What is the difference?

millerman 3732

I'am sure this has been answered a thousand times, but, I missed all of those so here goes.

What is the difference in say, 100w from a good AVR (Denon,HK,or Onkyo) and 100w from a pre amp/amp set up

Frank Z

A watt is a watt is a watt, but where it comes from is a whole 'nuther ballgame. Many receivers are highly over-rated with regards to the total output available with all channels driven. Make sure you look closely at the spec's for the receiver your interested in and confirm that the output ratings are for "All Channels Driven."

The biggest difference really is that an amp is not sharing a power supply with a processor, a tuner, and whatever else may be crammed into the the receiver chassis. An amp should do one thing, amplify the signal it receives from the source. No more, no less.

millerman 3732

thanks Frank, but does that mean that that 100w from a good AVR won't sound as good as a 100w pre amp/amp set up and if so why , its like you said ''a watts a watt'' if the specs on an AVR are correct that is.

cfrizz

In a word, Power!

Receivers have everything all in one box, which makes it convenient, however, there is a compromise there in that most of the receivers focus on the processing side while the amp portion takes a hit since if it is 7 channel receiver, it has to split that 100 watts 7 ways, and at the same time doing all the fancy processing for your movies, ect.

Meanwhile, a Preamp/Amp is just that. Each box focuses on only one function thereby devoting all of its resources to that function. So your amplifier is truly supplying 100 watts per channel to your speakers, and your preamp is able to focus on doing its thing. Naturally you will need more space & outlets for this setup.

A good compromise is to get an up-to-date, but cheaper receiver that has pre-outs & plan on buying 2-7 channel amplifier to support your speakers when you have the cash.

steveinaz

+1 Cfrizz nailed it.

You can buy a Geo Metro and go 100mph, or you can buy a Corvette and go 100mph, which did a better job of getting you there?

RuSsMaN

Depends, were you looking to save gas and haul some groceries, or get up to speed fast?

Car/audio references NEVER work.

ledhed

personally, I don't believe a watt is a watt. That is like saying a car is a car. I built a simple amplifier from scratch. It sounded like crap, not because of anything wrong, the amplifier chip was just crap-that simple. Recievers use cheaper parts thn found in separates in order to keep cost down.

speakergeek

Frank Z wrote:

The biggest difference really is that an amp is not sharing a power supply with a processor, a tuner, and whatever else may be crammed into the the receiver chassis. An amp should do one thing, amplify the signal it receives from the source. No more, no less.

Many of the newer AVRs have a separate power supply to power the processor/tuner components.

heiney9

speakergeek wrote:

Many of the newer AVRs have a separate power supply to power the processor/tuner components.

Some flagship models might . Mostly they have something called discrete circuits which tend to isolate the different sections but are still run off the (1) single power supply which in most is woefully under powered (no headroom). Most rec are designed to run (the power supply) close to the max at the rated output. Cost/size savings. An alternative is to use "trick" powers supplys or switching power supplys. These are also fairly big compromises as well. Reciever = Compromise. Not nec a negative thing, just something to be aware of and understand what you are getting ( and not getting).

FWIW

H9

gregure

millerman 3732 wrote:

I'am sure this has been answered a thousand times, but, I missed all of those so here goes.

What is the difference in say, 100w from a good AVR (Denon,HK,or Onkyo) and 100w from a pre amp/amp set up

Well, your question has been answered, but could be elaborated on some more.
First of all, a watt is a watt, but all amps have different qualities, so a watt isn't a watt. Got that? Really, though, most receiver specs are not accurate. Of the three you mentioned, only HK really comes close to delivering the stated wattage to all channels when all channels are driven. Onkyo isn't even close, and Denon is only a little bit better. Ever notice that HK's $1000 receiver only rates 75wpc, whereas Onkyo and Denon are up to 120 or higher in their $1000 price bracket?

The reality is that true headroom and quality sound only come from high current amps, and only expensive AVR's include high current, quality sounding amps. Truly, a "good" AVR is not what you would normally think of in terms of typical consumer brands. B&K, Rotel, Lexicon, and the models from Onkyo, Denon and HK that are in the $3000+ range are good units that use quality parts and start to really rival entry level separates systems. I wouldn't recommend spending less that $1500 on a receiver if you want a "good" one, and if you ever listen to music with any expectation of quality for a discerning listener. Look for receivers that use a torroidal transformer, that will start to get you to good performance. A separate amp will almost undoubtedly get you cleaner sound, and more headroom, especially if you're using 200 watt amps.

In short, to get true, quality 100 watts from an AVR that will rival a separate 100 wpc amp, look to spend at least $1500-2000.

GATOR3000

Gregure,

Nice write up! You have nailed it right on. This is so true. If one wants a good music sound you have to go at least 200wpc and separets for sure.

Shizelbs

Cathy's post is one of the more eloquent ones on this board. I move that it be made a sticky.

cfrizz

Whatever I say now was ALL learned on this board! I'm just trying to spread the word!

Shizelbs wrote:

Cathy's post is one of the more eloquent ones on this board. I move that it be made a sticky.

reeltrouble1

Yes Cat, but you did not learn all that putz, rutz, dutz, naming that we guys sometimes resort to when rattling our sabres.

Millerman--As far as receivers go, the others have pretty much summed up my feelings. If you want to play music then I would look to buy gear that is made to do just that. The thing about music is for some reason you can listen to a tune hundreds of times and its still visceral, watch the same movie or scene that many times!! Ugh, I sure cant. Thats what I now look for in a component, wire or tweak, how involving does it make the music.

RT1

RT1

cfrizz

WAAAAAAAAAAAA!!!!!

reeltrouble1 wrote:

Yes Cat, but you did not learn all that putz, rutz, dutz, naming that we guys sometimes resort to when rattling our sabres.
RT1

RT1

steveinaz

The car anaology works fine, think about it...100mph is 100mph, now hit a steep hill at 100mph (hard to drive speaker); The Geo starts losing it, quickly--The Vette, powers right on up, no problem; no coughing, wheezing, no struggling, hardly any loss in performace.

jcaut

I used to think that a watt was a watt. Then I bought an amp. Then I discovered that I was wrong.

While I agree with everything that's already been mentioned, about sharing power supplies, the way manufacturers rate their amps, etc.. I think there's more to it than that. Current is a component of Watts (should be capitalized, no?) and it's really the key to the point I'm about to make. You all can correct me if I'm wrong here, but here's my take:

You have to look at those Watts from your loudspeaker's point of view. Amplifiers are current limited. If they had infinite current capability, they could put out as many watts as they cared to and could drive any load that was presented to them. When driving a speaker, the current required from the amp depends on the impedance of the speaker: A four Ohm load requires twice the current from an amp, versus an 8 Ohm load. Here's where it gets tricky: Though you may think of your speakers as "8 Ohm" or "4 Ohm", their impedance really varies with frequency (some speakers don't vary much, but that's another story). I've attached a picture of an impedance curve from a speaker. It looks a little strange and that leads me to believe it's probably from a speaker I built , but I can't remember. Anyway, you see that the impedance varies from about 23 Ohms down to maybe 3 Ohms. That's a lot of difference. There are some frequencies where an amp driving this speaker would have to put out a LOT more current than others. Now, on a complex musical signal, what happens when the amp can deliver the required current into some frequencies, but not into others? I don't really know. I guess it depends on the amp, but I imagine that some frequencies get shortchanged.

Most good amps have enough reserve current capacity that they can roughly double their output power as impedance is halved. I've seen very few receivers that claim to have that capability. Most of them are rated pretty much AT maximum current in order to get that "Watts per channel" label as high as possible.

Whether or not what I've described above is what's really going on here, I do know that the difference a good amp makes is not hard to hear. If you're curious, you should try it and find out.

Jason
Cathy's secret admirer.