Idle Power Draw of Amplifiers

All general audio posts go here.
User avatar
Philidor
Posts: 25
Joined: Thu Oct 01, 2015 10:54 am
Has thanked: 0
Been thanked: 0

Idle Power Draw of Amplifiers

Unread post by Philidor »

My Local Dealer is trying to sell me a Parasound Halo A21 Power Amp. Upon investigation I discover that this amp is drawing 149W of power when idle!

I'm already doing enough to melt the Polar ice caps and kill Polar bears. I don't need this on my conscience or electric bill.

This is by no means the worst offender. I see a review of the Usher Reference 1.5 over at TNT-Audio which claims:

"Power consumption is a problem with this monster. It already uses about 55 Watt when still switched off! Yes, indeed, it probably uses more power when not even on than most other power amps playing music! Part of the circuitry is always switched on, it seems, even if the main switch at the front is off. Switching the whole amp on raises the power consumption to about 260 watt, which is what you would expect from an amp like this." Maarten van Casteren

Is there any justification for this kind of profligate use of power?

User avatar
wallace
Posts: 980
Joined: Thu Jul 12, 2012 9:03 am
Location: Bridgwater ,Somerset.
Has thanked: 0
Been thanked: 0

Re: Idle Power Draw of Amplifiers

Unread post by wallace »

Good job i've got solar panels then,i have never switched any of my NVA amps off...
Revox B795,,NVA PHONO 1,Teac PD-H500C,Squeezebox Touch,Bushmaster MKII,NVA AP70,LS5,Royd Minstrels i/c's SSC's. .
Sony Laptop,E-Dac, NVA AP10P, LS3,SSC,Royd Coniston R.Grado RS1

User avatar
Dr Bunsen Honeydew
Posts: 30758
Joined: Wed Jul 11, 2012 7:26 pm
Location: Muppet Labs
Has thanked: 0
Been thanked: 48 times

Re: Idle Power Draw of Amplifiers

Unread post by Dr Bunsen Honeydew »

NVA amps draw Sweet FA, milliwatts when left on.

User avatar
Lindsayt
Posts: 4213
Joined: Fri Jul 13, 2012 9:06 pm
Has thanked: 1079 times
Been thanked: 692 times
Nauru

Re: Idle Power Draw of Amplifiers

Unread post by Lindsayt »

My 8 watt SET's draw about 80 watts per channel. I don't leave them on when not in use. With them being class A it makes little difference if they're playing music or not. I probably spend more on valves than electricity with this amp. The 300b valves are expensive little bastards when it comes to time to replace them.

My Creek CAS4040 draws one or two watts when in use with my EV Sentry speakers.

And then you get the big old Krells, which draw washing machine levels of power.

AshM750.
Posts: 513
Joined: Sat Dec 20, 2014 7:48 pm
Location: Yeovil, Somerset
Has thanked: 0
Been thanked: 0

Re: Idle Power Draw of Amplifiers

Unread post by AshM750. »

What about the BMU does that waste power when left on, surely there's a degree of loss?

Please tell me if its a stupid question.

User avatar
Dr Bunsen Honeydew
Posts: 30758
Joined: Wed Jul 11, 2012 7:26 pm
Location: Muppet Labs
Has thanked: 0
Been thanked: 48 times

Re: Idle Power Draw of Amplifiers

Unread post by Dr Bunsen Honeydew »

Next to none, there is very small amount of warmth generated by the transformers, so that means some current is being used, but again it is milliamps or milliwatts, not much more than a LED being left on.

User avatar
Dr Bunsen Honeydew
Posts: 30758
Joined: Wed Jul 11, 2012 7:26 pm
Location: Muppet Labs
Has thanked: 0
Been thanked: 48 times

Re: Idle Power Draw of Amplifiers

Unread post by Dr Bunsen Honeydew »

Anyway power being used by a circuit is not being wasted. The laws of physics, energy can never be lost only converted into something else, in this case heat. Now we all have heating in our houses, so basically it is just helping that in a small way. Only wasted in the few weeks in summer when the central heating doesn't fire up. Significant in valve or class A amps, insignificant in class AB or class B transistor amps or a BMU.

AshM750.
Posts: 513
Joined: Sat Dec 20, 2014 7:48 pm
Location: Yeovil, Somerset
Has thanked: 0
Been thanked: 0

Re: Idle Power Draw of Amplifiers

Unread post by AshM750. »

Cheers for the explanation Doc, it makes sense. ;)

Post Reply