Class D

in the GHz range

or even GHz.

You really think these don't say the same?  He clearly said,  "or even GHz".  That is a silly statement that shows a clear lack of understanding of the fundamental way in which Class-D works.


The PUTZ is you George and that is being kind.  Is that the level of name calling YOU need to use when you have absolutely 0 ability to form a proper argument?  That says far more about you than about me.

As Atmasphere has clearly said, and as actual measurements have shown, you don't need multi-MHz and certainly not GHz switching speeds to not have phase shift or switching noise in the audio band.  YOUR knowledge is evidently sorely lacking in this area.  Common sense would tell you that signa-delta DACs don't need to "switch" in the GHz range in order to not have switching noise in audio band. It should tell you that. What that tells you is a mystery.

I think Cyrill Hammer (of Soulution) https://soulution-audio.com/
knows more about solid state circuit design in his little toe than you and ralph combined could wish to know in your lifetimes.

Given his comment about 1GHz for Class-D, that statement you just made is obviously not true. I would say it is self evident to someone who understands the technology with any degree of competence (that would exclude George), that Atmasphere and I, on this area, seem to know far more.

I am sure there are areas of circuit design that Cyrill is more competent than I. I am also pretty confident there are areas where I am more competent, and again, that ludicrous GHz comment makes me question who is the high powered technical talent at Soulution. A link to a website proves nothing. Let’s do a little digging ...

When Audiolabor went under, Cyrill and Roland hired its chief designer Christoph Schürmann to develop their own series of amps, preamps, and CD players. Costs were no object; bullet-proof sonic excellence was. What the boys from Dulliken were after was the inherent musicality and low time-related distortion of tubes combined with the high current/drive capability and low THD of solid-state. What they wanted, in a nutshell, was an amp with all the virtues and none of the vices of both technologies. What they wanted was an amp with no pronounced sonic signature of its own.

It took Schürmann better than half a decade to pull off this little trick.

Darn, I must be clairvoyant! ... or just experienced enough to know people who really know what they are talking about and those that do not?


Then again, based on his work experience which has been more on the business side, less on the technical, maybe I was giving too much credit?

Experience

• Business Unit Manager

  soulution

  Dates Employed Aug 2002 – Present Employment Duration 18 yrs 6 mos Location Dulliken
• Owner

  Company Name

  Spemot AG

  Dates Employed Jan 1997 – Present Employment Duration 24 yrs 1 mo Location Dulliken
• Project Leader

  Company Name

  The Boston Consulting Group

  Dates Employed Aug 1997 – Aug 2002 Employment Duration 5 yrs 1 mo Location Zürich
• Mitglied der Geschäftsleitung

  Company Name

  SWISS COMBI - W. Kunz dryTec AG

  Dates Employed Aug 1992 – Jul 1997 Employment Duration 5 yrs

I will give him props, even if just repeating what his designer said,

Cyrill Hammer: For a “solid-state” amplifier design the speed (e.g., bandwidth) of amplification is one of the most important criteria. This speed or bandwidth has nothing to do with the MHz-range frequencies that can be reproduced by such an amplifier; the bandwidth is required to make the “feedback loops” of solid-state designs work properly.

Hey @atmasphere , sound familiar? ... of course, I take exception to their claims to be pioneers in either recognizing this or designing with this in mind. A friend did an app-note in the 90’s on a current feedback audio power amp topology that accomplished this. Of course op-amps have been doing this for quite a few decades as well.

Sorry, @zappas for derailing your thread, but @georgehifi has been on a one man crusade or spreading misinformation w.r.t. Class-D amplifier. He single handedly has spread more misinformation on this topic on this site than everyone else combined. 

Please show what you’ve done in solid state amp design, that can even come anywhere near close to Cyril Hammer’s Soulution range of power amps. You should at least believe him about Class-D switching frequency if not me.