idle power consumption class–a vs class–d

[SkipperGW]

i'm torn between class–a and class–d.
i still have an old yamaha rx–a3080 sitting around here, and the two main speakers are driven by an even older korsun v8i.
now it has turned out that the korsun offers a lot of power and controls the speakers very well, and also relieves the avr, but it consumes a lot of power when there is no signal, i.e. when it is idle.
most data sheets for amplifiers often only state how much power such a device consumes in standby and how much it can deliver at maximum due to the power supply, but almost never the idle consumption.
now my question is, is the idle power consuption significant better for class-d amplifiers than for class–a amplifiers?
and how can you find out what idle consumption devices have?
i mean, i can't buy every device and then measure it at home.
anyway, for the best wife of all, the power consumption is definitely an argument (waf), that's where my question comes from.
so i'm thinking about keeping the korsun, or buying a class-d amplifier with purifi 1et9040ba chipset; but that's only worthwhile for me if the power consumption is significantly lower, especially the idle power consumption.
thoughts…?⁇

 

[olieb]

anyway, for the best wife of all, the power consumption is definitely an argument (waf), that's where my question comes from.

I totally agree with your wife.
I do not understand the problem though.
If your Korsun uses a lot of power in idle, I guess it does not have a standby mode?
Many class D amps will go into standby, so the (rather low) idle consumption is not so important. Unless you take great care to prevent standby mode of course.
And then there is always the option to use a switch ;-)
Not to forget that producing a new amp will take a lot of energy, too.

 

[AnalogSteph]

but it consumes a lot of power when there is no signal, i.e. when it is idle.

How much exactly would that be in this case? I couldn't find any typical figures for this model. According to the manufacturer, the V8i isn't even a straight Class A affair (which would require far more heatsinking that what it has) but rather using "adaptive bias". A chunky 250 wpc amp can easily use 120 W at idle even in classic AB.

A 1ET9040A module uses only 3 W at idle by itself, so take that x2 plus power supply losses. We've typically seen about 20-50 W mains-side in moderately high to high power class D amps. So the difference to AB ampd isn't quite as big as you'd think (Class G / Class H isn't automatically worse) but still fairly substantial.

 

[dualazmak]

Just for your interest and reference, I am hosting this thread;
Apparent power consumption of whole audio system during daily audio listening sessions: how SDGs-friendly is it? (not the idle power, please.)

You can measure "live" AC current consumption by all of, or any gears of, your audio system using Clamp-On Current Tester like YOKOGAWA CL220 which I usually use.

Spoiler

If you would measure the AC "current", and you know well the "voltage" of your AC, then you can easily calculate nominal power consumption.

 

[SkipperGW]

thank you very much, indeed.

okay, i didn't realise that class–d automatically goes into standby when there is no signal; the korsun just keeps running – and no, it doesn't know standby.
the problem also arises because i often forget to switch off the device.
or i forget to switch the music on again when i have switched it off because of a phone call, for example.

the problem is that there are no idle wattages for almost any amplifier, only standby wattages.
the korsun usually consumes between 50 and 60 watts in idle mode.
when it has been playing for a while and the music is off, it still consumes 120 to 130 watts for a while.
as i said, it does not know standby.
even the yamaha rx–a3080 avr consumes significantly less in idle mode.

however, i'm surprised that a class–d needs between 20–50 watts in idle mode, so that wouldn't necessarily speak in favour of replacing the korsun.
the nickname for devices like the korsun over here is ‘iron hog’.
is it true, though, that a class–d amp automatically switches to standby if there's no signal?

in any case, if it is true that the difference in power consumption is not that great, there may be be no reason to replace it, as there is nothing else wrong with the device.
and there's nothing wrong with the sound for my old ears.

and thanks for the tip about the tester.
however, this is beyond my capabilities – i simply measured the wattage with a socket that also measures; and that's how i found out how much the korsun consumes.
only the old plasma tv consumes significantly more.

 

[SkipperGW]

i asked audiophonics.
their answer:

the standby power is 0.1w for the hpa-dm750et as for the hpa-t400et and the lpa-m750et.
the power consumed when the device is on and there is no signal is about 30w per amplifiers.
class d amplifier are definetely better than class a on this point if you wonder

that's roundabout half as much idle power as my old korsun.
thus my question is answered.

 

[dfiler]

The idle consumption from the power supply on a class D amp is a significant factor. The amp circuitry is efficient but the power supply is average. That means that at low volume the overall power draw of class D is just ok. Where they excel is at higher volume. The efficiency of amplification is a higher percentage of the total power consumption as you go up in volume.

This is the reason 12v triggers and auto-on functionality is built into most separate amps, including class D. It allows the amp to move into an ultra low power standby mode rather than idle with the power supplies still burning power.

 

[DVDdoug]

IMO - Class-A is "just dumb" for power amplifiers. It's class-A because it was the 1st amplifier design, not because it's the best. Back in the tube days it was common because class A/B needs another tube, which adds cost.

Now, and extra transistor or MOSFET costs almost nothing and the cost is more than offset by using lower-power devices since they don't have to dissipate heat, and you can get-by with smaller heatsinks.

Economically, class-D is similar. It's a lot more complicated, but the additional semiconductors are in a chip (so cheap) and the output transistors/MSOFETs can be even lower-power than class A/B, and the heatsinks can also be even-smaller.

and how can you find out what idle consumption devices have?

Kill-A-Watt

The wasted energy is converted to heat so in the winter or when you're heating your house it (slightly) lowers the load on your furnace and the energy isn't wasted. But electrical heat tends to be more expensive than other energy sources.

In the summer it's REALLY BAD if you have air conditioning because the amplifier is generating heat and wasting energy and your A/C wastes MORE energy offsetting it, like running the furnace and A/C at the same time!

 

[Greenman]

IMO - Class-A is "just dumb" for power amplifiers. It's class-A because it was the 1st amplifier design, not because it's the best

It’s could be considered pretty dumb for high power amps certainly, but the advantage can be just working in the linear range of the valve or transistor and not having to deal with crossover issues/distortions etc. For low power applications these advantages might outweigh the extra power usage.

For guitar amplifiers Class A is valued for its particular distortion characteristics, so useful in this application as well.

 

[xrqp]

Below are all class D amps, except the Parasound JC5 is class AB and is by far the worst and should have an auto standby at low watts, but does not. These are my measurements with a Kill-A-Watt wall plug meter.

Make	Model	Watts	VA	Description
Buckeye	2ch NCx500	26​	55​	on, w no music
Buckeye	2ch NCx500	13​	32​	standby. Auto standby works well (works if no music for some time.)
Ayima	A07	4.6​		on w no music, and the same when moderatley loud. Does not have a standby mode.
Outlaw	Sub, Ultra 13	1.8​		each sub: 1.8w stdby, 40w loud, 100w very loud. Auto standby works well.
Parasound	JC5	240​		on w no music (200w per mfg, 240w measured). Off is 1.5w. Does not have a standby mode.

 

[Willem]

In the EU all audio gear has to have a low power mode of 0.5 watt that switches on after a reasonable period of time. See here: https://energy-efficient-products.ec.europa.eu/product-list/standby-networked-standby-and-mode_en

 

[antcollinet]

In the EU all audio gear has to have a low power mode of 0.5 watt that switches on after a reasonable period of time. See here: https://energy-efficient-products.ec.europa.eu/product-list/standby-networked-standby-and-mode_en

Not many of the simple chip amps are doing that though.

 

[Willem]

Not many of the simple chip amps are doing that though.

Makes them illegal in the EU.

 

[antcollinet]

Makes them illegal in the EU.

Yep. But not many people seem to be worrying too much about that.

 

[Hear Here]

Below are all class D amps, except the Parasound JC5 is class AB and is by far the worst and should have an auto standby at low watts, but does not. These are my measurements with a Kill-A-Watt wall plug meter.

Make	Model	Watts	VA	Description
Buckeye	2ch NCx500	26​	55​	on, w no music
Buckeye	2ch NCx500	13​	32​	standby. Auto standby works well (works if no music for some time.)
Ayima	A07	4.6​		on w no music, and the same when moderatley loud. Does not have a standby mode.
Outlaw	Sub, Ultra 13	1.8​		each sub: 1.8w stdby, 40w loud, 100w very loud. Auto standby works well.
Parasound	JC5	240​		on w no music (200w per mfg, 240w measured). Off is 1.5w. Does not have a standby mode.

My Atma-Sphere Class D mono amps consume 7 watts each on Idle (on but no signal).

My NAD M33 all-in-one with Purifi Class D amp consumes 12 watts in Standby and 26 watts in Idle.

NAD's Spec shows "Standby <0.5W", but that really isn't true. The unit can be put into a deep coma (called Vacation Mode in the M66) by a change within Settings, but it can then only be resurrected manually by using the unit's own top-panel switch - not from the app. A bit naughty for a major brand!

 

[Matias]

Here

Let's stop calling Class D amplifiers "efficient" when they are not.

Tell me, how much power do your class D amplifiers consume, just idling along, doing nothing, or even playing slightly loudly? Measure it and be shocked. Report back here with your results. Class D "efficiency" is utter and complete bullsh#t. My stereo class AB amp with MOSFET output stage and...

www.audiosciencereview.com

 

[Hear Here]

Here

Let's stop calling Class D amplifiers "efficient" when they are not.

Tell me, how much power do your class D amplifiers consume, just idling along, doing nothing, or even playing slightly loudly? Measure it and be shocked. Report back here with your results. Class D "efficiency" is utter and complete bullsh#t. My stereo class AB amp with MOSFET output stage and...

www.audiosciencereview.com

I'm not sure that table tells us anything about the idle power consumption of the listed amps.

A position in this list bears little if any correlation to how good the amplifier actually sounds, but that's another matter!

 

[Willem]

Of course, audio gear only represents a small part of total energy consumption, but it all adds up. There are similar mandatory EU standards for other equipment such as televisions, refrigerators or washing machines. In many cases the current models only consume about a quarter of that by their ancestors of some fifteeen years ago. It incentivizes technological innovation and stops manufacturers being lazy.

 

[amper42]

i'm torn between class–a and class–d.
i still have an old yamaha rx–a3080 sitting around here, and the two main speakers are driven by an even older korsun v8i.
now it has turned out that the korsun offers a lot of power and controls the speakers very well, and also relieves the avr, but it consumes a lot of power when there is no signal, i.e. when it is idle.
most data sheets for amplifiers often only state how much power such a device consumes in standby and how much it can deliver at maximum due to the power supply, but almost never the idle consumption.
now my question is, is the idle power consuption significant better for class-d amplifiers than for class–a amplifiers?
and how can you find out what idle consumption devices have?
i mean, i can't buy every device and then measure it at home.
anyway, for the best wife of all, the power consumption is definitely an argument (waf), that's where my question comes from.
so i'm thinking about keeping the korsun, or buying a class-d amplifier with purifi 1et9040ba chipset; but that's only worthwhile for me if the power consumption is significantly lower, especially the idle power consumption.
thoughts…?⁇

The korsun v8i uses 55W in idle mode. That's on the high side but not terrible. Here's my advice:

1. The best advice I can offer is to place the korsun v8i on a surge protector and turn it off when not playing music.

2. Or purchase a Boxem Arthur 4216/E2 that uses 15W while idle and after 11 minutes of no music shuts down to standby mode at 1W. It turns back on automatically when music is playing.

3. Not all Class-d amps offer standby mode and some work better on standby than others. Some builders offer the ability to turn off standby as users noticed with low SPL classical music the amp went into standby. Implementation matters.

Personally, I would go with turning off the amp when not in use if energy savings is the moving reason for change. It's doubtful you will save enough in energy to pay for a new amp solely based on idle power use?

 

[Willem]

I'm not sure that table tells us anything about the idle power consumption of the listed amps.

A position in this list bears little if any correlation to how good the amplifier actually sounds, but that's another matter!

The table gives you just that: idle power consumption. And as for sound quality, do you know of a controled double blind test that shows sonic differences?