Looks like Ralph Karsten of Atma-Sphere has change over to a GaN Class-D model in their poweramp line up. (bet it's got a tube in there somewhere)
http://www.atma-sphere.com/en/classD.html
PS: No tubes by the look of it. (but linear power supplyđź‘Ť)
https://hifiplus.com/articles/atma-sphere-music-systems-class-d-amplifier/
Not very high wattage, but high price
https://www.electra-fidelity.live/atmasphere-class-d-amplifier
Absolute Sounds:
"Atma-Sphere Class D amplifiers. That’s right: a brand known for tube amplifiers has built a Class D unit. I must say, true to the manufacturer’s word, the amps had tube-like warmth and sweetness. But their 100-watt GaNFET output stage and 800:1 damping factor also produced thunderous bass and high-jumping dynamics. Highs were clean, extended, and never exaggerated."
Cheers George
http://www.atma-sphere.com/en/classD.html
PS: No tubes by the look of it. (but linear power supplyđź‘Ť)
https://hifiplus.com/articles/atma-sphere-music-systems-class-d-amplifier/
Not very high wattage, but high price
https://www.electra-fidelity.live/atmasphere-class-d-amplifier
Absolute Sounds:
"Atma-Sphere Class D amplifiers. That’s right: a brand known for tube amplifiers has built a Class D unit. I must say, true to the manufacturer’s word, the amps had tube-like warmth and sweetness. But their 100-watt GaNFET output stage and 800:1 damping factor also produced thunderous bass and high-jumping dynamics. Highs were clean, extended, and never exaggerated."
Cheers George
Agreed, the article isn't comprehensive, but describes some advantages of GaN FETs.
These prompted Ralph Karstens the development of his mono amps.
His design philosophy really appeals to me and I'm not the only one, given the popularity of the amps.
Those looking for the lowest distortion figures and lots of power should opt for Hypex or Purifi.
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His refusal to publish a complete set of specs a la Hypex and Purifi really doesn't appeal to me. For the price of his class d amp you can buy like 4 Hypex or Purifi amps and get better performance to boot.
No it doesn't or does it barely at best.
But can you explain what the appeal is for something that performs less and costs more?
Like @cab also mentioned?
I would like to know what benefit Ralph Karstens is squeezing out of the GaN devices that makes their usage a material benefit over traditional devices at 5 times the price of the market performance leaders...???
When this question was put to him previously he mentioned he is using a more expensive linear supply and an extensive dealer network which can offer better customer experience. He also mentioned that his amps are made in the US and that they are made to last 30 years or better. He has also mentioned that his amps are made to reach a "different market" than the hypex/purifi amps. I can only speculate as to what that market is, lol....
When this question was put to him previously he mentioned he is using a more expensive linear supply and an extensive dealer network which can offer better customer experience. He also mentioned that his amps are made in the US and that they are made to last 30 years or better. He has also mentioned that his amps are made to reach a "different market" than the hypex/purifi amps. I can only speculate as to what that market is, lol....
This is about the old objectivist - subjectivist debate.
Ralph has published a lot about this.
Yes, you get more objective performance/watts per dollar with Hypex/Purifi. And if measurement data is leading, the choice is obvious.
There's obviously some price skimming involved, judging by the interior of the mono blocks, even though the amplifiers are handmade.
You obviously haven't studied his design philosophy.
"I used to be abused of the notion that there are things that you can hear that can't be measured. The problem is most of the important measurements are either never made and/or not published. Those differences you hear between various amps? Other than frequency response issues (often having to do with how the amp interfaces with the load due to output impedance), its the distortion signature that's being described (again, this is because the ear converts all forms of distortion to tonality). That is very measurable! But there is IMO a lack of awareness of what the significance of what these measurements tell us."
Last month, I had a fairly long conversation with Bruno Putzeys, following the introduction of the new Kii SEVEN.
He spoke, among other things, about his development methodology, which almost entirely takes place in the lab/scientific/theoretical domain.
When my brother asked him whether he also listens to his creations, the answer was: "Mainly to verify whether it works".
However, when asked whether he also appreciates tube amplifiers, he replied: "Some tube amps clearly reflect the result of a very sophisticated/long-term empirical optimization process".
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I have heard this from him before. He talks about measurements, etc., and doesn't provide them in any detail, unlike Hypex/Purifi.
Bruno designs amplifiers, which as the word implies, take a small signal and make it larger with as little distortion of the original signal as possible. Others make effects boxes, which take a small input signal, add some sort of distortion, and output the sum in a larger form.
Entire tribes of people truly believe all sorts of things. The words "high fidelity" have a meaning: fidelity to the (input) signal. Is there any other benchmark? Of course everyone is entitled to their own interpretation of what sounds "best" and that is why there are tone controls. Like a good steak, I prefer an amp to be unseasoned so that I can add my own if I desire, rather than have someone else season it for me.
Isn't the hole point of objective measurements, to leave out the believing part or at least make it as small and little as possible?
What other method do you propose?
Randomly listen to things with all kinds of variables and bias at play?
Anyway, we were talking about the technical parts of things and why they are technically better.
Therefor they also need technical testing methods to test those claimed differences.
Otherwise we can just put cork on everything and claim that your life will be better.......
Which, btw, I have absolutely zero problems with if that makes people happy.
But leave out all these made up technical claims and quasi scientific reasoning and discussions.
The reason in that case is ultra simple; I believe in it and it makes me happy!
Great, so we can all move and sleep at night! 🙂
Because THAT is a clear answer.
When people come with some technical story, you can expect that other people are gonna tests these claims on the physics and objective data that is available.
It ain't lookin" bright in that case.
Don't mix technical things with taste.
There are plenty of moments I really enjoy some old tube amplifier.
But I am never gonna claim it's gonna be better, because it simply isn't, if I like it or not.
Funnily enough that is how most engineering works or did you think that bridge design was subjective?
He's given longer answers in interviews on the internet. The listening test is last in his methodology. Which is again how you engineer a product. That's what Bruno does and if you want something made by an alchemist rather than an engineer there are plenty of companies ready to take your money. And if that makes you happy all is good.
That's seems a very sensible and correct statement. What is your problem with it?
Funnily enough that totally depends.
I have seen and worked for many companies and projects.
Some engineering starts from a very academic level, others from a far more practical approach.
And anything in between, including bridges.
Rules of thumb have a basis in academic research. But if someone builds a road bridge now without simulating the **** out of it I'm not sure I want to walk over it. A scaffold plank across a brook I'd probably walk across though 🙂. But my point was made because Ro808 seems to think it's bad to use computer tools to design an amplifier.
More like I believe in it and I'll be happy to sell you on that belief as well. A little less gate charge to evoke the same drain current; the driver must be having an easier time than if it was driving just a vanilla FET; I believe that's something you can hear: For Sale! "You should be able to hear it too - I can!"
As a floor salesman working at Olsons, their buyers would bring stereo equipment into the store that I just...couldnt believe in. That effected my salesmanship. I was a bad salesman, because I was supposed to sell you anything and some stuff, from my at university for EE degree perspective, I just couldnt. Do that to somebody...
Made up technical claims and quasi scientific reasoning is salesmanship. No wonder when you ask for the measurements, it's "excuse me, I have to help the fellow over there". Or perhaps it's worked out that the best tack is to provide some, not all - and leave just enough mystery to turn a nibble into a bite.
Looks like he using global feedback with that kind of DF, unlike Peachtree's local feedback on thier GaN-1 and Carina-GaN.
Cheers George
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