bi amp

Msabot1

At least you admitted it......that is a step in the right direction.....

pitdogg2

F1nut wrote: »

You owe me an apology.

WRONG he owes ALL of us an apology as we were the "STUPID" people....

Hows that crow taste David7544

David7544

I was all ready to apologize, but guess what? The receiver is capable of a total output of 1225 watts. And it is capable of outputing 80 watts per channel into 7 channels at the same time. Also, I emailed Yamaha, told them I was considering their receiver, and asked the same question. They say their receiver, also, is capable of delivering full rated power into all seven channels at once. The reason the spec states "2chdriven" is because the spec is quoting the output of the amplifier channels in pairs. The receiver allegedly has 7 power amps. I'm still not completely convinced I'm right, by the way. But a tech at best buy showed me the electrical diagram on a computer screen for the receiver and it specifically says '1225 wrms total output cap.'

Dennis Gardner

The reason why they show 2 channels driven is that unlike a movie, music is a constant signal for long periods of time and most music is heard in 2 channel/stereo mode. Again, a marketing choice to show this rating and this rating should be higher than the 7 channel rating since the power supply is putting all of its power to 2 channels.

The majority of 7 channel AVRs simply can't provide enough power to meet their 7 channel ratings regardless of the factory claims. Look for some lab or magazine reviews.

I think you are asking good questions about what to look for in gear, but don't believe what you hear from their customer service techs as they are paid to make you happy with choosing their gear, not tell the truth.

We are interested in helping you find the right gear, but you were the first to put an attitude forward when you didn't want to hear from anyone but an engineer. Company engineers for the most part, don't waste their times on the forums of any given company.

Dennis Gardner

What Yamaha model are you looking at?

pitdogg2

David7544 wrote: »

I was all ready to apologize, but guess what? The receiver is capable of a total output of 1225 watts. And it is capable of outputing 80 watts per channel into 7 channels at the same time. Also, I emailed Yamaha, told them I was considering their receiver, and asked the same question. They say their receiver, also, is capable of delivering full rated power into all seven channels at once. The reason the spec states "2chdriven" is because the spec is quoting the output of the amplifier channels in pairs. The receiver allegedly has 7 power amps. I'm still not completely convinced I'm right, by the way. But a tech at best buy showed me the electrical diagram on a computer screen for the receiver and it specifically says '1225 wrms total output cap.'

well then all my audio mag and reviewer's are wrong. When these are tested output at 2 ch is slightly more than their rated power. Like yours at 80wpc would be like 110 wpc but with ALL channels driven they are down to 45-50wpc. My Denon 3805 is 120wpc and one of the few that with all channels driven was still at 95wpc EVEN though it is rated at 120 x 7

believe it or not you were right once when you stated that it would weigh 50+ pounds.

Then again if they rate it at 1Khz then that is still not a true spec as those would be at 20hz-20Khz full range. It is very easy to say that it is such and such with such a narrow freq like 1khz

David7544

Dennis, Hi, You're right most AVR's can't output their rated power into 7 channels at once. But maybe this new one can. You're also right about my attitude. I apologize for that. Like I said, I'm still not convinced I'm right. If it turns out I'm wrong, I absolutely will apologize to everyone. The schematic I was shown by a service tech at best buy clearly shows seven separate amplifier configurations, and each one said "80wrms output" I even emailed the Audio Engineering Society, but they don't answer peoples questions(I was told) Pittdog, It doesn't mean all your audio mag reviewers are wrong, it just means they haven't put this particular AVR on a test bench yet. I hope they do.

Dennis Gardner

Just because an AVR can't meet the rated specs doesn't mean that it won't sound good. You must realize how ratings work and the fact that you most likely can't even hear the difference in 80 watts and 120 watts. 120 watts will only be 1.5 decibels louder than 80 watts. This is barely noticeable in a dynamic music passage.

I would rather have an honest underrating given that I can trust to be delivered over the full spectrum than the more common overrating at a single frequency that most of them give. I don't listen to music with only a single frequency in it.......

Some makers have been getting better about rating their products partly due to forums like this and reviewers calling them out on these practices, but others continue to cut quality and stretch the truth.

One avenue that hasn't been brought up during this thread is that many makers are going to a digital switching type of amp design that doesn't require huge power supplies and heavy weight anymore to make power. These receivers weigh much less than their earlier models yet still produce good sound and ratings. Pioneer started this trend in their lines a few years back with the line of ICE amps in their receivers. But that is a discussion for another day........

David7544

actually, the only thing I use it for is stereo. I don't want surround sound. And I don't care about movies. I've got 4 amp output channels active, 2 to each speaker. one amp connected to each driver. my speakers are Polk Rtia5's.

tonyb

What you really have is one amp connected to 2 speakers in a bi-wire configuration. There is not 7 amps in that receiver, only one. You have 7 different ways to slice up one amp is all.

ZLTFUL

Let's simplify this a bit.

You have a 1 gallon container full of water.
If you have (2) - 1/2 gallon containers, you can split the original 1 gallon of water between both 1/2 gallon containers and fill them both.

But now lets add 2 more 1/2 gallon containers...now you have 4 containers of 1/2 gallon each and only your 1 original gallon of water.
What happens? You can only fill each of the 1/2 gallon containers half full.


Think of the original 1 gallon of water as your power reserves. You have a finite amount of water to pour into the other containers and as you add more containers (because now you are hooking up 4 8 ohm loads instead of the original 2 8 ohm loads...) the original gallon has to be divided more to give water to the additional containers.

voltz

I had a Denon 1911 I think that said it had 7 discrete amps in it. that is why it is sitting under the bed collecting dust while my NAD T-758 runs the show now my NAD's manual say in plain English that if I run it in a 7.1 setup that its 110 WPC with 2 driven will fall down to 60 wpc... they openly tell you the truth with no bull.
that is why I added a Adcom 5503 which is a 200wpc x3 amp that runs my 2 front speakers and my center thus leaving my NAD to run the 2 rear channels and can give them the full 110 wpc .

F1nut

The receiver is capable of a total output of 1225 watts

Must be some new math as it's maximum draw is 460 watts and it's not a digital switching type.

F1nut

One avenue that hasn't been brought up during this thread is that many makers are going to a digital switching type of amp design that doesn't require huge power supplies and heavy weight anymore to make power. These receivers weigh much less than their earlier models yet still produce good sound and ratings. Pioneer started this trend in their lines a few years back with the line of ICE amps in their receivers. But that is a discussion for another day........

My Pioneer Elite AVR weighs 50lbs. and actually puts out its rated 135wpc with 5 channels driven, just slightly less with 7 driven. It was also a lot more money that the $499.00 list of the OP's Denon.

David7544

I hear what you guys are saying. 30 years ago I had an SAE power amp which put out 300 wpc, 2 channels driven. It was so heavy you could hardly pick it up.It had two big black steel handles bolted to the front panel at each end. It must have weighed at least 40 lbs. Go to Pioneers website and look at the SC-81 AVR. This could be my explanation.

David7544

ZLTFUL, yes, I agree. but what if I've got seven buckets full of water, and a siphon hose in one of them,siphoning the water out, with the other six sitting there with all that water in them going nowhere. Then I add a second siphon into a second bucket. Now I'm getting twice as much water. I realize there's only one power supply, so I see what your saying.

ZLTFUL

There is no siphon hose. The original 1 gallon of water is your transformer and it can only put out 1 gallon of water in this case. The other containers or speakers demand X amount per "bucket" but the original bucket can still only offer up its one gallon of water.

When you get into larger transformers, then we start talking about the original bucket increasing in size to say 5 gallons...and this is where reserve power comes into play.

Digital switching power supplies are still beholden to the "capacity" of their transformers and power supply capacitors

David7544

I don't understand the internal configuration of the amp. Does it have seven power supplies? I don't think so. There is a menu in it for "amp assign" which features an option "bi-amp".I was assured by a Denon tech and a best buy tech that I have doubled the power being delivered to the speaker by connecting a second amp output channel to it, by I'm not sure I believe this. I think you're probably right that I'm not bi-amping. I'd love for someone to put this AVR on a test bench and measure the output power from each output channel. Does one amp channel draw power(when required) from another? I don't know. If it has truly separate amps, then there is a siphon hose.

ZLTFUL

You have 7 discreet amplifier *boards*. But all 7 of those boards draw power from the same power supply.

So there is no siphon hose...just not all 7 buckets using the original bucket's water so to speak.
If you were driving 7 speakers (when you "bi-amp" you are turning a single speaker into 2 speakers.) then the power supply's bucket of power is split 7 ways.
Since you are running 2 speakers, it is split 2 ways...until you split the speakers into 2 additional loads but removing the jumpers. Now the power is split 4 ways.

Dennis Gardner

No one has mentioned what happens when you decouple terminals. Does the 8 ohm speaker now show 2-16 ohm loads since they are now separate? If so, then the amp just lost volume by 3dB for each load, so the power gained by bi amping was lost in impedance, so no gain was made. You would have 2 amps potentially capable of both putting 80 watts into each new speaker terminal, but since they are 16 ohms each, the level of sound remains the same. IE: 80 watts into 8 Ohms is the same and 160 watts into 16 ohms.

This is dependent on the crossover working in the manner assumed......I could be wrong, as I have never taken the time to measure separate post loads.

David7544

This is probably a dumb question, but wouldn't powering only one driver (tweeter) instead of two(tweeter and woofer) result in reducing the impedance rather than increasing it?

Dennis Gardner

David7544 wrote: »

This is probably a dumb question, but wouldn't powering only one driver (tweeter) instead of two(tweeter and woofer) result in reducing the impedance rather than increasing it?

The answer to your question is odd in that a higher impedance number means reduced load. 16 Ohm speaker is an easier load to drive than an 8 Ohm load.

This is only true for speakers wired in parallel, the reverse is true if the speakers are wired in series. 2- 8ohm speakers in parallel = 4 ohms and 2-8 ohm speakers in series = 16 ohms.

David7544

I thought an amp that delivers 50 watts into an 8ohm load will deliver 80 watts into a four ohm load, therefore lower impedance means less "resistance". (?)
Does anyone here own the pure audio blu-ray disc of Neil Young's "Psychedelic Pill"?
Or the SACD of Pink Floyds "Wish you were here"?

Dennis Gardner

David7544 wrote: »

I thought an amp that delivers 50 watts into an 8ohm load will deliver 80 watts into a four ohm load, therefore lower impedance means less "resistance". (?)

You have it correct.

tonyb

The impedance of the speaker doesn't change however using just the top or bottom post.

Dennis Gardner

tonyb wrote: »

The impedance of the speaker doesn't change however using just the top or bottom post.

The top posts on a speaker that I tested, don't register any resistance. The bottom showed the same whether strapped to the top or not, so it really is simply the crossover's load that you are measuring, not driver resistances.

ZLTFUL

Still 8 ohms in the case of the RTiA5

tonyb

ZLTFUL wrote: »

Still 8 ohms in the case of the RTiA5

Exactly, which is why I don't understand the OP's concern over it. At my age though, understanding certain things isn't my strong suit.

David7544

so ZLTFUL, if I've removed the jumpers on my Rtia5's, the impedance remaines 8ohms at each of the two pairs of input terminals on the backs of the speakers?

tonyb

Correct David....I'm wearing my ZLTFUL hat at the moment.