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At low power the FET temperature is very nearly equal to the temperature of the mounting base.Capacitor lifetime works as follows: the manufacturer gives a baseline lifetime at a given temperature and under rated load conditions. From that baseline, lifetime doubles for every 10°C reduction in temperature. Rated ripple current is usually taken to contribute 10°C to temperature, so no or very low ripple current constitutes another doubling of lifetime. Running the capacitor at a lower than rated voltage once again multiplies lifetime by a factor that goes up fairly quickly with dropping voltage.The baseline lifetime of the caps on the NC400 is given as 2000 hours at 105°C. At idle or during normal listening (i.e. low ripple current) and 60°C we can thus multiply lifetime with a factor 2^((105-60)/10+1)=45. Expected lifetime works out as 90000 hours, or just over 10 years of continuous operation. At that point the capacitor will go out of spec, but not fail outright.There is some irony to temperature and class D. People expect class D to run cool. That would only be true if one substituted a class D power stage for a class A amp and kept the heat sink as it were. Of course it would run stone cold under those conditions. But the point of course is to cash in on the diminished heat output and reduce heatsink capacity until the final temperature is the same.
Thanks, Bruno. Appreciate your time to comment on the subject very much. And I truly appreciate your incredible amplifier design that gets me so much closer to the music!
I just finished assembling mine this week. I had not attached the front or top panels of the chassis, so open air situation. I also used silver thermal compound between amp modules and chassis to improve thermal conductivity to chassis. After an hour of listening the first night, I put my hand over power supply and amp module to see how hot they were. I was surprised how much heat was coming off the amp module. I touched one of the capacitors with my finger, and It was warm enough that I didn't want to keep my finger there more than a few seconds. I don't have equipment to measure surface temps.Does this fit with others' experiences?The next day, I plugged one of the monoblocks into the wall using my Kill-A-Watt meter to determine power requirements. With the ampon muting engaged, the amp was using 13 watts. Turning muting off, but without any playback, it consumes 18 watts. that's for a single monoblock.
At low power the FET temperature is very nearly equal to the temperature of the mounting base.Capacitor lifetime works as follows: the manufacturer gives a baseline lifetime at a given temperature and under rated load conditions. From that baseline, lifetime doubles for every 10°C reduction in temperature. Rated ripple current is usually taken to contribute 10°C to temperature, so no or very low ripple current constitutes another doubling of lifetime. Running the capacitor at a lower than rated voltage once again multiplies lifetime by a factor that goes up fairly quickly with dropping voltage.The baseline lifetime of the caps on the NC400 is given as 2000 hours at 105°C. At idle or during normal listening (i.e. low ripple current) and 60°C we can thus multiply lifetime with a factor 2^((105-60)/10+1)=45. Expected lifetime works out as 90000 hours, or just over 10 years of continuous operation. At that point the capacitor will go out of spec, but not fail outright.There is some irony to temperature and class D. People expect class D to run cool. That would only be true if one substituted a class D power stage for a class A amp and kept the heat sink as it were. Of course it would run stone cold under those conditions. But the point of course is to cash in on the diminished heat output and reduce heatsink capacity until the final temperature is the same. (Back to hiding. I'm not actively monitoring this forum, but I'd like to take advantage of the occasion to give three cheers to jtwrace for setting up this Circle and organising the listening tour.)
FAILED POWER SUPPLY! SMPS600You guys can believe what you wish, however I guess opening my mouth gave me some payback.ONE of the 2 power supplies failed that I just installed within about 3 days. I believe it was a weak or faulty relay and probably from being on the heat helped kill it even earlier than it would have failed. Of course 90% of the time something like this happens within 30 days of an electronic being installed.I have a new power supply already installed, the old one went back to Hypex so in any case I am back with dual mono and some fast customer service.They do get hot, I don't believe the heat is a good thing, and I don't believe you should think its the best option putting the NC400 in the case without decent cooling and believe it is not getting extra heat kickback from this power supply raising the temp. more than necessary.Anyway, I have a vented chassis, and I have considerable space keeping the amp reasonably cool. We may never know why this first power supply failed, I just think its worth the extra precautions to not trap too much heat on these power supplies and in turn transferring it back to the NC400 modules.And no it was not just a fuse that burnt out on this SMPS600 power supply
I'll let you know when my enclosed sealed ncore monoblocs break down. They've been powered up continuously since 21st April so far
Hello Bhakti,I am using two of these CPU heat sinks on the SMPS600 large HS:AAVID THERMALLOY 9000000958 (special) $1.39 ea. USDhttp://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2150942_-1DavidT
