[Gallium Nitride amplifier] Impressions of the Mini Gan 5 by Premium Audio, pictures / video inside

[JayGilb]

Another hypothesis from a US user

"that is a very interesting claim indeed. Air has a much higher thermal impedance than a thermal compound or thermal interface material designed for heat transfer, so one can only wonder what they were doing differently between the two setups to end up having the current solution being more effective at removing heat from the components.

The only thing I can think of is that they may have unintentionally used shorter non-metal standoffs when trying the compound/TIM and that resulted in a higher thermal impedance between the PCB copper and the heatsink, but that would seem like a pretty obvious difference to notice during testing. The GaN FETs have the least thermal impedance through the solder joints and into the PCB copper, which is why pulling heat out of the PCB near the FETs is the best way to cool them down, but surely using the compound/TIM along with metal standoffs between the PCB and heatsink would only further reduce the thermal impedance and improve the thermal transfer. Anyway, this is all speculation."

If they can adequately cool the device via the heat sink conductance/pcb connections, that would be a much cleaner design than applying compound to each individual GaN FET. There are many other components in the GaN FET's proximity with varying heights that would make designing as heat sink difficult.

 

[whislai]

If they can adequately cool the device via the heat sink conductance/pcb connections, that would be a much cleaner design than applying compound to each individual GaN FET. There are many other components in the GaN FET's proximity with varying heights that would make designing as heat sink difficult.

hmm so far I din have any signal disruption problem due to heat dissipated, it's hot but not to the boiling point as I experience, compare to my previous SDS amp which has burning heat issue (I believe can boil egg aha) that causing signal disruption, which I solve using few coins on top of the heat sink.

 

[daniboun]

hmm so far I din have any signal disruption problem due to heat dissipated, it's hot but not to the boiling point as I experience, compare to my previous SDS amp which has burning heat issue (I believe can boil egg aha) that causing signal disruption, which I solve using few coins on top of the heat sink.

I confirm this point, as I said before... those heatsinks are very weird and remain a mystery. For my part, I have nothing to report on overheating and I can put my hand flat on the amp even after 4 hours of listening

 

[whislai]

I confirm this point, as I said before... those heatsinks are very weird and remain a mystery. For my part, I have nothing to report on overheating and I can put my hand flat on the amp even after 4 hours of listening

Yeah, it's unbelievable incredible small but powerful amp, just brute force and straightforward.

 

[antcollinet]

I've spent 30 years pre retirement developing, and project managing the development of high power electronic products (up to 90kW)

PCB's (even with a copper plane) are very poor conductors of heat over any distance. The board will give up nearly all the heat to air before it reaches the pillar. The PCB to pillar arrangement they have here will also be poor, and the small surface area between pillar, PCB and heatsink will basically do nothing to carry away heat from the power devices compared with the device to air conduction and then convection.

IMO those heat-sinks as they are currently placed are not contributing to cooling in any significant way - in fact they will probably make things worse by disrupting the vertical flow of convected hot air.

The "co-incidental" re-positioning of the heatsink, at the same time as needing mechanical support for the new chokes tells a very clear story in my opinion, as I have described up-thread.

It could be relatively easily measured - if the temperature of the hottest air just below the heatsink were measured, and the temperature of the heatsink itself on the top side - if the heatsink is not significantly hotter than the surrounding air, it is doing nothing.

 

[antcollinet]

Pretty close to my description up-thread. I was just a little more generous though.

[Gallium Nitride amplifier] Impressions of the Mini Gan 5 by Premium Audio, pictures / video inside

Agree. But question for you : Do you think the Purifi is transparent ? The same for the TPA3255 and for the MA12070 ? Do they have flat frequency response and low distortion?

www.audiosciencereview.com

 

[JeffS7444]

I agree, just trying to give them a defense for such a poor engineering decision.

Oh, but the heatsinks do serve an important function: They jazz up the appearance of the PCB! The technololgy is genuinely cool (haha) but maybe not what audiophiles expect to see. Maybe someone will want to custom-order a batch in polished T03 cases and bolt them onto massive heatsinks, just because.

 

[sychan]

Oh, but the heatsinks do serve an important function: They jazz up the appearance of the PCB! The technololgy is genuinely cool (haha) but maybe not what audiophiles expect to see.

Maybe the air gapped heatsink does work better...if you turn the amp on it's side and can use a chimney effect between the heatsink and the pcb for cooling.

 

[whislai]

Ok my further subjective review for comparison between the SDS-470C and GAN 5, it turns out that I feel there is more soul to the sound from SDS, I can't explain it, from song to song, the GAN is a little bit more balanced for the whole frequency spectrum presentation, but the SDS seem catch your heart better on certain frequency, and I love that. Also my overall impression is the SDS is a bit more forgiving especially on poorer recordings. I suspect this is because of the pull back of bass that can cause boominess and a little sugar on the treble region without a hint of harshness tweak that somehow works. Also I feel the SDS seem sound "louder" at lower volume, always feel a bit short of power from the GAN, hmm...so I think this amp need a final stage of tweak.

 

[BDWoody]

Ok my further subjective review

Any effort at implementing controls? Any basic level or sight controls at least?

 

[whislai]

Any effort at implementing controls? Any basic level or sight controls at least?

aha I just make it "organic" by ears, most probably need a bit more time to tell naturally my ears love which one better, so far that's my impressions, cannot say it's 100% accurate yet...

 

[BDWoody]

aha I just make it "organic" by ears, most probably need a bit more time to tell naturally my ears love which one better, so far that's my impressions, cannot say it's 100% accurate yet...

Why not try a long term blinded test? Get a helper, switch (or not) every few weeks. Without controls, your impressions are going to be tainted by knowing which is which.

This forum tries to separate anecdote from meaningful evidence. Without any controls, we are stuck in the realm of bias filled anecdote.

Amir just did a video that might be helpful, if you were interested in upping your evaluation game.

 

[whislai]

Why not try a long term blinded test? Get a helper, switch (or not) every few weeks. Without controls, your impressions are going to be tainted by knowing which is which.

This forum tries to separate anecdote from meaningful evidence. Without any controls, we are stuck in the realm of bias filled anecdote.

Amir just did a video that might be helpful, if you were interested in upping your evaluation game.

Yeah that might works, but you know I dun want make it so intentional and by compulsion, or like religion. As I said, time is a main factor that will tell how my ears react naturally. Things keep changing..

 

[BDWoody]

Yeah that might works, but you know I dun want make it so intentional and by compulsion, or like religion. As I said, time is a main factor that will tell how my ears react naturally. Things keep changing..

You aren't alone in that for sure. Seems that lots of people might not want to know...they like playing with the idea of teasing out subtle differences over time, just like they hear their favorite reviewers claim to do.

Problem is the results are going to be relatively meaningless if you know what you are listening to. Bias is tricky business.

 

[daniboun]

Ok my further subjective review for comparison between the SDS-470C and GAN 5, it turns out that I feel there is more soul to the sound from SDS, I can't explain it, from song to song, the GAN is a little bit more balanced for the whole frequency spectrum presentation, but the SDS seem catch your heart better on certain frequency, and I love that. Also my overall impression is the SDS is a bit more forgiving especially on poorer recordings. I suspect this is because of the pull back of bass that can cause boominess and a little sugar on the treble region without a hint of harshness tweak that somehow works. Also I feel the SDS seem sound "louder" at lower volume, always feel a bit short of power from the GAN, hmm...so I think this amp need a final stage of tweak.

I guess you re using the Mini Gan with unbalanced inputs ? You should give with the XLR inputs....
I continued my listening this week, and I really find it neck and neck with my Purifi. I use floor speakers with ribbon tweeters and love the very precise transcription of cymbals, strings and other high pitched instruments.

Here my speakers :

 

[whislai]

I guess you re using the Mini Gan with unbalanced inputs ? You should give with the XLR inputs....
I continued my listening this week, and I really find it neck and neck with my Purifi. I use floor speakers with ribbon tweeters and love the very precise transcription of cymbals, strings and other high pitched instruments.

Here my speakers :

That's a big speakers aha, yeah the GAN has a little bit more clearer layers and details compare to the SDS, would not say it's night and day difference with the SDS.

 

[oldsysop]

This thread looks like an infomercial by daniboun and whislai

 

[daniboun]

That's a big speakers aha, yeah the GAN has a little bit more clearer layers and details compare to the SDS, would not say it's night and day difference with the SDS.

Thanks. Enjoy your amp )

 

[sychan]

Here's the fix...

Put some controls on those subjective observations so they DO have value. Otherwise, they really don't.

I remembered an article I read about symphony auditions - these are entirely subjective, but it turns out that they were heavily biased before they instituted fully blind auditions. Without appropriate controls, you may not be selecting the best amp, just what your internal biases steer you towards:

What Business Leaders Are Getting Wrong About Bias Training | Entrepreneur

There's little evidence that bias awareness training accomplishes its goals.

www.entrepreneur.com

 

[whislai]

I remembered an article I read about symphony auditions - these are entirely subjective, but it turns out that they were heavily biased before they instituted fully blind auditions. Without appropriate controls, you may not be selecting the best amp, just what your internal biases steer you towards:

What Business Leaders Are Getting Wrong About Bias Training | Entrepreneur

There's little evidence that bias awareness training accomplishes its goals.

www.entrepreneur.com

Well, it does not matter for some people, though I have no objection if people to follow this way, and we should thank you for any objective contribution and scientific data, but for me it's like "the only parameter is you, you decide what you think is the right for you"