[kingdeezie]

Hmmm wonder how they’d sound driving Sound Labs?

Not enough juice. SLs get up into the 30-ohm region in the bass. You’d be getting 25 watts.

[ACHiPo]

That’s kinda what I was thinking.  May ping Ralph to confirm.

[goryu]

He also said that this was the first SS amp that can sound as good or better than tube amps.  Hi is going to post additional measurements to better understand how the amp actually performs.

Subjective impressions by the seller. Not exactly a surprise.

I think there's also something to be said for less feedback.  Not everyone is sensitive to the affects of feedback on sound, but I am. 



This amp uses quite a bit of feedback. Perhaps you are unaware of the differences in the proper implementation of feedback control loops in class d design:

From the designer:

"Class D offers the possibility of using loop negative feedback in a way that was previously not possible due to stability concerns.

Legacy solid state and tube designs lack the Gain Bandwidth Product needed to support very high amounts of feedback. This causes the amplifier to have increasing distortion with frequency, resulting in harshness and brightness since the ear assigns tonality to distortion.

In addition the prior art has issues with phase margins in the design. Adding too much feedback can cause oscillation. For these reasons feedback has gotten a bad reputation with music lovers.

Class D offers a way around those problems."

[SET Man]

Hey!

   Class D from Atmasphere?! 

   This reminded me of when Bel Canto switched to Class D. But of course Atmasphere have been around much longer making tube stuffs.

Buddy

[Freo-1]

Speaking of oscillation:  Had to add coils on the plates of a 1625 tube (12V version of the 807 tube) monoblock amp to keep it from oscillating. 

[Freo-1]

He also said that this was the first SS amp that can sound as good or better than tube amps.  He is going to post additional measurements to better understand how the amp actually performs.

Subjective impressions by the seller. Not exactly a surprise.

Sure, but considering he's been the business for 40 years, I'll give him the benefit of the doubt on creditability.  I really don't think he would release any amp that wasn't up to snuff.   

[Tyson]

I think there's also something to be said for less feedback.  Not everyone is sensitive to the affects of feedback on sound, but I am. 



This amp uses quite a bit of feedback. Perhaps you are unaware of the differences in the proper implementation of feedback control loops in class d design:

From the designer:

"Class D offers the possibility of using loop negative feedback in a way that was previously not possible due to stability concerns.

Legacy solid state and tube designs lack the Gain Bandwidth Product needed to support very high amounts of feedback. This causes the amplifier to have increasing distortion with frequency, resulting in harshness and brightness since the ear assigns tonality to distortion.

In addition the prior art has issues with phase margins in the design. Adding too much feedback can cause oscillation. For these reasons feedback has gotten a bad reputation with music lovers.

Class D offers a way around those problems."

Interesting.  And you may be right, it might be something more specific than just 'negative feedback'.  I remember the first generation of digital amps were quite awful sounding.  But, there were changes made to the designs and then they Purifi and Hypex latest generation came out and they were not awful sounding anymore.  Merely mediocre sounding is which was actually quite an improvement.  With the GaN amps it seems we might have a jump in sound quality again, moving from 'meh' to 'actually good'.  At least that is my hope.  Seems very promising so far!

[goryu]

Most first generation class d amps didn't have feedback from after the output filter which resulted in load dependent frequency response. Depending on one's speaker's load, it was rather hit or miss as to whether or not the amp performed well. Later designs, such as those from Hypex, solved this issue and created modules which are both basically load independent and extremely neutral.

There won't be any "jump in sound quality" as that is subjective and not everyone will agree. Objectively, since class d has reached a point where the distortion performance is beyond audibility the benefits of the GaN technology are mostly in efficiency, though it is possible clever designers will squeeze even lower distortion out of them but if -130dB is inaudible, -140dB really won't matter much.

There are those who simply like and prefer a certain distortion spectrum over a wire with gain. That's not something one can blame on a properly designed and performing amp but rather it's the taste of the listener. Some people will put steak sauce on Kobe beef after all. No doubt there will be those who tailor their GaN design to produce the types of distortion products that some people like rather than simply design for optimum performance. That is nothing new. Someone who has been selling tube amps for 40 years, for example.

[Tyson]

You are right, having heard the Hypex and Purifi amps, they are much better than the Ncore based designs that came before.  Some people like them, I do not.  As you stated, it's all subjective.  To me, subjectively, based on my direct experience with them (in multiple instances across multiple systems), they were lifeless and boring.  So they will certainly never find a place in my system because I prefer amps that are musical and lifelike.  Again, as you point out, those are my subjective opinions.

Oh wait, I realized I made a mistake.  There is one place I've heard them that they actually do very well indeed - subwoofer amps.  I actually REALLY like them as sub amps, their super-tight, iron fisted sound really works well in that application.  Again, in my subjective experience.

Anyway, we've been down this rabbit hole before, so you can post a reply if you want but I won't be posting anything else to this thread.

[Freo-1]

There is no such thing as "A straight wire with gain" .  The Hafler XL600 was advertised as one.  It wasn't,  and neither is any other amp. 


The measurements provided regarding amplifiers tell one some factors,  but they don't necessarily provide insight as to how they will sound in one's target environment.  There are additional measurements that could be conducted which could provide additional insight regarding sonics, but it still doesn't tell one how it will sound in a specific target environment. 


Given the  fact that Atma-Sphere has a solid reputation,  I feel confident this product will perform and sound excellent in the right setting.

[goryu]

Of course there is no amp that is a perfect wire with gain. It's a goal that many aim for, and a goal that some, like Purifi, come very close to meeting. Nothing will ever tell us how an amplifier "sounds" as a properly designed amplifier isn't suppose to "sound" like anything, never mind the fact that we all perceive sound in our own way, making any sort of objective judgment of our subjective impressions rather meaningless. As has been stated and shown previously, correlating objective measurements to subjective preferences does not work on an individual basis.

No doubt the Atmosphere product will have its fans, just like every other amp manufacturer that has been around a while. Whether or not it "sounds excellent" will depend on who you ask. Glad to hear you have already made your mind up without hearing it. No doubt your confirmation bias will be proven true.

[Freo-1]

No doubt the Atmosphere product will have its fans, just like every other amp manufacturer that has been around a while. Whether or not it "sounds excellent" will depend on who you ask. Glad to hear you have already made your mind up without hearing it. No doubt your confirmation bias will be proven true.

Now you are again making assumptions not in evidence.  You know what they say about "assumptions ".


I haven't heard either the Atma-Sphere or the Purifi.  I will not pass any judgements without hearing them in my target environment. I don't do conformation bias.  Been at this too long to make that mistake. 


We do have a frame of reference from which to judge how something sounds.  It's called music. 

[goryu]

"I feel confident this product will perform and sound excellent in the right setting."

"I will not pass any judgements without hearing them in my target environment."

Huh?

"We do have a frame of reference from which to judge how something sounds.  It's called music."

And each of our judgments is only valid for ourselves.

[rollo]

  It appears Gan technology has its merit. I would compare it to my Hybrid Class "D" monoblocks. Until I hear it in my system cannot offer an opinion.

charles

[Freo-1]

  It appears Gan technology has its merit. I would compare it to my Hybrid Class "D" monoblocks. Until I hear it in my system cannot offer an opinion.

charles

Yep.  Need to hear it in one's own system.   The Gan400 from Peachtree is a nice sounding amp, but it's not in the same class as Devialet. 

[JCarney]

What I do not understand, is why only a hundred watts into 8ohms? My class d 2 channel amp is 350 into 8ohms, and the same company makes 1500 watt modules. Does the GaNFET contribute to the low power numbers? Thank You in advance for any help understanding why only 100 watts.

JCarney

[Freo-1]

What I do not understand, is why only a hundred watts into 8ohms? My class d 2 channel amp is 350 into 8ohms, and the same company makes 1500 watt modules. Does the GaNFET contribute to the low power numbers? Thank You in advance for any help understanding why only 100 watts.

JCarney

It has to do with the GanFET physical properties. Attaching heat sinks to them to dissipate the heat safely is a bit tricky.  Ralph from Atma-Sphere is working on this, and there are plans to make a higher powered amp. 

[goryu]

What I do not understand, is why only a hundred watts into 8ohms? My class d 2 channel amp is 350 into 8ohms, and the same company makes 1500 watt modules. Does the GaNFET contribute to the low power numbers? Thank You in advance for any help understanding why only 100 watts.

JCarney

His customer base is mostly tube lovers, who mostly have speakers that don't need 350 watts into 8 ohms. Notice the amp is spec'ed into 16 ohms, something you don't see with other class d amps. These are meant for those replacing tube amps it would seem...

[Freo-1]

His customer base is mostly tube lovers, who mostly have speakers that don't need 350 watts into 8 ohms. Notice the amp is spec'ed into 16 ohms, something you don't see with other class d amps. These are meant for those replacing tube amps it would seem...

Good point. 


He is working on a higher powered version.

[Don_S]

His customer base is mostly tube lovers, who mostly have speakers that don't need 350 watts into 8 ohms. Notice the amp is spec'ed into 16 ohms, something you don't see with other class d amps. These are meant for those replacing tube amps it would seem...

"Tube lovers", smile when you say that.    Maybe replacing completely or just seasonally. I do not run my tube amplifier in the summer. It gets >100⁰F here too often.