The Hifi Trajectory Of Class D Amplifiers


.
I bought my first digital SLR camera back in 2005. Film SLR cameras were still king back then. Longtime film camera hobbyists and pros thumbed their noses at digital. Ten years later, film cameras have been surpassed by digital cameras and are nearly extinct. Millions of people use cameras. The market was already in place for anyone that would advance the technology of digital photography.

With Class D amps, you don't have a marketplace the size of the camera marketplace. There doesn't seem to be enough economic incentive to spend the necessary research dollars to advance the technology to get the same sort of improvement trajectory that digital photography has enjoyed.

Anyone care to speculate how long it will take for Class D amps to consistently rival the best tube, Class A and Class A/B across the board....and do it without resorting to the stratospheric prices that current non-Class D amps are priced at.
.
128x128mitch4t

Showing 5 responses by kijanki

Couple of people reported on another thread, that Rowland's new $38k class D integrated had the best sound of NY Audio show. Feel free to keep discussing bass guitar applications.
Atmasphere, Bass amps were and often are made as cheap, crude implementation of class D, where you can get a lot of power in inexpensive portable package. Because of that many think of class D only as a crude inexpensive way to get lots of power. I'm not sure why you even brought the case of 500W class D not being able to keep up with 400W tube amp, since it is irrelevant to our discussion and refers to particular design and the way power was specified (only 6.7% difference in perceived loudness between 400W and 500W). In addition, in last decades bass amplification in larger venues got into PA system, making raw power of the bass amp relevant only for small theaters. Class D can be designed with any headroom, often has line and load regulated power supply, that doesn't sag under big loads and soft clipping similar to tube amps (whole Icepower family). In contrast, class A SS amps have very limited headroom, mostly unregulated power supply and hard clipping, but they are great example why suitability of given amp class for bass head says absolutely nothing about sound quality in home stereo system.
Mapman, there are some highly praised class D bass heads (like Ampeg micro or Gens-Benz Shuttle series) and some really bad ones, like with anything else.

To me liquid midrange of class D, that you mentioned, is closer to tube amp than SS amp sound. Other than that my class D amp is pretty neutral sounding. You like a little bit of warmth, that tube preamp gives you and I get the same from my warm sounding speakers. Either way, Icepower is a very good amp, for the money.

Class D progress, in my opinion, is related more to switching speed of output Mosfets that would allow to lessen phase shift by extending audio bandwidth. Companies like Fairchild or International Rectifiers announce new faster, higher power Mosfets every year. That is bottleneck IMHO. Everything else is only matter of integration level. It is also worth mentioning that modern class D modulator is not a simple ramp and comparator but resembles more Delta Sigma A/D converter. In fact PWM is a byproduct of Delta Sigma conversion, that appears alone as SACD. SACD is pretty much class D output (PWM) at high carrier frequency (2.8MHz) before filtering.
Rushton, I don't question anybody's qualifications but rather particular example. I'm pretty sure we can find 500W tube amp that doesn't keep up with 400W class D bass amp, but again it wouldn't be relevant to the issue we discuss (class D sound in home stereo system). If anything, class D amplifiers keep extremely well with music peaks (mentioned in many reviews) when equipped with regulated power supply (SPMS).
Bombaywalla, comparison film vs. digital SLR is very unfortunate here, since class D is purely analog with unlimited resolution.
Still, you can take equivalent quality pictures using medium frame size film camera for much less money than digital, but in case of 35mm frame film camera has no chance. Digital cameras have better resolution, lower noise, bigger dynamic range and much higher sensitivity (ISO) not to mention overall convenience.

http://petapixel.com/2015/05/26/film-vs-digital-a-comparison-of-the-advantages-and-disadvantages/