I'm refering to the information printed on the back side of the AVR. On this photo (taken from:
https://nadelectronics.com/product/t778-surround-amplifier/) it states, that the power rating is 1200W. On the model, that I have at home, it states only 1000W. The found the difference also in some documents posted by NAD: check aut page nr. 2 in the specs sheat:
https://nadelectronics.com/wp-content/uploads/2019/07/NAD-T-778-Surround-Amplifier-Data-Sheet-1.pdf) and the different information (1000W) in the owners manual (check out page 7: https://nadelectronics.com/wp-content/uploads/2019/07/T778-OM-EN-v12.pdf).
So, which is it?
Sorry, no simple answer to your question, it may be neither, either, or it depends..
The number that you are seeing is POWER CONSUMPTION FROM THE AC LINE, this is NOT the power rating of the audio amplifier. This is the maximum current drawn from the power line. Likely you are seeing a different in rating depending on the government regulations in the country where the NAD was sold; different countries will define power consumption differently....
Agreed in general, if such countries have some relevant, however loose and vague rules/standards they may be, manufacturers would likely do something to cover themselves, and that would invariably mean the numbers could be different, the varieties of the 100, 115, 120, 220, 240 V and 50 or 60 Hz may also be factors. But the "This is the maximum current drawn from the power line." part, technically speaking does not seem right (See Gene's comments that covered one reason, there are more..)
I would just like to add the following that may sound like ranting, out of my frustration in seeing how audio equipment manufacturers get away with not having to define their "power consumption" specs, likely because of, but not limited to the following:
a) most consumers don't really care, for various reasons, one being they don't really contributed much to their electricity bill.
b) governments may not consider them a high risk, due to their lack of knowledge in this field, and while some amps, avrs would blow up in smoke as reported on AV forums, I am not aware any documented incident of such equipment resulted in the fire departments being called.
c) they apparently do realize that unlike appliances such as Fridge, electric heaters, air conditioners, fans, that when in use would typically draw more or less constant "power", so it is easy to report the "maximum power consumption" based on their "maximum setting", for example maximum speed, temperature setting (min/max) etc., but it would be tough to do with audio devices such as AVRs and amplifiers.
It is sad that the industry don't follow certain standards/rules. The closest it has come to something somewhat (but not really) official finally, thanks to Gene's recent article in which he sort of quoted SU. I am going to bookmark the following link for future reference. Still that just applies to Denon and Marantz AVRs, not sure if that would apply to their integrated amps, and certainly cannot be applied to their much older models. Bottom line, if one wants to know what it is for NAD, one should contact NAD but I doubt their first level customer support would give an answer unless they are authorized to provide the official one from their engineering/manufacturing departments. Marketing/sales typically don't get into such details.
Ever wonder how your favorite manufacturer rates power consumption on their AV receivers and how it relates to maximum available output power to your speakers? The answer may surprise you so read on.
www.audioholics.com
What does the back panel power consumption rating mean?
- Unless it says "max power" don't assume it's a max power rating with all channels driven.
- ·According to Sound United, they follow IEC 62368-1 electrical safety standard for rating power, specifically Annex B for operating conditions and Annex E for test conditions.
- Amplifier to be tested at 1/8th unclipped de-rated power @ 1kHz & rated load impedance.
- Sound United follows IEC 62368-1, the electrical safety standard for audio, video and similar equipment for their AV receivers.
- Follow operating condition under Annex B: Normal operating condition tests, abnormal operating condition tests and single fault condition tests, and the amplifier output conditions defined under Annex E: Test conditions for equipment containing audio amplifiers.
- Measured input current/power under normal operating conditions shall NOT exceed the rated current/power by > 10%. Note: ACD testing is NOT considered a "normal operating" condition.