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Heat Data on Receivers

post #1 of 19
Thread Starter 
Hi Everyone,

This is my first post, so if this topic is covered elsewhere, please let me know.

I did some heat-generation comparisons of four entry level receivers in a confined shelf. The results, in order of final stable temperature, were:

Denon AVR-1610: 102 F
Sony HT-DH800 : 112 F
Yamaha v563 : 122 F
Pioneer VSX-919 : 133 F

Hopefully this is of some use to others who are looking for heat information on receivers.

I haven't yet decided which (if any) of these receivers I'm keeping, but given the Denon's strong showing, it is the most likely right now. The biggest thing I'm not sure about is what the temperatures mean for the running of the receiver. Sure, 102F is better than 133F, but is either one cool enough? Most electronics have a warning not to run at over 95F, so long-term I might be in trouble. At the same time, 133F didn't trigger the pioneer's heat sensor, so does that mean it could run forever and be just fine? If anyone out there has thoughts on this, they would be welcome.

I'm keeping this post short and sweet, find a full test write up in my next post.

Cheers
post #2 of 19
Thread Starter 
Hi Everyone,

This is a longer explanation of my heat tests from above.

I'm looking for an entry level blu-ray 5.1 receiver that can go into a 7'' high shelf, so I've been very concerned with heat generation. I know that cool-running digital amps like the Panasonic SA-BX500 would be ideal, but I was hoping to spend less than $500. I've been lurking on the forms for a while, and haven't found any side by side heat comparisons on receivers to see how well they do. So, I did some. Find results below.

I tested four receivers:
Denon AVR-1610
Pioneer VSX-919
Sony HT-DH800
Yamaha v563 (last years model that I picked up cheap)

30 day return policies is a wonderful thing.

Each, in turn, was connected to:
Panasonic TH-42Px77u Plasma TV
Samsung BD3600 blu ray player
Energy Take Classic Speakers with Monster XP cables
Audiosource Fifteen Subwoofer

For the tests volume levels were kept between -45db and -30db, varying them through the test. I ran each for at least three hours usually starting with a blu ray disk, then switching to TV, this was long enough in each case for the temperature to plateau and stableize for at least an hour. Between each test I waited to allow the shelf to return to ambient temperature (80 F), and started each receiver from ambient temp with the appropriate microphone-based automatic room calibration for each unit. Measurements were taken by means of a kitchen thermometer resting on the top of each unit, taking readings every 5 to 15 minutes. Thermometer had a measurement error of +/- 1 degrees, but I report as closely as I could measure.

And now the results (in alphabetic order)!

Denon AVR-1610
Beginning operating Temp: 80 F
Final Operating Temp: 102 F
Change in Temp: 22F
Time to plateau at final temp: 90 min

Pioneer VSX-919
Beginning operating Temp: 80 F
Final Operating Temp: 133 F
Change in Temp: 53F
Time to plateau at final temp: 60 min

Sony HT-DH800
Beginning operating Temp: 80 F
Final Operating Temp: 112 F
Change in Temp: 32F
Time to plateau at final temp: 125 min

Yamaha v563
Beginning operating Temp: 80 F
Final Operating Temp: 122 F
Change in Temp: 42F
Time to plateau at final temp: 135 min

I was very surprised by these results. The Denon is clearly the coolest-running, followed by the Sony. I was so surprised by the Denon that I actually waited over night and ran it again, and go the same results.

I can't really explain why they came out this way. I was expecting temperature to be most dependent on the gap between the top of the receiver and the shelf, which meant that I thought the Yamaha would do best (1 1/8 inches) followed by the Pioneer and Sony (3/4 inch) followed by the Denon (1/3 inch). Another hypothesis was per channel power, or possibly total unit power consumption, but those don't fit the results, either.

I can post the full up time-series data, if there's interest.

Hopefully this is of some use to others who are looking for heat information on receivers. I'd be curious if owners of other receivers might be interested in doing similar tests so we can compare results. Onkyos, for example, aren't on the list.

Like I said before, I haven't yet decided which (if any) of these receivers I'm keeping, but given the Denon's strong showing, it is the most likely right now. The biggest thing I'm not sure about is what the temperatures mean for the running of the receiver. Sure, 102F is better than 133F, but is either one cool enough? Most electronics have a warning not to run at over 95F, so long-term I might be in trouble. At the same time, 133F didn't trigger the pioneer's heat sensor, so does that mean it could run forever and be just fine? If anyone out there has thoughts on this, they would be welcome.

Cheers
post #3 of 19
I would guess that the set of ASICs used in the receiver might contribute the most amount of waste heat. The receiver's CPU, video processing chips, and other ASICs may contribute a fair amount of heat.

It's not clear to me how two class AB, 7-channel receivers of approximately the same power would differ a lot in the amount of heat from the amp stage given how similar in design they are.

I have wondered whether a different receiver design might better spread out heat producing components and thus run cooler. But I am not even sure that idea makes sense! I mean the overall heat would be the same, but "hot spots" might be cooler.

The top of my RX-V3900 measured about 123 F. Some spots were cooler than others. But even cool spots with a vent ran about 116.

It's an interesting topic, to be sure.
post #4 of 19
Thread Starter 
Woah, fast reply.

Yeah, the heat layout was something I thought about in the measurements. I tried to rest the thermometer on the hottest part of the top of the case. Something I did notice, looking through the vents, is that the Denon seems to have the most empty space in their case. That might be contributing.
post #5 of 19
Denon might have a lower than normal component count. Each component adds a little heat.

I noticed when looking at service manuals for the latest Yamaha receivers, they were able to consolidate functions more than in my 3900. The new lower end Yamahas use Sanyo amp modules, less HDMI chips, and some other part saving options I can't recall at the moment. Perhaps Denon has done the same.
post #6 of 19
Quote:
Originally Posted by Notnil View Post

Hi Everyone,
Sure, 102F is better than 133F, but is either one cool enough? Most electronics have a warning not to run at over 95F, so long-term I might be in trouble. At the same time, 133F didn't trigger the pioneer's heat sensor, so does that mean it could run forever and be just fine? If anyone out there has thoughts on this, they would be welcome.

Cheers

Most electronics indeed have a spec of >>environmental<< temperature not to be over 95F (35-40 deg Celsius), which is not the same as >>internal<< temperature of the device. The environmental spec is given so the device can at least dissipate its heat.
For the electronic internals itself, the spec is (at component level, elco's not included) 175F (80 deg Celsius), which is way up of your measurements.
Also it is very important where you take the measurements: on the internal components, between the internal components, on top of the amps cover, halfway between the amps cover and the shelf above it, ....
AND of course the actual air volume inside your shelf, the airflow it allows in open and closed status, the distance between the amp and the shelf (all sides), the material (heat conductivity) of the enclosure etc.
I do not doubt your measurements, but there's not enough information on the actual measurement and measurement conditions etc. You only have a relative measurement between amps in your (non-detailed) conditions.
And yes, amps do run hot... when reading the service manual of the tx-sr705 you'll see the dissipation of the power stages themselves varies from 7W (at cold startup) to 35W (heat-settled), calculated values from the factory specs in the manual, in which 35W is indeed alot of heat in steady state. Remember it's 7 channels all contributing to the total of 35W (=5W / channel idle state, which still is a fair value)

Edit: Just after answering this, I saw your answer specifying "measurement on the hottest spot", so at least that's solved.

greetz
post #7 of 19
Thread Starter 
You're right, the ideal place to measure would be inside the receiver itself--short of taking off the enclosure, however, I wasn't sure how to do that with a metal thermometer. These were all measurements taken on the top of each receiver, over the air vents. I suppose the argument could be made that those receivers with the highest readings have actually done the best job expelling the heat from inside them and so actually have the coolest internals...but part of me feels that way madness lies.

Thanks for the information on the component level temperature spec. It makes me think that the Pioneer might be viable.

Do you guys know if all these models have heat shut-off sensors? And what happens if they trip?
post #8 of 19
i wonder if there is a correlation to total weight? one might think from this data that the denon has more in the way of heat sinks, than say the pioneer. just a thought.
post #9 of 19
Quote:
Originally Posted by G-star View Post

i wonder if there is a correlation to total weight? one might think from this data that the denon has more in the way of heat sinks, than say the pioneer. just a thought.

That may be. My Emotiva UPA-7 amp weighs 71 pounds and runs cooler than the Onkyo SC885 preamp processor even after a 2 hour action flick.
post #10 of 19
Quote:
Originally Posted by Knucklehead90 View Post

That may be. My Emotiva UPA-7 amp weighs 71 pounds and runs cooler than the Onkyo SC885 preamp processor even after a 2 hour action flick.

When trying to correlate "heat" to "weight" one has to include "power of the amp", "number of channels" etc too...
Logic says that whenever there's an output-power difference, also the weight of the internal power supply by itself will vary.
Next to take into account is for instance the enclosure itself: plastic, aluminum or solid steel ?
Don't be fooled by just saying "it's pretty heavy so it will run cool", that's not the way to go since there's alot more involved. For instance: The lighter one (aluminum that is) might run cooler, since it's a better overall heat conductor.
Also don't be fooled by thinking that a "cool running amp" has less "lost power to sustain itself" as one running fairly hot, it might be the opposite, just some better spreading (and thus masking) of the actual dissipated heat.

greetz
post #11 of 19
Quote:
Originally Posted by Knucklehead90 View Post

That may be. My Emotiva UPA-7 amp weighs 71 pounds and runs cooler than the Onkyo SC885 preamp processor even after a 2 hour action flick.

Try turning off the Reon processor. It will run much cooler.

On the list of needed features, I would think that HEAT would be at line item 101 of the top 100.

I have a Kenwood, THX Receiver that was moved to my bedroom over 10 years ago and it always ran hot. It still works. What always worries me about Threads like this is that people will get the wrong idea and will not ventilate their receiver properly. They will get a false sense of security that they only need an inch of ventilation from the top of the cabinet because they found the cooler receiver. What they should do is buy the proper size cabinet and not worry about heat.

just my .02 cents
post #12 of 19
Quote:
Originally Posted by peter273 View Post

When trying to correlate "heat" to "weight" one has to include "power of the amp", "number of channels" etc too...
Logic says that whenever there's an output-power difference, also the weight of the internal power supply by itself will vary.
Next to take into account is for instance the enclosure itself: plastic, aluminum or solid steel ?
Don't be fooled by just saying "it's pretty heavy so it will run cool", that's not the way to go since there's alot more involved. For instance: The lighter one (aluminum that is) might run cooler, since it's a better overall heat conductor.
Also don't be fooled by thinking that a "cool running amp" has less "lost power to sustain itself" as one running fairly hot, it might be the opposite, just some better spreading (and thus masking) of the actual dissipated heat.

greetz

I think you put a lot of words into my post that I didn't.

I made a simple observation - you made a bunch of extrapolations from it.

I am not fooled.
post #13 of 19
Quote:
Originally Posted by Knucklehead90 View Post

I think you put a lot of words into my post that I didn't.
I made a simple observation - you made a bunch of extrapolations from it.
I am not fooled.

Welll.... I saw you answering to G-stars question "I wonder if there is a correlation to total weight?", and your answer "That may be", meanwhile mentioning the 71 pound receiver in the flow of the thread "running cooler" above.

Being an electronics designer myself (hardware, firmware and software that is) I often encounter people (usually non-techies) making lots of faulty assumptions by judging only things like the weight/size of equipment.

Elaborating the subject might be somewhat of a professional deviation, the "designer kicking in" due to everyday solving of the difficult balance in such complex things like power management etc.

Sorry if misinterpreting your statement... but nevertheless I stick to everything I said before with respect to the "weight versus heat" statement higher up.

And no, nobody is trying to fool anybody here, just mentioning whatever springs to mind of the designer with respect to involvement to the (not at all that simple) equation "heat versus weight".

greetz
post #14 of 19
My first post here, but the subject caught my eye since I just did the same sort of analysis on the Onkyo 905 I just bought.

A couple of observations to the OP:

I like that you kept the source the same during your test -- I think that is important, as would be the content of the source (the units will run hotter or cooler depending on the source's demand).

It was unclear as to how much variability there was in your volume control (how often the volume changed and for how long at each setting, and did you control this between the units), since this is also a key parameter, as is keeping the source, source material and the test time all the same would be improtant to "control" your study, and have repeatable and consistent data.

It was also unclear as to your dermination of the "hot spot" on each unit -- how long did you run each to find this and did you use the same basic procedure as your actual test?

I'm not at all trying to be critical here, just some Qs or food for thought. It took me hours to just test my one receiver to determine where to place a fan, which btw, absolutely took any effect heat has on your selection (if it ever does matter, like you said) out of the decision.

I found a $12 (delivered) AC fan on eBay (item number 250463885760) that runs 28db, hooked it into my switched AC and by testing locations with all else being the same (at very low amp demand) took the temp from 127 deg F (measured hottest spot) to ambient plus 2 deg max. It was quite impressive to me that a little fan made that big a difference.

If you decide to go the fan route, one of the most important things (for me) in selection of a fan is it's noise, and usually the major factors contributing to that is the rpm and cfm it is trying to perform at, as well as placement from the top of your case (airflow noise trying to pull air thru the grate). You don't need much cfm's to have a huge effect -- mine's less than 50cfm and when raised 1/4 inch above the case gave resonable airflow induced noise relative to the heat reduction in the case.

What was interesting in my tests was that the hottest part of the case (rear-most center of the top right side) was not the optimal place for the fan to do it's best overall cooling. Turned out the center of the top left rear produced an almost flat temperature across the whole unit...

Great thread you started, and I applaud your work and reporting it...
post #15 of 19
Quote:
Originally Posted by peter273 View Post

Welll.... I saw you answering to G-stars question "I wonder if there is a correlation to total weight?", and your answer "That may be", meanwhile mentioning the 71 pound receiver in the flow of the thread "running cooler" above.

greetz

It isn't a receiver - it is an amp.

And I made no assumption - I made an observation. They aren't the same thing.
post #16 of 19
Quote:
Originally Posted by diesel_dan View Post


Great thread you started, and I applaud your work and reporting it...

1, here is a great thread you should check out.

HT 101

http://www.avsforum.com/avs-vb/showthread.php?t=824554
post #17 of 19
Thread Starter 
Quote:
Originally Posted by B&W700guy View Post

What always worries me about Threads like this is that people will get the wrong idea and will not ventilate their receiver properly. They will get a false sense of security that they only need an inch of ventilation from the top of the cabinet because they found the cooler receiver. What they should do is buy the proper size cabinet and not worry about heat.

just my .02 cents

yeah, being a noob, part of my reason for starting this thread was to get an idea of exactly that sort of issue. In an ideal world, one would get cabinets that meet the specified ventellation and be done with it. But unfortunately the receiver manfacturors often times over spec the requirement to cover their asses (I think it's the pioneer that asks for 60cm vertical clearance--more than two feet, which seems excessive) and also (perversely) there aren't that many cabinet makers who take ventillation into account when designing the shelves.

Looking through the posts, the consensus it seems clear that none of the options I've tried will work long term--if 85 degrees is the goal then I need to find another solution than just having the coolest receiver in a cramped space. The fan suggested seems like a great option. Another is to look for digial amp receivers. Another might be to go higher in price to a receiver with an OSD overlay--in conjunction with an IR repeater I should be able to put the receiver behind the tv on the floor (the tv is in the corner) and do everything via remote.
post #18 of 19
Thread Starter 
Thanks for the encouragement, and on the info on the onkyo and on the fan. It's a great find that I'll likely try. I set up a small desk fan to blow on the receiver, but it wasn't magnetically sheilded and caused interferance...so I didn't use it.

To asnswer you question about the sources, they weren't all the same bluray, but they were all different episodes of the planet earth series. So you're right, that could have been a variable.

Cheers!



Quote:
Originally Posted by diesel_dan View Post

My first post here, but the subject caught my eye since I just did the same sort of analysis on the Onkyo 905 I just bought.

A couple of observations to the OP:

I like that you kept the source the same during your test -- I think that is important, as would be the content of the source (the units will run hotter or cooler depending on the source's demand).

It was unclear as to how much variability there was in your volume control (how often the volume changed and for how long at each setting, and did you control this between the units), since this is also a key parameter, as is keeping the source, source material and the test time all the same would be improtant to "control" your study, and have repeatable and consistent data.

It was also unclear as to your dermination of the "hot spot" on each unit -- how long did you run each to find this and did you use the same basic procedure as your actual test?

I'm not at all trying to be critical here, just some Qs or food for thought. It took me hours to just test my one receiver to determine where to place a fan, which btw, absolutely took any effect heat has on your selection (if it ever does matter, like you said) out of the decision.

I found a $12 (delivered) AC fan on eBay (item number 250463885760) that runs 28db, hooked it into my switched AC and by testing locations with all else being the same (at very low amp demand) took the temp from 127 deg F (measured hottest spot) to ambient plus 2 deg max. It was quite impressive to me that a little fan made that big a difference.

If you decide to go the fan route, one of the most important things (for me) in selection of a fan is it's noise, and usually the major factors contributing to that is the rpm and cfm it is trying to perform at, as well as placement from the top of your case (airflow noise trying to pull air thru the grate). You don't need much cfm's to have a huge effect -- mine's less than 50cfm and when raised 1/4 inch above the case gave resonable airflow induced noise relative to the heat reduction in the case.

What was interesting in my tests was that the hottest part of the case (rear-most center of the top right side) was not the optimal place for the fan to do it's best overall cooling. Turned out the center of the top left rear produced an almost flat temperature across the whole unit...

Great thread you started, and I applaud your work and reporting it...
post #19 of 19
Peter273 hit the target when he pointed out that the reference to manufacturers' operating temp relates to the environment the AVR is operating in not the heat generated by the unit. Of course the argument appears to be circular in that the AVR adds significant heat to the environment but that's whats expected. They're supposed to be designed to transfer as much as heat as possible to the outside of the unit. If a heat sink is warm vs one that's hot it could be the heat sink isn't doing its job.

The transformers generate heat but in today's AVRs the CPUs throw a lot of heat which explains the hot spots in many AVRs. Temps to 100c aren't uncommon.

I have an Onkyo 705 that will display the temp. I've seen 140f+. The fans don't turn on until the CPU overheats and the temp approaches 150F. I've talked w' Onk and they don't get excited about unit temps below 155f. They do run hot. My Pioneer VSX-01 get's barely warm. More efficient A/B. Could be. Pio does use some heat compensating circuitry in my AVR amp circuit.

As was posted above, heat is way down on my list of concerns but many are concerned by it. Best bet is to create an environment conducive to heat dissipation and get the AVR w' the features and performance you want.
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