quote:
Originally Posted by M Code View Post

Keep in mind...
Although individual manufacturer's specifications vary, the majority of electrical distribution and control equipment is designed to operate properly and achieve normal life expectancy under ambient air conditions ranging from 40°50°C [104°-122°F]. It is generally accepted that operating temperatures above this range reduce life expectancy: Every ten degree rise in temperature shortens the average reliability of electrical/electronic components by 50%.

Here is the link for more info..

http://www.kooltronic.com/component-lifespan-white-paper.aspx


Just my $0.02... 👍😉

Interesting, thanks for the info...

I pulled a couple fans out of my box of old computer stuff, now I'm looking at placement and mounting options...
post #12 of 15
A couple of additional observations...
If the external AVR cabinet temperature is too high, you can surely bet their internal components are 10-20% hotter...
Since we have a very close relationship with one of the largest factory warranty stations in SoCal for the major AVR brands, their lead technican is constantly talking about AVRs sent under warranty and the damage done by hot thermal conditions. The importance of having adequate free-air clearance cannot be overstressed..

Just my $0.02... 👍😉
post #13 of 15
Thread Starter 
Quote:
Originally Posted by M Code View Post

A couple of additional observations...
If the external AVR cabinet temperature is too high, you can surely bet their internal components are 10-20% hotter...

Which brings me back to the original question, what would be a safe maximum temperature?
Given the previous statement that...
Quote:
Although individual manufacturer's specifications vary, the majority of electrical distribution and control equipment is designed to operate properly and achieve normal life expectancy under ambient air conditions ranging from 40°50°C [104°-122°F].

If the top center of the AVR case reads 100~105F, it would stand to reason the ambient air around that point would be equal to or slightly less than those numbers. Is this excessive heat? Or, can this be considered safe?
Quote:
Originally Posted by M Code View Post

Since we have a very close relationship with one of the largest factory warranty stations in SoCal for the major AVR brands, their lead technican is constantly talking about AVRs sent under warranty and the damage done by hot thermal conditions. The importance of having adequate free-air clearance cannot be overstressed..

While adequate free-air space is the optimal situation, we all don't have that option, as WAF and space limitations force some of us into less than optimal situations. When done right, air flow can reduce the need for free space, to a certain extent.
Which, again, leads me back to the original question....
post #14 of 15
Quote:
Originally Posted by ceh383 View Post

Which brings me back to the original question, what would be a safe maximum temperature?
Can't answer that totally depends upon the brand, product and cost. But I can tell you that the average internal thermal protection threshold in CE AVRs is 80 degrees C (175 F)
Quote:
Given the previous statement that...
If the top center of the AVR case reads 100~105F, it would stand to reason the ambient air around that point would be equal to or slightly less than those numbers. Is this excessive heat? Or, can this be considered safe?
Yes..
Quote:
While adequate free-air space is the optimal situation, we all don't have that option, as WAF and space limitations force some of us into less than optimal situations. When done right, air flow can reduce the need for free space, to a certain extent.
Which, again, leads me back to the original question....

Every system has its own criteria including WAF..
But I can tell you in our business of designing/installing AV systems from $10K up to $100K+, we insist upon the necessary free-air clearance specs. Thats one reason we often build design/build custom equipment enclosures as well. If there are any failures the costs of sending our tech back out replacing products is simply too expensive, and our reputation is too valuable to take short cuts.. if the customer wants to cut corners, we pass and he/she can always call the Geek Squad..

Just my $0.02... 👍😉
post #15 of 15
Thread Starter 
Quote:
Originally Posted by M Code View Post

Can't answer that totally depends upon the brand, product and cost. But I can tell you that the average internal thermal protection threshold in CE AVRs is 80 degrees C (175 F)
Quote:
Originally Posted by M Code View Post

Every system has its own criteria including WAF..
But I can tell you in our business of designing/installing AV systems from $10K up to $100K+, we insist upon the necessary free-air clearance specs. Thats one reason we often build design/build custom equipment enclosures as well. If there are any failures the costs of sending our tech back out replacing products is simply too expensive, and our reputation is too valuable to take short cuts.. if the customer wants to cut corners, we pass and he/she can always call the Geek Squad..

Just my $0.02... 👍😉

Understandable position, making a mistake in design or implementation on a customers system, can cost a company considerable $$$. (The company I work for is looking at a 50k repair due to poor design on one of our systems (nothing to do with audio...weather radar)
I have severe space limitations based on room layout, these limitations are beyond my control and I have to make the best of it.
The best I can do is circulate air as best as possible to reduce heat as much as possible to prolong component life.

Right now I'm doing a layout for mounting brackets and wiring to triple the airflow....
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