• To directly access the forum, ensure your bookmark url includes /forum.

class a power consumption

karlsushi

Wammer
Wammer
Feb 1, 2022
654
1,251
108
Melton Mowbray, East Midlands
HiFi Trade?
  1. No
The biggest waste of energy with Class A is leaving it to idle. With pure class A the transistors are on all of the time so I guess it uses the same power whether or not you're listening to music.

I guess that's the reason they run hot when idling because the energy has to go somewhere. Comes out as music when it's playing, but as heat when idling.

When Class A is playing music though, it's not a waste of money in my view, because it sounds amazing. I'm happy to pay for good sound, but I do acknowledge they aren't a very green option.

I have an Aleph 3 in my small system and an Aleph 5 (clone) in my living room system (30W and 60W respectively). Neither are going anywhere any time soon.
 
  • Like
Reactions: Lawrence001

hearhere

Wammer
Wammer
Apr 9, 2013
842
601
113
Portsmouth, UK
AKA
Peter
HiFi Trade?
  1. No
I need to point something out when they are being pushed hard they run cooler and are more efficient . When they are idling then they generate more heat .
This is something many owners don't realise. Unlike Class AB or D, Class A amps use just as much mains power when idling as when playing at full volume. They should be turned off when not required.
 

Richdirector

Wammer
Wammer
Sep 16, 2015
370
177
63
Glasgee Skottishland
AKA
Richard
HiFi Trade?
  1. No
My luxman is 20w A-class and 'only' draws 170w at idle to 230w when working... I know it goes into AB at much higher volumes (if needed) so that may account for the extra bits....
 

cynix

Wammer
Wammer
Jan 7, 2011
228
68
43
Scotland
HiFi Trade?
  1. No
For under 20 quid I found one of these very useful when considering power draw of my own class A amp recently.

 

bigrod

Super Wammer .. Pussy 🐈 lover
Wammer
Mar 12, 2013
4,342
5,397
183
D H LAWRENCE TOWN
AKA
Julian
HiFi Trade?
  1. No
If it’s a toss up between running my HiFi or Diane’s weekly eyebrow session and nail painting to save money,, we all know who’s going to win …
 
  • Upvote
Reactions: Bazzer

jtc

Wammer
Wammer
Apr 10, 2007
333
4
48
Fife Riviera, UK
AKA
John
My amp pulls just under 300w to deliver 30w at class A. It gets quite toasty but I turn it off when I’m not using it and (sadly) I don’t have as much free listening time as I’d like to notice it hammering my electric bill!
 

The_Krell

Newbie
Wammer
Sep 13, 2022
94
54
18
HiFi Trade?
  1. No
It's not necessarily the on cost but the standby cost.
My old A/B amp chewed 70w in standby. That's approx 1.7kwh a day at 33p/kwh that's £200 ish a year to just sit there.
Now granted I can offset that vs the saving in heating when the heating is on but still...I mean think of the records I could get instead :)
 

Music At Home

Google Bot
Wammer
Jul 31, 2011
198
103
73
Argyll
HiFi Trade?
  1. No
Don’t forget that the heat output from your amp will offset heating costs for the house, so in cooler weather you‘re effectively reducing your heating bill. The reduction in heating costs won’t be the full amount that it costs to run the amp unless you’re using a really costly form of heating like electric bar or fan heaters.

If you have gas central heating (or an air source heat pump) about a third of the amp’s running cost will be offset against your heating bill.
 

hearhere

Wammer
Wammer
Apr 9, 2013
842
601
113
Portsmouth, UK
AKA
Peter
HiFi Trade?
  1. No
Don’t forget that the heat output from your amp will offset heating costs for the house, so in cooler weather you‘re effectively reducing your heating bill. The reduction in heating costs won’t be the full amount that it costs to run the amp unless you’re using a really costly form of heating like electric bar or fan heaters.

If you have gas central heating (or an air source heat pump) about a third of the amp’s running cost will be offset against your heating bill.
That's a pretty bizarre way to look at unnecessary electricity use. Then in summer, you'll be looking to air conditioning to keep your house cool - more unnecessary power consumption to reduce the unnecessary heat generated by the inefficient amp! Leaving lights on winter and summer will offset your heating bill but that's an equally crazy idea.

I ditched my SET mono amps 3 years ago, although only partly for environmental reasons. The Class A amps I bought or borrowed offered no better sound than the best AB ones or the Class D one I eventually went for – and this can be put against any of the 12 amps I home tested and good enough to pick up every Stereophile Best Of award going. Now my hi-fi (200 watt all-in-one, 2x1000 watt built-in speaker amps, mains filter and even router) consume just 60 watts when playing loudly. Yes, I find this pretty amazing, but that’s what my watt meter shows and it’s accurate with other measurements that can easily be verified. My highly sensitive speakers help of course.
 

Batty

Wammer
Wammer
Oct 8, 2009
918
288
93
Adelaide. Oztrayliya
AKA
Steve
HiFi Trade?
  1. No
My M2x consumes 160w all the time it is on, 25 watts per channel 40w into 4ohms.
My ACA consumes around 70w it is 8w per channel .
Both class A obviously.
 

Music At Home

Google Bot
Wammer
Jul 31, 2011
198
103
73
Argyll
HiFi Trade?
  1. No
That's a pretty bizarre way to look at unnecessary electricity use. Then in summer, you'll be looking to air conditioning to keep your house cool - more unnecessary power consumption to reduce the unnecessary heat generated by the inefficient amp! Leaving lights on winter and summer will offset your heating bill but that's an equally crazy idea.
Sorry, just trying to be informative. Not trying to justify anything as I don‘t run a Class A amp myself.
 

Forum statistics

Threads
108,002
Messages
2,286,715
Members
69,139
Latest member
beatmania