GaN amplifier from GaN themselves limited supply!!!

All I can say to that is,  "thanks for the bump"

This is for others that are interested in this GaN by GaN amp

Here is a test/measurement made by Amirm of Audio Science Review, one of the most highly respected sites for the truth on anything audio related.

This GaN amp complete was loaned to them by an owner for test/measurement and "it had it’s variable feedback" "set to low" via GaN’s laptop downloadable program because the owner loaned it in to him in that way, trouble is a couple of measurements won’t be as good as they could have been Amrim says that in the tests, and reflects in his conclusion statement.

"Performance here is above average compared to median of all amps I have tested (which lands around 78 dB SINAD). But it not stellar. Speaking with the designer, his focus was to keep the level of feedback low to show the advantage of the GaN transistors not needing much. He was not aiming to produce the best performance possible. Personally I wish he had targeted that given that is what we like to see here.
All in all it was superb in tests and measurements all aspects that matter."

As for heat there’s virtually none.

" Again, no heatsink due to high efficiency.s for heat sinking it runs so cool there’s no need for it. Practical MOSFETs take time to switch and during that time, they generate losses in the form of heat and limit how fast you can switch them. GaN transistors aim to solve this problem as these few slides from GaN systems show:"

Distortion at high power for a Class-D is incredible

"We see that the distortion is still under control instead of shooting through the roof.!!"

"I don’t think I have ever tested a switching amplifier with this level of frequency independence. Even Class AB linear amps struggle to produce such an absolutely clean response. Amplifiers with high amount of feedback run out of gain at higher frequencies and hence distort more. Not this design."

Even techs with follow up comments on the thread were very impressed.
https://www.audiosciencereview.com/forum/index.php?threads/gan-systems-amplifier-eval-board-measurem....

As for me getting one, all here know I only have Class-D preference for one, the Technics SE-R1 with it’s 1.5mhz switching frequency, even this GaN by GaN I started here, won’t shift my linear amps, yet!!

Cheers George

Why, on earth, did the mods remove this?

”@georgehifi

Designing an amp is a bit more involved than making a volume control…

Perhaps Ralph, who knows a thing or two about what an amp can sound like, is applying that knowledge to the D class amps - which are at the Beta stage (look at the link I posted) . And perhaps, building a world class amp, can take a minute to sort out, especially when you know what it should sound like.

But, feel free to keep on naysaying. Seems that is what you do best.”

Explain this to me please?

Yeah, my prior post got deleted as well. George gets very defensive whenever anyone questions anything about things he recommends here to the point where when even very knowledgeable and respected people here bring up valid points he feels the need to lash out at them and tries to discredit them by saying they have an ulterior profit or business-related motive (total bunk BTW). Oddly his unfounded claims against the reputations of these respected members are allowed to remain for some strange reason while posts questioning George’s motives or claims get deleted. Frankly I don’t get the double standard, but whatever. Still interesting to hear about amps made with these modules and exciting to see where the newer GaN, Purify, etc. technologies are taking the world of amplification.

@siox

Yeah, thats the very confusing part. Ralph has said nothing negative about the tech, just calling out application.

Meanwhile, George gets to throw his vitriol about.

Not cool...

And I am also curious about the new tech that is around the bend. Especially curious when a designer like Ralph does what could be argued as a complete 180 from OTL tubes to D class amps.

That is very interesting!

 

The first mentioned history of the new GaN output devices here on Audiogon

The new GaN transistors were reported here some 4-5years ago about how they will transform Class-D, especially the way Technics used them with the SE-R1 and it’s 1.5mhz switching speed instead of what everyone else uses around 500-600khz.

Here are the first post on Audiogon mentioning the new GaN transistors from "Alex Lidow" of EPC who was the inventor of the Mosfet, or one of them.
https://forum.audiogon.com/discussions/class-d-is-just-dandy/post?postid=1413463#1413463

https://forum.audiogon.com/discussions/class-d-is-just-dandy/post?postid=1413469#1413469

https://epc-co.com/epc/Applications/ClassDAudio.aspx
And the video he uses and measures the original older GaN by GaN evo board this thread is about the newer model.

And dht4me who has been in direct contact with Rick Reigel from GaN, says there is another "Reference Board" in the design stages.

This present unit bodes very well for the members here who can do very simple kit assembly themselves, basically mount the GaN board it in a box add some rca sockets and speaker terminals.

You got a killer Class-D GaN integrated amp with dac!! and variable feedback for well under $1500 that "could" blow any others here away, as dht4me reported when he demoed it to the LA audio crew and said,
"I have built 4 of these to date, the first was for me but as soon al local Las Vegas audiophiles heard it they were begging me to build them one."

Cheers George

@dht4me 

@dht4me

Do you know what the RCA input impedance of this board is, as I've looked and can't find it anywhere, maybe Rick Reigel could let you know if you don't?

Cheers George

Here we have the video on the $1300 Gan by Gan Class-D and Power supply, fully loaded with a dac, volume control, switchable inputs two digital and two analog and variable feedback (closed loop/open loop) this is plug and play almost, all you need is a box.

https://gansystems.com/webinar-playback-class-d/

44th minute onward shows you how to use the feedback control in real time while listening to pick the right amout to suit your liking, so listening comparisons can be made. And as I said it also the Scamp connection which also gives many DSP control values to be had via you laptop.

There is is the development stage another one from GaN which they call the Reference board which sounds to me like it could be even better? That could take a while though.

Cheers George

Looks like there must have been a few purchases done since this thread went up, as they’ve now run out of stock.
It says you can still back order though, 10 more units expected on the 28th Oct.

https://au.mouser.com/ProductDetail/GaN-Systems/GS-EVB-AUD-BUNDLE1-GS?
qs=vHuUswq2%252BszP6hR0ubJmfw%...

There are other places they were sent to though, bottom of this page. https://gansystems.com/where-to-buy/


Pics from the video

https://ibb.co/wMf0nGS

https://ibb.co/wMf0nGS

https://ibb.co/r3zjQyR


Cheers George

For those wanting one, here’s a place (subsidiary of Arrow Electronics) that has 5 of them, and they’re cheaper here too, only $940!!!
https://www.richardsonrfpd.com/Products/Product/GS-EVB-AUD-BUND

There must be others as GaN has about 50 outlets world wide on the GaN where to buy page, bottom of this page. https://gansystems.com/where-to-buy/

Cheers George

What is going on with this thread?
The moderation appears peverse. The OP was misbehaving and got defensive.
Then everyone else's posts got removed?
What a strange place this is. Reminds me of the Tekton thread where any opinion on the speaker's appearance was removed. So we can discuss components but not their appearance?
It seems some, rather shrill in tone posters, get to wag the dog

None of my posts have been removed.


The fact that these have sold out is probably not due to popularity in the high end audio community so much as GaNFETs are hard to get right now and there probably isn't stock to build the evaluation boards. When you can't get the product to sell, why in the world would you populate a promotional product??


I noticed George repeating himself in his quotes from Amirm but oddly he leaves out Amirm's concluding remarks so here they are from Amirm's website:

Conclusions
MOSFET transistors have revolutionized computing and switching power designs. It is nice to see a new type become available after decades of refinement of MOSFET. GaN transistors offered by GaN systems show a path to cooler running, more efficient and better performing amplifiers and power supplies. The eval unit unfortunately doesn't show the improved performance due to different target for it. So best to look at commercial implementations that shoot for state of the art implementations.

Note the last two statements.
Although George was rankled by this he didn't let on here on this website. He asked Amirm only a few days ago (most of the thread is from June) about changing the feedback to get better measurements- here's what he asked (on page 7 of the review) https://www.audiosciencereview.com/forum/index.php?threads/gan-systems-amplifier-eval-board-measurem...

Any chance of doing the couple of measurements again that didn't impress like the others did, but with the feedback set up higher where you think it should be, as this may well flip your conclusion around??.

Obviously George is aware of Amirm's conclusion.


Amirim indicates that he is concerned the evaluation board will go into oscillation if too much feedback is applied (for those technically minded: with too much feedback the phase margin of the circuit would be exceeded, resulting in oscillation). This is a clue into the design of the circuit. It indicates that its not self-oscillating. Since it can also be run with zero feedback (see measurements on page 1 of the review) this suggests a straight forward Pulse Width Modulated encoding scheme.


A PWM encoding scheme with no feedback has noise associated with frequency drift in the triangle wave oscillator. For this reason the oscillator has to have a lot of attention paid to its stability, but the simple fact is it will drift. You can see the result in the noise spectrum which is the final measurement Amirm shows.


One more thing: If you note the 4 ohm power measurement as opposed to the 8 ohm power you see that its actually **lower** (114 watts) than the 8 ohm power!


This is not a mistake.

I've already said why earlier on this thread- because the eval board is for evaluation only its not supplied with heatsinking means. Heatsinks that can actually allow the amp to run at full power into 4 ohms are not a trivial cost- they would be the most expensive part(s) in the kit due to the precision machining required. So the amp is teamed with a SMPS unit that is unable to provide the current needed into 4 ohms (and is probably actively current limiting). This prevents the board from overheating its output devices. 


So if you are planning this amp as your power amplifier, just be aware that its really only 114 watts into 4 ohms.