Benchmark...first watt....ABX...facepalm!

[Nightlord]

I respectfully disagree. Sunfire amps used a similar idea. They were better amps. NAD 208 isn't that special. Not even as special as some of the newer NAD class D offerings. Back in those days a Conrad-Johnson MOSFET of equal power and greater current output without the problems was a much better amp. Those will have resale values for years to come. Made like a brick shitehouse. I beat one badly for years on my horridly inefficient Soundlabs and all it did was put out nice music without complaint or issue. Dead quiet amps too. Even it doesn't match my current class D Wyred4Sound amps. They sound almost like a monstrously powerful Spectral.

New NAD class D will be detected in a Before/After blind listening test, NAD208 is not detected at all until you reach the switch to the higher power rail and then it's still only very faint coloration. Best amp tested is the Bryston 14BSST2 and the NAD 208 doesn't test that far behind. Inbetween the two you find the Rotel 1090. There's also an old extremely expensive Halcro that's made it, and a few Swedish amps. Everything else have been quite a bit easier to disqualify as transparent. I'm, as you might understand by now, not interested in amps that sound anything, I'm interested in amps that doesn't. And that's where you find the NAD 208 and that's why it's so special. If you don't want transparent amps, then of course it's nothing special.

On a technical side... Sunfire's tracking downconverter and the class-G in the NAD is quite a bit different, as the NAD uses two power rails and Sunfire use a technology to vary the level on the power rail to stay just a few volts over what's needed (up to about 10kHz). I had the first Sunfire Load Invariant power amp myself once. (Got rid of it after I had blown up the powersupply twice.)

 

[RayDunzl]

I always feel so left out when people start talking different amps and comparisons.

What do mine sound like?

 

[Nightlord]

I always feel so left out when people start talking different amps and comparisons.

What do mine sound like?

Hopefully nothing, or very close to nothing. ( Don't think anyone has lent out one of those babies to LTS for testing. )

Your DAC went through the test flawlessly, I seem to remember. ( Possibly that you should not volume to max, there might have been a clipping note on it. )
Myself, can't afford it yet, so I have to stick with the slightly inferior DAC1. But it will probably go down to reasonable prices on the used market some day so I can swap then.

 

[Purité Audio]

What is a before after/listening test, 'transparency' will be defined in the amps measurements.
Keith

 

[Nightlord]

What is a before after/listening test, 'transparency' will be defined in the amps measurements.
Keith

No, this is a listening test!

Here's the schematic setup:

Translation:
Källa - > Source
F-volym -> Before-volume
Testobject -> Test subject
Belastning -> Test load. This is an electric circuit that has the same impedance characteristics as a (rather difficult) speaker.
E-volym -> After-volume
F/E-omkopplare -> Before/After switch
Lyssningsförstärkare -> Listening amplifier

Before and after the amp in test is volume matched... and then you switch between listening to the music before the amp... and to how it sounds after the amp. And the only thing you are trying to do is to identify statistically a difference. You can also in this way test the amp at output levels you don't want to listen at... or run it very softly without having to listen at such a low volume.

 

[March Audio]

No, this is a listening test!

Here's the schematic setup:

Translation:
Källa - > Source
F-volym -> Before-volume
Testobject -> Test subject
Belastning -> Test load. This is an electric circuit that has the same impedance characteristics as a (rather difficult) speaker.
E-volym -> After-volume
F/E-omkopplare -> Before/After switch
Lyssningsförstärkare -> Listening amplifier

Before and after the amp in test is volume matched... and then you switch between listening to the music before the amp... and to how it sounds after the amp. And the only thing you are trying to do is to identify statistically a difference. You can also in this way test the amp at output levels you don't want to listen at... or run it very softly without having to listen at such a low volume.

How was the NAD Class D output filtered before input into the listening amp? Filtering would be required to remove the 400kHz switching signal which would otherwise affect the listening amp.

 

[Nightlord]

How was the NAD Class D output filtered before input into the listening amp? Filtering would be required to remove the 400kHz switching signal which would otherwise affect the listening amp.

It's not tested to my knowledge, that was my personal comment regarding it. (LTS never/seldom reports on what they test, if it's not of use to the members) I'm pretty certain it would need a 0 more after the comma in the THD+N measurements to stand a chance of preventing the panel to make a detection. I could be wrong, of course. I have no knowledge of how they would do filtering of such an output, or they'd just opt not to recommend it based on the existence of such a signal. ( How stong is it? Would it lead to unnecessary heating of tweeter voice coil? )

 

[March Audio]

This is my Ncore NC400. I believe the NADSs are based on Ncore modules. This will have no significant heating effect on the tweeter. Has potential to affect an amp input in a test as you described.

I dont see any reason to not recommend it based on the existence of the signal, it's how class D works .

Oh it should be noted that Ncore supply a specific OEM amp module to the likes of NAD etc without input circuitry precisely because their modules are very neutral sounding. This allows the manufacturers to add their own input circuit and their own "flavour" to the sound.

Who / what is LTS?

 

[Deleted member 65]

This is my Ncore NC400. I believe the NADSs are based on Ncore modules. This will have no significant heating effect on the tweeter. Has potential to affect an amp input in a test as you described.

I dont see any reason to not recommend it based on the existence of the signal, it's how class D works .

Oh it should be noted that Ncore supply a specific OEM amp module to the likes of NAD etc without input circuitry precisely because their modules are very neutral sounding. This allows the manufacturers to add their own input circuit and their own "flavour" to the sound.

Who / what is LTS?

View attachment 5870

LTS = Ljud Tekniska Sällskapet (Sound Technical Society)

 

[oivavoi]

Do you guys from the Swedish house mafia know whether LTS has tested any of the newer high end class D amps? Which one was the Class D amp from NAD that was deemed as not transparent, for example?

I would be interested in knowing how these fare in the LTS test: Hypex Ncore, Icepower (for example Wyred4Sound), NewClassD ...

 

[Deleted member 65]

Do you guys from the Swedish house mafia know whether LTS has tested any of the newer high end class D amps? Which one was the Class D amp from NAD that was deemed as not transparent, for example?

I would be interested in knowing how these fare in the LTS test: Hypex Ncore, Icepower (for example Wyred4Sound), NewClassD ...

I think LTS is quite dormant these days.

I do personally have experience of nCore NC400 since I built a pair of monoblocks a few years back, now sold. Drove my now current second setup speakers (EA MicroOnes) with them, no great success, thin lifeless sound. As I've now brought the speakers back to life in new room I installed them with my amp from my third setup (summer house), Onkyo A5-VL (Class D, 10.5 Kg) not expensive amp. This new combo beats the nCore monoblocks in my setup with same speakers, could maybe be related to Onkyo's LPS compared to nCore's SMPS.

PS: Found another Onkyo A5-VL at a pawn shop for 80 USD, summer house system now back in order. DS

 

[oivavoi]

I think LTS is quite dormant these days.

I do personally have experience of nCore NC400 since I built a pair of monoblocks a few years back, now sold. Drove my now current second setup speakers (EA MicroOnes) with them, no great success, thin lifeless sound. As I've now brought the speakers back to life in new room I installed them with my amp from my third setup (summer house), Onkyo A5-VL (Class D, 10.5 Kg) not expensive amp. This new combo beats the nCore monoblocks in my setup with same speakers, could maybe be related to Onkyo's LPS compared to nCore's SMPS.

PS: Found another Onkyo A5-VL at a pawn shop for 80 USD, summer house system now back in order. DS

Thanks! So no hoping for more LTS testing of budget amps, then.

Concerning your experiences: Could it be down to other factors? I assume the bass might behave differently in the new room, for example. That being said, it might be that the Ncores simply had so much control over the bass that it made the speakers feel "thin". Their damping factor is extremely high. I've learned in this forum that Nelson Pass purposely designs amps with low damping factor for that reason, he prefers the thicker sound it can make.

 

[Deleted member 65]

Thanks! So no hoping for more LTS testing of budget amps, then.

Concerning your experiences: Could it be down to other factors? I assume the bass might behave differently in the new room, for example. That being said, it might be that the Ncores simply had so much control over the bass that it made the speakers feel "thin". Their damping factor is extremely high. I've learned in this forum that Nelson Pass purposely designs amps with low damping factor for that reason, he prefers the thicker sound it can make.

You're most likely right, could also be related to pre I had at that time AudioLab MDAC serving as Pre/DAC.

 

[amirm]

I have written about LTS extensively before. It takes an amplifier, backs out its gain, and then lets you AB against its input. If it adds nothing but gain, listeners cannot tell the difference. Only a handful of amp have passed this test with Bryston being one of them.

Critics say it uses too difficult of a simulated speaker load.

Regardless, it allows the amp to be pushed to its limit and compared to its input. You can't normally do that with amplifiers because the listening levels get too loud. And at any rate you can't listen to the input at the same time.

It is a very clever test and wish it was adopted by others. You can read more about it here: http://www.sonicdesign.se/amptest.htm

 

[Deleted member 65]

I have written about LTS extensively before. It takes an amplifier, backs out its gain, and then lets you AB against its input. If it adds nothing but gain, listeners cannot tell the difference. Only a handful of amp have passed this test with Bryston being one of them.

Critics say it uses too difficult of a simulated speaker load.

Regardless, it allows the amp to be pushed to its limit and compared to its input. You can't normally do that with amplifiers because the listening levels get too loud. And at any rate you can't listen to the input at the same time.

It is a very clever test and wish it was adopted by others. You can read more about it here: http://www.sonicdesign.se/amptest.htm

Link to LTS - - > http://www.lts.a.se/

Prior visiting site above you should visit this one - - > https://www.babbel.com/en/magazine/top-5-reasons-to-learn-swedish

 

[amirm]

Back when I first discovered them they used to have a lot of documentation on these tests. A few years later unfortunately it all got deleted. I suffered through hours of really, really bad Google translation to try to figure out what they were saying. So yes, the second link certainly would come in handy for this.

 

[Nightlord]

@LarsS - it's not dormant, the member magazines come out the number of times they should, and if you live around Stockholm, there are mails coming out about local activities there every now and then. The last one from 2016 had a long review of headphones, tested two cd-players, had a convention report, plenty of tips about classical cd:s and some more for instance.

 

[Nightlord]

I have written about LTS extensively before. It takes an amplifier, backs out its gain, and then lets you AB against its input. If it adds nothing but gain, listeners cannot tell the difference. Only a handful of amp have passed this test with Bryston being one of them.

Critics say it uses too difficult of a simulated speaker load.

Regardless, it allows the amp to be pushed to its limit and compared to its input. You can't normally do that with amplifiers because the listening levels get too loud. And at any rate you can't listen to the input at the same time.

It is a very clever test and wish it was adopted by others. You can read more about it here: http://www.sonicdesign.se/amptest.htm

That is funny, as it originally was criticised for having a too easy load.

To be totally clear, and I must confess to being slopping on the definitions now and then... there is no "pass" for this test really. The two outcomes are
1) the amp has been statistically proven to change the signal
2) the listeners failed to prove any signal change

Taken in consideration that about everything tested this way has been very easy to detect, the conclusion of course leads to that amps that give the panel some work in finding a difference are good amp and the one that fail the panel are state-of-the-art. Nothing has been proven though, as you cannot prove that something doesn't exist.

 

[amirm]

I think that is a bit of political correctness which is not necessary. When we do rigorous tests and find no differences, then we can say that there is none. Saying it is a negative outcome and can't prove a negative is just argumentative and doesn't help anything even though it is factually correct.

 

[oivavoi]

The last one from 2016 had a long review of headphones, tested two cd-players, had a convention report, plenty of tips about classical cd:s and some more for instance.

How do they test CD players? Is it only a test of the dac, or also of the transport? Do they test them more or less in the same way as they test amps? My assumption is that a CD-player, when feeding an external dac digitally, can be nothing but transparent. But perhaps I'm mistaken.