Piracy of designs which a company sunk huge money into developing in an unfortunate reality. If I owned a company, I certainly wouldn't want to devote a year or so of R&D time only to give my work away for free so somebody can use my design to create cheap knock-offs. Keeping schematics confidential helps, although it isn't a total solution since things can be reverse engineered.
This is true, and cheap knock-offs can occur through reverse engineering. The way to fight this is of course with greater economy of scale. However, much of the larger scale piracy often happens when a manufacturer decides to become even more cost competitive and sends their design to China for production at better economy of scale, and they work together with the plant officials to get a plant fully geared up to build their product at the appropriate quality, ensuring adequate QC steps. However, they only actually need 8 hours a day of the plant operating to meet their demand quantity. They hope that demand quantity will eventually increase and even more production can be generated, allowing the plant to operate longer each day.
Maybe in some cases this generalization is true, given the same enclosure volume and heat sinking for all classes. The comparison goes out the window when you factor in that a designer of a hotter running amplifier class designs for that. Plus you have the generalization that Class D has high idle inefficiency.
So 40 years for the original, but only another 20 if you refurbish?
Depends on the usage. Many of these SRM 1 were sitting unused for long time which means they might have their original capacitors and still work. It is good idea to change the capacitors every 20 years even if they work to prevent catastrophic failure. Its like riding a car with old dirty black oil as lubricant, it will run but its good idea to change it.
I suspect it is the other signal processing in the Yamaha streaming amplifier and not (just) the class D audio amplifier that is increasing idle consumption. It is true that efficiency drops for class D amplifiers at low output, just as for any other class of amplifier, but is still generally better than class AB at comparable power. You'd have to know more about where the power is being used to make a true comparison.
www.audiosciencereview.com
This is the thing. Class D amplifiers themselves are efficient and have low idle power, but when the power supplies are considered there is often little difference between some Class AB. The ATI nCore amps with linear PS idle at something like 30W. @pma measured 17W idle for the NC252MP which isn't too out of line with the Hypex data sheet.I suspect it is the other signal processing in the Yamaha streaming amplifier and not (just) the class D audio amplifier that is increasing idle consumption. It is true that efficiency drops for class D amplifiers at low output, just as for any other class of amplifier, but is still generally better than class AB at comparable power. You'd have to know more about where the power is being used to make a true comparison.
Here is a random picture pulled from the Internet for a class D amplifier module (by ICEpower):
This indicates very low efficiency at low power, but consider the actual idle power for this amplifier:
A class-AB amplifier with ~100 W output may have idle power around 10 W or so depending upon the design (some use more, some less, but I do not know of any with only 1 W idle consumption).
HTH - Don
The data sheet states 8.5 watts for the power supply and 3.5 watts for the amplifier.
SMPS + 2 channels. If you look in Hypex datasheets, it is just normal. Just to read them. This is engineering, not feelings. 8.5W SMPS, 3.5W amp channel x 2. This makes 15.5W. The remaining 1.5W would be the softstart module.
The ATI nCore amps have a sleep function which places the modules into low power standby after 10 minutes or so. The linear supply is still operating though and there is power being used there.
And... ahem... I am still thinking that comparison of the two topologies under in between conditions (i.e., where the amps actually operate most of the time) might also be interesting and informative.
Of course, it would be nice if all amps provided a plot of power consumption vs. output power, and there was a map to the Big Rock Candy Mountain, but...And... ahem... I am still thinking that comparison of the two topologies under in between conditions (i.e., where the amps actually operate most of the time) might also be interesting and informative.
The info in recent posts to this thread about power supply consumption is interesting, too.
My Purifi-based NAD C298 is room temperature at idle and during active use. Absolutely no discernable warmth added to the enclosure in which it resides. I don't have a wattmeter to verify, though.
