What about Class ND (another fudge)?

[Vhond]

Somebody who has heard of class ND?
It would be a combination of Class A and Class D, but for me it's abracadabra: About Class ND

Does it make sense? They write about that they have a patent, but why not publish this patent or link to it?
And which part is class D and which class A??

 

[YouDontHaveEnoughBass]

Why add complexity to a technology already able to deliver high power cleanly and cheaply (both in terms of cost of the unit and running efficiency), seems like a solution looking for a problem to fix imo

 

[fpitas]

There's a lot of hand-waving and snake-oil claims there. I would take it with a grain of salt.

 

[VintageFlanker]

They write about that they have a patent,

When esoteric Audio companies come which such a statement, without pointing to the actual patent... 95% of the time, they're just lying.

. Because we build devices for people with a sense of the special

Then, I call it bullshit.

Your should post this where it belongs, which is there :

Snake Oil Department, Top This

https://www.theabsolutesound.com/articles/shunyata-research-sigma-nr-v2-power-cord A $3500 power cord. "This power cord brings an accuracy of timbre and harmony, a musical veracity, that I’ve simply not experienced before. Yes, it’s got all the audiophile virtues I’ve described in my previous...

www.audiosciencereview.com

 

[fpitas]

Marketing-wise, I have to guess they are trying to weld the audiophile allure of class A, which has no crossover distortion, to that of class D (which also has no crossover distortion).

 

[Vincent Kars]

Reminds me of Devialet ADH Technology, a combination of class A and D both driving the same output terminals.

 

[fpitas]

Reminds me of Devialet ADH Technology, a combination of class A and D both driving the same output terminals.

https://www.devialet.com/en-us/amplifiers/expert-pro/expert-pro-technologies/hybrid-amplification/?srsltid=AfmBOorQv8FpCS4WYpbD6UjgSMBF1Pt2XXYQP5MNHRppuP7qW5kMg3Ou

Interesting I guess, but it's still not clear what is achieved compared to modern Purifi or Hypex amps.

 

[audio_tony]

They write about that they have a patent

It looks like it's an old (1997) patent (US5825247A) if this is the correct one.

US5825247A - Electric power amplifier and method for its operation - Google Patents

An improved power amplifier having complimentary power transistors connected in push-pull arrangement, and having a bias voltage source coupled to the transistors for generating a transverse idling current flowing through the complimentary pair of transistors. A regulating, feedback control...

patents.google.com

I have attached the PDF.

 

[Redacted]

It's all made up!

As soon as you see "The aim was to unify the advantages of the class A technology as well as the class D technology without their disadvantages." you know they are off into hyperspace without a ticket home.... And their published, but not (AFAIK) independently verified measurements don't show much to pop any eyeballs.

It does not seem to have taken over the word in the last (nearly) 30 years....

 

[fpitas]

It's all made up!

As soon as you see "The aim was to unify the advantages of the class A technology as well as the class D technology without their disadvantages." you know they are off into hyperspace without a ticket home.... And their published, but not (AFAIK) independently verified measurements don't show much to pop any eyeballs.

It does not seem to have taken over the word in the last (nearly) 30 years....

Yes, perhaps long ago that scheme offered something.

 

[egellings]

Marketing-wise, I have to guess they are trying to weld the audiophile allure of class A, which has no crossover distortion, to that of class D (which also has no crossover distortion).

AB done right won't have any, either.

 

[fpitas]

AB done right won't have any, either.

It used to, a few years back. But yes, these days it's far better.

 

[DonH56]

Seems like marketing-speak to me. I've never heard of class N as they describe but similar schemes have been around for decades, e.g. some 1970's amps promising "class-A performance" by utilizing a small class A "helper" amplifier in parallel with a class B high-power stage, and similar schemes by a number of manufacturers ("current dumping" and so forth). Personally I am glad the ultrawideband fad has (mostly) faded away. The last thing I want in my audio system is an amp that can pass 1 MHz to my speakers.

 

[egellings]

Agree. Why ask for a drop forge when all you need is a tack hammer?

 

[pma]

Somebody who has heard of class ND?
It would be a combination of Class A and Class D, but for me it's abracadabra: About Class ND

I have read the link briefly. Sounds like a BS to me.

 

[fpitas]

They'll sell a few to audiophiles who imagine class D is flat-sounding, or whatever the adjectives are this year.

 

[voodooless]

It’s just a class G/H amp with wide bandwidth with a circuit to keep output stage bias constant. Might be somewhat innovative, but the numbers aren’t super impressive, other than the massive output current capacity.

 

[Sokel]

Reminds me of Devialet ADH Technology, a combination of class A and D both driving the same output terminals.

Peachtree also combined them (an "audiophile" class A buffer followed by an ice 1200as2) but the language was definitely less flowery.

 

[KSTR]

Interesting I guess, but it's still not clear what is achieved compared to modern Purifi or Hypex amps.

Usually the idea is to use a high current (10's of Amperes) but low voltage (like only +-10V or so) class-A analog circuit core. To augment the voltage range and keep the power dissipation in check, the rails of the class-A amp are modulated with the signal. So, basically a fancy SMPS/PWM tracking power supply.

The Ella amp from Mircea Naiu is following this concept.

Devialet's scheme is different, though.

 

[fpitas]

Usually the idea is to use a high current (10's of Amperes) but low voltage (like only +-10V or so) class-A analog circuit core. To augment the voltage range and keep the power dissipation in check, the rails of the class-A amp are modulated with the signal. So, basically a fancy SMPS/PWM tracking power supply.

The Ella amp from Mircea Naiu is following this concept.

Devialet's scheme is different, though.

Very well. But what does it achieve, beyond simply using say, a Purifi amp?