2. amps-preamps
  3. 156346-1453

Discussion of Class D Amps Application & Experiences

With all the time off that our current situation has allowed recently, I became intrigued by the idea of class D amplification. I have always been against this type of amplifier but the more I have read the more I have also learned. There are lots of threads here on this subject many of which result in arguments about which amplifier class is better. I do not want to do that here. As I consider a class D amp I need to let you know that I currently use a fairly powerful class A/B SS amp and pre-amp into an efficient pair of speakers rated at 4 ohms. My choice of equipment has always been focused on musicality over absolute detail. I want the music to sound natural and not sterile. I seem to have achieved that sound. If I switched to class D amplification that would also be my intended goal although a bit more refined detail would be fine. I have considered pairing the amp with a tube pre to help achieve my desired sound. So why would I change? My goal would be to save money over my current gear while maintaining my desired sound.

I have researched brands such as Nord, Primare, AGD & Nuprime. I have also looked at brands such as Jeff Rowland & Merrill but those are way out of my price range. My target would be $6000 - $7000 or less. I'm about performance not price. So given that background information I would like to hear from those who have made the leap, what your experience has been (likes and dislikes), what amp did you replace and any comments about one brand over the other. Your experience with demos etc. Do you use a tube or SS line stage?
Thanks
128x128falconquest

Showing 3 responses by atmasphere

atmasphere's avatar
atmasphere
11,640 posts
 
Because of their high frq noise, Class D amps can be a problem for tweeters with wide band frequency response and high frequency break up. Excess energy (not music related) can cause the breakup to induce distortion.
This statement is entirely mythological. Class D amps do put out a small sine wave called the 'Residual'; even with a powerful amp the residual is of no concern to any tweeter.
atmasphere's avatar
atmasphere
11,640 posts
 
So, based on your response would you say this a 10% improvement? 20%?
Hard to say in that regard! If properly engineered, its probably not that big a deal, as MOSFETs have gotten faster in the last few years since the GaNFETs were introduced. @arion  makes extremely good points in his post; this reflects my own experience. Some class D amps are extremely boring, some are bass shy (usually older units) and others sound extremely musical (mostly newer units).
atmasphere's avatar
atmasphere
11,640 posts
 
Is gallium nitride a game changer
No- but it **is** a game improver :)

They allow for faster switching times, but in practice they work even better if you take advantage of their ability to turn on and off so much faster- this helps to minimize dead time constraints. Dead time is a constant regardless of switching frequency; therefore there is a quickly diminishing return if you simply use them to switch at a higher speed!
More to discover