Premium Audio Mini GaN 5 Review (Stereo Amplifier)

[GimeDsp]

I am in touch with the Manufacturer and and we had a lot of discussions, which I have also shared here.
Premium Audio is a brand of ClassDaudio and I spoke with both brand representatives

As you could read it above, i made a hypothesis: was the model tested by Amir defective?

I sincerely wish that Tom from ClassDAudio could send another model back to Amir to clear the doubt and confirm or deny the results.
for the time being, Amir's test is final)

I would hope they would want to clear these things up.
But if this is the amp with floating heatsinks I cant say im surprised.

 

[DanielT]

Ok, then lets Bruno Putzeys what he thinks? I mean, who better to just ask than somebody who designs state of the art amplification.

Well that would be interesting. What that Mr. Morello is complaining about in the thread I referred to is the measurement itself. I'll translate a little more. He got counter questions. Other than that, I only provide what is written. Do not shoot the messenger. For those who are interested, you just have to go into that thread. Enter google translate.

Morello wrote:
I do not think you understood what I wrote. If a power amplifier exhibits THD of 1% at 20 kHz with a dominant third tone, it means that the third tone has a frequency of 60 kHz. If you measure with 25 kHz bandwidth, the third tone will be attenuated by, for example, 40 dB (depending on the flank attenuation of the filter) and the measurement will show THD of 0.01%. The measurement thus gives a false result.

Belker
I understand your argument, and Amir and co certainly do, but they do not seem to think it is a practical problem. Or they think otherwise. In any case, they do not seem to think they are making irrelevant measurements.

Morello
Again: the question is not subjective and something to think about. If THD is A% and the measurement shows B% and where A is significant (beyond reasonable tolerances) separate from B means that the measurement is irrelevant.

I-or
What Morello has tried to convey above (and in many older threads) is that the nonlinearities that give rise to inaudible spectral components above 20 kHz when measuring THD also give rise to clearly audible intermodulation distortion (in the audible range). If you measure IMD instead, this will be clear.

......And so on in that thread ...

I do not actually understand what it is that is so strange in what was seen above. Mr Morello may be wrong. Someone with more knowledge will hopefully clarify if thats the case.

faktiskt.io • Visa tråd - NAD C 298

Edit:
By the way. What can one read, interpret from this?

Fig.2 NAD C 298, stereo mode, small-signal, 10kHz squarewave into 8 ohms

NAD C 298 power amplifier Measurements

Sidebar 4: Measurements

www.stereophile.com

 

[Helicopter]

Thanks Amir.

Too bad they weren't honest about the performance. For a boutique piece with an unusual custom case and novel technology, I don't think $800 is too bad. I also like the way the back is laid out, except the jumpers. I hate jumpers. I wouldn't buy one and I definitely won't recommend one over class D modules or something else that performs better, but I can see the attraction of GaN for the right nerdy hobbyist.

 

[antcollinet]

Well that would be interesting. What that Mr. Morello is complaining about in the thread I referred to is the measurement itself. I'll translate a little more. He got counter questions. Other than that, I only provide what is written. Do not shoot the messenger. For those who are interested, you just have to go into that thread. Enter google translate.

Morello wrote:
I do not think you understood what I wrote. If a power amplifier exhibits THD of 1% at 20 kHz with a dominant third tone, it means that the third tone has a frequency of 60 kHz. If you measure with 25 kHz bandwidth, the third tone will be attenuated by, for example, 40 dB (depending on the flank attenuation of the filter) and the measurement will show THD of 0.01%. The measurement thus gives a false result.

Belker
I understand your argument, and Amir and co certainly do, but they do not seem to think it is a practical problem. Or they think otherwise. In any case, they do not seem to think they are making irrelevant measurements.

Morello
Again: the question is not subjective and something to think about. If THD is A% and the measurement shows B% and where A is significant (beyond reasonable tolerances) separate from B means that the measurement is irrelevant.

I-or
What Morello has tried to convey above (and in many older threads) is that the nonlinearities that give rise to inaudible spectral components above 20 kHz when measuring THD also give rise to clearly audible intermodulation distortion (in the audible range). If you measure IMD instead, this will be clear.

......And so on in that thread ...

faktiskt.io • Visa tråd - NAD C 298

So Morrello correctly points out that the 60KHz third harmonic is supersonic and hence inaudible and irrelevant - but also that it will (via intermodulation distortion) cause audible distortion frequencies.

Which is one reason why Amirm normally (and in this case) runs the multitone test. The 2nd 3rd (and higher) harmonics of the higher tones in that test may well via intermodulation distortion, cause lower frequency distortion. BUT that will be visible in the test result (in fact will be part of the spray of frequencies visible in the measurement - below about -80 to -90dB in this case)

So anything audible is seen. Anything above 20kHz is inaudible (except to super humans and dogs), can't be rendered by the speakers in any case, and therefore doesn't need to be measured.

 

[rdenney]

Here we go, the faulty unit excuse has arrived.

Why don't you take your fight somewhere else?

I wasn't defending the amp. But when an amp's actual performance differs so much from its published specs, then the possibility of a faulty unit cannot be rejected out of hand, or waved off as fan-boyism. Why do we so readily jump to the conclusion that the manufacturer is dishonest in addition to being incompetent? Okay, I didn't ready the other thread about "floating heatsinks", so whatever. We complain about journalist reviewers, and often with undeniable justification. But one journalistic principle that seems to me to apply here is that you always give the guilty party an opportunity to comment before you publish. Again, I'm not saying that is Amir's job, but it is a courtesy and a matter of due diligence.

The amp's owner has taken those steps since I first posted, and I'm glad he did.

Rick "not in the market for this amp so I really don't give a crap" Denney

 

[GimeDsp]

Thanks Amir.

Too bad they weren't honest about the performance. For a boutique piece with an unusual custom case and novel technology, I don't think $800 is too bad. I also like the way the back is laid out, except the jumpers. I hate jumpers. I wouldn't buy one and I definitely won't recommend one over class D modules or something else that performs better, but I can see the attraction of GaN for the right nerdy hobbyist.

Jumpers on the outside? yikes.

 

[antcollinet]

Why don't you take your fight somewhere else?

I wasn't defending the amp. But when an amp's actual performance differs so much from its published specs, then the possibility of a faulty unit cannot be rejected out of hand, or waved off as fan-boyism. We complain about journalist reviewers, and often with undeniable justification. But one journalistic principle that applies here is that you always give the guilty party an opportunity to comment before you publish. Again, I'm not saying that is Amir's job, but it is a courtesy and a matter of due diligence.

Rick "not in the market for this amp so I really don't give a crap" Denney

*grin*

Tony "loves Rick's signoffs at the end of his posts" Collins.

 

[amirm]

I sincerely wish that Tom from ClassDAudio could send another model back to Amir to clear the doubt and confirm or deny the results.
for the time being, Amir's test is final)

Well, the proper "wish" is that they measure the amplifiers during design and production. If so, that is all we need to see to figure out what is going on. If they have no such measurements, then they need to remedy that first and would be in no position to know my amplifier is broken.

To be clear, I am not their QC department to run tests for them at the expense of reviewing some other product. They can contact me and I can run the full suite of measurements for a fee and they would then know where they stand. But I can't risk testing another amp, just to find the same results.

 

[amirm]

Hi amigos,

Just talked to Tom from ClassDAudio when I read this :

What is the reason? That we extensively test his product and find issues with it? He surely is not going to endear himself to us with that type of attitude.

 

[rdenney]

I am in touch with the Manufacturer and and we had a lot of discussions, which I have also shared here.
Premium Audio is a brand of ClassDaudio and I spoke with both brand representatives

As you could read it above, i made a hypothesis: was the model tested by Amir defective?

I sincerely wish that Tom from ClassDAudio could send another model back to Amir to clear the doubt and confirm or deny the results.
for the time being, Amir's test is final)

I agree with Amir that it isn't his job to perform QC testing for manufacturers. But now that we know the manufacturer is aware, he has the opportunity to respond once he sees the returned amp. Or not.

Rick "recalling the March P502 review with much following discussion about the one channel underperforming the other, leading to the general conclusion that it probably wasn't a thing" Denney

 

[GimeDsp]

If you want to balance out the negative chi of this amp all you need is to hook it up to ifi Zen.

 

[sarumbear]

But one journalistic principle that seems to me to apply here is that you always give the guilty party an opportunity to comment before you publish. Again, I'm not saying that is Amir's job, but it is a courtesy and a matter of due diligence.

ASR is not a journal and @amirm is not a journalist. He is a tester. Testers’s job is to show what they have tested as is. They are not expected to give you a second chance. Excuses are other party’s job.

 

[Killingbeans]

Edit: looks like GanSystem do make reference design. Maybe the value of the tech should be assesed by measuring those...

< 0.01% THD+N (8Ω, 1W, 20Hz to 20kHz)

That doesn't really correlate much with "a new level of performance"... unless that refers to the 96% efficiency

 

[DanielT]

So Morrello correctly points out that the 60KHz third harmonic is supersonic and hence inaudible and irrelevant - but also that it will (via intermodulation distortion) cause audible distortion frequencies.

Which is one reason why Amirm normally (and in this case) runs the multitone test. The 2nd 3rd (and higher) harmonics of the higher tones in that test may well via intermodulation distortion, cause lower frequency distortion. BUT that will be visible in the test result (in fact will be part of the spray of frequencies visible in the measurement - below about -80 to -90dB in this case)

So anything audible is seen. Anything above 20kHz is inaudible (except to super humans and dogs), can't be rendered by the speakers in any case, and therefore doesn't need to be measured.

It seems sensible. I am not a designer of amplifiers, like Morello, my knowledge is definitely not at that level. Morello is not here and can explain himself. Just want to point out Morello comments ONE specific measurement, if I get it all right.

No, this will be too strange and stupid for me to run the text from a Swedish hifi forum through google translate and via copy and paste report this. My suggestion . For those who are more interested. Start a new thread on the subject here at ASR (however, my gut feeling tells me that the issue has been addressed here before).

 

[PeteL]

ASR is not a journal and @amirm is not a journalist. He is a tester. Testers’s job is to show what they have tested as is. They are not expected to give you a second chance. Excuses are other party’s job.

They publish reviews, It's a media.

 

[PeteL]

< 0.01% THD+N (8Ω, 1W, 20Hz to 20kHz)

That doesn't really correlate much with "a new level of performance"... unless that refers to the 96% efficiency

AH OK, I don't get the hype then. It should indeed say "A new level of efficiency, at a reasonable performance cost".

 

[antcollinet]

It seems sensible. I am not a designer of amplifiers, like Morello, my knowledge is definitely not at that level. Morello is not here and can explain himself. Just want to point out Morello comments ONE specific measurement, if I get it all right.

No, this will be too strange and stupid for me to run the text from a Swedish hifi forum through google translate and via copy and paste report this. My suggestion . For those who are more interested. Start a new thread on the subject here at ASR (however, my gut feeling tells me that the issue has been addressed here before).

That is my gut feeling also. I'm satisfied that the tests Amirm runs are sufficient to tell us all (or at least the 99%) of what we need to know about what he is testing.

So you can count me amongst the "not more interested"

 

[sarumbear]

They publish reviews, It's a media.

Not every media is a journal. Not everything published is a journal. If you really want to check the use of media: a CD is a media, a technical paper is not a journal.

 

[Mulder]

So Morrello correctly points out that the 60KHz third harmonic is supersonic and hence inaudible and irrelevant - but also that it will (via intermodulation distortion) cause audible distortion frequencies.

Which is one reason why Amirm normally (and in this case) runs the multitone test. The 2nd 3rd (and higher) harmonics of the higher tones in that test may well via intermodulation distortion, cause lower frequency distortion. BUT that will be visible in the test result (in fact will be part of the spray of frequencies visible in the measurement - below about -80 to -90dB in this case)

So anything audible is seen. Anything above 20kHz is inaudible (except to super humans and dogs), can't be rendered by the speakers in any case, and therefore doesn't need to be measured.

Yes, but this test has not allways been provided earlier, for example previous tests of purify amps do not show this multitone test.

 

[PeteL]

View attachment 157401

What is the reason? That we extensively test his product and find issues with it? He surely is not going to endear himself to us with that type of attitude.

It's a private message Amir, I first strongly disagree with the original poster to decide to broadcast it when his "friend" say he doesn't wan't to get involved in the forum... But I also strongly disagree that you can judge of his attitude from not willing to participate in forum. There are indeed plenty of good reason for a manufacturer to not interact publicly. It's his own reasons. You don't know them.