Denon AVR-2805 kicks out

audiobliss

Originally posted by Mike682
Actually, HK has been pretty close to spec in reviews regarding output w/all ch driven.

Indeed, it has. Not to sound defensive or anything, but I just stated that we found 'actual' outputs on Denon, H/K, Sony, etc. I didn't make any comments on what it was we found.

And, actually, there wasn't much of a 'we' about it, lol. I didn't do anything but read it!

cfrizz

Just get receivers with pre-outs so you can buy separate amps when you need more power!:rolleyes:

shiu

unc has said more than once that the Denon's power consumption may not be maximum. For those who own a 3803, 05 etc., take a look at the back or the manual, they do not say it is "maximum". Why insist it is? As for HK, they clearly stated the 890W for the 235 is "maximum" but they did not say whether it is a continuous rating.

I am not sure about the 2805 but in my 12X18X8 room, I get 75 dB at 13' away from my speakers (87 dB sensitivity), with the 3805 volume set to 0. It is way too loud and I am not surprise the amp would trip after 30 min.

Ricardo

Originally posted by TheReaper
My friend and I were pondering the high HK AV630 max power consumption, considering the a/c input on the back states 550W.

From the HK AVR630 manual:

Power Consumption 59W idle, 1000W at rated power output (7 channels driven)

From the back of the HK AVR630:

AC INPUT ~120V/60hz 550W

Hmmmm.........:rolleyes: :rolleyes: :rolleyes: :rolleyes: :rolleyes:

audiobliss

The back of my Yammy says:

120V 500watts
630VA 60Hz

Toxis

Originally posted by TheReaper
1000W at rated power output (7 channels driven)

OH S**T! It's a 1000 WATT? DAAAAAAAMN!

audiobliss

ROFL

glemay

Well thanks for your thoughts guys. A friend gave me two small fans to help cool the receiver. If I plug in on the trigger on the back of the receiver, will I just keep taking more power from the unit or should the fans on the trigger be fine?

Thanks

unc2701

1000 watts... hehe.

Anyhow, take all this with a grain of salt- don't turn it into your new spec to look for. Just be suspicious if the rated power somehow excedes the maximum power consumption.

On the other flip side of this (and why the manufacturers can get away with it)- for most 7 channel applications, you don't need full rated power going to all the speakers at the same time; the fronts rarely hit at the exact same time as the rears.

glemay: there should be a tigger amperage rating on the back of the amp or in the specs and an amperage on the fans- if the ones on the fans add up to more than the trigger rating (very likely), just get a 12v wallwart and plug it into the switched outlet on the back of the reciever.

edit:Yeah, deffinitely get a wallwart to run 'em- those tiggers are only rated for 25mA each, and most computer fans pull over 100mA.

shiu

One good thing about HK, they are more specific, examples: they give you the consumption at idling, 2 ch. driven power, 7 ch. driven power, instantaneous current, and maximum power consumption. Look at Denon's spec, no 5 or 7 channel driven power output, no instantaneous current values, yet they do claim "high current capability", and no maximum power consumption, just power consumption, so you cannot even calculate backward. May be they want people to think they cost less in electricity.

If you have to run a mid level receiver at "0", an external fan is a great idea. I think all HK models (may be except for the flag ship model) are equipped with an internal fan. The Denon 3805 does not have a fan. I doubt the 2805 has one.

John K.

Two questions, relating to power ratings and power consumption, have been discussed here. On the matter of the listed power consumption, it should be noted, as was suggested, that the consumption figure isn't a maximum figure(unless language such as "maximum", "full power, all channels driven", etc. is specifically used). In general the number shown is an average(rather than maximum)consumption figure, and typically the average is calculated on the basis of all the channels being driven at 1/8th of the rated maximum power. The 1/8th standard is used by safety testing organizations such as Underwriters Laboratory as a requirement for continuous operation without overheating, and represents the approximate average power needed from amplifiers over a long time period in playing music which varies from a very low level to one requiring the maximum power output. While a typical class AB amplifier is roughly 50% efficient( about 80% for the power supply section, about 60% for the amplification section)at full power, at lower power levels efficiency is much less, in the area of 20% or even lower. The bottom line here is that there's no inconsistency when the 7x100 watt amp has a label showing 500 watts consumption. The figure isn't derived using 700 watts output, but rather 1/8th of that, i.e. about 88 watts, reflecting an efficiency of under 20% at that power level. Likewise a maximum power consumption figure is derived using full power and about 50% efficiency.

On the question of the accuracy of published power ratings, it's somewhat ironic that while some are willing to take seriously bizarre claims about the "sound" of amplifiers, players and even wires which have no factual basis, they view with suspicion the only area of audio in which there are fairly specific federal regulations which a manufacturer would be foolish to violate. The FTC regulations define the procedure for arriving at the power rating. It should be noted that contrary to the misconception that the rating has to be with all channels driven, the actual requirement is for all "associated" channels to be driven. When the reg came into effect in 1974 there were very few amps with more than two channels and "associated" was considered to mean two stereo channels. This is still the view today, although as shown in this FTC Notice more specific multi-channel requirements were to be considered about five years ago. No action has resulted, although the FTC has left the matter open. So, all manufacturers arrive at their power ratings in compliance with the FTC procedure and the great majority(Denon, Onkyo, Yamaha, etc.)arrive at it by driving two channels simultaneously. Of course, manufacturers have the option to specifically use a figure with all channels simultaneously driven at full power for five minutes(although this isn't a realistic scenario for home use)and some, e.g. HK, do this; but whatever the case may be published amplifier power ratings can be relied upon as being accurate.

shiu

John, whether what you stated are right or not, it seems to make logical sense. Another ironic thing is that while HK rates their power outputs relatively lower than their competitors within the same price group, many believe they are actually more powerful because they rate their outputs conservatively. Yet, if you look at some of the lab measurement results S&V, HT mag etc., they are in line with other leading brands such as Denon, Yamaha, Pioneer, and even Sony (not the DE series of course) when tested under the same conditions. Isn't it true that honesty is the best policy.

Sorry about getting off topic.

bknauss

John - there is currently an initiative with CEA to revise the testing procedure and marketing claims of power from receivers. CEA is hoping the standard will be accepted by the FTC and become not only a standard, but law.

It should be stated that companies like Denon are posting power ratings based on standards/rules/laws, but it doesn't mean they are posting what reality is. The FTC link provided by John says (in summary): you get rated power by applying a signal to the aux input of the receiver (*cough* TWO CHANNEL *cough*), make sure it doesn't go above a certain THD threshold, and measure the power output during a 5 minute span. Since there is no mention of using all aux inputs possible, you can read it as measuring two channels and deriving the power output of the rest of the channels from that by simply hitting "copy" and "paste". You can thank marketers everywhere for stuff like this