Power Consumption is it a sign of quailty?

[Stereoguy]

Hi: I have a question about this my Pioneer Elite 56 Txi has a rate of 600 watts in the manual under "power consumption" a Denon 3806 say it uses 7.1 amps(how many watts is this?) in it's manual,Marantz 8001 is 780 watts.Would the difference indicate that both the 3806 and the Marantz have better power supplies than my pioneer? My pioneer has 27,000 mircofads(sp)main capacitors.Thanks for any help.

 

[Lordoftherings]

Hi Stereoguy,

That is a kind of hard to answer simply question.
Power consumption is indeed one indicator between other ones too.
There are so many variables that you have to take into account.
I'm not sure where to start. But I'll start and hopefully others will chime in.

1. Ok, your Pioneer 56 is rated at 600 watts with two big caps at 27,000uF, that's quite a good rating.
2. Now, the Denon 3806 (I own the 3805, same rating) is rated at 7.1 amps.
anf the two caps are 15,000uF each. Now, according to the experts here at Audioholics, 7.1 amps is about 850 watts (120 x 7.1). Hmmm... That seems to be too much from my own perspective, but what do I know.
3. Finally, the Marantz 8001 is rated at 780 watts, which again seems like a lot.
I believe the 8001 uses a toroid, but I'm not sure about it's capacitance, my guess is that it is about 20,000uF per cap.
4. I will add to this equation another receiver that I own, the Yamaha RX-V2092, which is rated at 500 watts and 640 Va (Variac), and the two caps are rated at 22,000uF each.
5. Last one now , honestly, my Onkyo TX-SR805, which is rated at 9.5 amps and the two caps are 15,000uF each. So, if we use the same formula as the Denon, we got (120 x 9.5) = 1,140 watts. Wow! That's quite a jump here.

Ok, let's begin the fun, by calling their weight now, and adding PC watts and total uF.

1. Pioneer 56 = 44.8 lbs (believe to be true net weight).........600 watts / 54,000uF
2. Denon 3806 = 38.6 lbs (inflated weight by approx. 3.5 lbs)..850 watts / 30,000uF
3. Marants 8001 = 33.1 lbs (believe to be true net weight).....780 watts / 40,000uF*
4. Yamaha 2092 = 44.1 lbs (true net weight).......................500 watts / 44,000uF
5. Onkyo 805 = 50.9 lbs (true net weight)........................1,140 watts / 30,000uF

* To be determined (40,000uF)
>> And only the Yamaha 2092 has a rating of 640 va (Variac), kind of related to the size of the transformer. Also to be determined by the experts (us or them?).

Now, let's look at the most watts vs. the less (1,140 vs. 500), Onkyo vs. Yamaha!
Seems very odd to me, the Onkyo more than twice the Yamaha! Is this makes sense?
And then your Pioneer is next after the Yamaha with 600 watts, but the Onkyo is still almost twice as much! But then, look at the total capacitance, 30,000uF Onkyo vs.
54,000uF Pioneer. Now the Pioneer is almost twice the Onkyo on total capacitance!
What a funny game, isn't? And then, we got the Denon with the same total capacitance as the Onkyo, 30,000uF. But the Denon is rated at 850 watts, less than the Onkyo by about 300 watts. And finally the Marantz with 780 watts, about 70 watts less than the Denon. * But I wish to know it's exact total capacitance.
I'll do some searching, and see what I can come up with...

Oh, and stick around, next are the bench tests. Hi ha... And I'm pretty much well cover there, with 2-channel (8 & 4 ohms), 5-channel, 7-channel, THD, SNR, FR, and more...
And then, the internal parts; DSPs, how many, the brands and #s, DACs, ADCs, how many, the brands and #s, and much more... Burr-Brown, wolfson, Crystal, Analog Devices, Texas Instruments, Cirrus Logic, ... Video processors, brands, how good (if you're interested, of course, if not, we'll pass on top of it, no sweat).

Ok, I'll submit this reply for now, and we can continue further as more info comes in,
or from us or from other members... That should be quite interesting.
Enjoy it so far Strereoguy?

And Happy Independence Day.

Bob

 

[Seth=L]

Comparing receivers from manufacturer to manufacturer, or even year to year of the same manufacturer of the same vein will have differing efficiency percentages. In the case of the Pioneer vs the Onkyo they seem to have gone two completely different directions. Pioneer has a smaller transformer but a higher storage in the capacitors, giving it lots of headroom above it's constant output power. The Onkyo relies heavily on it's oversized E core transformer to store and distribute energy, and it's far less efficient. The Onkyo has a clear advantage in constant output power as well as ability to handle difficult loads without taxing the power supply.

You also must take into consideration that different companies have different reasons for stating the power consumption the way they do. H/K comes to mind in terms of consumption ratings, they are usually stated higher than the competitive models from other companies. This doesn't mean they consume more power, just that they inflated the spec to maximum draw under short term conditions to fit their marketing.

 

[PENG]

This interesting questions has been asked before but I guess not recently. I see that Bob and Seth=L have provided lots of info already but I thought Yamaha has, in some cases, done an excellent job specifying their power consumptions figures. I found one such example in the instruction manual for the RX-V2700. I pasted the relevant part below.

From page 155 (http://www.yamaha.ca/av/PDFs/Receivers/Manuals/RXV2700.pdf):

GENERAL
• Power Supply
[U.S.A. and Canada models] .............................. AC 120 V, 60 Hz
[General and Asia model]
....................................... AC 110/120/220/230–240 V, 50/60 Hz
[China model] .................................................... AC 220 V, 50 Hz
[Korea model] .................................................... AC 220 V, 60 Hz
[Australia model] ............................................... AC 240 V, 50 Hz
[U.K. and Europe models] ................................. AC 230 V, 50 Hz
• Power Consumption
[U.S.A. and Canada models] ................................. 500 W/630 VA[Other models] ................................................................... 500 W
• Standby Power Consumption
[U.S.A. and Canada models] .................................... 0.1 W or less
[General model] (AC 240 V, 50 Hz) ...................... 0.33 W or less
[Other models] ......................................................... 0.1 W or less
• Maximum Power Consumption [General model only]
6ch, 10% THD ................................................................. 1100 W

So you can see that it covers the power consumptions for various conditions including standby (obviously minimum), and maximum (1100W in this case).

It is still unclear to me how everyone specifies their "power consumption" without qualifying it by conditions such as "standby" and "maximum", or at "xxx% distortion, y-z Hz, X channel driven etc. It has been mentioned before that this so called “power consumption” or “current” figure is somehow determined by applying certain parts of the FTC rules but I am not totally sure if we can assume this is done consistently among manufacturers.

I noticed Bob's minor technical error in stating that VA means variac. VA is simply the short form of volt-Amp. Volt is a unit of measure of voltage and Amp is a unit of measure of current so 630 VA means the product of voltage and current=630.

As an extreme example, you can get 630 VA if the applied voltage is 1 V and the resulting current flow is 630A or 630V with 1A current flow. As Bob stated, Denon specifies 7.1A for the 3806 and since you know the voltage is 120V so you can calculate the VA. Using the formula 120X7.1=852VA. The small problem with using watts is that it depends on the power factor that is influenced by the phase angle between the voltage and the current. The larger the angle the lower is the power factor. The theoretically power factor for a pure reactive load (inductor coils or capacitors) is zero so you can have very high current and very low watts. So the unit that specifies in watts does not tell you what the current draw is while for the unit that specifies VA tell you nothing about the current draw. The RX-V2700 manual shows both.

I agree with Seth, it is difficult to compare the power consumption figures between receivers. You need more info than just "power consumption", in order to reach any useful conclusions.

 

[Seth=L]

I agree with Seth, it is difficult to compare the power consumption figures between receivers. You need more info than just "power consumption", in order to reach any useful conclusions.

Exactly, basically we have to consider all parts between the power supply to the output stages and how they work together to reach a useful conclusion on how it might perform compared to another product. Of course a benchtest will resolve this question very quickly.

Yamaha rocks.

 

[mtrycrafts]

Simple answer to your basic question is no, power consumption is not an indicator of Quality

 

[Lordoftherings]

Clarification.

Thank you Peng for the small correction and your excellent explanation.

True, VA is Voltage/Amperage. I don't know where I got Variac from.
Must have something to do with the transformer.

And yes, I should have been more precise:*

"Based on the fuse rating of 7.1 amps, we can deduce that the power transformer of the Denon AVR-3806 ia about 852 VA (7.1 Amps x 120Volts). Taking into account amplifier and power supply efficiency and processor overhead, true output power in 7-channels all-channels-driven would be about 850 x 0.7 - 50 = 545 Watts / 7 = 78 watts per channel assuming the receiver doesn't have built-in-current limiting (it does not, and no impedance setting either)."

* This quote is directly taken from Clint DeBoer on his review of the Denon AVR-3805 (same amp rating as the 3806) on June 2004.
--> So my figure of 850 Watts (Denon AVR-3806) should have been 850 VA and equal about 550 Watts.
And for the Onkyo TX-SR805 (9.5 amps), the figure should have been, using the same formula: 1,140 x 0.7 - 50 = 748 Watts / 7 = 107 watts per channel... (no current limiting here, unless you select the 4-ohm setting).
So, the Onkyo 805 would be 1.14 KVA (1,140 VA) and about 750 Watts.

1. And from Sound & Vision review of the Denon AVR-3806 from June 2006 by Daniel Kumin, the 3806 outputs 108 Watts into 8 ohms at 1 kHz with 6 channels driven and 0.3% THD.
2. The Yamaha RX-V2600 outputs 119 Watts into thev exact same figures with the same number of channels driven (6).
3. The Denon AVR-3805, reviewed by David Ranada for the same magazine in the July/August 2004 issue, from the lab tests, mentioned that the 3805 outputs 93 Watts, 7 channels driven again with all the same figures as the 3806 and 2600. I want to emphasise that the THD is at 0.3% for that wattage.
4. In the review of the Denon AVR-3805 from Home Theater by Mark Fleischmann in the August 2004 issue, the 3805 driving five channels into 8-ohm loads and at 0.1% distortion is outputting 115 Watts. And at 1% distortion, it is outputting 125 Watts.

<> I know, I know, different results from different ways of measurements.
Nonetheless, an average and still a good account of overall performance.

*** Now, I just want to make a small note here about the Marantz SR8001.
I did more searching to find out the exact value of the two main block capacitors, but could not get the information.
Anyway, after scrutinizing some more internal pictures, I came to the conclusion that the value of those caps is more closely rated to 18,000uF or even 15,000uF. I just wanted to share my most recent findings.

Ok, that's it for now. Don't forget to tune in next week for the second part of our program.
Till then, Good night, Good day & Good luck.

Take good care, and of your love ones too (very important),

Bob

 

[PENG]

You are right you must be thinking about transformers. IMHO the calculations/numbers you quoted could be taken as just "rule of thumb" kind of things. Even within the same class A/B group, they do have different characteristics in terms of power supply and output section efficiencies, dynamic response capabilities (e.g. larger transformer with smaller caps vs smaller transformer with larger caps etc.), among other things. Further, the overall efficiency of an amp is not necessarily linear from no load to rated load or from rated distortion to clipping as you have cited already.

 

[Lordoftherings]

You are right you must be thinking about transformers. IMHO the calculations/numbers you quoted could be taken as just "rule of thumb" kind of things. Even within the same class A/B group, they do have different characteristics in terms of power supply and output section efficiencies, dynamic response capabilities (e.g. larger transformer with smaller caps vs smaller transformer with larger caps etc.), among other things. Further, the overall efficiency of an amp is not necessarily linear from no load to rated load or from rated distortion to clipping as you have cited already.

Yep, power transformers are rated in Variac, or is it?

Very true, but we have to start by looking somewhere isn't it?

And if the bench tests are done in the same situations with the same instruments and numbers, then it is a good place to based our decisions about their meanings, isn't it?

Hey Peng, what would you prefer, a small transformer with big caps, or a big transformer with smaller caps?

 

[PENG]

Yep, power transformers are rated in Variac, or is it?

Transformers power rating are typically specified in VA (Volt-ampere)

Variac is a variable transformer that allows you to adjust the voltage ratio.

Hey Peng, what would you prefer, a small transformer with big caps, or a big transformer with smaller caps?

I prefer both big. Seriously, if I cannot have both, I would take the one with a bigger transformer as long as the filter capacitors are still big enough.

 

[Lordoftherings]

I prefer both big. Seriously, if I cannot have both, I would take the one with a bigger transformer as long as the filter capacitors are still big enough.

Okie-dookie. Me, I'll go for current over dynamic headroom. But that's just me.

* I need that extra current for my 4-ohms speakers.