Look at my system in my signature. The curious thing is is that the 7500 runs quite cool and in fact runs all 5 channels very hard on the fronts and center (bi-amping the fronts). so the 2200 only run one surround speaker with the scant info sent to them. Even when no audio is being sent, the speakers seem quite warm to the touch . . . heating pad warm. I don't really mind it, but I can help but think these things are 1) wasting electricity and 2) maybe not very efficient.

Thoughts?

Those Polks are tough loads to drive. I'm not surprised that the 7500 works well for the front soundstage - it's a beast of an amp - but the LSi15's are a rare case where I think bi-amping the speaker is worthwhile. The LSi9 isn't as challenging as the LSi15, but it's still a 4ohm load - and surrounds in a 5.1 system get a fair bit of material to chew on these days. While it's typically OK to stack a couple 2200's right on top of each other (that's how my 200's are), with Polk LSi's it's probably best to give them a touch more breathing room.

As to the question about wasting electricity, it's an interesting subject that I've been known to think too much about (occupational hazard of designing HVAC systems for some fairly unusual buildings). The energy needed to get the surface of a shallow amp like the 2200 up to "heating pad" warmth isn't as great as you might think, and the first 120W or so of its output (I suspect that the transition point moves up from 80W since the LSi9's are 4 ohm speakers) is class AB so it will get warm.

let me be more to the point. they are connected to the 990 by the 12 volt trigger. even with the 990 is off and the orange light is visible by all the components, the 2200 still is very warm. this to me is kinda unacceptable.

How long do they stay warm? Are we talking about an hour or so, or are we talking a day later? Also, how much clearance is around them for ventilation?

go here and look at the pics:

http://www.polkaudio.com/forums/showthread.php?t=44340&page=2

same username. the outlaws have been off all night. the led is orange. if you put your have on the left side (top) of the unit, I would estimate it is around 100 degrees f/h. That's off. If I manually flip the on/off switch in the back then ofcourse they are much cooler. room temp. I just feel like I am wasting electricity. In my basement, it get's very cold during winter. I'll be anxious to see how these little heaters do. I have a fan I can put on top of the 2200's (coreless 120mm) but it gets very loud when it gets fast. If I could slow down the speed of the fine it would do a nice cooling job and be quiet. there is probably something I could buy at Radio Shack for that.

It's interesting to see that someone else has the same problem as I do. Everyone else claims that their amps don't get hot even when driven hard. I have 5xM2200 in a stack of 3 and a stack of 2 with about 1-2'' of breathing room on top of each stack. When in stand-by the amps are warm (~90F, just a guesstimate). When cranking the whole system for more than an hour (990 at -6 dB, whole system sucking ~8-9 amps and SPL of ~105-110 dB) some of the amps occasionally switch into protected mode. I am currently thinking of buying a new custom shelving system (Salamander) to give the amps more room to breathe when driven hard. Also, I am considering of using the 990's trigger to switch the power line conditioner and use the switched outlets of this unit to turn the M2200 on/off. If anyone has any suggestion, maybe for the audio furniture as the Salamander stuff is not really cheap (but I need at least 18''-21'' shelf depth), I'll be happy to hear them.

I use a power conditioner to switch all three of my amps on and off (a 7500 and two 200's), so I'm not a good reference for power consumption in standby mode. According to the M2200 specs , standby power consumption is on the order of 3 watts. I'm not sure what the standby consumption are for the 990 and 7500, but there could be a few more watts there as well - and that heat would rise through knownalien's rack to heat the air entering the 2200 stack. As I type this, I'm trying to figure out how much energy it would take to warm the top amp to 20F or 25F higher than ambient (and I may take a stab at it later if I can come up with some approximations for the other variables), but it's dependent on a lot of factors.

Knownalien, if we assume that each component in the rack is burning 3W in standby (990, 7500, both 2200's, and the megachanger), that's a total consumption of 15W when everything's off. Assuming you never turn the system on in a month, that's 720 hours at 15W, or 10.8kWh. Since energy costs have gone up lately, we'll say that your rate might be $0.12/kWh - that's $1.30 a month in electricity ($0.52 of which is from the 2200's).

Benson, what speakers are you driving? It sounds like you're giving the 2200's quite a workout - enough so that it would probably be good to give them a bit more breathing room if possible. That should be enough to keep them out of protected mode.

Their is something different between the model 2200's and the older model 200's. I have ten model 200's and three of the model 2200's. I have them stacked in three stacks of three and one stack of four, and all stay in standby mode until I trigger them with a 12v signal. In standby mode the 2200's stay at about 108F-118F while the 200's stay at about 90-100F. They are located in a room kept at 75F and of course the highest temp reading for all amps were in the transformer region. I take the readings first thing in the morning after the amps have been off for 7-8 hours and I used a Fluke IR temp reader which is pretty accurate. I thought that the higher temp for the 2200's were due to their being new and not broken in but I have had them for several months now and nothing has changed.
As far as heating up during use, I have had no problems with the 200's getting anything other than very warm when pushed hard in a four ohm load. Unfortunately I am not sure how hot the 2200's get since they have fans on them during use (When the TV is on they are blocked by the cabinet door and therefore do not get any airflow so I have fans cut on whenever they are in use).
Also someone had mentioned using fans to cool the amps but the fans made too much noise. Their are several ways around that. First us only DC fans, AC fans can generate noise in the amplifiers and heard through the speakers. Once you have picked out a DC fan(s) you can control the speed in three ways (probably more but these are the ones that I know). If you understand ohm's law than you can place a resistor inline with the fan and reduce the speed that way (easiest to find and cheapest), or you can buy an adjustable wall wart (AC-DC transformer) that has an adjustable voltage switch (radio shack carries these, fairly easy to find and somewhat cheap), or last you can buy a DC fan speed control that will control the speed with a dial (hardest to find and most expensive).

Hopefully this will help some.

gonk,

you can see from the pick that the 990/7500 sit below the 2200's. Your theory that the bottom components are somehow heating the air arriving at the 2200's can be tested I think if I place a fan blow down only below the 2200's like the coreless I mentioned. Therefore moving the hot air away from everything. I will try that shortly.

Gonk, I am driving Onix RS1000 as my mains (http://www.av123.com/products_product.php?section=speakers&product=46.1), RSC200 as center and RS550 as surrounds. All should be rated at 8 Ohms and should not present a difficult load for the amps. Let me know what you think.