Nad t757 avr

[AcuDefTechGuy]

Just got my December issue of Home Theater Magazine today.

Quickly looked over the measurements to see if anything caught my eyes.

SNR -105dB, 0.027% THD, flat FR - so far so good.

Then the crosstalk. It was -58dB @ 1kHz! WTF!

So @ 20kHz, is it -38dB?

For $1600 brand name so-called "high-end", this crosstalk is just pathetic!

 

[3db]

Check out the PSB's mini's frequency response...smooth as a baby's behind!!

 

[3db]

Just got my December issue of Home Theater Magazine today.

Quickly looked over the measurements to see if anything caught my eyes.

SNR -105dB, 0.027% THD, flat FR - so far so good.

Then the crosstalk. It was -58dB @ 1kHz! WTF!

So @ 20kHz, is it -38dB?

For $1600 brand name so-called "high-end", this crosstalk is just pathetic!

I wonder if there aren't some typos in their reported specs.

 

[cpp]

I wonder if there aren't some typos in their reported specs.

got to be a typo from the NAD site

FTC 7 x 110W
Full Disclosure Power (all channels driven simultaneously) 7 x 60W (0.05% THD, 20-20kHz)

IHF Dynamic Power 8 ohms 137W
4 ohms 243W

Total Harmonic Distortion at rated power <0.08%
IM distortion at rated power <0.08%
Damping Factor, 8 ohms >60
Input Sensitivity and Impedance 250mV/50kohms
Frequency Response ±0.8dB (ref. 1kHz, 20Hz-20kHz)
Signal/Noise Ratio >100dB (ref. rated power at 8 ohms, A-WTD)
>90dB (ref. 1W at 8ohms, A-WTD)

 

[AcuDefTechGuy]

Check out the PSB's mini's frequency response...smooth as a baby's behind!!

Yes, I noticed both the PSB and Paradigm speakers measured extremely well as usual.

On first glance, the Martin Logan EM towers looked bad since it is down -6dB @ 200Hz, but from 300Hz-10kHz it looked pretty good.

What also caught my attention was the $7500 JVC 4K projector that upscales 1080P to 3.8K resolution.

Then I remembered InTheIndustry telling me that he was not impressed at all with the JVC booth @ CES.

 

[PENG]

got to be a typo from the NAD site

FTC 7 x 110W
Full Disclosure Power (all channels driven simultaneously) 7 x 60W (0.05% THD, 20-20kHz)

IHF Dynamic Power 8 ohms 137W
4 ohms 243W

Total Harmonic Distortion at rated power <0.08%
IM distortion at rated power <0.08%
Damping Factor, 8 ohms >60
Input Sensitivity and Impedance 250mV/50kohms
Frequency Response ±0.8dB (ref. 1kHz, 20Hz-20kHz)
Signal/Noise Ratio >100dB (ref. rated power at 8 ohms, A-WTD)
>90dB (ref. 1W at 8ohms, A-WTD)

I am not sure how to define 'full' disclosure but the above specs certainly provide more details than Yamaha, Pioneer, Denon, Onkyo, HK and many other products. It does not mean they are more 'powerful' than the others in the same or slightly lower price range. That belief, remains a myth......

 

[markw]

Dunno what all the hoopla about crosstalk is all about. In the real world it's pretty much a moot point and well below where it makes an audiable difference. After all, when phono cartridges were all the rage, 15 db is all that was required for great sound and seperation.

 

[PENG]

Dunno what all the hoopla about crosstalk is all about. In the real world it's pretty much a moot point and well below where it makes an audiable difference. After all, when phono cartridges were all the rage, 15 db is all that was required for great sound and seperation.

I agree with you that it probably matter little. The point though is, why? Given today's technology, if they pay more attention to the the power supply and circuit board layout the numbers should easily be much better. In the old days amps also ran higher THD+N but today 0.1% or lower is not difficult to achieve, even though most people probably won't be bothered by 0.3%.

In the case of this particular HTM lab measurements, I also suspect there might have been something wrong in the process, either someone made a mistake in the procedure, instrument not calibrated right, typo etc. I am losing faith in their measurements. The only ones I have had more (just a little more) faith in are their group tests, when at least I may assume (to a degree only) whatever errors/mistakes applied to one would likely be applicable to the others so for comparison purposes they might be relatively more valid. Still, nothing could be sure about those numbers, that's why I have to use words like might, could, would, to a degree, assume etc.

 

[ski2xblack]

I am not sure how to define 'full' disclosure but the above specs certainly provide more details than Yamaha, Pioneer, Denon, Onkyo, HK and many other products...

"Full disclosure power" = all channels driven; full 20-20k bandwidth; and within specified distortion limit. It is more honest than most, as you note.

It does not mean they are more 'powerful' than the others in the same or slightly lower price range. That belief, remains a myth......

NAD still publishes the old-school IHF dynamic power, since their 'PowerDrive' approach allows them to excel in such tests. Even if it's only available for short times, that is real power. A '60 watt' amp that has more power on tap, however briefly, will sound more 'powerful' than a similarly rated amp that lacks it.

I recall an old (very old, as in published back in the '80s) AES article regarding an amp's ability to deliver unclipped transient peaks, and even if such output is only sustained for extremely short time, that is all that is practically required, as the transient peaks in music typically are only a few microseconds at most. It at least lends credence to the approach that NAD has taken with their amps, although they hype it for max marketing effect.

Wheather or not NAD's current offerings are cost competitive is another matter entirely. I think they've forgotten their budget/value roots, and ceded that ground to Emotiva long ago.

 

[markw]

I agree with you that it probably matter little. The point though is, why? Given today's technology, if they pay more attention to the the power supply and circuit board layout the numbers should easily be much better. In the old days amps also ran higher THD+N but today 0.1% or lower is not difficult to achieve, even though most people probably won't be bothered by 0.3%.

In the case of this particular HTM lab measurements, I also suspect there might have been something wrong in the process, either someone made a mistake in the procedure, instrument not calibrated right, typo etc. I am losing faith in their measurements. The only ones I have had more (just a little more) faith in are their group tests, when at least I may assume (to a degree only) whatever errors/mistakes applied to one would likely be applicable to the others so for comparison purposes they might be relatively more valid. Still, nothing could be sure about those numbers, that's why I have to use words like might, could, would, to a degree, assume etc.

And again I say wy bother? As long as something is way below the threshhold of making any audiable difference, why bother massaging it? Their efforts would be better spend on endeavors that do make an audiable improvement, no? If it "increases" as a side effect of some other audiable imrovement, fine, but why go out of the way to simply make prettier numbers one cannot appreciate with ones ears?

 

[AcuDefTechGuy]

And again I say wy bother? As long as something is way below the threshhold of making any audiable difference, why bother massaging it? Their efforts would be better spend on endeavors that do make an audiable improvement, no? If it "increases" as a side effect of some other audiable imrovement, fine, but why go out of the way to simply make prettier numbers one cannot appreciate with ones ears?

Why bother?

Because we are audioholics.

We demand better standards.

We expect a $1600 AVR to measure better than a $500 Sony AVR.

No excuses.

Do you think when Gene measures an Emotiva amp and gets a crosstalk of -50dB @ 1kHz and -40dB @ 10kHz, he will just say, "Oh, that's okay, you probably can't tell the difference anyway?"

If an amp has a THD of 1% compared to 0.01% on all the other amps, do we say, "Oh, that's OK, it's inaudible?

If a $200,000 speaker has a FR of 20Hz-20kHz +/- 3dB & THD+N of 1%, do we say, "Oh, that's OK, it's inaudible?

 

[markw]

Oh, puh-leeze!

Why bother?

Because we are audioholics.

We demand better standards.

We expect a $1600 AVR to measure better than a $500 Sony AVR.

No excuses.

Do you think when Gene measures an Emotiva amp and gets a crosstalk of -50dB @ 1kHz and -40dB @ 10kHz, he will just say, "Oh, that's okay, you probably can't tell the difference anyway?"

If an amp has a THD of 1% compared to 0.01% on all the other amps, do we say, "Oh, that's OK, it's inaudible?

It's this kind of mental masturbation that makes my skin crawl when people refer to me as an "audiophile". Maybe "audioholic" should be added to that list?

Pssst... you CAN'T hear the difference.

 

[AcuDefTechGuy]

It's this kind of mental masturbation that makes my skin crawl when people refer to me as an "audiophile". Maybe "audioholic" should be added to that list?

Pssst... you CAN'T hear the difference.

Well let's not bother to measure another AVR, amp, pre- pro ever again since we can't hear the difference.

Come to think of it, let's not bother to measure anything since all the measurements are inaudible.

 

[Adam]

It's this kind of mental masturbation that makes my skin crawl...

It's tough to tell if that means you're doing it wrong...or very right.

 

[markw]

Not to worry.

It's tough to tell if that means you're doing it wrong...or very right.

I've got Acc Def Tech Guy to coach me on it. He's an ex-spurt on this.

 

[markw]

Well let's not bother to measure another AVR, amp, pre- pro ever again since we can't hear the difference.

Come to think of it, let's not bother to measure anything since all the measurements are inaudible.

That wouldn't work for you. You depend on those numbers to tell you what you're hearing.

 

[PENG]

"Full disclosure power" = all channels driven; full 20-20k bandwidth; and within specified distortion limit. It is more honest than most, as you note.



NAD still publishes the old-school IHF dynamic power, since their 'PowerDrive' approach allows them to excel in such tests. Even if it's only available for short times, that is real power. A '60 watt' amp that has more power on tap, however briefly, will sound more 'powerful' than a similarly rated amp that lacks it.

I recall an old (very old, as in published back in the '80s) AES article regarding an amp's ability to deliver unclipped transient peaks, and even if such output is only sustained for extremely short time, that is all that is practically required, as the transient peaks in music typically are only a few microseconds at most. It at least lends credence to the approach that NAD has taken with their amps, although they hype it for max marketing effect.

Wheather or not NAD's current offerings are cost competitive is another matter entirely. I think they've forgotten their budget/value roots, and ceded that ground to Emotiva long ago.

I understand what you are saying, but I maintain what I referred to earlier as myths are still myths, or at lease almost...

Take a Yamaha RX-AXXXX for example that is, say rated by them as 120WPC, and is in the same price range as that NAD. Now think of it as a 60WPC AVR, and then measured their X microsecond unclipped transient power, as well as power into 4 ohms, I will bet you they will come up with numbers equal or better than that NAD. NAD, HK rated their gear more conservatively, but they are not more powerful from a W/$, everything else (SQ, features etc.) being more or less equal. The optics are there mainly because they (manufacturers) are allowed to rate their power outputs based on different standard. And sorry, I still don't know how to define what full disclosure means, it is not up to one person to define it I don't think. If there is some kind of well recognized body, council, institution that has provided a definition for it then perhaps I would take it seriously.

Now if one insists on ignoring price ($/W and of comparable SQ based on verifiable specs), then I would agree a 60W rated NAD will most likely be more powerful than a 60W rated Denon, Yamaha, Pioneer, Onkyo etc., no argument from me.

 

[PENG]

And again I say wy bother? As long as something is way below the threshhold of making any audiable difference, why bother massaging it? Their efforts would be better spend on endeavors that do make an audiable improvement, no? If it "increases" as a side effect of some other audiable imrovement, fine, but why go out of the way to simply make prettier numbers one cannot appreciate with ones ears?

That's a little too extreme for me. I am going to agree to disagree.

 

[ski2xblack]

I understand what you are saying, but I maintain what I referred to earlier as myths are still myths, or at lease almost...

Take a Yamaha RX-AXXXX for example that is, say rated by them as 120WPC, and is in the same price range as that NAD. Now think of it as a 60WPC AVR, and then measured their X microsecond unclipped transient power, as well as power into 4 ohms, I will bet you they will come up with numbers equal or better than that NAD. NAD, HK rated their gear more conservatively, but they are not more powerful from a W/$, everything else (SQ, features etc.) being more or less equal. The optics are there mainly because they (manufacturers) are allowed to rate their power outputs based on different standard...

Now if one insists on ignoring price ($/W and of comparable SQ based on verifiable specs), then I would agree a 60W rated NAD will most likely be more powerful than a 60W rated Denon, Yamaha, Pioneer, Onkyo etc., no argument from me.

I completely agree. The myths slip in when comparing a conventional class AB to class G/H, which all of the NAD 'PowerDrive' amps happen to be. But if they 'fully disclosed' that fact, then their claims of being more powerful than similarly rated receivers/amps would be expected. Playing loosely with what in reality are apples to oranges comparisons has been their marketing bread and butter. Better to confuse the consumer and perpetuate the mythology than just lay out all the facts, I guess. Your hypothetical Yamaha example illustrates the point quite well.

I don't mean to rip on NAD too much. I own a couple of their amps, and they're great. One of them is over 20 years old and still going strong.

...I still don't know how to define what full disclosure means, it is not up to one person to define it I don't think. If there is some kind of well recognized body, council, institution that has provided a definition for it then perhaps I would take it seriously.

'Full Disclosure Power' is just NAD's marketing handle for the three restrictions listed in my earlier post. At least they get that part right.

 

[PENG]

'Full Disclosure Power' is just NAD's marketing handle for the three restrictions listed in my earlier post. At least they get that part right.

Thanks, I thought I was quite familiar with the NAD website but I missed that part. I also have great respect for NAD products, and that's why I suspect/believe there is something wrong the way HTM did their measurements (re: the poor X-talk figures). I just can't believe NAD AVR/amps would perform so poorly in that department.