Review and Measurements of Audio-gd NFB28.28 DAC and Headphone Amp

[Addicted to music]

they're not wrong ... "Massive 3rd Harmonic Distortion", lol

And if you don’t like the SQ initially the other thing that gets Instantly suggested is that it needs 400 hrs + for burn in! Hence the reason I never bought the brand. I have no patients for products to “burn in”.

 

[amirm]

With the permission of the owner, I opened the unit and found this lose screw in it:

Looks like it was threaded into something but I could not find where it went. It was trapped by the ribbon cables for the front panel so did not do any damage. But could easily have including shorting out mains!

While I was in there, I looked around and found this improper wiring for the front headphone jack:

In addition to picking up hum from mains, it could touch and become shorted directly to mains and energizing the headphone wire! The above picture was after I played with it a bit. It was touching it before that. I folded it the other way before putting the unit back together.

The whole design gives me the shivers with mains switch so close to that jack. As a minimum they should have selected a different switch that did not have those contacts for slide-in connectors that are unused. Better yet, it should have at least an inch of clearance from the headphone jack.

I then looked around and found this chassis screw almost ready to fall out!

It is strange because it has glue on top of it yet it still worked itself lose. I tightened it back up.

I then checked the screws that are holding the mains transformer. All four of them were lose. I tightened all of them.

I see no regulatory safety or emissions certifications or marks on this unit. Folks, if you are going to buy something from China, please be careful when it is mains operated and the supply is inside. Where possible, get one with an external power supply instead of one inside.

 

[gvl]

At least it looks like the chassis is grounded.

 

[Addicted to music]

@amirm

You know that taking the cover off voids warranty....LOL!

 

[amirm]

@amirm

You know that taking the cover off voids warranty....LOL!

As if someone was going to ship this back to China anyway. But yes, that is why I asked permission from its owner. Given the instructions to change jumpers inside and the safety hazard of a screw lose inside the unit, I LOVE for them to deny warranty repair on this!

 

[Krunok]

i find changing cables periodically makes me hear new things.

Flowers? Really?!?

 

[Thomas savage]

Flowers? Really?!?

It’s Remembrance Sunday here and 100 years since the Great War , the poppy is a symbol of the fallen and a mark of respect for their sacrifice.

 

[Krunok]

It’s Remembrance Sunday here and 100 years since the Great War , the poppy is a symbol of the fallen and a mark of respect for their sacrifice.

Oh, didn't know that. I apologise for my ignorance.

 

[Thomas savage]

Oh, didn't know that. I apologise for my ignorance.

Don’t worry Iv not gone all hippy soft handshake on ya.

 

[Krunok]

Don’t worry Iv not gone all hippy soft handshake on ya.

I already loosen up the belt on my trousers to be prepared to put it on my head.

 

[Thomas savage]

I already loosen up the belt on my trousers to be prepared to put it on my head.

As long as that’s the real reason ...

 

[Krunok]

As long as that’s the real reason ...

Oh, it's not the other thing - I alredy done that for this quarter.

 

[andreasmaaan]

I understand that IMD is supposed to do this and I have been in the discussions about multitone tests. But as has been shown before, performance can be different when different tones are being tested.
That's all I was saying.

There's a good discussion of the usefulness and interpretation of multitone tests on this thread, in case you missed it.

I agree that performance can be different when different tones are selected, but I it is virtually inconceivable that these differences could be significant (i.e. risk crossing the threshold of audibility) when IMD is in the range of -100 to -120dB on the SMPTE test that Amir uses, which combines a 60Hz tone with a 7Khz tone at 1/4 the amplitude (-12dB).

 

[Timbo2]

Don’t worry Iv not gone all hippy soft handshake on ya.

In fairness, they are so small I didn't realize they were poppies. I knew it was Remembrance Day and didn't associate your changed avatar with it.

In Flanders Fields

 

[Addicted to music]

As if someone was going to ship this back to China anyway. But yes, that is why I asked permission from its owner. Given the instructions to change jumpers inside and the safety hazard of a screw lose inside the unit, I LOVE for them to deny warranty repair on this!

Good to see you doing warranty work for them! Must be karma that the unit got sent to ya!

 

[Johnny2Bad]

" ... I started to unscrew the top to find out what it was, only to notice one of those stickers on it saying warranty void if opened. ..."

That declaration and those kinds of stickers are illegal and unenforceable in the US. As the manufacturer shipped the product directly to a US-based address, I see no reason why the law should not apply.

The Department of Commerce has in the past sent letters to such firms as Samsung, LG, and others reminding them of the law, although such a letter is not required to enforce it.

 

[amirm]

" ... I started to unscrew the top to find out what it was, only to notice one of those stickers on it saying warranty void if opened. ..."

That declaration and those kinds of stickers are illegal and unenforceable in the US. As the manufacturer shipped the product directly to a US-based address, I see no reason why the law should not apply.

The Department of Commerce has in the past sent letters to such firms as Samsung, LG, and others reminding them of the law, although such a letter is not required to enforce it.

Ah, very good to know. Thanks.

 

[JJB70]

" ... I started to unscrew the top to find out what it was, only to notice one of those stickers on it saying warranty void if opened. ..."

That declaration and those kinds of stickers are illegal and unenforceable in the US. As the manufacturer shipped the product directly to a US-based address, I see no reason why the law should not apply.

The Department of Commerce has in the past sent letters to such firms as Samsung, LG, and others reminding them of the law, although such a letter is not required to enforce it.

Good points, but a lot depends on where you buy something. If you buy from a seller via a Chinese sales site in China then they will abide by Chinese consumer law. If you buy from an overseas seller via a local sales site then local laws will apply but the reality is that things may not be that simple regardless of what the law says. This is why on the whole I buy from UK sellers for any pricey purchases , it's nothing to do with any ideas that they might be better or overseas sellers worse and purely for peace of mind in case anything goes wrong.

 

[VintageFlanker]

Funny thing but a bit off topic: Audiophonics.fr (One of the biggest audio seller in France and the first EU Audio-GD distributor) linked ASR reviews on their Khadas Tone Board and Topping DX3 product pages. But this is probably a bad move, since on the same website, you can also see how horrible AGD products measure...

 

[Veri]

Funny thing but a bit off topic: Audiophonics.fr (One of the biggest audio seller in France and the first EU Audio-GD distributor) linked ASR reviews on their Khadas Tone Board and Topping DX3 product pages. But this is probably a bad move, since on the same website, you can also see how horrible AGD products measure...

True AGD fanboys will say measurements don't matter, listen "with your ears"