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Heat from amps?

Looking through the forum threads on amplifiers I’ve read posts stating how the Pass Labs x250.8 gets warm enough for the occupants in the room to take notice, along with comments of being thankful for having an air conditioned room. In degrees, how much are we talking about at what levels of volume? I’d like to take all things into consideration while comparing power amplifiers. I have not been playing my Bryston 4B3 demo at loud volumes for long periods of time, but, as of yet, and the heat sinks have only gotten warm to the touch.

update : Keith English at Pass Labs had me call the dealer who I,ports Harbeth. "The 250.8 is too powerful, the XA25.8 is what we recommend." When asked about the XA30.8 I was told there is little difference compared to the XA25.8," and they reiterated the recommendation of the XA25.8 which has more than capable for handling my Harbeth 30.2 XDs. I thought dealers like to up sell? I'm worried about the handling of the bass on the XA25.8.
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jimob
88 posts
 
I have a coda amp ,integrated and you have get 3 choices of  power and first watts from 5, 18  and doubles watts down from 8-2 ohms 
with  highest amperage largest potted transformer then Anything in its price class and above 3kva , a true great piece of engineering and bargain.
rh67
307 posts
 
I have the Pass XA25 and while it gets warm to the touch it does not radiate heat like a tube amp. The XA 25 is a very special amp once you reach 200 hrs.
fuzztone's avatar
fuzztone
5,624 posts
 
You'll get warmer than "occupants" when you see your electric bill.
tomcy6's avatar
tomcy6
2,597 posts
 
As jaytor pointed out you need to know how many watts the amp draws at idle. An amp that draws 450 watts at idle will put out the same amount of heat as 4 100 watt light bulbs and one 50 watter while idling.

Class D amps put out the least amount of heat, then Class A/B amps which switch over to Class B at low watts, say one watt. The more watts the amp puts out before switching to Class B the more heat it will produce. Some A/B amps switch at 10 watts, some 25, etc. Class A amps run at full power all the time and most of the electricity they use is turned into heat. A 25 or 30 watt Class A amp will not cause heat problems for most people, though. Finally, if you really want some heat, get a tube amp. This is an overly simplified explanation, but maybe it will be some help.
dougeyjones's avatar
dougeyjones
163 posts
 
Kinda shocked to hear people say that they have multiple amps idling at 400+ watts and they didn’t notice the temperature change. My Pass X5 idles around 200w and I can notice the room temp change within thirty minutes. 
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