Hi All,

My 7100 gets very warm even at rest. I have 4” above the unit with opening front and back on the shelf. Interestingly the 7100 do not seem to get much warmer even when pushed. It seems to reach a certain level and maintain.

Why does it get so warm, even at idle?

Bob

Even at idle, an amp will naturally produce heat when it is on. It is due to inherent inefficiencies in amplifier design, and is one reason that digital switching amps have generated so much interest - they are much more efficient, but they are still maturing and aside from use in subwoofers there are very few such amps in production today.

What sort of temperatures are you seeing above the 7100? You appear to have some good ventilation in place. Is the temperature in the 80's or low 90's? If so, I would consider it to be normal.

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I noticed the same thing with my 7100 when I first got it but as far as I can tell it is normal. I took a keychain thermometer that I had and just laid it on top of the 7100 to test the heat and found that 90-95 is normal with the volume off and after watching a movie at what I consider a loud level the most I've ever seen is 112. If your running around that level don't worry mine has been that way for almost a year without problems. Hope this helps

Lasher

I have a 770 and the most I have seen using Raytek mini contactless thermometer is 112 as well. That was only on the center channel circuit board, the rest were a few degrees lower.

There are about 5 inches of clearence and the front of my cabinet is closed by glass, so only venting from the back. Nothing to worry about.

I wouldn't complain too much! An amplifier that runs warmer at idle than another one (assuming adequate ventiilation) undoubtedly has been designed to have it's output stage biased "richer" with more standing current then an amplifier that runs stone cold. This is a good thing! At the extreme end of the scale, a high-end class "A" amplifier will run very hot, and this type of output stage is known for it's sound quality.

I'd much rather have an amplifier that is designed to run with more bias current (and subsequently runs warmer at idle) than one that runs a very lean bias and runs very cool. An amplifer that has very little bias current is going to generate more crossover distortion that must be masked by higher amounts of negative feedback - not a good thing.

One of the reasons tube amplifiers get so hot is the high amounts of standing bias current that is running through the output tubes at idle (the filaments contribute much less of the heat).

[This message has been edited by soundhound (edited October 04, 2004).]

I know you could roast hotdogs on my Dynaco

Hi all, I put thermometer on top of my 7100. It never cleared 95 degrees so I am normal.

Soundhound, that makes sence on the bias current.

Thanks all for the replies.

Bob

It's totally normal for a power amp to be warm to the touch about 80-95 is normal