I would assume that the amps running the left, right and center channels would get more "work" then the amps driving the surround channels.

If I was going to stack two or three 200's on top of each other, I thought it made the most sense to put Left on top of Left surround, and Right on top of right surround. Then to put center on top of Left rear and Right rear. This should give the most air to the amps doing the most work.

Furthermore, I was wondering if it made sense to rotate which amps were driving the main speakers every so often, and how often that might be.

Any thoughts?

It is possible that you would get more heat gain from the main and center channels than the surrounds, so your placement makes sense. I don't know how much more heat gain will actually be experienced, as I've always had a hard time getting solid numbers on real world heat gain from home theater equipment, but I would expect it to be marginal (a few degrees) -- unless you were in stereo mode and the surrounds weren't even turned on.

As for rotating the role of the different amps, I have no idea. I haven't ever heard of folks rotating which channels of a multichannel amp serve which speakers, which would be very similar to rotating the assignments of different monoblocks, and I don't know what real world benefits you might see from taking the time to juggle wires that way. It is an intriguing question, though, and I'll be curious to see what others think about it.

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

On my 770, where seven channels are “packed” together, I ignore the rear labeling which bunches “heavy use” channels together. In a theory similar to yours, I put the main L & R channels at the left and right ends. I put the center channel in the center. I put the rear surrounds on either side of the center, and the regular surrounds adjacent to the L & R mains.

I gotta think there's a bit of overkill going on here.

I agree that stacking a bunch of amps is not a good idea if it does not allow any one of them to cool properly - and heat's a potential killer of electronics - over extended periods at high temperatures.

However the mechanics (actual heat transfer / fluid dynamics) regarding a stack of components (alike or otherwise) is not a simple back-of-the-envelope (or off-the-top-of-the-head) calculation. Without some proper experimenting / modelling, I doubt that anyone could say, for sure, that channels stacked in a certain way will be inherently better than another, insofar as assuring that critical components are properly cooled. For example putting the hotter-running components on the bottom of the stack just might induce a higher mass flow rate of air through the stack, leading to an overall better net cooling effect. But then again it might not.

Likewise, you cannot know for sure that arranging channels on a multi-channel amp in a certain way will also have a better net cooling effect.

And even if you did know the answers - how would it actually translate into longer component life?

Perhaps one way of tackling the problem would be to ask service shops about which channels in a certain multi-channel amp fail the most frequently, and try to relate that back to your initial guesstimates. I assume that the majority of users actually hook up their amps as labelled - or if not labelled, without thought as to loading.

Besides, if I were designing a multi-channel amp, and labelling its channels, I'd design the heat sinking , and cooling fan / flow, to take into account channel loading - if it were an issue. Wouldn't you?

Jeff Mackwood

Good point. That's exactly what crossed my mind also. If there are going to be any differences in between channels of a multi-channel amp, you would think the manufacturer would take this into consideration when labeling and instructing the user on how to properly set it up.

I use multi-channel pre-amps at the studio I work at and I can tell you there are differences from channel to channel in relationship to how close each channel is to the power supply. The closer you get to the power supply, the more noise is inherent in the signal at high gain levels (ribbon mics). I would think the same holds true for multi-channel power amps. The manufacturer would probably arrange the channels in some sort of relationship to the power supply to maximize signal quality. Of course, I could be completely wrong.

As for monoblocks, unless you listen to tons of multi-channel audio, I would guess there could be a difference in heat between channels. However, I don't think that difference would be enough to change stacking arrangements. I would just stack according to manufacturer recommendations. I think in Outlaw's case, that's well stated in the manual.

As for rotating amps, that makes very little sense to me. You'll get used to the sound of each channel pretty quickly. If you change out the amp, you could be changing this sound, even if it's the same model amp. Even if it's a matched pair you're switching, there would still be the possibitly and the very likelyness of audible differences.

I would keep the channels the same. At worst, if the front channels happen to fail, you know you have a less used amp to switch in its place.

I don't think this is a large issue. The only time I think it really matters is at the extremes, either someone that mounts multiple amps in a rack, one right on top of the other with no thought as to cooling, or someone that drives the amp(s) at near capacity for almost uniterrupted periods.

My arrangement of channels on a 770 is has more to do with my tendency for geekishness and over-engineering. This tendency has mattered in a quite a few professional situations over the years, where others were not thinking/observing/planning well, but at home it is more a matter of just being consistent in my quirkiness. After all, these are my “toys”, right?!?

I suppose if the 770 were designed such that one transformer handled three of the channels, and the other handled four, then I’ve got more to think about. I am assuming that the transformers share the load more equitably. People operating seven 200's don't have this particular issue, but have others. For me, part of enjoying the results is the process of getting to the results.

The seven channel amps have two torrodial transformers. This implies to me that 4 channels are sharing one of the transformers, and the other one only powers 3.

This is a guess, but I'd be inclined to follow the channel labels on the back of the multi-channel amp.