ALL-Channel driven simultaneously power tests anyone?

[mtrycrafts]

For 20 to 20,000 Hz I expect the numbers would drop. Not sure by how much, probably 10 to 15% based on what I read before when they did both. Still, that's just my educated guess, what do you think? As always, I value your opinion, knowing that you have the advantage of being an insider.

It's around 10% when you see some tested amps both ways. Not a biggie.

 

[3db]

I think separates to him means serious separates. I totally agree with you on this. As a matter of fact, I have the Marantz pair AV7005/MM8003 that actually offer less power than flag shop models of Denon, Yamaha, Pioneer and NAD. As crazy as it sounds, I did not buy the pair for power. If I did I would have picked up one of those flag ship AVR I mentioned and be done with it.

Why did you go the seperates root?

 

[Rickster71]

That same plug limitation also limits seperates.

Not really; a dedicated circuit can feed each amp when using separates.
We're limited to one circuit with an AVR.
I don't think everyone needs a separate amp for each channel, though they do remove many of the compromises of a single AVR. Just my $0.02
It's explained very well here: http://www.audioholics.com/education/amplifier-technology/the-all-channels-driven-acd-amplifier-test

 

[jeannot]

I must say I find this thread a little strange.

A receiver is at its essence built to a price consumer gear with compromises you would expect.

You have heat and space limitations. The plug in the wall is a limitation.

So where do you need the power generally? Its the front right and left, the center as well. However there are usually space constraints on the center, and therefore another inherent compromise.

The surround channels with most sources are called to deliver little power and in most receiver systems are more often than not puny miserable speakers.

Now a big power supply will take up a lot of the space. So that would push me in the direction of limiting the power supply and current.

The amps in receivers usually have a close spaced small output devices. You don't want them all heating up at once. Limiting current and power therefore likely contributes to extend life before it an output device fails and the receiver goes into continuous reset.

I don't think you should consider any receiver for a reference system. If that is what you are trying to build, the get a pre/pro and good power amps.

When it comes to testing I know of very few amps tested with varying phase angles just resistive loads.

Even when you design a reference system, it probably is not wise to design for equal power to all speakers.

For instance I allowed 750 watts for each main, and 500 watts for the center.

I allowed 100 watts for each surround, and 200 watts for each rear back. However that was because the surrounds and rear backs where from legacy systems and the speakers too good to put out to pasture.

Only a few of my SACDS really make heavy demands on the rear backs. (Those are the correct speakers to use for European mastered SACDs).

So the bottom line is that if you want to play the Aho symphony No 12 with Laplanders hitting huge drums hard all the way round the room it will cost you.

So you do have to judge a device for the purpose intended. Receivers are by their designers intent limited and compromised, and that is the only practical solution.

I wholeheartedly agree that an AVR is a compromise. That should not stop us from looking for the best compromise, and the indications on the quality of a power supply are clear in a stereo VS ACD tests. When the two numbers are close it means a more stable power supply, and a better bang for our small buck.

 

[TLS Guy]

I wholeheartedly agree that an AVR is a compromise. That should not stop us from looking for the best compromise, and the indications on the quality of a power supply are clear in a stereo VS ACD tests. When the two numbers are close it means a more stable power supply, and a better bang for our small buck.

Yes, and as I pointed out it likely will result on more blown output stages. The output stage has to be commensurate with the power supply.

Dropping voltage on cheaper consumer gear is not such a bad thing. Remember the heating in the devices falls as the square of the current and vice versa. The heating effect in the output stage is not linear.

 

[PENG]

Why did you go the seperates root?

The reasons are:

1) So that from now on I only have to upgrade the prepro every 3 to 4 years.
2) I believe a $1000 amp in my application will sound the same as a $5000 amp. I was considering a near new NAD C272, then found a good deal on a new MCA20.
3) Got an excellent deal on the MM8003, beating US prices by $400 to $500. I thought that was unbelievable.
4) Could not resist the good look of the AV7005.
5) Craziness, stupidity.

 

[TLS Guy]

Not really; a dedicated circuit can feed each amp when using separates.
We're limited to one circuit with an AVR.
I don't think everyone needs a separate amp for each channel, though they do remove many of the compromises of a single AVR. Just my $0.02
It's explained very well here: http://www.audioholics.com/education/amplifier-technology/the-all-channels-driven-acd-amplifier-test

Yes, there are three circuits to my amp case.

 

[TLS Guy]

Why did you go the seperates root?

It is a decision I bet PENG will never regret.

Once you get to the serious stage separates are a must if you are really serious about audio.

Here is a picture of the amp board of an Onkyo TX SR106 receiver, posted by another member.

Now there is an amp board containing seven really miserable amplifiers, and yes, I mean really miserable. There are only two small devices, less than the size a thumb nail per channel.

Now take a look at a separate. You will see six good sized power transistors per channel, on a decent heat sink, in triplets widely spaced.

Now this is important, as the output will not be thermally or current limited within in its specification even at prolonged full power.

In the receiver the bias will have to be set too far to far to class B operation and away from class A. This will lead to very significant crossover distortion (not THD). This is why these receivers sound so gritty and drive people to seek tubes.

This type of approach leads to the prospect of long term reliability and therefore your amp can be enjoyed over a lifetime as likely as not. Then the pre can be changed with the whims of fashion without throwing lovely amps away.

I highly recommend you give separates a try. You won't ever regret it. If you are passionate about music reproduction in the home it is the way to go.

 

[M Code]

Yes, and as I pointed out it likely will result on more blown output stages. The output stage has to be commensurate with the power supply.

Dropping voltage on cheaper consumer gear is not such a bad thing. Remember the heating in the devices falls as the square of the current and vice versa. The heating effect in the output stage is not linear.

As mentioned previously..
Low cost AVRs (SRP <$699) use loose regulation and their power supplies have wide voltage swings. Thats why they do good on peak power measurements (1 or 2 channels), but decrease significantly when asked to drive a low impedance/sensitivity loudspeaker. Actually the sag of the power supply rails provides a limit to max available power which is a crude form of protection....
This was done by Bob Carver in his old Phase Linear days for the 400 & 700, plus very common today in price-point 12V car audio power amplifiers as well..

Just my $0.02...

 

[M Code]

Here is a picture of the amp board of an Onkyo TX SR106 receiver, posted by another member.

Actually the displayed image is the output stage and power supply capacitors for an Onkyo TX SR806.. The 806 was rated @ 130W @ x 7, into 8 Ohms and was THX Select certified..

For your info the bill of materials on an 806 is < $300...

Just my $0.02..

 

[GranteedEV]

In the receiver the bias will have to be set too far to far to class B operation and away from class A. This will lead to very significant crossover distortion (not THD). This is why these receivers sound so gritty and drive people to seek tubes.

That's an assumption. From what I understand, the onkyo biasing is fine within audible thresholds, the thing just runs super hot like an oven

But... keep feeding me reasons to spend $1000 on something that'll sound the same, i need to justify my likely unjustifiable ucd700s somehow ...although i'm convinced my marantz amp sections are way better than an onkyo...they have to be because the chassis corners are nice and round.

 

[M Code]

That's an assumption. From what I understand, the onkyo biasing is fine within audible thresholds, the thing just runs super hot like an oven

But... keep feeding me reasons to spend $1000 on something that'll sound the same, i need to justify my likely unjustifiable ucd700s somehow ...although i'm convinced my marantz amp sections are way better than an onkyo...they have to be because the chassis corners are nice and round.

Actually Onkyo AVRs are designed by the same team that did HK AVRs..
They tend to bias their amplifiers on the high side, more toward Class A operation thats why they typically run hotter even @ idle..

Just my $0.02....

 

[jeannot]

As mentioned previously..
Low cost AVRs (SRP <$699) use loose regulation and their power supplies have wide voltage swings. Thats why they do good on peak power measurements (1 or 2 channels), but decrease significantly when asked to drive a low impedance/sensitivity loudspeaker. Actually the sag of the power supply rails provides a limit to max available power which is a crude form of protection....
This was done by Bob Carver in his old Phase Linear days for the 400 & 700, plus very common today in price-point 12V car audio power amplifiers as well..

Just my $0.02...

Amen to that. Higher voltage/Lower current transformers also have the advantage of weighting less, which is a good thing when you have to haul these receivers from the factory across the globe.

However, that is not reserved to cheap Receivers. The Marantz MM8003 is an example of an expensive (over $2k) amplifier with a sagging power supply. It has been tested at 174.8 per channel in stereo (52.9V peak), but 109.7 watts per channel (41.9V peak) with ACD, a drop of more than 20% in supply voltage. The Denon 3808CI boasts the very same ratios (187/113 watts). The Marantz may sound better than the Denon, which is what really matters. But one must wonder when a company cannot put a better power supply in a $2400 power amp than $1600 Denon receiver.
http://www.hometheater.com/content/marantz-av8003-processor-and-mm8003-amplifier-ht-labs-measures

 

[TLS Guy]

Actually Onkyo AVRs are designed by the same team that did HK AVRs..
They tend to bias their amplifiers on the high side, more toward Class A operation thats why they typically run hotter even @ idle..

Just my $0.02....

If those tiny power transistors delivering those sort of powers were biased to true high fidelity performance they would blow.

 

[M Code]

Amen to that. Higher voltage/Lower current transformers also have the advantage of weighting less, which is a good thing when you have to haul these receivers from the factory across the globe.

However, that is not reserved to cheap Receivers. The Marantz MM8003 is an example of an expensive (over $2k) amplifier with a sagging power supply. It has been tested at 174.8 per channel in stereo (52.9V peak), but 109.7 watts per channel (41.9V peak) with ACD, a drop of more than 20% in supply voltage. The Denon 3808CI boasts the very same ratios (187/113 watts). The Marantz may sound better than the Denon, which is what really matters. But one must wonder when a company cannot put a better power supply in a $2400 power amp than $1600 Denon receiver.
http://www.hometheater.com/content/marantz-av8003-processor-and-mm8003-amplifier-ht-labs-measures

All is cost related..

But I would urge one to be careful when comparing design parameters for an AVR such as the 3808 to a present model. The 3808 was designed over 5 years ago and significant changes in costly HD features (and royalties) and slow global economy resulting in very different market conditions today..

Just my $0.02...

 

[jeannot]

All is cost related..

But I would urge one to be careful when comparing design parameters for an AVR such as the 3808 to a present model. The 3808 was designed over 5 years ago and significant changes in costly HD features (and royalties) and slow global economy resulting in very different market conditions today..

Just my $0.02...

Agreed. My comparison was skewed... For example the 4310CI is less powerful than the 3808CI, which is really sad. And another reason to go with separates: you don't have to downgrade your power amp when you upgrade your preamp/receiver.

 

[M Code]

Agreed. My comparison was skewed... For example the 4310CI is less powerful than the 3808CI, which is really sad. And another reason to go with separates: you don't have to downgrade your power amp when you upgrade your preamp/receiver.

Doing separates delivers more flexibility in component choices and future updates..
However..
In many of today's home theater systems, the form factors are decreasing both in depth & width as the wife will likely have some comments about where to put all of the boxes...

Just my $0.02...

 

[jeannot]

Doing separates delivers more flexibility in component choices and future updates..
However..
In many of today's home theater systems, the form factors are decreasing both in depth & width as the wife will likely have some comments about where to put all of the boxes...

Just my $0.02...

Last time the wife complained about my AV stack, I suggested hanging the cooking pots we use most often on hooks in the kitchen, and installing a urinal in the bathroom. That was 13 years ago, never heard an equipment-related comment ever since.