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
falconquest

Showing 11 responses by djones51

The most neutral Class D amplifier at the moment would be one that uses Purifi Amp modules at least they are the best measuring after that the Ncore modules. As far as neutral amp with detail I haven't seen one that betters the Benchmark AHB2 With SINAD of 113@5Watts 4 Ohm but that's class AB.
I wouldn't worry to much about the op amp the stock TI LM 4562 will measure right there with any discrete sparkos or sonic imagery. The newer iterations of Class D show better bench numbers but when you start getting into harmonic distortion numbers <-100 you're not going to be able to tell any difference anyway. Adding tubes to Class D amps seems self defeating to me you're adding distortion to an amp made for neutrality. The best at giving great detail without fatigue I have heard are amps with Purifi but Hypex is very close I haven't heard  ICE amps so they could be better though the few  measurements  I have seen on them aren't as good.
The best at giving great detail without fatigue I have heard are amps with Purifi 


Sorry maybe you missed that in my post I get carried away sometimes. I think these Class D amps are very good but I went back to Class AB. I liked the amps I heard with Purifi and Hypex but from just my subjective opinion I like the sound of AB. I've had McIntosh, B&K old ones, Micromega, Anthem. I'm  not getting into an OP Amp discussion,  I've heard different ones I couldn't tell the difference the measurements are within 1% of each other on the ones mentioned here. Maybe my ears aren't good enough.  Nords are good but I would advise if you get one to try, take the cover off and make sure they didn't wire the speakers wrong, yes I've seen that. March Purifi is good VTV is another I would look inside the XLR might have pin 1 wired wrong and no ground on the mains. NAD doesn't sound bad good detail  and soundstage they're coming out with a new Purifi the M33? Need to watch their build quality as well. 
Another Class D that looks like it could drive most any speaker but I know nothing about is the Anthem M1.  They look interesting.  Pair of monoblocks are $7000. 
The new NAD M33 that uses the Purifi amps looks interesting.  I would avoid "modded" versions of kitchen table builds.
An air coil will have more resistance than ferrite unless it's huge. 3000 watt power supply is crazy,  600 watts is plenty for a purifi module, use a 1200 watt on dual. 
There is post filter feedback on these self oscillating amps do not touch the coil, others do not buy an amp where some nut has messed with the coils.
I'd like to hear Kii 3 or Dutch and Dutch 8c both which use class D one of those might be my next speaker.