[Jonathon Janusz]

Please keep in mind that I know little to nothing about low-power amps. 

I have been kind of watching some of the developments among the folks building digital amps (ncore, the buzz on DAC's new amps, etc.) and currently run a tripath amp from Virtue.  I like the idea of what these digital amps offer both in running cool and being comparatively energy efficient.  I like energy efficiency both from the perspective of environmental friendliness and from the benefits to lowering my monthly energy bills while still enjoying my stereo.

Now this may sound like a completely stupid question, but here it is.  I know that a class A solid state amp is categorically the least efficient when it comes to power consumption to power output (as well as idle power usage).  I also understand that tube amps aren't the most efficient using electricity either.  What I am wondering is if going with a low-power offering in either of these kind of amps would more or less wash out the difference in power consumption when compared to a higher powered digital solid state offering?  Are low-power amps similarly low power consumption at idle?

Again, probably a silly question, but thanks for your time!

[Freo-1]

Well, here is a link to a high level explanation of amplifier classes:
 
http://www.hifivision.com/amplifiers/174-types-amplifiers-class-class-b-class-ab-class-d.html
 
 
Just for the record, most folks who are low wattage system enthusiasts are not worried much about amp efficiency.  Setting aside the hype associated with the N core amp, generally, Class A is thought to subjectively sound the best, as it does the least to modify the input signal.  The more efficient the amp is, the more modification is required to obtain an output, and hence, the more penalty is paid for that efficiency. 
 
Now, this is a generality, and there are always exceptions to the general rules.  Having said that, they often hold more true than not.
 
 

[opnly bafld]

Another post that does not attempt to answer your question. 

Taken from the First Watt Faq page:

"Q: Isn't Class A bad for the environment?

A: Everything is bad for the environment, in case you haven't noticed. When I look at the cost of enjoying my 25 watt/ch class A amplifier as compared to watching a big screen television or running a porch light all night, I see that I get as much or more value for the same sort of consumption. If I drive down the hill to shop at Fry's, I consume about as much power as running one of my amplifiers for 2 hours a day for a year. So I go to Fry's less often, and I turn the amp off when I'm done."

As an owner of a 20w class A amp and several tube amps this helps me sleep at night. 

[Chromisdesigns]

There is an easy solution to this:

In the winter (or if you are in San Francisco in the summer...) run your class A room heaters all you want.  It's as efficient as electric baseboard heating.

In warm weather, swap out for something that doesn't eat your air conditioning alive!

 

[Freo-1]

Another post that does not attempt to answer your question. 

Taken from the First Watt Faq page:

"Q: Isn't Class A bad for the environment?

A: Everything is bad for the environment, in case you haven't noticed. When I look at the cost of enjoying my 25 watt/ch class A amplifier as compared to watching a big screen television or running a porch light all night, I see that I get as much or more value for the same sort of consumption. If I drive down the hill to shop at Fry's, I consume about as much power as running one of my amplifiers for 2 hours a day for a year. So I go to Fry's less often, and I turn the amp off when I'm done."

As an owner of a 20w class A amp and several tube amps this helps me sleep at night. 

I guess subtle responses are not your strong suit.   
 
The following was included in the response:
 
“Just for the record, most folks who are low wattage system enthusiasts are not worried much about amp efficiency”. 
 
 
As for the rest of your post, am in total agreement!

[JLM]

Jonathon,

You're right, Class A and tubes are the least efficient designs.

Besides all the Tripath designs, you could also look into NuForce (here at AC) for a variety of small/quality/efficient "digital" designs.

[opnly bafld]

What I am wondering is if going with a low-power offering in either of these kind of amps would more or less wash out the difference in power consumption when compared to a higher powered digital solid state offering? 
Are low-power amps similarly low power consumption at idle?

1) No (or at least not likely)
2) No, depends on class of operation

[Jonathon Janusz]

Thank you for the responses.  Following along with the quote from the First Watt FAQ posted above, I would like if possible to put this in perspective using real world numbers.  I understand that "most" of the folks using these amps aren't concerned with such things, but would anyone with the proper measuring equipment (or relevant manufacturers' specifications) be able to quote some typical power usage (running and at idle) numbers?

Granted, "everything" may be bad for the environment, but other than curiosity, I don't see any harm in trying to be as little "bad" for the environment as I can be while still enjoying a hobby.  Also, a few dollars saved on the monthly power bill means maybe a few more CDs worth of music added to the collection each year.   

Last, where I live the temperatures swing anywhere from 100+ degrees above zero to 10 or more degrees below zero. . . and most of the year is enough of a roll of the dice that even running two sets of amps ("summer" and "winter") would probably be sketchy at best, considering the spring and fall can swing from snow to sunshine within hours one way or the other on any given day.

Thanks again!

[JLM]

When considering the life cycle environmental impact also consider the cost to produce/shipping the raw products, how the raw products are produced (by EU/US or 3rd world standards), how/how far shipping of each material/component is required, possible component (tube) replacement, and disposal impact (weight/hazard).

A low-powered 20 pound amp with 6 tubes (4 that are replaced annually) that uses 100 watts has a much bigger environmental footprint than a 1 pound digital that idles at 0.5 watts and is 90% efficient.

[genjamon]

A bigger impact just on the energy consumption front is probably more in the associated electronics than the amplifiers.  I have a constant draw of 30 watts just in my preamp, phono pre, and DAC, none of which have on/off switches and all of which benefit greatly sonically from being on all the time.  That impact adds up to a lot more throughout the entire year than having an amp that draws a lot of watts, even class A at idle.  Now, that changes greatly if you have SS amps that you keep on all the time for sonics and idle at somewhere around 100+ watts.  The energy consumed by devices at idle in the 3/4 or more of time when you're not using your system is a huge amount of the total energy consumption of most electric devices over their lifecycle.  Often times multiples of the total energy used through direct use of the device.