power consumption and power output

[nandac]

if an amp maker has two integrated amp products, one which consumes 300 watts and outputs 60 watts and the other product consumes 300 watts and outputs 100 watts - would the first one output 'better' watts?

is there anything to be inferenced from such specifications?

appreciate any insights.

 

[doors666]

if an amp maker has two integrated amp products, one which consumes 300 watts and outputs 60 watts and the other product consumes 300 watts and outputs 100 watts - would the first one output 'better' watts?

is there anything to be inferenced from such specifications?

appreciate any insights.

nope


nope

 

[nandac]

conversely would an amp consuming 400 watts and outputting 100 watts be better than one consuming 300 watts and outputting 100 watts? both products of the same company.

 

[baijuxavior]

If the line voltage is low, the higher wattage rated amp will be better as it can handle the increased current requirement at low voltage.

 

[wlg]

if an amp maker has two integrated amp products, one which consumes 300 watts and outputs 60 watts and the other product consumes 300 watts and outputs 100 watts - would the first one output 'better' watts?

is there anything to be inferenced from such specifications?

appreciate any insights.

Not really. A valve amp will consume a lot more current for heating valves and driving spkrs, yet it's output may be low.

 

[nandac]

If the line voltage is low, the higher wattage rated amp will be better as it can handle the increased current requirement at low voltage.

not sure if i get this. by the above do you mean an amp which consumes 300 watts and outputs 100 watts will be better than an amp which consumes 400 watts and outputs 100 watts?

 

[Thad E Ginathom]

The day I upgraded from a 120w/ch amplifier to one rated at 50w/ch I realised what a useless specification this is.

It may be necessary to know that an amp has enough power to fill your room with sound, if you have a big room. I'm not even sure that the output-wattage is really important for this even: I don't know about valve amps, but don't we have members with really-low-wattage amps enjoying big rooms full of sound?

if an amp maker has two integrated amp products, one which consumes 300 watts and outputs 60 watts and the other product consumes 300 watts and outputs 100 watts - would the first one output 'better' watts?

Only in the sense that your electricity bill might be lower for the same amount of volume produced.

In that sense, the right word (assuming equivalent sound quality) would be more efficient rather than better.

 

[baijuxavior]

not sure if i get this. by the above do you mean an amp which consumes 300 watts and outputs 100 watts will be better than an amp which consumes 400 watts and outputs 100 watts?

No. I meant the amp with 400W PSU will be better than the 300W PSU amp. Just because the back panel of the amp says it's power consumption is 400W doesn't mean it will consume 400W continously.

Edit: By the term 'better' I don't mean better sound quality.

 

[Dr.Bass]

The day I upgraded from a 120w/ch amplifier to one rated at 50w/ch I realised what a useless specification this is.

Finally !!

But dont you think the higher powered amp measures better at least in power ratings ? Only after you heard a 50 watter sounding more authoritative than a 120 watter you realized this spec can be thrown out of the window (though not exactly). I am sure you could not have come to this conclusion without listening. Listen more and many more such specs will go out of the window, even though they measure well..period.

 

[Shivam]

A lot depends on the design of the amplifier. Class A amplifiers have high power consumption than Class B or AB. Class D are the champs in terms of low power consumption.

Power consumption is however not indicative of power output or the quality. If you compare the power output (with all other things equal) then you are just looking at the 'efficiency' of the design.

 

[Thad E Ginathom]

Dr. Bass, where did I ever say I took any notice of specifications?

 

[Dr.Bass]

Dr. Bass, where did I ever say I took any notice of specifications?

Since you emphasize a lot on measurements, I thought so. Specs are after all reflection of how an equipment measures on the test bench, isnt it ?

 

[jls001]

The power consumed (say 400 Watts) and the output thus produced (say 100 Watts) is an indication of the efficiency of the amplifier. It will in no way tell you whether another amp drawing the same power of 400W but giving only 60W will be sonically inferior to the one putting out 100W. The only thing that can be inferred is that the later is less efficient in terms of power consumption.

General rule:
1. Class A amplifiers are the least efficient as they are always on/biased, produce a prodigious amount of heat (all that power drawn from the mains has to go somewhere - principle of conservation of energy), is loved by a section of audioheads. Efficiency of Class A (IIRC) is around 20%.

2. Class B is more efficient (theoretically 50%).

3. Class D is most efficient, in the region of 80%.

There are many other classes, sub classes and hybrids. One of the most common implementation of power amplifiers is Class AB which is more efficient than Class B.

OT: some of the priciest amps on the planet produce piddling power output measurable in single digits.

 

[Thad E Ginathom]

Since you emphasize a lot on measurements, I thought so. Specs are after all reflection of how an equipment measures on the test bench, isnt it ?

No, Dr... I emphasise on the possibility of measurement.

 

[ravi_d]

General rule:
1. Class A amplifiers are the least efficient as they are always on/biased, produce a prodigious amount of heat (all that power drawn from the mains has to go somewhere - principle of conservation of energy), is loved by a section of audioheads. Efficiency of Class A (IIRC) is around 20%.

2. Class B is more efficient (theoretically 50%).

3. Class D is most efficient, in the region of 80%.

Class B is about 75% and Class D about 95% or more efficient at least theoretically. Class AB is about 50%-55% efficient.

There are many other classes, sub classes and hybrids. One of the most common implementation of power amplifiers is Class AB which is more efficient than Class B.

Class B is more efficient than Class AB.

 

[Dr.Bass]

No, Dr... I emphasise on the possibility of measurement.

The most important spec of an amplifier is its power rating. If such an important spec can be rendered useless when it comes to playing real world music, wouldnt that be a good indication that most of the things that is possibly measurable may not hold a lot of water in real world situations ? Are we just happy with measuring or do we look for usable results ?

 

[Thad E Ginathom]

Are we happy with just arguing, or should we argue about the same thing?

Everything that comes out of your speakers and reaches your ears must be measurable. If not, your speaker cones would not have moved, and neither would the bones in your ear. All forms of measurement.

When is that fact useful? If, for instance, you insist that music sounds better on a Thursday, I prefer Wednesdays, and someone else says neither can can possibly have any effect whatsoever. If we can afford the time, trouble and expense, we can put it to test.

Otherwise it is not important or relevant. We just enjoy music, or we enjoy comparison of equipment by subjective means.

The most important spec of an amplifier is its power rating.

Can it move the speakers; will it blow them up? Is is dangerously under- or over-powered? Yes, I know there more to it.

If we were really concerned about the power output of our amplifiers, we would probably have to measure it for ourselves. Are you any more trusting of what marketing departments write than I am?

Whilst, ultimately, it is all about music, there is another side too. I spent a lot of Saturday appreciating equipment, but very little of it appreciating music!

If I ever get the chance to take your recommendations on amplifiers and speakers, the very last thing I would talk about is numbers!

 

[nandac]

but there are some speakers which are said to require very high current - sonus faber for example. and there are some amps which are considered 'high current amplifiers'.

compare these three amps for example and check the specs and let me know your thoughts on which you would choose if your speakers require high current :

rotel ra-1062 (priced at $700 usd)
http://www.rotel.com/content/leaflets/ra1062_infosheet_lr.pdf

rotel ra-1070 (advertised as a 'high current amp' - priced at $1100 usd)
Home Theater System Surround Sound Amplifier DVD Player - Rotel PRODUCT SPECIFICATIONS

rotel rx-1052 (a stereo receiver - priced at $900 usd)
http://www.rotel.com/content/leaflets/rx1052-leaflet.pdf


i am not necessarily saying that a rotel should be used to drive speakers like sonus faber. but trying to understand the distinction between these models.

 

[anuragn]

Going back to the fundamentals of electrical engg, I would ask: What is meant by speakers requiring high current?
I guess it basically means that the speakers present a lower impedence to the amplifier and hence draw higher current. So such speakers would be those with relatively lower impedence.
So should we check the response of the amp at lower impedences if they are to drive these speakers?
These are questions that I do not know the answers and looking forward to learning experience.

 

[vktarun]

I agree with you Anurag,

Just add Lower sensitivity(<= 86db) to the low Impedance and the Speaker will pose real challenge to the Amp. Now you need High power, High current, High investment whatever you say.


That is the reason most of the average commercial amplifiers do not specify power at 4 ohms. They are not able to provide enough Current to drive such loads. If tried can damage the outout devices. :indifferent14: