Class D at low volume

I've been into high end audio since 1970,and these class d amps wyred for sound and nuprime/nuforce are killing my very expensive WYETECH ruby

Serge,

I agree with the previous repliers that the class D amps I've used perform very well at low to high volumes. In fact, this was one of the characteristics I was pleasantly surprised with when I installed my first class D amp in my system, a ClassD Audio SDS440-CS amp; I quickly noticed that the full frequency range, from deepest bass to highest highs and all frequencies in between, was presented in proper perspective no matter what level I played back at. This was a revelation to me. My prior amp was a class A/B Aragon 4004 that outputted about the same power (400 w into 4ohm speakers) but was many times larger, heavier and hotter. I would typically play music at high volume, with the Aragon, to attain what I considered to be the proper frequency response from bass through treble. I quickly realized the class D amp was different; the frequency response was well balanced at low volumes up to extremely high volumes. My wife was actually the first to notice I was playing my music back at a somewhat lower volume with the new ClassD Audio amp.

This issue reminds me of the 'Loudness Controls' found on receivers back in the 1970's and 1980's, which boosted the bass and treble when listening at lower volume levels to compensate for their perceived absence at lower listening levels. In my opinion, the class D amps that I've heard have no need for loudness controls since they maintain a proper frequency range perspective no matter what volume level is chosen. I'm not suggesting these amps boost the bass and treble, just that they get it right somehow.

I am not an audio engineer but I have a theory why class D amps seem to have such good frequency response that maintains proper perspective at various volume levels:

It's my understanding that class D power conversion modules typically use high levels of global feedback. The input signal is constantly being compared to the output signal (thousands of times per second) prior to the output signal being amplified. The output signal is only sent to be amplified once it matches the input signal and any necessary adjustments have been made. This high level of global feedback, which designers of more traditional amp topologies typically try to avoid at all costs, is a mainstay of class D amp design. My theory is that this high reliance on high levels of global feedback is responsible for class D amps' astounding neutrality and their performing so close to the ideal of 'a straight wire with gain'. Also, my theory is that this design results in excellent frequency response at all volume levels.

As I've stated I have no technical training on amplifier design or electronics. The above is based on personal reading about class D amplification combined with any small amount of rational thought and common sense I may possess. I may have this entirely wrong, however, and would welcome comments and thoughts on my theory from those with more technical knowledge on class D amps than myself.

Regardless of my theory, I do own 3 class D amps (D-Sonic M600-M mono-blocs, a stereo ClassD audio SDS-440CS and a stereo Emerald Physics EP100.2SE operated in bridged mono configuration) and can confirm that all perform very well at all volume levels as unanimously reported from others thus far.

I would suggest you won't be disappointed, especially considering many class D amp sellers offer in-home trial periods to ensure your satisfaction.

Good luck,
Tim

Thanks to everyone who answered. It sounds like class D could be the way to go. I think I can answer the second part of my question: 1000-watt pro amps will be too noisy on Klipsch Forte II at low volume no matter the topology.

Thanks Noble100. Speaking of feedback, what do you think of Benchmark AHB2.

Thanks Pavpet,

"I've been into high end audio since 1970,and these class d amps wyred for sound and nuprime/nuforce are killing my very expensive WYETECH ruby"

How long have you been listening to wyred? Where do wyetechs fail in comparison?