Watts vs Watts

[The Dude]

About that one good watt, what is considered a good watt. The reason I ask is referring to a post I posted earlier(in two channel), my question is how does something along the lines of Kenwoods wattage compare to lets just say McIntosh's wattage. Would 1 to 50 or maybe 100 of McIntosh watts beat down Kenwoods 1 to 200 watts. If this makes any sense.

Thanks

Duder

[ricktate]

Well my Yamaha reciever had 80 watts and my HK430 1970s reciever has 25 watts and pretty much put the Yamaha to shame. So i would guess the make of an amp does make a difference. Rick

[2point1]

I check to see if the amps power doubles going from 8 ohm to 4 ohm.

Some cheap ht rec's might only gain 20-30%.

Krell KST100...... 100w @ 8ohm , 200w @ 4ohm, 400w @ 2ohm

Parasound 275...... 75w @ 8ohm, 120w @ 4 ohm

Pioneer A35R...... 45W @ 8 ohm, 65W@ 4 ohm

[mustang guy]

I check to see if the amps power doubles going from 8 ohm to 4 ohm.

Some cheap ht rec's might only gain 20-30%.

Krell KST100...... 100w @ 8ohm , 200w @ 4ohm, 400w @ 2ohm

Parasound 275...... 75w @ 8ohm, 120w @ 4 ohm

Pioneer A35R...... 45W @ 8 ohm, 65W@ 4 ohm

On the same topic, look at what happens as you add channels. Seems like cap size has a bit to do with it as well. Not an expert, but they are things I personally look for.

I also look at noise. Anthem amps, for instance have very low noise.

[Don Richard]

Watts=VoltsXAmperes. However, the marketing departments of some manufacturers have taken liberty in the past with amplifier ratings which led to the FTC standards for rating home stereo amplifiers back in the 1970s. Google "FTC amplifier rating" for complete info. Amplifiers built before the standard was implemented may or may not be correctly rated, with the better brands built before the FTC standards such as Macintosh more likely to be honestly spec'd.

There is also the matter of dynamic headroom. Some amplifiers will output more than the FTC power rating for brief periods of time, such as when playing music.They will sound louder than their FTC rating would suggest. Often it is the better quality product that will do this.

Note that the FTC rating method is only required for home stereo equipment. Autosound, home theater, and pro sound amplifiers are not required to be rated by FTC methodology.

The best way to determine the answer to which specific amplifier would sound louder and cleaner is to listen and compare in your room with your speakers. Only you can be the judge of that.

[artto]

Watts=VoltsXAmperes. However, the marketing departments of some manufacturers have taken liberty in the past with amplifier ratings which led to the FTC standards for rating home stereo amplifiers back in the 1970s. Google "FTC amplifier rating" for complete info. Amplifiers built before the standard was implemented may or may not be correctly rated, with the better brands built before the FTC standards such as Macintosh more likely to be honestly spec'd.

There is also the matter of dynamic headroom. Some amplifiers will output more than the FTC power rating for brief periods of time, such as when playing music.They will sound louder than their FTC rating would suggest. Often it is the better quality product that will do this.

Note that the FTC rating method is only required for home stereo equipment. Autosound, home theater, and pro sound amplifiers are not required to be rated by FTC methodology.

The best way to determine the answer to which specific amplifier would sound louder and cleaner is to listen and compare in your room with your speakers. Only you can be the judge of that.

BING!!!

Let me tell a little story. Back in my H.S. days, I thought (I can't believe this, but it's true) that Zenith (remember Zenith?) was "the best" (YIKES). So I plunked down my money on the "second best" Zenith console at the time(circa 1969). It was advertised as "140 watts (music power).

But in reality, that was for both channels, so it was really 70 watts/channel. But that was peak "music power". In general you can calculate the RMS (root mean square) power as 0.707 of the peak. So 70 watts/channel is now actually 50 watts/channel. But wait, that was with only one channel operating. With both channels operating utilizing the same less than robust power supplyyou can probably subtract another 10-20% bringing the watts/CH down to maybe 40 watts. And then of course you have to take into account how that power was measured. At 1KHz maybe it could deliver 40watts/CH but at 100Hz or full bandwidth it would be lucky to deliver half of that. Now we have maybe a 25 watt/CH amplifier. And then there's the distortion levels that it was measured at. In the end the result is that the "140 watts" that the marketing department came up with was in reality a 15 to 20 watt/CH at best.

Its not that bad and uncomparable today thanks to the FTC leveling the playing field so to speak (government regulations are bad - right?) but there are still other things that can make a difference such as the quality and capacity of the power supply, or that valve amplifiers tend to have more "usuable" headroom because of their tendency to "compress" the peak levels as opposed to simply clipping them, etc.

The reputation and quality of the manufacturer still matters.

[Schu]

Watts=Volts*Amperes

fixed...

[JJkizak]

My older Denon 55 watt per channel stereo receiver blew away my newer Denon 720 watt 7.1 channel receiver for loudness, maybe close to 10 db difference.

JJK

[Guest " "]

hearing a WATT is just about as practical as feeling a BTU. Take the case of air conditioners...which 5000 BTU air conditioner do you like better and why? the one that blow's air faster..but still is 5000 BTU, or the one that is quieter but still is 5000 BTU, or the one that cost less to operate but is still 5000 BTU, or the one that does not surge my room lighting when it comes on but is still 5000 BTU.

[sunnysal]

the phrase about 5 good watts (which is what I assume you are referring to) is about the quality of the sound. When one is dealing with such high efficiency speakers as Klipschorns, etc. every shortcoming in an amp´s sound is amplified and heard. hiss, hum, distortion, etc. all obvious when listened to via a >100db efficient speaker (and often hidden by less efficient speakers). At normal listening levels many would argue that these type of speakers are only using a few watts of power. thus the phrase relates to the idea that we need "5 good watts" instead of dozens or hundreds of bad watts. I have had 50 and 100 watt solid state amps and 30 and 13 watt tube amps hooked up to my k-horns and have settled for the 13 watts amps and not looked back. others feel the need for more umph...I think the issue is still not settled as to how much is enough. IMHO it is whatever pleases you musically that is correct. tony

[The Dude]

Good answerers lads, I think I have the answer I was looking for and yes it will just come down to me trying the different amp out. Just when you think your there you have a whole another journey awaiting for you.

thanks

Duder

[Coytee]

I'm curious...

Would you engineer type feel this is a reasonable analogy?

If you take a 12 HP "tractor" (gas variety, LawnBoy or other type mower) and compare it to a 12 HP "tractor" (Yanmar, Kubota, something with a diesel engine)

Both tractors might put out 12 HP at a certain RPM however, it's the torque (curve?) of the diesel that will make it FEEL like it has a lot more power. Though they might both put out 12 HP, the power under the curve for the diesel is much wider and user friendly.

Was I even in the ballpark in case I ever use this one again?

[mustang guy]

I'm curious...

Would you engineer type feel this is a reasonable analogy?

If you take a 12 HP "tractor" (gas variety, LawnBoy or other type mower) and compare it to a 12 HP "tractor" (Yanmar, Kubota, something with a diesel engine)

Both tractors might put out 12 HP at a certain RPM however, it's the torque (curve?) of the diesel that will make it FEEL like it has a lot more power. Though they might both put out 12 HP, the power under the curve for the diesel is much wider and user friendly.

Was I even in the ballpark in case I ever use this one again?

Perhaps when comparing a tube amp to a solid state amp, that is a good analogy.

Comparing a stereo amp to an AVR, however, would be more like comparing an apple to an orange. The problem is wattage is usually way overrated or just plain misleading on AVR's. On stereo amps, the ratings are standardized, so they are accurate.

[T.H.E. Droid]

If you're talking about a light bulb or space heater, wattage ratings are simple math and are completely equivalent. Hi-fi is a different story, because simply expressing amplifier performance leaves out an important component. How many watts, but at what level of distortion? It's possible to build a very powerful amplifier but one that produces high levels of distortion. That's won't be a very useful amplifier, especially if you can't stand to listen to it at any level over very low power.

So I'd say there is a big difference between premium amplifier products like McIntosh, which will likely produce their rated outputs at very low levels of distortion and for unlimited periods of time, versus an inexpensive amp that produces the same output but with much more (and hearable) distortion, and one that shuts down due to overheating.

[Boxx]

I've always found it interesting the McIntosh amps (and possibly others) do not vary in their output rating whether you are connecting to a 4 ohm or 8 ohm speaker system.

All I know for sure is this, and speaking from experience, when making connections with a McIntosh 602 amp make "darn" sure that no electrical power is running to it.... the result can be unsettling....

[wdrazek]

Some NAD designs have had the same specs.

For me, watts are not equal from one mfr to another, based on experience. There are ways to fudge the numbers, and AVR's are notorious for it. Stick with the better brands and you will be better off. A typical Mac, Bryston or NAD or such will easily outplay twice the power rating from mass market brands. As PWK said (with his speakers) what this country needs is a good 5 watt amplifier.

[Islander]

Another power/distortion factor depends on the intended use of the amplifier. Pro sound amps are meant to be run at near full power most of the time, so they are engineered to have the lowest distortion at near full power.

Amps designed for home use, especially high-powered amps, will likely be running at low output most of the time, and use their high power for headroom to produce realistic musical transients. Those amps are sometimes designed to have their very lowest distortion at fairly low output levels, along with fairly low distortion across the rest of the power range.

[JohnA]

A watt is a watt, no matter what the source, period. A tube watt is the same as a transistor watt. (You will find you like the sound of a clipping tube amp and hate the sound of a clipping transistor amp, giving rise to the claim that tube watts are "bigger".)

The capacity of an amp to double it's power into half the impedance is a measure of the manufacturer's rating system and NOTHING else. No amplifier design is that linear. However, that thinking is heading in the direction of detecting a good power supply and heat sink design. If an amp can almost double it's 8 ohm power into 4 ohms, it will have a hefty power supply and plenty of cooling ability. A B&K M-200 would put 200 watts into 8 ohms and 380 into 4 ohms (reported to me by B&K). That's the best you can find.

Neither of the above is a measure of quality (sound or build). An aggregate if the specs can "suggest" one amp is better than another (damping factor, slewing rate, TIM distortion, power into lower impedance, S/N ratio, etc)

[derrickdj1]

All I know for sure is this, and speaking from experience, when making connections with a McIntosh 602 amp make "darn" sure that no electrical power is running to it.... the result can be unsettling....

Now that is funny!

On a side note, it is the design of the amp and not so much a watt. For example, some amps have larger power transformer, faster voltage swings, lower noise floor, ect. It all comes down to quaity parts and craftmanship.