Opinions on Nuprime vs D-sonic vs Red Dragon vs Class D Audio

I'm looking to try a class D based power amplifier. Please share your experiences with the NuPrime, D-Sonic,  Red Dragon or Clas D Audio lines of power amplifiers. Thanks!
Thanks Kenny. I've been participating in that great thread, but I felt bad about going off on tangents so I thought I'd ask it separately. I still may pose the question there though!
This is a question I would like to know the answer also. Hopefully, someone had a chance to compare. 
Hello all,

I have over 500 hrs on my S-500 and thought I might comment a little about it.I think it's a step up in Sound vs nc400 and ref600m,these are the 3 class d amps that I own and I have access to more through a local audio club where we lend and or borrow equipment or occasionally listen to each other's systems.

I have been using a bel canto pre3 with all the diff. amps just to make a even playing field,the pre 3 is a pure water no coloration preamp.

The S-500 is the best class d amp I have had in my system and it has the warmest most engaging midrange with very sweet nicely extended top end that has more air and separation with the individual instruments making the entire frequency range very coherent.The bass is equally as good maybe better than my other class d amps listed.

I borrowed a Nuprime st10 to try out and found it too be a very close match to the S-500,with the nod to the S-500 for the best overall sound especially the midrange.

Offcourse this is in my system with my ears and judging the musical presentation that I prefer.

The next test will be comparison with a modwright kwa100se that I have owned for a few years but I haven't used it in about 3 years,I have loaned it out to club members though.I know it's a very good amp but can it equal or beat the S-500,only time will tell.

So many very good choices out there nowadays,

Thanks Kenny,  nice to hear that someone has done some comparisons firsthand. Even though its through your ears, its very helpful information.  If you ever hear of someone wanting to let go of their  Red Dragon Stereo amp, please let me know!  Have you listened to any of the other Nuprime amps?  Theres quite a bi price jump from their other models to the ST10, so I;m wondering if the sound is that much of a jump too.
Had the IDA-16 in for a trial and found it to be unlistenable during break in period and still harsh and dry treble after break in.   

Also got a chance to go head to head with some class AB amps vs. my NAD M12/M22 combo that I thought sounded pretty good and the class AB amps all sounded better.  They made M12 sound dry and analytical by comparison.  This was in a well damped dealer showroom that really lets you hear minute differences in gear.

I'm done with Class D.

Pick one with a 30 day return policy and don't buy in to the break in talk. If they needed to be broken in the amp maker would do this in advance. 
My Primare I32 integrated won out over an older Creek Classic 5350SE that was very well reviewed, a Belles Aria, and a Belles Soloist.

I realize that my humble integrated is not in the same echelon as high-end separates; however I believe that Primare is a company whose products employ some unique engineering and perform very well with about 24 hours of breakin. Notes just seem to appear out of nowhere and music is so enjoyable. On some of my better recordings it's like hearing a different, better version. (I won't say 'hearing them for the for the time.' That's bullshit.)

So you might want to add something like the Primare A60 to your list. I know how a list can grow and become paralysing; but I'm glad I took the time to listen to this product from a manufacturer I had never even heard of before. 
Just want to give a nod to Wyred 4 Sound (W4S).  I run a W4S DAC-2 straight into a ST-500 Mk II.  Got a "combo" deal from The Music Room through AGon.  I did a lot of reading (probably what you're doing) then became exhausted with all the research and opinions (there are lot, as i'm sure you've discovered).   So, I just took a dive in and am more than pleased.  Lots of oomph in my system but not bright.  Has been great for all kinds of music.  

The other reason I "invested" in W4S is that they are constantly offering upgrades to their existing products.  The upgrades are waaaaay more cost effective than purchasing a whole new X (fill in the blank).  When the upgrade bug bites or technology changes I can change with it.  

In the end, I think you can't lose out with what you're looking at.  

I like some of the ideas above where you can purchase something and send it back.  W4S does this too.  They are having what they call a "B-stock sale" and are offering pretty hefty discounts right now.  

Hope this helps.  Good luck.


I can’t give you opinions about how NuPrime compares to other class-D manufactures. But I can tell you that my NuPrime IDA-16 is one of the finest amps I have listened to.

As has been mentioned class-D has a lengthy burn-in process. My IDA-16 sounded powerful right out of the box but a bit rough. At about the 300 hour mark it started to open up and also started to refine and smooth out. Things progressed and improved steadily and then at about the 500 hour mark there was another big improvement; it opened up big time with the mids on up getting fuller and fuller and the treble smoothing out. From the lower mids down it’s one of the best amps I’ve heard.

Anyways, that’s a bit of my experience with NuPrime. Great sound, great build quality and excellent customer service.


I had Red Dragon amps in my system for while, some moons ago.

They were dimensional and a joy to listen to. Not analytical, but still detailed. I liked them a lot, but wasn't in the market for amps at the time.
Thanks guys I really appreciate the opinions. Glad to hear that it seems the ones Ive narrowed it down to all seem to great performers. Now I have to wait for the right price to pop up!
The only Class D amps I ever tried in my own system are the Arion Audio RS-500s.  I thought they were really good, powerful and non-digital sounding.  I think they come with a home trial, and owner/designer Mike Kallelis is a great guy. 
I bought the D-Sonic M3a-800S (2 x 400w) last year and haven’t looked back.

I went through two class A/B SS set-ups over the past 10 years--a NAD M3 (good built quality, sound was too muddled for my tastes) and a Bryston set-up (BP26, Byston DAC, 4BSST2 power amp--wonderful, solid, totally neutral and dead silent). Have also cycled through various speaker set-ups, Dynaudio, Paradigm Studio and Signature series, Magnepan 1.7 and 3.7s.

The Bryston set-up with the Magnepan 3.7s was supposed to be my retirement system, but when we reduced our living footprint, my listening space dropped from a 30 x 50 living room to a 10 x 12 a pocket office.

Long story short--sold off my Bryston gear and replaced it with the D-Sonic amp coupled with a passive pre-amp from Luminous Audio driving Legacy Studio HD monitors. Near-field listening only given the space constraints...

I’ve been totally impressed with the D-Sonic--dead quiet, dynamic range, fast, neutral (maybe to a fault), and of course no problem driving my Legacy HD Studios (I love the AMT folded ribbon tweeters more than even the sound of the Maggie 3.7 ribbon tweeter). Build quality is first rate and the gentlemen who runs the business is very responsive both by phone and email.

Now to be fair, I’m 60 years old with hearing loss above 7K in both ears. I think this is fairly typical for my age group. And of course I’m comparing apples to pomegranates--my Bryston kit was connected to the Maggies and Paradigms in a large room--my D-Sonic/Legacy set-up is barely 7 feet away from me.

Still, for the kind of music i love, jazz and classical piano, string quartets, female jazz vocals, etc, and given the cost to find out, couldn’t be more pleased.

I just ordered a Class D Audio SDS470C (complete kit).
Looking forward to getting it put together and powered-up!
I'll post more once I've used it for a week or so.

I've had a red dragon S500 in my system for about a year. The amp continues to amaze me. It plays with such authority and control while able to produce a nuanced and balanced sound. I've found the amp to pair well with my LS50's and my roommate's tannoy XT-8f's, fairly different speakers but similar performance. Most recently I've been using a passive TVC volume control with the S500 which really shows off the amp's ability to produce a very holographic sound. The music just hangs in the air. I found an aftermarket power cable to really improve the sound as well.

I previously had a yamaha A-S501 and a peachtree nova 150 which was a great amp, but I just prefer the S500 and the passive combo. I really think your amp choice depends on the rest of your system, especially your front end for a class D amp. My roomate has a nuprime oversampling USB DAC that just doesn't play well with the S500, whereas my NOS R2R DAC really makes the amp sing and is far more laid back.

What are your speakers and your front end and why class D?

I received my Class D Audio SDS470C;
Started to assemble it this morning; I hope to finish it soon.
Can hardly wait to power it up.
I've been listening to the my new Class D Audio SDS470C; I love it!
Gobs of power! I'm actually surprised at how good this amp sounds with a simple Schiit Sys passive preamp!
It's quite heavy for it's size.

I can't wait to hear it when I get the Tortuga LDR300 installed.


I went with a Class D, mainly because of space restraints.
I was looking at Red Dragon; but absolutely no contact from him and all of his amps were sold-out.

My front-end is pretty simple: 
Simaudio Moon 260DT CD transport.
Schiit Gungnir Multibit DAC
Schiit Sys passive preamp( soon to be Tortuga LDR300).
Speakers are JBL Studio 230 on 24" San us stands.
Pretty simple; but for a condo, just right!
Nice front end, I'll be interested to hear what you think of the tortuga vs the sys. I was using a sys before my current passive and was looking at the tortuga but ended up saving some money and going with the promitheus. Another cool passive worth looking at are the Hattor passives. They have a lot of the same functionality as the tortuga but a different methodology (ladder resistors vs LDR).

I think Red Dragon is coming out with a new series of amps so I'm sure Ryan is busy.

Never heard of class D audio but the price point is right and it sounds like you really enjoy it! I've always been interested in some of the DIY kits but just never have bit.
I am going to chime in. I have a separate thread where I was asking about the newer Classe class D. It has really impressed me so far. Does not sound like my previous experience with class d. Sounds like a very musical and accurate class a/b but with a ton of power on tap for tight and pronounced mid bass. I was very skeptical with a $4k msrp. I am very happy. However Classe tuned this amp, they did a really good job. Renewed my faith in class d. I will keep it for quite some time. 

    I'm not surprised at all that you're really enjoying your Class D Audio SDS-470C.  My first class D amp was a Class D Audio SDS-440SC that I bought as a completed amp, not as the kit version. 
     I consider Class D Audio to be the company offering the best bargains (highest sound quality per dollar) not just in class D amps (both kits and completely built amps) but home audio amps in general. 
      I only paid about $600 for my amp and it outperformed my former class AB Aragon 4004MKII, that was 3 times the size, weight and price of the Class D Audio amp.  The 440SC bettered my old amp in literally every area I considered important on my Magnepan 2.7QR speakers; a touch more power (440 w/ch vs 400 w/ch into 4 ohms), better bass, a more detailed and a smoother mid-range and treble, a lower noise floor, lower distortion levels, and better dynamics.  Both amps were roughly equal in their abilities to create a solid and stable sound stage illusion.  I'm fairly certain you're enjoying a similar high level of quality with the performance of your amp. 
      Encouraged by the exceptional quality of this initial class D amplification experience, I have since bought a few more class D amps more out of curiosity than anything else.  I bought an Emerald Physics EP100.SE stereo and a pair of D-Sonic M3-600-M mono-block amps. 
      All of the class D amps I've used thus far in my system are similar in several characteristics.  They all have  a very neutral presentation (like a 'straight wire with gain') that seemingly adds or subtracts nothing to the inputted signals, excellent bass response due to the amp format's high Damping Factors (the ability to quickly start and stop woofer drivers), exceptionally low noise floors due to very low distortion levels and very high Signal to Noise Ratios, very good dynamics due to very fast Slew Rates and an abundance of reserve power and a very detailed presentation without the presence of shrillness or harshness. 
     The D-Sonic mono-blocks are definitely the best performing class D amps, or any other type of amps, I've ever used to drive my Magnepans.  They're by far the most powerful (1,200 w/ch into 4 ohms) which may help explain their superior dynamics but I also notice other superior qualities such as their dead-quiet background noise level, increased details and neutrality that clearly reveals the varying quality levels of recordings and upstream components as well as more easily determining the different affects alternate power cords, interconnects, speaker cables or any other changes have on my system's overall sound quality.
      Due to their superiority over my prior good quality class AB amps, my combo 2-ch music and ht system now uses completely class D amplification; my original Class D Audio stereo amp drives my rear surround Infinity spkrs, my Emerald Physics stereo amp in bridged mono mode drives my Magnepan CC3 center spkr and my most recently purchased D-Sonics mono-blocks drive my main L+R spkrs.        Sorry, I haven't listened yet to the Nuprime or Red Dragon class D amps but I've read very good reviews on them from pro reviews and here on Audiogon.

Does anyone know if Red Dragon is still a viable company?  Seems they were MIA even back in early 2019 as scratcha said. 
They seem to be sold out of everything.
I have emailed them with no response for a few days.  I am considering buying a used one and don't know if there is any support to speak of from them. 
Does anyone know if Red Dragon is still a viable company?
Still dealing by the looks of these two links.

If you are lucky enough to get hold of the $800 M500 monoblocks or S500 stereo, which are always sold out.
They are basically the same poweramp/s except for the $$$$ chassis as the $10k Rowland Continuum II
That use Pascal "stroked" Sanway Chinese Class-D Pro-2 modules


From 6Moons
Jeff Rowland have been one of Pascal’s earliest customers among high-end manufacturers to release a few ‘entry-level’ products based on that module like the bridgeable 525 stereo power amp and the integrated Continuum S2. Red Dragon’s S500 beats with the same heart in a less high-end chassis

Cheers George
@evo_no_revo I'll be selling my black S500 in August if you are interested.

No word on the company, last I heard they were working on a new generation but that was some time ago. Amp is built like a tank.