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Premium Audio Mini GaN 5 Review (Stereo Amplifier)

amirm

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This is a review and detailed measurements of the Premium Audio Mini GaN 5 Stereo Class D power amplifier. It was kindly sent to me by a member and costs US $799 (recent price increase).

The GaN 5 comes in a compact enclosure with plenty of ventilation at the cost of decent looks:

Premium Audio Mini Gan 5 Review Power Amplifier Stereo.jpg


Beside the sole power button and blue indicator, there are two red LEDs that turn on when you power the unit on and then go off. Strangely, when the amplifier goes into protection, they do not light up and getting the unit working again requires a power cycle. I like to see protection circuits that self recover when the extreme condition goes away.

The back panel shows binding posts that are too close together for easy fitment of my large banana speaker cables. But I like the inclusion of balanced XLR inputs:

Premium Audio Mini Gan 5 Review Class D Power Amplifier Stereo.jpg


As you see, there are also jumpers to change the gain setting although the range is not very large (26, 28 and 32). Most of my testing was with medium gain which is as shipped.

I had trouble getting the amplifier to function initially. It would simply not output anything. I played with grounding as I have seen some very low end amps cause AP to not be able to capture their output due to high level of noise (despite my use of AES-17 filter). This didn't work at first so I switched inputs to RCA. That did not work either. After some fiddling and switching back to balanced input, the amp all of a sudden started to work. Not sure how much of this is interaction with Audio Precision or design issue. Either way, it is an exception to the rule of 95% of amplifiers I have measured.

As the name indicates, this amplifier uses the new Gallium Nitride transistors (GaN) which has some advantages over classic Mosfet transistors. All else being equal, it can produce higher efficiency and better performance at expense of higher cost.

Mini GaN 5 Measurements
As noted, I started my testing in medium gain which produced near nominal 29 dB which is my standard for amplifiers. XLR input was used per introduction:

Premium Audio Mini Gan 5 Measurements Amplifier.png


Well, this is disappointing. Distortion is fairly high causing SINAD which is the sum of distortion+noise to be worse than a number of budget desktop amplifiers:

Best class D amplifier review.png


Noise performance by itself is not good either:

Premium Audio Mini Gan 5 Measurements SNR Power Amplifier Stereo.png


I had trouble getting the amplifier to go to full power for the right graph. It would shut down at just 0.7 volt input. Strangely, later on it accepted higher levels of input. I think the impulse nature of this measurement was causing it trouble. So maybe it can produce higher SNR at higher power but still, none of this is competitive.

On the other hand, crosstalk was very good:

Premium Audio Mini Gan 5 Measurements Crosstalk Power Amplifier Stereo.png


Multitone performance was also reasonable:

Premium Audio Mini Gan 5 Measurements Multitone Power Amplifier Stereo.png


What is not reasonable is high dependence on speaker load when it comes to frequency response:

Premium Audio Mini Gan 5 Measurements Frequency Response Power Amplifier Stereo.png


This is just not proper. Clearly the output filter is interacting with the load.

Power measurements were quite puzzling:

Premium Audio Mini Gan 5 Measurements Power into 4 ohm Power Amplifier Stereo.png


Notice the pull back due to some protection kicking in, likely the power supply rather than the amplifier. I could not remotely get the power rating they specify using medium gain. I thought maybe low gain does better but then the pull back occurred at even low power (blue and green)! Beside lack of power, distortion is also quite high for this price class and category. We are talking about poor Audio/Video Receiver amplifier performance!

Switching to 8 ohm tamed the output a bit but power shortfall is still significant:

Premium Audio Mini Gan 5 Measurements Power into 8 ohm Power Amplifier Stereo.png


This being the second amplifier I have recently tested with such power shortfall, I started to doubt my instrumentation. So I pulled out my Purifi reference design and measured it. It tracked the dashed line in the above graph from a year ago 100%. Someone had posted this from their website:

index.php


600 watts per channel??? Into 8 ohm? This is the spec from the manual:
1633414038759.png


How on earth did they measure 600 watts when the spec is 200 watts? Strangely, that graph is nowhere to be found on their site. There is some talk about a larger amplifier of which is a shrunk version? Maybe that is the one that produced higher power but why does it say "mini" in the title of above graph?

FYI, this amplifier has the green board which I understand to be the newer design. Maybe the older red one had more power. Hard to say.

Anyway, I tried to run my max and burst power:
Premium Audio Mini Gan 5 Measurements Max Power into 4 ohm Power Amplifier Stereo.png


In Burst mode, the amplifier would keep going into pull back and so I could not compute anything for that. Likewise the THD+N vs frequency and power could not be run. As the frequencies got lower and lower, the point where the amp would pull back would also shrink to lower and lower wattages. What I could get did not show great transfer function.

Conclusions
While I leave the door ever so slightly ajar to some interaction with Audio Precision, the measurements seem to indicate an amplifier that has both design issues and inability to meet specifications. The fact that the company took away the only measurement graph makes it suspect that maybe they had have modified the design and selling something different than what they originally intended. As it is, it is a waste of GaN technology as it brings nothing to the party but high expense.

I can't recommend the Premium Audio Mini GaN 5 amplifier.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 
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001

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Thank you for yet another review. It is disappointing to see this performance from this implementation of GaN technology. I am certainly looking forward to see positive reactions from Audio Precision. GaN deserves a future.
 

respice finem

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The takeaway for me: Only because a technology can and should be a step forward, doesn't mean it is in reality.
Second thought: Would it be possible to just replace the transistors in a known good design with GaN parts, to see what difference it really makes?
 
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amirm

amirm

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Secont thought: Would it be possible to just replace the transistors in a known good design with GaN parts, to see what difference it really makes?
No, the benefits require a redesign to reduce for example the dead time between transistors switching. There are also other design criteria that make a swap like this impossible.
 

mcdn

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Manufacturer spec is 0.005% THD+N at 5W 1kHz, but the result is 0.02%, and the distortion spray is nasty. GaN supposedly allows the switching frequency to be made higher for better efficiency and smaller filter components but I'm not sure this even beats an AIYIMA A07 for performance.
 

sgent

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So this seems to prove that just finding a good board (Purfi, etc.) doesn't mean the implementation is worthwhile. All the people recommending various amps based on either chip or board implementations should check themselves if they haven't measured the full amp.
 

VintageFlanker

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Thanks, @amirm for this do not buy warning ;)

Speaking of which, is there any plan to measure Starkrimson (Édit : Ultra) modules from @orchardaudio ?
All the people recommending various amps based on either chip or board implementations should check themselves if they haven't measured the full amp
Except there are many all-in-one modules (Ncore NC-MP, IcePower, Pascal), that don't require implementation... You cannot mess with them, unless intentionally.
 
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amirm

amirm

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amirm

amirm

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So this seems to prove that just finding a good board (Purfi, etc.) doesn't mean the implementation is worthwhile. All the people recommending various amps based on either chip or board implementations should check themselves if they haven't measured the full amp.
The amp implementations based on modules tend to come close or match the specifications (only the choice of buffer stage and power supply can impact performance). Chip amps, yes, there could be much larger variation. Still, performance of both needs to be verified and hence the reason I measure them all. And continue to do so.
 

mcdn

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So this seems to prove that just finding a good board (Purfi, etc.) doesn't mean the implementation is worthwhile. All the people recommending various amps based on either chip or board implementations should check themselves if they haven't measured the full amp.
It proves the opposite, that you should buy a well known module instead of a one-off implementation like this.
 

antcollinet

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Thanks for the review. I'd been looking forward to this one, but the results are disappointing. Good to know though. Now waiting for the promised new Topping higher power amps.


@amirm
Just a couple of typos/clarifications I noticed:

Someone had post this from their website = Someone had posted this from Premium Audio's website. (posted, and Premium Audio as distinct from the posters website)

bust power = burst power
 

gvl

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And it’s not even all that expensive, what could “Premium” refer to now that we know it’s not the performance ?
 

antcollinet

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@amirm Not wanting to teach Grandmother to suck eggs, but I've just looked at the manual - there is a voltage selector switch on the underside of the device. Given the misbehaviour at first power on and the lack of power - is it possible this arrived set to 230V?
 
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amirm

amirm

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@amirm Not wanting to teach Grandmother to suck eggs, but I've just looked at the manual - there is a voltage selector switch on the underside of the device. Given the misbehaviour at first power on and the lack of power - is it possible this arrived set to 230V?
I checked that. As best I can identify, it is set to 110. I am not sure what the switch is doing anyway as this has a switching power supply.
 

mononoaware

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There seems to be some confusion surrounding this amplifier.

Here is something I found from another thread regarding the 600W @ 8ohms graph.

A bit vague but I assume they are talking about the “Mini Gan”.

The thread also has comments on the “floating” heatsinks, which is another source of confusion as the official statement is the amplifier runs cooler with this setup.
Also in the thread a user posted thermal camera images of their purify amp, after which they commented the Mini Gan ran cooler than the purify to the touch (they did not take a thermal image).
Meaning the entire amp runs cool so there is no real need for the heatsinks at all?
 
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