I just purchased my first Class D amp and got to say I am pleased so far. But how does an amp rated 200 Watts output have a rated power consumption of 30 Watts? (Info source is the labeling on the amp.) Anybody know anything about this?
Yes. It's an average usage under normal conditions. Nothing to worry about, just a regulatory rating.
Regulatory agencies determine this based on 1/8-rated power duty cycle for safety and EMC agency testing. It's a global thing. Take rated audio power divided by efficiency then multiply by 1/8 duty cycle and you should be close to the minimum rating for average power consumption. In this case, 200w/85% = 230W 230W x 1/8 = 29W Nothing marketing, nothing nefarious, just simple math and regulations.
According to the manual average draw is 30w, maximum is 240w. 30w would be the 1/8 power figure. Most pro-sound power amps are rated for current draw at 1/8 power, because if you run at much more than that you don't have enough headroom. Why they show power draw instead of current draw is unusual, but the two are linear, so it's a valid number.
Oh, the number is 1/8 power? Like an average between resting and outputtng at good headroom levels? Thanks for your help. And yes Elf, and I like it so far.
More like the actual power at average playing levels. You use a lot less power than you think you do.
These days, it's becoming universal to use power rather than current for the ratings because more and more gear is capable of operating from 100-240V and using power GREATLY simplifies managing the back panel graphics.
Well, it is NOT equal to 230 W in this case or any other case, as it is not 15% more... Actually, 200 W/0,85 is a bit over 235 W... Changes nothing in this context, but the glaring "=" looks just... wrong... But sure, there is no magic numbers in play. It can be a bit frustrating to see how techno-phobic people inte MI fail over and over to grasp the concepts of energy storage, duty cycle, phase angle etc. A 5 kW amp hooked up to a 230 V 10A wall outlet is no perpetum mobile, it will only re-package energy that is available from the power lines.
Andy or Rick would know for sure, bit I think 1/8 of max. is the minimum they can claim for audio. My network stuff at work is labeled at some insane max. power. That would probably be valid if all interfaces were in use, CPU and memory maxed from activity of an overloaded network, and PoE was used to it maximum available. I had to measure the reality, and got between .5 and 1 amp. Called it 2 Amps for power planning. The UPS/PDUs (fancy power strips) indicate my measurements were correct during peak netwok activity. If our amps were rated at max. power at the cord, the big hitters would need some special power arrangements. The gear in my datacenter is running off of two 30 Amp 220 VAC dedicated circuits. We run at less than half that.
Yes, it's a ratings thing, but part of me imagines there's a small nuclear reactor on board to supply the power it doesn't get from the wall - just like our space probes that go to the outer solar system. If the amp is warm when it's not plugged in, I'd pass.
I think it was Venus or Saturn we nuked. If little green men live in there, under ground, or under the gasses, I'll bet they're pissed.
If little green men live on Saturn, they're likely swimming in liquid hydrogen (our present best guess is there is no "ground"/solid surface). A few pellets of Plutonium dispersed over their ocean probably won't wreck their day - I'd guess they're a pretty tough lot.
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