• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

idle power consumption class–a vs class–d

Besides Air Conditioning, the Dryer can be one of the biggest energy users in a household.
Do Americans not put their washing on a outside line to dry? The weather and climate (the US is a large place) isn't always in your favour, but is it really something of a cultural/class taboo? I have heard as much, but don't know how true this is.
 
This is the farcical aspect of new, "environmentally friendly" products. They are often only environmentally friendly compared to building a new product, in the old way, from scratch, but If an older product works, then the excess energy made to produce it (often higher than it will consume in its lifetime) is already accounted for. Any costs in running it compared to a new product must outweigh the initial cost for a new product, add in the often shorter lifespan of the newer product and all is not what it seems.

If products were truly environmentally friendly, then they should come with a 25 year warranty and some, economically feasible, way of fixing the item should the company go bust. There should be legislation and infrastructure to back up the warranty, so that an item should be repaired by some entity.

Will 90% of the active speakers running today (or class D amps generally) be anything other than landfill in 15 to 20 years time?

It is all a bit robbing Peter to pay Paul. A game of musical chairs around a flimsy concept of 'environmentally friendly'.

Anyone who has ever owned active speakers knows the amp almost always breaks before speaker components.
Passive speaker designs can last 25 years and still work great. You might repair a speaker surround but that's a $25 job.
On the other hand, show me an active speaker that lasts 12 years and I will be very surprised.
 
Your previous post had 2 clickable links - I clicked the SINAD table. This shows no idle power consumption figures as far as I can see. It has only these column headings:

THD+N
(5W, 4 ohms)
SINAD (dB)
(5W, 4 ohms)
Power (W)
(1% THD+N, 4 ohms)
Price (USD)Source

The other link is to a thread generally discussing Class D "efficiency", started with an apparently ill-informed opinion. I've not found a table there, just contributions from members offering a few examples - mostly about non-Class D amps, illustrating that these amps are far less efficient. Have I missed a useful table? Thanks
It was the table in the link posted by Matias.
 
Anyone who has ever owned active speakers knows the amp almost always breaks before speaker components.
Passive speaker designs can last 25 years and still work great. You might repair a speaker surround but that's a $25 job.
On the other hand, show me an active speaker that lasts 12 years and I will be very surprised.
This is a valid concern and add on top of this battery power. Headphones used to last until you sat on them. Now they last until the batteries fail.

Though I think 12 years is a bit pessimistic in regard to powered speakers. I've had plenty of subwoofers last well over 12 years. My expectations have outgrown them quicker than they have failed.

As for idle power, I'm more interested in other criteria for evaluating power consumption. Though it is still a useful number to have for these calculations. Standby consumption, that's a number I care about. My amps are in standby most of their existence.

When not in standby, the number I'm interested in is power consumption at my typical listening level. Some of this is accounted for by the base level (idle) draw of the amp and power supply. As volume increases, the efficiency of the amp becomes the primary factor in power consumption (I think). Many class-D amps have high enough idle draw that low-volume efficiency is merely ok. Their efficiency begins to pay off at higher volumes. This is noticeable on my hypex amps. They're not especially cool at low volume but you can raise the volume to ear-shattering levels without the heat getting out of control.
 
This is the farcical aspect of new, "environmentally friendly" products. They are often only environmentally friendly compared to building a new product, in the old way, from scratch, but If an older product works, then the excess energy made to produce it (often higher than it will consume in its lifetime) is already accounted for. Any costs in running it compared to a new product must outweigh the initial cost for a new product, add in the often shorter lifespan of the newer product and all is not what it seems.

If products were truly environmentally friendly, then they should come with a 25 year warranty and some, economically feasible, way of fixing the item should the company go bust. There should be legislation and infrastructure to back up the warranty, so that an item should be repaired by some entity.

Will 90% of the active speakers running today (or class D amps generally) be anything other than landfill in 15 to 20 years time?

It is all a bit robbing Peter to pay Paul. A game of musical chairs around a flimsy concept of 'environmentally friendly'.
The EU will have such legislation in the not too distant future. The snag is that many new products are much harder to repair, and certainly audio products. On the other hand, many modern products are actually much better. Just try to remember old televisions with vacuum tubes, or old cars for that matter. We tend to have a far too rosy picture of the past (says me, the historian).
There is actually quite a bit of research on total lifetime environmental cost of various products, and the result is that, yes, throwing away some good stuff is wasteful, but also that the energy benefits of modern efficient equipment may override the benefits of keeping functional older gear within a remarkably short period of time. There is no universal right answer here. In our own case, we still have 26 year old quite good double glazing. Modern double glazing is better, but by how much to warrant throwing away the old glass? For now we are holding on to the existing glass.
 
When not in standby, the number I'm interested in is power consumption at my typical listening level. Some of this is accounted for by the base level (idle) draw of the amp and power supply. As volume increases, the efficiency of the amp becomes the primary factor in power consumption (I think). Many class-D amps have high enough idle draw that low-volume efficiency is merely ok. Their efficiency begins to pay off at higher volumes. This is noticeable on my hypex amps. They're not especially cool at low volume but you can raise the volume to ear-shattering levels without the heat getting out of control.

With the class D amps I have tested including Purifi and NC502MP designs the idle power use is within 1-2 Watts of the power use when the speakers are reaching 76dB. For example:

A Buckeye, Boxem or March Audio Purifi 400ET amp will idle at 14-15W. Add 1-2 watts to get to a comfortable listening level.

This is why the idle power use of Class D amps is of interest to me. It's also very close to real life playback energy usage at reasonable levels.
 
And to return to the original question, my hunch would be that it is worthwhile with a class A amplifier, and if not financially, then at least environmentally. On the other hand, I doubt it is worthwhile to replace an AB amplifier, even though I would never buy one again.
 
And to return to the original question, my hunch would be that it is worthwhile with a class A amplifier, and if not financially, then at least environmentally. On the other hand, I doubt it is worthwhile to replace an AB amplifier, even though I would never buy one again.

Denon 4700 - idle - 135W -> 160W at normal listening levels (11 speakers)
Denon 4700 in full preamp mode = 46W at all volumes
March Purifi P452 Stereo = 16W - idle
Denon CD player - 12W
Adcom GFA-7000 - 56W idle (5 channels)
Stereo Boxem Arthur 4215/E2 - 14W idle
Stereo Buckeye Purifi - 15W idle

The pattern you see is:
More channels = higher idle
Stereo amps use less power than a 4-8 channel amp. Basic physics.
 
And to return to the original question, my hunch would be that it is worthwhile with a class A amplifier, and if not financially, then at least environmentally.
Isn't the most energy used in the creation of new goods rather than their use though? There is probably some equation for time used vs energy consumed, including in creation of product.
 
Last edited:
Isn't the most energy used in the creation of new goods rather than their use though?
Mostly no, but it obviously depends on the product. It is likely true for a frugal DAC/preamp, but not for a power amplifier.
 
Denon 4700 - idle - 135W -> 160W at normal listening levels (11 speakers)
Denon 4700 in full preamp mode = 46W at all volumes
March Purifi P452 Stereo = 16W - idle
Denon CD player - 12W
Adcom GFA-7000 - 56W idle (5 channels)
Stereo Boxem Arthur 4215/E2 - 14W idle
Stereo Buckeye Purifi - 15W idle

The pattern you see is:
More channels = higher idle
Stereo amps use less power than a 4-8 channel amp. Basic physics.
And even here, a frugal standby mode at the EU's mandated 0.5 watt consumes even less. 15 watt at 24/7 still adds up to over 100 kWh a year.
 
Do Americans not put their washing on a outside line to dry? The weather and climate (the US is a large place) isn't always in your favour, but is it really something of a cultural/class taboo? I have heard as much, but don't know how true this is.
I'm American and I dry my washing on a rack. It has wheels. I roll it outside in good weather, and roll it back to a covered patio room when it rains. In the summer it can take a couple of days to dry due to the humidity here, but in the winter everything is dry in two or three hours. When I lived up north I dried everything on a rack indoors in the winter. I'm sure that many Americans dry their wash on a rack or a line outside. Otherwise why would stores stock those items (most home goods stores as well as that giant online retailer do stock them)?

And even here, a frugal standby mode at the EU's mandated 0.5 watt consumes even less. 15 watt at 24/7 still adds up to over 100 kWh a year.
Back to the topic at hand. I have a pair of Buckeye eight channel 252 power amps. They use around 57 watts at idle, and about the same when playing music. I have a Rythmik sub which I believe uses an A/B power amp. I don't know what it uses at idle, I can't find my meter to measure it, but it doesn't really matter because I have it on a power strip and I shut the power down completely when it is not in use.

Actually, I shut the power down completely for any audio gear not in use. I have a Tripplite strip with individual switches for six outlets. Whatever isn't active, gets no power. Incidentally, Buckeye power amps have an actual, real, power switch on the back so they can be powered off completely without using a strip (though I find the strip more convenient because as seems the fashion these days, power switches are in the back, a design flaw, in my opinion.)

This gives a better result than the European standard. My equipment uses zero power when not in use.
 
i mean, i can't buy every device and then measure it at home.
I do. Measuring is done in seconds maby some minutes till the device is entering idle mode.
Most power consumption in our house is done by the wife. Thats why we bought a new tv, dishwasher, dryer an washing machine last few years. :facepalm:
Measuring did cut > 30% in power consumption. Audio gear compared to above (when shut off after use) is harmless imo an measurement.
Another piece of audio gear that makes here happy is a Bose Wave II it consume basically nothing an sounds in our acousticly horrible living quite good. Audio Mancave is off limits. :cool:
 

Attachments

  • IMG-20240114-WA0003.jpeg
    IMG-20240114-WA0003.jpeg
    111.9 KB · Views: 21
Last edited:
This gives a better result than the European standard. My equipment uses zero power when not in use.
This is what I also do for most gear. My Quad 606-2 power amp does not have a standby function, and the on/off switch is at the back, so I switch it with a sensor power strip. My RME ADI-2 has very low standby power consumption, so I leave that on. The subwoofers are on standby because walking around them every time I turn on the system is a bit of a hassle. The Plasma TV is switched off completely, if only to reduce the fire hazard. Anyway, nothing is kept on at levels above low standby consumption. Until some time ago we had a Samsung set top box for the TV, and that used 75 watt 24/7. It needed a noisy fan to keep cool.... Fortunately the cable company then changed it for a more frugal unit. Since then, we moved to fiber, with an even more frugal decoder.
In general, it pays to investigate power consumption of all gear that is on 24/7. As an example, we have floor heating, with two pumps to circulate the warm water. I had a look at their consumption, and they used 75 watt each, for a total of 3.6 kWh a day. When we had a heat pump system installed last February to heat our home and provide hot tap water, we also ordered new and modern circulation pumps. They only consume about 10 watts each (technical progress does exist). Few people are aware of such hidden energy wasters. Compared to these examples, audio gear is really frugal as long as you don't go the class A and tube route.
 
This is what I also do for most gear. My Quad 606-2 power amp does not have a standby function, and the on/off switch is at the back, so I switch it with a sensor power strip. My RME ADI-2 has very low standby power consumption, so I leave that on. The subwoofers are on standby because walking around them every time I turn on the system is a bit of a hassle. The Plasma TV is switched off completely, if only to reduce the fire hazard. Anyway, nothing is kept on at levels above low standby consumption. Until some time ago we had a Samsung set top box for the TV, and that used 75 watt 24/7. It needed a noisy fan to keep cool.... Fortunately the cable company then changed it for a more frugal unit. Since then, we moved to fiber, with an even more frugal decoder.
In general, it pays to investigate power consumption of all gear that is on 24/7. As an example, we have floor heating, with two pumps to circulate the warm water. I had a look at their consumption, and they used 75 watt each, for a total of 3.6 kWh a day. When we had a heat pump system installed last February to heat our home and provide hot tap water, we also ordered new and modern circulation pumps. They only consume about 10 watts each (technical progress does exist). Few people are aware of such hidden energy wasters. Compared to these examples, audio gear is really frugal as long as you don't go the class A and tube route.
Changing a laptop 1TB HDD for a 2TB SSD did cut power consumption quite a bit.

 
My current NUC I7 consumes about a quarter of what my old computer consumed: probably some 70 watt compared to an average of 300 watt before. Since I work mostly at home, this adds up to a lot.
 
My current NUC I7 consumes about a quarter of what my old computer consumed: probably some 70 watt compared to an average of 300 watt before. Since I work mostly at home, this adds up to a
Same with my Lenovo laptop I5 processor 2014 used as audio media center. It draws around 30 a 40 watt screen on an using the old HDD which encourage the fan to cool. With the fast SSD, screen on fan is practical not active any more which cut power consumption considerable to around 16 watt most of the time.
 
Just used a kill-a-watt on my 12 year-old TA2020 and 13.5V brick;

1.4-1.7W idling
28-29W just short of obvious clipping with a bass sine, nominal 6 Ohm speakers so should be in the region of 12+12W. ETA >> bookshelf speakers with ports at 80Hz, I used a 24Hz tone where they will likely be very close to the nominal figure.

The amp's case is absolutely tiny (not much bigger than a fag packet), measured its temp this AM before playing anything, 7°C warmer than ambient (27.2°C vs 20.5°C) which will presumably be the temperature inside the case, but whatever is producing the heat will be a hotspot at somewhat higher temp.

ETA >> occurs that I should have measured with Foobar's attenuation at 6dB down from max to get a number for roughly 50% output.
 
Last edited:
Passive speaker designs can last 25 years and still work great. You might repair a speaker surround but that's a $25 job.
On the other hand, show me an active speaker that lasts 12 years and I will be very surprised.
The Genelecs I currently listen to are something like 26 years old, and still working great.
 
Back
Top Bottom