Power consumption confusion

[saint0]

I am not an electrical engineer, so I might be using the wrong kind of reasoning here.

The Pioneer VSX-1015TX outputs 120W x 7 for a total of 840 Watts. But in the manual, on the second to last page, it says "Power Consumption..... 480W, 630VA"

So which one is it? 840W or 480W?

I need to buy a step down transformer (220V -> 110V) and I need to know what wattage rating to get.

 

[mike c]

personally Id get a 1000w or 750w transformer just to be sure (unrelated to the max power consumption)

anyway, 120w x 7 simply means EACH of the channels are capable of 120w RMS but NOT all at the same time. that unit will most likely do 120w x 2 channels driven. that said, like so many times mentioned in this forum, you don't need your receiver to put out 120w ALL CHANNELS DRIVEN because no movie or music will ask for that.

misleading yes. illegal no. (not yet hopefully)

 

[saint0]

I see, so it works like that for all manufacturers? Like for example the Yamaha RX-V1600 has the same rating per channel. This receiver also works the way you explained?

Do you know where I could source in the US the General model of the Yamaha RX-V1600? The General model has an internal switchable voltage selector for 110/220/230-240 volts. Or any of the other models that accept 220v...

 

[mike c]

it works like that for yamaha too. harman kardon however, publishes ratings equal to and slightly lower than what it can actually do (they are conservative with their ratings), but the wattages are pretty low to start with. I think I would prefer high peaks than equally low all channel ratings.

I am unfamiliar with the term "general model". have you checked out this link? www.yamaha.com/yec

edited: wrong wording = totally different meaning

 

[gene]

Power consumption rating on receivers is usually not MAX figure. Its usually with 2 channels at full power and the others at 1/8th.

 

[j_garcia]

Some of the output power comes from energy stored in the capacitors, so the unit can theoretically put out a bit more power than what it draws from the wall. Actual rating for the 1014 was 110x2 straight from the manual. I believe the 1015 has the exact same amp section.

 

[PENG]

This question has been asked and answered before, and I see that gene answered it again. You could do a search.

Some Harman Kardon models give you that typically lower "Power consumption" number at the back panel of the receiver. They call it "AC Input". In the manual, they give you the "Maximum" consumption, so you get both.

Example, the HKAVR340 has an AC Input (same as power consumption) of 370W but its maximum consumption is 890W.

Others such as Denon, Yamaha and Pioneer typically only publish their power consumption number.

Example: Denon 3805 - 7.1A at 120V (=852 VA)
Yamaha RX-V2500 - 500W (or 630 VA, that is 5.25A at 120V)

However, I did notice that the latest Yamaha RX-V models, such as the RX-V2600 now provides both numbers (like Harman Kardon).

RX-V2600 - Power consumption 500W, Maximum 1100W.

Finally, you should get a transformer that can handle the maximum. If the Pioneer's consumption is 480W, or 630VA, you should get a 1000 VA or even 1200 VA (allow for the losses) transformer. Hope this helps.

 

[Josuah]

I think I saw in one of the Audioholics press releases that for UL approval, transformers can only output 80% of their input? So if you've got a power conditioner that pulls 1000W from the wall max, it can only provide 800W to the stuff plugged into it max.

I can't be sure of this though, so someone more knowledgeable might be able to provide confirmation.

 

[PENG]

I think I saw in one of the Audioholics press releases that for UL approval, transformers can only output 80% of their input? So if you've got a power conditioner that pulls 1000W from the wall max, it can only provide 800W to the stuff plugged into it max.

I can't be sure of this though, so someone more knowledgeable might be able to provide confirmation.

I am not sure about that, but typically we specify the power rating of a transformer in VA, or kVA. VA=V*A, that is, Voltage (Volts) X Current (Amps).

Power in watts = VA*p.f.,
p.f.(power factor) is the cosine of the phase angle between the voltage and the current phasor (known as vector in early days). So assuming the p.f. of a typical loaded amp=0.8, a 1000 VA transformer will get you 1000*0.8=800W of output. After you factor in the efficiency of the amp, at the amp output you end up with around 400W. Again, these are just rough numbers.

 

[sjdgpt]

Question to Gene

Power consumption rating on receivers is usually not MAX figure. Its usually with 2 channels at full power and the others at 1/8th.

? Electrical powered equipment (refrigerators, stoves, microwaves, power saws, etc) are rated at peak electrical draw ? Correct? Peak draw and continous draw would be part of the UL certification and the information would be needed to determine the size of the circuit breaker.

So ..... wouldn't the same standard apply to receivers and amps?

 

[Josuah]

I don't think any of those use capacitors to store juice for use during transients.