Review and Measurements of NAD T758 V3 AVR

[Sal1950]

Yuck, makes me wonder how bad my Pioneer Elite SC-35 (that i almost sold my kidney for) really is

Amir measured the SC-61, it's one of the better AVR's we've seen. https://www.audiosciencereview.com/...s/measurements-of-the-pioneer-sc-61-avr.8951/

According to Pioneer, the power output is 7 x 140W while consuming 330W. I don't know how this is possible without using some (ahem) creative test conditions.

They use the magic dust, same way Santa gets the Reindeer to fly.

 

[GrimSurfer]

They use the magic dust, same way Santa gets the Reindeer to fly.

Yup. And when you try to get 7x140W out of them, the AVR goes "poof" and releases a cloud of magic dust. Then magic no workie no more and you need to write to Santa for a replacement.

 

[xhattan]

According to Pioneer, the power output is 7 x 140W while consuming 330W. I don't know how this is possible without using some (ahem) creative test conditions.

So I'd take your kidney off of Pirate Bay and stop asking questions whose answers are likely to be... uncomfortable.

That power output is 2 channel driven only. Very misleading specs.

 

[GrimSurfer]

That power output is 2 channel driven only. Very misleading specs.

Misleading appears to be the norm in the AVR segment.

 

[Baaha]

Upgrade available now
MCU v2.14(2.13) DSP v1.20(1.16) Video v1.10(1.09) BluOS/OSD v3.6.3(3.4.20)
Would have been interessting to see if there are any improvements?

 

[amirm]

I returned it already.

 

[Baaha]

To bad.. Maybe you Will get the chance to test it again some other time! I hope So, then we can get some comparison on what the upgrades really do with the sound performance

 

[amirm]

I think you should assume no improvement unless otherwise shown. Electrical circuits cannot be changed with firmware updates.

 

[Baaha]

I also assume that no improvement is done here, but i'm no engineer on soundequipment. But I do wonder what the firmwareupgrade on the MCU and DSP really does... I don't know exactly what the MCU does in an amp, but doesnt it controll the gain? I'm really green on this, so forgive me.
The DSP does the signal processing, as far as i know.. Could a Firmwareupgrade on the DSP result in a higher conversion of 24-bit samples?
Keep up the good job, amirm!

 

[skipost-it]

To bad.. Maybe you Will get the chance to test it again some other time! I hope So, then we can get some comparison on what the upgrades really do with the sound performance

Why??? Do you know how many firmware upgrades there are been since its release in Oct 17.
Maybe some *tuned unit like mine could offer improvements in Amir's analyzer, but maybe not even like that ...

*My upgrade consisted of an improvement of the power supply in the digital section, rectification and capacitors, change of master jitter clocks in the digital circuit, new welds in the Audio route with Silver tin, change in certain sections of 6N copper wiring, as well as the replacement of voltage regulators in digital section, and improvement in the output of Headphones, that's All ...

 

[Baaha]

Why??? Do you know how many firmware upgrades there are been since its release in Oct 17.
Maybe some *tuned unit like mine could offer improvements in Amir's analyzer, but maybe not even like that ...

Yes, i know there have been a numberous of upgrades. But that have been primary on the BluOS system, as far as I know.. Have there been many firmwareupgrades on the DSP and MCU? But i've havent had the AMP more than 10 months. I would like to know if the firmwareupgrades "upgrades" soundquality, or if its just bugfixes. Can I do something about it? not at ALL!

*My upgrade consisted of an improvement of the power supply in the digital section, rectification and capacitors, change of master jitter clocks in the digital circuit, new welds in the Audio route with Silver tin, change in certain sections of 6N copper wiring, as well as the replacement of voltage regulators in digital section, and improvement in the output of Headphones, that's All ...

You have upgraded your unit yourself? Nice work!

I must say, for my use, the NAD does the job. Will I upgrade to something else in a few years? Probably.

 

[Theriverlethe]

While the performance is very disappointing from an engineering standpoint, it’s silly to see people complaining that the T758 sounds bad as a result. If I understand correctly, you would need a full scale signal with volume set to 0dB to see the -52dB distortion. In many cases, distortion above 1% (-40dB) is inaudible because of masking effects. Even if you have exceptional hearing, you won’t have it very long after listening to the 100dB+ SPL you would get with this receiver set at 0dB and a brick walled input signal.

 

[amirm]

In many cases, distortion above 1% (-40dB) is inaudible because of masking effects.

There is no way masking will at 1 khz will help you with distortion spectrum that goes right to 20 kHz and beyond:

This is going to sound bright and harsh as you push it which is not what you want in a $1,400 audio device.

The problem occurs at levels below that:

Now if you use it with the internal amp, you will hear them clipping just as bad as the DAC is so it is water over the dam. You just can't improve the situation with an external amp much.

 

[Theriverlethe]

There is no way masking will at 1 khz will help you with distortion spectrum that goes right to 20 kHz and beyond:

View attachment 36499

This is going to sound bright and harsh as you push it which is not what you want in a $1,400 audio device.

The problem occurs at levels below that:

Now if you use it with the internal amp, you will hear them clipping just as bad as the DAC is so it is water over the dam. You just can't improve the situation with an external amp much.

Only the third harmonic approaches a level one might reasonably expect to be audible, and then only under extreme conditions. I’m still skeptical this is a real-world problem, without double-blind testing.

 

[Theriverlethe]

In my Dirac-calibrated setup with a Umik-1 and -20dB pink noise, SPL reaches 85dBA at -14dB on the volume setting. 0dB volume setting SHOULD correspond to 85dB (or 75dB for home use), but obviously does not on this model.

 

[amirm]

Only the third harmonic approaches a level one might reasonably expect to be audible, and then only under extreme conditions. I’m still skeptical this is a real-world problem, without double-blind testing.

We use psychoacoustics so that we don't have to run out and perform double blind tests every minute. I explained why perceptual masking does not help you here. You can't counter that with "I don't think so" and demand a double-blind test.

Look at this graph:

That high distortion goes way down to 20 Hz as it should since the circuit is operating well outside of its design metrics (due to amp clipping). So -now take that 1 kHz tone and move it down in frequency such that those harmonics land in 2 to 5 kHz. Then look at Fletcher-Munson curves:

See how the thresholds for hearing anything there is actually negative SPL? And therefore way way lower than the harmonics we are seeing here?

Those harmonics keep going higher where the amplitude of content is very low. It mixes with them and potentially makes them higher pitched.

So your skepticism is not based what we have measured and what we know about science of what we hear.

 

[Dj7675]

We use psychoacoustics so that we don't have to run out and perform double blind tests every minute. I explained why perceptual masking does not help you here. You can't counter that with "I don't think so" and demand a double-blind test.

Look at this graph:

That high distortion goes way down to 20 Hz as it should since the circuit is operating well outside of its design metrics (due to amp clipping). So -now take that 1 kHz tone and move it down in frequency such that those harmonics land in 2 to 5 kHz. Then look at Fletcher-Munson curves:

See how the thresholds for hearing anything there is actually negative SPL? And therefore way way lower than the harmonics we are seeing here?

Those harmonics keep going higher where the amplitude of content is very low. It mixes with them and potentially makes them higher pitched.

So your skepticism is not based what we have measured and what we know about science of what we hear.

Thanks for taking the time for this in depth explanation.

 

[temujin44]

Thanks for taking the time for this in depth explanation.

LOL not going to help/convince those who are skeptical of quantitative reasoning.

 

[Dj7675]

LOL not going to help/convince those who are skeptical of quantitative reasoning.

I have to agree with this... it is definitely helpful to have it explained why these really poor measurements aren’t ok and can and do affect audibility. It is easy to look at the -6db measurements and for someone like me and conclude.. as long as I don’t go louder than -6 it will be fine. This explanation helps explain why that is likely not the case. At lease that is how I’m understanding it!

 

[Theriverlethe]

I have to agree with this... it is definitely helpful to have it explained why these really poor measurements aren’t ok and can and do affect audibility. It is easy to look at the -6db measurements and for someone like me and conclude.. as long as I don’t go louder than -6 it will be fine. This explanation helps explain why that is likely not the case. At lease that is how I’m understanding it!

I don’t think he said that at all.