I have a 990 on the way and I am a bit worried about the size of this thing and my rack. My rack is about 9" high and I see the 990 is 7.75" high. Does this thing produce a large amount of heat where I will need more ventilation? My rack is open on all sides, but the top rack sits 1.25" above it. I have my amps sitting on butcher blocks in the open. I just hope I won't have to put this thing on a block as well...

If you have over an inch clear above the 990 in that open a cabinet, you should be just fine - I have slightly more space above my 990 but have closed sides and front.

Thanks Gonk. Looking forward to hearing this and see if I like it for my 2-channel reference listening as well...

It's hard to tell you exactly how much heat the 990 puts out but....

My B&K Ref 31 used to get really warm to the touch. So much so that I'd be concerned with only an inch of clearance.

The main vents on the 990 are squares in the top back left and top back right. They hardly get warm at all after a regular length movie.

Big difference in heat between the B&K and the 990.

I have both the 990 & 7700 and have not had any problems with heat. The 990 is in a wood cabinet with glass front doors (barely fit). The 7700 also runs cooler relative to other equipment I have had.

I have a glass and metal rack with all of the sides open. The 990 sits in a shelf with only about 2/3 of an inch between it and the top of the glass shelf. I have not had a problem with heat and I have had it playing movies for 4-5 hours without stopping. Granted the glass rack above it get's pretty warm but not hot. I was much more concerend with the heat output of the 7500. I have that in the same rack with about 3 inches between it and the top of the rack. That thing has never gotten above moderately warm

I haven't noticed any heat from my 990. it has no amps.. so it should run very cool.

Kind of funny, my 990 is actually warmer than my 7500 90% of the time. But, the 990 is never actually hot, just warm.
I have a very small apartment, so rarely get to warm up the 7500

Very strange...my 990 is never warm, heck it's always just at room temperature. You wouldn't even know it was on.

that's what i'm talking about too... it really shouldn't give off any heat, right? maybe if someone has an amp(s) nearby.. that's where the heat is coming from. Sure some heat is generated, but I would think it would be so minor, and hardly detectable.

There will be some heat generated from electronics, and amps aren't going to be the only source (look at how hot most digital cable boxes get). The 990's got a pretty decent sized power supply in there, and it's going to generate some heat. It's rated for 50W of power consumption, so in theory you could get as much heat off of it as a 50W light bulb. In reality, the heat output is probably not that high and is spread out over a much larger area. If heat is rising from a source below, that will also add to the heat from the 990.

Hi everyone.

In my cabinet where I have the 990 it only has 1" above it. The rear is totally open and to the left side and front there are black screens to help with ventilation.

I have the Emotiva UPA-7 amp & it is right below the 990 in the lower shelf and also has 1" of clearance above it. Now last night I had the 990 and the UPA-7 on for 3-4 hours and both components were warm the touch.

I placed a digital thermometer in there earlier in the evening to see how hot things got since this is my 1st foray into seperates and premium gear.

I found the temp in the cabinet got to 105 degrees farenheit after a couple of hours. When all the gear was in standby the temp was around 82 degrees farenheit. room temp was 78 degrees farenheit.

Again all gear was warm to the touch but should I be concerned with this heat? Are these temps normal? Should I get some fans to help move air away from the cabinent?

I think the heat is coming from the UPA-7 but just to be sure should I put 120mm fans above the 2 rear top vents of the 990?

I found some nice fans from Cool Components but their stuff was pricey. If anyone has any recommendations on cooling I'm open to them.

Thanks JD

I've looked at cool components, also Active Thermal Management and also toyed with using some laptop coolers. To your point CC and ATM are pricey, and laptop coolers are next to useless, so I decided to DIY it. If you don't want to spend the scratch, it's pretty easy.

I wired up 4 80mm 12v fans in parallel to a 9v wall wart (I've used 6v too). 9v makes the fans run a little slower and quieter, you just need to be sure the combined amp draw for the fans is less than the amp rating on the wart (each is 160mA, so the wart needs to provide >640mA - mine is 800).

I mounted them to the inside of my cabinet's plywood back (actually one to each side), and the wall warts stick out the back and plug into the delayed outlets on my line conditioner so they turn on whenever I power up my system.

The fans I bought at Frys, I think a 6-pack for $5, and the wall warts were recycles, but you can buy them at Parts Express.

I would warn that, if you're not totally comfy with working with electrical, this probably isn't for you. Mistakes can be expensive!

I can take some pics and post if you want to see the results.

105F is probably a bit on the high side, although I've run gear at higher temperatures. The amp is probably the culprit, as it's going to generate heat that then rises through the components above it. Weight and cabling tend to make a low placement of the amp desirable, but heat ends up being

I hadn't looked at Cool Components before. They're use of "CFMs" in their venting and cooling notes drives me nuts. (It's sort of a pet peeve - "CFM" stands for "cubic feet per minute" unless you are specifically dealing with just one cubic foot, and is thus already plural. "CFMs" reads as "cubic feet per minutes" in my brain and makes my eye twitch. Same issue with "GPMs" or "RPMs"...)

Quiet fans are going to cost more than the typical fans (which are generally loud) but, as sluggo suggested, running them at lower than the design RPM will help even if you don't shell out for a really good fan. I'd focus any fan efforts on the amp, and make sure that you have a clear path for air intake and exhaust. Stirring the heat around won't really help. You'll need some way to get fresh air in and a way to remove the hot air.

I agree that 105F isn't anything to worry about. I wouldn't even begin to worry unless the component temps got another 20-30F hotter.

My equipment rack is one of those metal/glass contraptions that you see in all the electronics stores. Given the height of both the 755 and the 990, it took a bit of shopping to find a unit that had proper shelf spacing. As things now stand, both the 990 and the 755 (predecessor to the 7500) are on the bottom shelf with about an inch of air space between them and the next shelf above. Even after extended listening at VERY high levels, I've never seen things go above 110F in that 1" air space when measuring with my little infrared gauge.

For folks that want a lot of power in a very confined space, a digital amp might be a better solution. That way, you attack the problem by increasing efficiency rather than increasing airflow (and noise) to expel energy wasted on heat production.

Best,

My dad did a lot of work with military spec electronics, and apparently in their testing, they found that it's better to pressurize (blow air into) and enclosure - and let it find it's way out - than to pull air out, as the air has a tendency to create "streams" and anything not in the path would lose heat more slowly. Of course, they did deal with much more powerful fans (and noise was not an issue).

I took a different tack. I replaced the glass front doors with perforated aluminum sheeting (aka decorative vent covering), and the fans are at the upper back of the cabinet. A tissue placed anywhere on the front of the cabinet shows that air pulls in evenly throughout the front, which gives me confidence that the heat is being pulled out the back appropriately.

Even after back to back reference level movie watching, my equipment is at most warm to the touch.

I have a 990 and 7700 combo in the center bay of an oak low-boy entertainment center. The bay inside is only slightly more than 18" high, and I'm experiencing similar operating temperatures to those stated here. The center bay is only open front and back, so I thought cutting two 4-inch holes in the cabinet bottom beneath the 7700 heat sinks might lower the temp. Surprisingly, it's hardly effected that at all. I'm still running around 105F in both 2-channel and 5-channel modes (don't have speakers for 7-channel yet). Doesn't matter how long the 990/7700 are on, after about five minutes it's 105. As previously suggested, the heat is mostly from the amp. The only improvement the holes made was to the cool-down time. It takes about 1/4 the time for the 7700 to cool to ambient after shut down.

Considering that my ambient temp is 81, the operating temp is only about a 25F rise which is not extreme. The 7700 should have no problems operating at this temp (probably up to 170F), although my preference is for a lower temp. I'm experimenting with some different arrangements and am considering mounting 100 mm muffin fans in the two holes I cut in the cabinet bottom. Newegg has some 1000 rpm units with a low noise spec for $8 that seem like just the thing. I'll post again with experiment results as I obtain them.

My previous setup used a 100 x 5 receiver in a different oak entertainment center that had adjustable shelves in equipment bays on either side of a space for a 36" direct-view TV. Initially, I left less than 2" above the receiver and the shelf above it, and I observed it ran quite warm (probably 105-110F), though never hot enough to trigger the fan in the receiver. I subsequently shuffled some equipment and raised the shelf above the receiver to provide 4-5 inches of space. The operating temp dropped substantially to barely warm. This indicates that for adequate natural convection, there needs to be a fair amount of space above the amp or receiver. Two to three inches, like in my current setup, is simply not enough to allow the heat to fully flow out of the amp naturally. A couple inches is probably fine for a lower power component such as a 990 or a disk player, but not for an amp or receiver. Someone will probably wonder why knowing this need for space I now have a cabinet and equipment arrangement that doesn't provide it. Well, I was planning to buy a 970/7125 combo when I purchased the cabinet, then changed my mind and bought the 990/7700. The shorter 970/7125 combo would have been fine. I wanted to keep the 990 and 7700 in the center bay to keep the cable runs shorter and neater, and here I am with a warmer running system than I would like. It's really only marginal, but I don't like doing marginal. I'd probably be shopping for another cabinet, but I don't have spousal approval for that.

Bill

Many thanks to TMH Sluggo Ritz2 & Gonk. All of your input was very informative and helpful to me. You guys really kow your stuff. As a test I took some stock Antec Case fans and used them to push air from left to right on my amp. It got the temps down to 95 degrees F but was a little noisy. I was watching Master and Commander and during the quiet parts of the movie I could hear the fans. I'm going to try similar set-up like Sluggo's with better fans and hopefully that will bring the temps down further and keep things quiet.

Thanks again. JD