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Class D Technology

So I get the obvious strengths of Class D. Efficiency, power output & running cool which allows for small form factors. I also understand the weaknesses somewhat. 1. Non-linear & lots of distortion that needs to be cleaned up with an output filter. 
So my question is, if it weren't for efficiency & power, would there be any reason to own a Class D amp? Do they beat Class A in any other categories that count for sound quality?  
seanheis1
guidocorona
4,298 posts
 

Hi seanheis1, as far as I know, preamplifiers cannot be implemented in class D... I have been told that their topology is the equivalent of class A. However, Preamps with regulated SMPS do exist... ANd the ones I have listened to are rather wonderful: e.g. Rowland Corus and Criterion, Rowland Capri and Capri S2, and the preamplifier section in the Continuum S2 integrated.


G.

guidocorona
4,298 posts
 

WOops... You are correct George: Theta Prometheus is indeed based on full NCore1200, not on the lower end NC500 module... My bad!!!!


G. 

kijanki's avatar
kijanki
4,432 posts
 
Maybe we will start seeing Class D preamps then...

Perhaps.  Delta-Sigma D/A, A/D converters, SACD and DSD are already class D.
georgehifi's avatar
georgehifi
10,312 posts
 
NCore1200, not on the lower end NC500 module... My bad!!!!
The NC500 is their newest most advanced module not mentioned anywhere on their site, avalible only to selected few, and is in the BelCanto Ref 600 monos, but BelCanto used their own filters instead of what comes with it.

Cheers George
noble100's avatar
noble100
2,419 posts
 
atmasphere,

     Good points about class D amps being immune from noise due to their modules or the  smps but that  RF radiated noise could be a problem for other equipment nearby and even pacemakers and other electronics either within or separate from one's system.   I was warned of possible RF radiation about the same time I purchased my first D amp.  

     I read a tip that a portable am/fm radio could be used as a crude detector for any RF radiation emitted by a component. The instructions were to tune to a spot on the dial that is between stations that is relatively quiet,  turn the volume control to about 3/4 and  move the portable radio slowly around all sides of the tested component.  The point being that if the component is radiating any RF signals/interference it will be indicated by the portable radio producing a change in sound once it is in the proximity of  any component being checked.  I did this test on my D amps on the am and pm bands (since the tipster didn't specify a specific band) and I noticed no changes in sound coming from the portable radio but I hope this was a valid method for RF radiation detection.  

     Seanheis1 stated:

" Maybe we will start seeing Class D pre-amps then... "

  My understanding is that class D pre-amps would not have  any significant advantages over traditional tubed and ss pre-amps,  that I believe all operate in class A.  This is mainly due to the signal amplification being so small in class A  pre-amps  that heat and energy efficiency are not significant issues as they are in tubed,class A and class A/B amps.  

Tim   
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