Power Consumption of Hi Fi at different volumes

Hi-Fi Corner
21

Thanks IB, the Spendor A4 have a sensitivity of 86dB

22

I recently checked my Nova, as did Alley_Cat.

Please see: Nova on standby cost - #13 by Alley_Cat and following.

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23

For my calculation to estimate electrical costs that is what I have now done. The measurements other people have done on their system gives lower power so hopefully in practice mine will be lower too.

24

Copied from your thread “ 28-38 W while playing internet radio or from the USB-drive, with volume up to 33/100”.

Thanks. That is quite a bit lower than what Naim specify for the Nova (140W), which makes me wonder how they measured this and what assumptions are made.

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You could ask Naim Customer Service…

26

Working this out on paper is a fool’s errand. The sustained output doesn’t accomodate transients which can hit nearly 500w (and the transformer is designed to cope with that). The volume also doesn’t increase power, it increases gain and as such there is no linear progression of volume to power. Yes it always goes up but twice as loud is not twice as much power. In fact, twice as loud is usually many times more power but then the AB cutover masks the first part of that.

What this boils down to, which others have said is:

  • If doing on paper, just go by Naims dicumented specs in the manual. Don’t bother with other calculations. The compounding of errors will just give you a number, not an answer.
  • You can get an accurate answer with a wattmeter. They cost peanuts and good ones even let you program in your hourly average cost per KWh. You won’t just get a point in time readout in watts, you’ll get average watts per hour and cost per day/hour.

I used such a device months back to profile the whole house. Brilliant device. Cost $15 and in the first month saved me $200. What you think costs money and what actually cost money to run aren’t always what you imagine.

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27

Get a Kill a Watt and you can watch it in realtime.

28

We hired a guy to measure and suggest, no big surprises as we live in a newly built flat with latest equipment. Just good to know. LED-lamps. Charging the car at night-time. I finally got around to sell the hardware synths and fx boxes replacing them with software.

I dont have the exact numbers in front of me but I think the hifi measured 58W (idle) and 64W (playing locally) on my Melco, Linn DSM, 300DR. Leaving it at 24/7 for now.

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29

In theory, there is nothing incorrect in that - an electronics textbook would agree entirely with you. The problem is that none of our systems is theoretical and, as many have pointed out, there are more confounding factors in a real system than any of us can shake a stick at. Note the ‘typical’ legend on the graphs you posted, and consider that real consumer amps have a lot more in them than just the amplifier section - switching, displays and so on.

The only point I was making is that if I were to do the same theoretical calculations for my system as you have with yours and then compared them to the actual measurements I took in practice, they do not match up, no matter how correct they might be in theory. I was therefore simply pointing out that any such simple theoretical calculation is very likely to be inaccurate in practice

But what do I know? Why not get a Wattmeter, measure it and then we’ll know for certain?

Mark

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30

Yes good point thanks. Yes I will look out for one but it was more of a casual interest than a concern. The power consumption of the electric oven, hob and electric shower is far greater which I wouldn’t be able to measure with a wattmeter. Using the 130W figure Naim published (which is higher than peoples measured values of 25 - 50W) then I would spend around £166 a year listening everyday for 10hrs which I can live with.

31

Did this myself, years ago, with an SN2… ISTR it was about 40W and it didn’t make much difference what the volume was.

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32

The more I try to understand this the more your explanation IB makes sense and I am now starting to get it. My speaker sensitivity is 86dB. I do sit 4m away from the speakers and my average listening level at 4m distance is 76dB(A) to 80dB(A). I have not worked it out, but based on this the actual wattage to drive the speakers is considerably lower than I was previously expecting.

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I will be getting a new smart meter installed soon so this should give me some idea what components are using i will keep you posted.

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