Do AVR pre amplifier/dac SINAD measurements matter if the power amp Sinad is a lot lower?

[DutchJay]

Hi All,

When reviewing eg the review of the Marantz SR8015 I see that Amir measured the pre amp dac section around 98 sinad while the amp section is only 85 db sinad.

Isn't the weakest link the bottleneck in the chain? So if you use it as a one box solution will the amp section not dictate the final sinad?

Or am I missing something?

Thanks,

Jeroen.

 

[Vincentponcet]

It matters when using an external amplifier which provides more Sinad, like purifi, ncx500 and so on.
Is it audible is another story.

 

[DutchJay]

It matters when using an external amplifier which provides more Sinad, like purifi, ncx500 and so on.
Is it audible is another story.

Yeah agree, that is why I typed "if you use ut as a one box solution".

Wanted to know if it matters in that case...

 

[Sokel]

It may be simple in a single box which (I hope) gain is optimized for the application,etc.
Combining lots of boxes though can be tricky,here's a good article about it:

The Signal Chain: How do noise and distortion propagate through my system?

This article is to explore how noise and distortion change through our system, and how different components can influence the final output. A common question is “If I have DAC A, preamp B, and amp C, where should I set the volume and gain controls for the best performance?” Usually this...

www.audiosciencereview.com

To cut it short everything may seem peachy till the moment gain comes to play.And gain where?
And then at what input levels and where?

One has to have the ability to at least measure some basic stuff,it's not hard these days.
But the whole subject is not simple,by all means.

 

[Blumlein 88]

Short answer is no, almost always no. If the SINAD is 15 db or more worse than the DAC it is the bottleneck. This is one place where separating THD and distortion can matter. The noise from the Marantz in question was low enough not to be a problem. The SINAD was limited by distortion. -85 db of distortion is not an issue. If you look at the power vs distortion measurements in the case of the SR8015 it is several db lower at 8 ohms than 4 ohms. It was distortion dominated into 4 ohms around -65 db which you still are not going to hear with music. With 8 ohms it was below -80 db at higher power levels -85 db.

This is an over simplified way of looking at it and you can get tripped up with raw numbers. In the case of the SR8015 it is accurate enough.

 

[peng]

Hi All,

When reviewing eg the review of the Marantz SR8015 I see that Amir measured the pre amp dac section around 98 sinad while the amp section is only 85 db sinad.

Isn't the weakest link the bottleneck in the chain? So if you use it as a one box solution will the amp section not dictate the final sinad?

Or am I missing something?

Thanks,

Jeroen.

I agreed that for such a gap, the power amp section is most likely the bottleneck. If the gap is smaller, such as less than 5-8 dB, then we have to look into the details, such as the SINAD vs frequency vs output levels, in order to do a proper bottleneck analysis.

 

[DVDdoug]

It's "links in a chain" so the distortion and noise do add-up. But with these low numbers you are unlikely to hear it anyway. The worst noise & distortion will dominate.

But think it's a Gaussian sum or something like that, and decibels aren't linear... And it depends on how it's measured and if they are comparable (A-weighted, etc.). If noise of the amplifier is measured relative to its maximum power output it may be worse than the measurements show at normal listening levels... Or if one has hum and the other has whine, you might hear both noises even though one is a lot quieter.

I expect a DAC to be audibly transparent. With a power amp, I'd check the noise measurements. I expect the distortion from an amp to be inaudible unless it's over-driven into clipping.

 

[DutchJay]

Short answer is no, almost always no. If the SINAD is 15 db or more worse than the DAC it is the bottleneck. This is one place where separating THD and distortion can matter. The noise from the Marantz in question was low enough not to be a problem. The SINAD was limited by distortion. -85 db of distortion is not an issue. If you look at the power vs distortion measurements in the case of the SR8015 it is several db lower at 8 ohms than 4 ohms. It was distortion dominated into 4 ohms around -65 db which you still are not going to hear with music. With 8 ohms it was below -80 db at higher power levels -85 db.

This is an over simplified way of looking at it and you can get tripped up with raw numbers. In the case of the SR8015 it is accurate enough.

Thanks!!

And if you look at the denon 3800 h for instance? Here we have a dac pre amp of 87 and the amp section is again 85 db.

Is this a case we're you need to look deeper or is the only reason to buy a higher model the power gain to drive difficult loudspeakers?

 

[Blumlein 88]

Thanks!!

And if you look at the denon 3800 h for instance? Here we have a dac pre amp of 87 and the amp section is again 85 db.

Is this a case we're you need to look deeper or is the only reason to buy a higher model the power gain to drive difficult loudspeakers?

When the power amp or any part of the chain is 15 db or more worse than the rest it is the dominating factor. With 87 and 85 db you'd need to look in more detail at what the result would be. You probably are still getting inaudible differences for most purposes, but the details matter. Without me looking at the results you might get a best result of combining those not far from -80 db. Which is still probably fine, but you get more interactions when some of the devices are closer in their values of distortion and noise. Or it maybe there is power supply hum which is limiting the one overall number.

 

[DutchJay]

When the power amp or any part of the chain is 15 db or more worse than the rest it is the dominating factor. With 87 and 85 db you'd need to look in more detail at what the result would be. You probably are still getting inaudible differences for most purposes, but the details matter. Without me looking at the results you might get a best result of combining those not far from -80 db. Which is still probably fine, but you get more interactions when some of the devices are closer in their values of distortion and noise. Or it maybe there is power supply hum which is limiting the one overall number.

I currently own the Denon 3800H which has sufficient power for my quite transparent speakers. As you seem to know a lot more than me, could I bother you to take a peak at the review of amir and see if you agree that moving up in the range of denon and marantz is not usefull for a SQ piont of view?

Denon AVR-X3800H Review

This is a review and detailed measurements of the Denon AVR-X3800H 9.4 Home Theater Audio/Video Receiver. It was kindly drop shipped to me by a member and costs US $1,699. Not much to say about the look of the unit as it is pretty much similar/same as last generations. Here is the back panel...

www.audiosciencereview.com

Understand if you don't have time, but I would be most thankfull if you do and will send you a big load of karma and thanks! ; )

 

[Chr1]

I suspect that you meant to say "efficient" rather than "transparent" speakers.
It's questionable whether most speakers could be described as transparent.

 

[Blumlein 88]

I currently own the Denon 3800H which has sufficient power for my quite transparent speakers. As you seem to know a lot more than me, could I bother you to take a peak at the review of amir and see if you agree that moving up in the range of denon and marantz is not usefull for a SQ piont of view?

Denon AVR-X3800H Review

This is a review and detailed measurements of the Denon AVR-X3800H 9.4 Home Theater Audio/Video Receiver. It was kindly drop shipped to me by a member and costs US $1,699. Not much to say about the look of the unit as it is pretty much similar/same as last generations. Here is the back panel...

www.audiosciencereview.com

Understand if you don't have time, but I would be most thankfull if you do and will send you a big load of karma and thanks! ; )

It probably is not. That unit had some odd results such as clipping at not very high voltage on the preamp if the on board amps were on, but not if those were off. Slightly better results otherwise too as a preamp. It isn't great, but I don't know that you would hear an improvement if your speakers are not taxing the unit very much. At full power it was doing pretty well. It did have low cross talk results, but those rarely matter. Anything over 25 db is good enough as hard as it is for people to believe. So I doubt if I would replace it if it otherwise does what you need it to do. It is not that it is awful, just that other units are a bit better strangely including the model it replaced.

 

[DutchJay]

THANKS for that!

 

[HaveMeterWillTravel]

It may be simple in a single box which (I hope) gain is optimized for the application,etc.
Combining lots of boxes though can be tricky,here's a good article about it:

The Signal Chain: How do noise and distortion propagate through my system?

This article is to explore how noise and distortion change through our system, and how different components can influence the final output. A common question is “If I have DAC A, preamp B, and amp C, where should I set the volume and gain controls for the best performance?” Usually this...

www.audiosciencereview.com

To cut it short everything may seem peachy till the moment gain comes to play.And gain where?
And then at what input levels and where?

One has to have the ability to at least measure some basic stuff,it's not hard these days.
But the whole subject is not simple,by all means.

The gain can be important. If a pre-amplifier has an unusually high distortion and/or noise floor, the amplifier is going to simply amplify that noise. If the amp has a very high gain (or input sensitivity) then it can be a poor combination.

 

[Will P]

Hi All,

When reviewing eg the review of the Marantz SR8015 I see that Amir measured the pre amp dac section around 98 sinad while the amp section is only 85 db sinad.

Isn't the weakest link the bottleneck in the chain? So if you use it as a one box solution will the amp section not dictate the final sinad?

Or am I missing something?

Thanks,

Jeroen.

==========================

Combining -98dB and -85dB would give you in the worst case scenario -83.2dB.

Whenever I want to get a reality check when having doubts about distortion, etc. I set the AVR at max output (0.0dB) to blast some music at over 120dB sound level, then quickly turn the knob from 0.0dB to -83dB just to hear the level of distortion.


It's an eye opener, I mean ear opener


37dB sound level. Usually that's below room noise.

That's like someone whispering 10ft away at a loud rock concert.

On the other hand if your normal listening sound level is 100dB then -83dB SINAD would be noise of 17dB sound level.
Recording studio room noise is 25dB and up.
You can't hear that 17dB noise level in a quiet recording studio.

So it's all good.

I'd be looking at the Speakers as a bottleneck.
0.5% distortion there (for the very very accurate ones) is like -46dB SINAD.
Speakers distort. Yep.

=============

 

[Will P]

The gain can be important. If a pre-amplifier has an unusually high distortion and/or noise floor, the amplifier is going to simply amplify that noise. If the amp has a very high gain (or input sensitivity) then it can be a poor combination.

=====

Amplifier gain by itself doesn't alter SINAD, distortion, noise of the pre-amp signal.


====

 

[Blumlein 88]

==========================

Combining -98dB and -85dB would give you in the worst case scenario -83.2dB.

Whenever I want to get a reality check when having doubts about distortion, etc. I set the AVR at max output (0.0dB) to blast some music at over 120dB sound level, then quickly turn the knob from 0.0dB to -83dB just to hear the level of distortion.


It's an eye opener, I mean ear opener


37dB sound level. Usually that's below room noise.

That's like someone whispering 10ft away at a loud rock concert.

On the other hand if your normal listening sound level is 100dB then -83dB SINAD would be noise of 17dB sound level.
Recording studio room noise is 25dB and up.
You can't hear that 17dB noise level in a quiet recording studio.

So it's all good.

I'd be looking at the Speakers as a bottleneck.
0.5% distortion there (for the very very accurate ones) is like -46dB SINAD.
Speakers distort. Yep.

=============

You are abusing the idea of SINAD and db. SINAD is noise and distortion. In discussions like this it is important to separate noise from distortion. I agree if it is -83.2 and if you hear no noise at max output you are fine, but you can trip yourself up using this too simplified approach.

 

[Blumlein 88]

=====

Amplifier gain by itself doesn't alter SINAD, distortion, noise of the pre-amp signal.


====

No amplifier gain does not alter distortion and noise of the preamp signal. It does however amplify it. Such amplification at high gain and low input sensitivity can push a noise floor up high enough to be heard over the speakers while lesser gain or lesser sensitivity would be no problem. We usually don't have much issue these days with the playback end. Can be important on the recording end using microphones and the high gain preamps needed for those. Gain staging for best results is a thing.

 

[Will P]

Yes, gain staging is a must

 

[Will P]

You are abusing the idea of SINAD and db. SINAD is noise and distortion. In discussions like this it is important to separate noise from distortion. I agree if it is -83.2 and if you hear no noise at max output you are fine, but you can trip yourself up using this too simplified approach.

SINAD is ratio presented in dB.
The ratio between the overall signal power level vs (distortion and noise) combined power level.
SINAD is a sound level difference and is measured in dB.

High SINAD means bigger difference between overall signal level and distortion/noise signal level.
High SINAD means cleaner overall signal.

There is nothing complicated about that.