976 is warm

I dont recall ever having a component that was warm to the touch while powered down. My 976 is warm, not hot, indicating it is consuming power. I suppose it is essentially in standby mode before switching it on with the crazy blue button.
Probably not an issue, just worthy of note !

Back in the day, when I was a true audiophile, regarding solid state components, the industry idea was that warm circuits sound better that cold ones...just say'in!

I have a 5" fan blowing rear-to-front on my 975 as an added precautionary measure. Sounds like that will continue when I receive my 976.

Side note: 976 manual p19 contains a "975" typo

My 976 does run warm. But, when powered down it cools off to no heat after a short time.

My 976 is not warm, it's hot. I measured the top of the case at 114 degrees when in standby. I've emailed support about this.

Good air flow is the best long term thing you can do for your equipment.

That* is not good. My 975 stays cool in Standby; gets warm(er) as I crank it higher. How long have you had it? Did you discover right away or did it manifest after some time?

On that note, when I receive mine*, I will plug it in and leave it in Stand by for several hours. I do NOT want to install only to remove & return - too much cabling.

I believe Bryan’s is WELL past what “good air flow” can reverse

Let us know ASAP. I hope you kept your box

You need that air flow to remove whatever heat is generated. Without air flow the main heat transfer method is radiative which requires the equipment to operate at a much higher temperature to get rid of the heat. With good air flow the heat is removed before the equipment can get hot thus preserving its life. Make sure you have plenty of space around it and put a quiet computer fan to draw air through it.

I agree w/your point, 100%. In Bryan’s case, something is clearly not right w/his 976. As others have posted, warm seems ok, but 114 degrees on STANDBY?! I don’t think so.

Further, several high CFM* fans “ain’t gonna take care of biz” for his unit.
* noisy to boot

As I just posted, I believe Bryan’s unit is WELL past what “good air flow” can reverse

I have fans that turn on when the 976 applies 5V to the trigger out. When something electronic is in "standby" mode, I expect it to consume as close to zero power as possible. At 115 degrees, my 976 is clearly pulling some serious current. If support comes back and tells me this is "normal", I'll probably sell the 976 (I'm just past the 30 day return) and go elsewhere.

I agree 100%.

Have faith. IME Tech Support will want to check out your unit. I had several go-arounds (unknowingly) due to faulty house wiring. If yours has always idled hot...

Tony

2" above my 976 is a shelf which contains a Mac mini and a network switch. I suppose I could re-locate those underneath the main cabinet and remove the shelf to see what temperature I would get on the 976 case. As a last resort, I could re-wire the fans so that one is on all the time, but that just seems wrong. In the other side of the cabinet, I have an Oppo DVD player and a Sony PS4 that generate zero heat when in standby.

Bryan, how are you measuring the temperature?
IMO, 2" is plenty of headspace. I have amps with less than that.

I've asked Bryan to let me know the temperature outside of his rack. If it is 115 degrees in standby, when not in an enclosure, something is definitely wrong and we will get him a new unit.

I taped the probe that came with my Fluke 87V to the top of the case.

As with most processor controlled powered on devices (those with standby power circuits) the 976 will supply about 5V to the microprocessor chip. The power transformer is only energized, when it's powered on by the processor.
Therefore, there should be no regulated voltage to result in heat radiation in standby. If you're experiencing this amount of heat in standby, definitely something wrong. My 976 measures about 95° when powered on, and cools off quite quickly within a couple of minutes.
I have it on a shelf with all open sides.

Ok, so I did some more investigating. I had never engaged the HDMI control settings before. So I turned them on.
With HDMI Pass Through turned on, the 976 generates as much heat as when in use, about 95° at the surface of the cover. This means the power transformer remains energized and the voltage regulators are active. This needs to be the case so the HDMI circuitry gets voltage so it can pass through the signal to the TV.
With only HDMI control turned on this isn't the case, as my 976 cools off relatively quickly.
Same for when neither settings are turned on.

Nice catch Helson! Ditto for me. With Pass through enabled, my 976 is 95 degrees in standby. After two hrs runtime, it did not get any hotter.

Yup. The temp is very steady in my set up too.

I pulled my 976 out of the cabinet this weekend and it measured 97 degrees in standby. I've replied to support in email and I will investigate turning off HDMI pass through.

I'm guessing your HDMI pass through is set to 'on'
97°, give or take a few degrees, is about what it should be with the transformers energized.
Mine reads 95° when on.

I disabled HDMI pass through and my 976 remains cold in standby mode. This solves my problem. A HUGE thank you to Helson for finding this!

Glad that was all it was.

Id still be concerned if indeed you were seeing 115 degrees !
Sounds as if 95 might be the norm. 115 is considerably hotter than 95 !

115° is definitely hotter than it should be inside your cabinet.
Is the fan you're using pulling the hot air out from the top of its shelf location? It should be.
You may want to experiment with fan location to try and achieve the best results for cooling.

95-115 is warm but nothing to be overly concerned about. Consumer grade electronics is spec'd to run at least to 85 C which is about 185 F. Electronics will happily run for a long time at a constant temp even if it's a high temp as long as the humidity is not overly high, say 65% or higher.

The other main killer of electronics is thermal shock. That is a rapid change from really high temperature to really low temperature. (e.g. -40 to +85 C in approx. 10 seconds). You better not be seeing these temp ranges in your house

It would be interesting to know what validation test Outlaw ran the unit through.

Just an FYI from an old submariner here. While pulling hot air out may provide sufficient cooling in typical HT applications, you will have better air displacement in a closed space by forcing cool air in than you will pulling hot air out.

I've heard both schools of thought on this. How cool is the ambient temp? How efficient are the fans? Does that matter?
I'm thinking a small fan should be used in combination with the radiation cooling that it's already been designed to accomplish on its own. Pulling hot air out, allows the cool air to be pulled in from the bottom vents, as its designed to do. Pushing air down into the device, well, where is the heated air going? Back upward. It just seems the heated air would be fighting the air being pushed down into the unit.
You may be right, or either way is just as effective. We can agree, cooling fans make a difference where radiational cooling isn't enough.

Using a small fan to remove the heat from the cabinet will extend the life of your equipment. Although the devices are designed to operate at a elevated temperature for a certain amount of time we can extend that time by never operating there. Pulling the heat out of the equipment is the key. Since heat naturally rises, pulling the air from the top is going to work best.

Oh you wouldn't place a fan pushing cool air in at the top. You're right, that would seriously mess with the thermal flows in the system. A fan blowing cooler air in would be placed lower in the cabinet. I didn't mean to imply one should just reverse the fan direction on top, although I can see where it might read that way.

My guess is that, given the sheer amount of top mount fans available for HT racks, that pulling hot air out works just fine for that particular application. I was just sharing some practical application knowledge. To get the best exchange of air in a space, you move more pushing air in vs. pulling it out. Burn dinner? Set the fan up to blow clean air into the space instead of setting it in the open doorway or window blowing outward.

Let's break it down.
Heat rises (at least on earth).
Heat is transferred by conduction, convection and radiation.
Heat flows from hot to cold.
Everything resists this flow.

What we are really concerned about is something called the Junction Temperature in the chips in our electronics. The junction is where the heat is actually generated. In order for us to feel the heat it must first flow through "stuff".

e.g. my 7075 (simplified)
transistor junction -> transistor case: Conduction
case -> heat sink: Conduction
heat sink -> air: Convection

Think of each of the "->" as a pipe which heat travels through. Each interface will only let so much heat through. This is called the thermal resistance of the interface.

Metal to metal conduction is pretty efficient at transferring heat (big pipe). That's why the transistors have metal tabs or metal cases bolted to metal heat sinks. The transfer from the heat sink to the air is much less efficient (little pipe)which is why the heat sink are so darned big (lots of little pipes-that's what the fins on the heat sink are for).

The one other factor that I haven't mentioned it that the greater the temperature difference on either side of the "->" the more heat flow you will get.

Sooooo....

Moving the air with a small fan is an easy way to get 20-30 degree more temperature difference which definitely helps. It really doesn't matter which way you blow the air as long as it's AWAY from your components. However heat still has to flow through those pipes and therefor the effect on junction temperature is going to be less than the 20-30 degree air temperature.

A rule of thumb is that for every 10 degrees C (junction temp) decrease you'll double the life of your power electronics. 10C is about 18F.

Now the real question is how long was the unit designed to last without forced air flow?

In answer to the next question, yes, work is a little slow at the moment.

If the manufacturer thought their gear needed fan cooling, they would have installed some. You are over thinking all this heat thing, really!

Not really. Admittedly we're having fun taking the topic to a bit of an extreme. However, it IS an important topic to keep in mind. Manufacturers design their gear based on sufficient ambient cooling being available. Once equipment is placed within racks, cabinets, or other types of enclosures, sufficient ambient cooling is often NOT available and the air must be circulated somehow to compensate.

Good point Owls. Id like to think a manufacturer would be anticipating a worst case environment, but i believe they anticipate us upgrading tech gear way before it reaches it life expectancy. In my case, that holds true for everything but amplifiers. I also believe a max 10 year life is also designed into everything these days. Now that im almost 60, i can look back at so many things that have reached the 10 year plateau, then died. Washing machines, refrigerators, water heaters, ovens, garage door openers, furnaces, air conditioners etc. Low quality often means getting a week beyond the warranty before it pops !
Remember your grandmothers washing machine that seemingly lasted Her whole life! Not going to sell a whole lot of anything if it lasts forever, so how do i get Kiwi to buy 6 of everything during his lifespan ?

IMHO, if the cabinet have rear vents at the bottom and the top, a natural draft will establish and should be enough even without fans, unless you are in tropical climate with no A/C!

There are exceptions! I have a few Bryston amps from the mid 80s that are powered 24/24 since I got them, still going strong. I once had a 2B-LP that got so much overheated in its previous life that the black anodized cooling fins had turned to purple!

But I disgress!

You bring up the other factor to be mindful of with these devices. If you're in a humid climate, condensation will be a concern. That, and heat buildup are the two things to be mindful of, and both can be handled with a small fan. With condensation, keeping the air moving is the key. As the unit is cooling after powering off, the condensation forms. Then a corrosive process begins from the moisture that settles on the internal components.

You would only get condensation if you cooled the unit below ambient air temperature. That is unlikely to happen unless you installed additional cooling equipment inside the gear. Moving ambient air past the components is not going to harm the equipment unless there is dirt in the air. I have a 1976 Yamaha CA-800 integrated amp that is still going strong and has never been in the shop.

In light of this thread, minimum space above a 976 for adequate ventilation? Didn’t see anything specific in the manual.

Sidenote: I have some (still functional) gear from the early & mid eighties...

Thnx, Tony

2 inches on each side and the top should be enough but if it is running too warm then add some forced ventilation.

Have read this thread with interest.
Ordered the 976 yesterday, will replace my 990 I have owned since 2006.
I have a HT cabinet which house all my HT gear on both ends of cabinet.It is inclosed
I have oblong cutouts under unit ( towards front) and 5 inch cooling fans on back panel towards the top, these fans activate at 100 deg.
I have yet to have any problems with any piece of equipment failing.
That includes 2 amps with out cooling fans.
The 990 sits at the bottom of this cabinet with a Carvin Amp sitting directly on top.
It has never ran hot. The fans at each end do a good job of keeping things cool.
Will the 976 generate more heat than the 990 ?

With the smaller box volume I would think that the 976 will feel warmer because the case is so much closer to the electronics. At the same time the electronics may be more or less efficient thus generating more or less heat. Hard to tell but the 990 power draw is 50 watts according to the rear plate whereas the 976 says 40 watts. You have the right setup with fans moving air/heat away from the equipment so I would not expect any issues.

If the numbers on the back panels of the units are correct then the answer is No, the 976 will not generate more heat than the 990. It will generate less.

But, there's always a but, the 976 MAY run warmer than the 990 because it's a smaller package. It's more about heat transfer than heat generation.

I would not expect the differences to be significant in your setup. Overall you are in a slightly better place from a heat generation point. If you have any moving air at all by the 976 then I think the heat transfer will be fine also.

I misspoke , the Carvin amp does have a fan , as it s sitting on top of 990 and a 4' hole cut in shelf above where a Marantz SACD/DVD-A player sits along with the Oppo 980H, the cabinet fan it to the rear of top shelf.
Every now and again I will reach in and press my finger against heat probe to make sure cabinet fan is still working...