Mytek slams Hypex in Stereophile Amp Review

@nugat

The website is incomplete, and misses the nc1200 :

https://www.stereophile.com/content/theta-digital-prometheus-monoblock-power-amplifier

And... why does 85C matter? All amplifiers are thermally limited. There’s no evidence that the Hypex modules cannot handle their rated power for extended periods of time if properly cooled.

https://www.stereophile.com/content/theta-digital-prometheus-monoblock-power-amplifier-measurements

The same is true for ICEpower modules. Stick them in a closed wooden box and they are not going to be able to perform to their spec as well as in fully heat dissipating enclosures.

On the other hand, in a normal enclosure, I defy you to get those amps anywhere near 85C/185F

All these class D companies utilize modules from several main suppliers which they modify to their own tastes... Yet, NuPrime manufactures their own modules and is the best Class D I have heard with the NuPrime ST-10. And, that is not even their best. People overlook this company not realizing they stirred a lot on interest in Class D when they were NuForce, now NuPrime.

NuPrime does not manufacture their own modules. When pressed on who their supplier for modules was, they refused to answer. That does not mean that they aren't actively involved with the engineering types of decisions. It just means that they are not a semi-conductor company. 

@erik_squires
NC1200 is for select customers only, and has been mostly replaced by NC500. They have the same power specs for 4 and 8ohms, the 2 ohm power output rating is higher for nc1200 .Datasheets can be easily googled. Bruno Putzeys designed all n-cores with "the same sonic signature", which did not help the NC1200 "high-end" priced unit.
Icepower 1200AS has a peak power rating of 1250wpc (4 ohm, 1kHz, THD1%) however "continuous output power without thermal shutdown" is 280 wpc for the same signal (page 11 of the manual). The test is conducted with the module mounted on an additional heatsink with Rth=0.8 K/W, free airflow (page 11).
Let’s keep in mind 1kHz sinewave is not music. AES/IEC recommend pink noise over a decade (IEC 40hz-5kHz) with a crest factor of 6dB to imitate a typical musical program.

Helomech: My experience is with Rogue’s Hypex-based Sphinx and Pharaoh. Neither could produce the lowest octave of my Monitor Audio Silver 8s (not the most efficient speakers, but certainly not anywhere near the worst). The same applied with my Epos Epic 2s - fairly efficient speakers. My $300 Yamaha embarrassed those amps when it came to bass.

I'd like to share a contrasting viewpoint to Helomech's.  I've had several amps driving my Magnepan 1.6s/1.7s over the years.  Of course, these speakers demand lots of current from an amp.  I had never given much attention to Class D amps, as most that I had previously heard sounded somewhat sterile to my ear.  Then I dropped a Rogue Sphinx into my system and my jaw dropped.  It was not only musical, but had excellent dynamics and power.  This was especially true in the bass.  It was difficult for me to believe that such a budget amp could mate so well with the Maggies.  I attribute some of the musical nature of this amp to the tube preamp section.  Some of the dynamic power may be due to its hefty linear (as opposed to switching) power supply.  In any case, it's an amp worth auditioning even if your budget can afford more.  BTW - I also tried the Pharaoh in my system and found it wanting.  There's something special about the Sphinx, at least in my system's configuration.  It's certainly not lacking power, including in the bass region. The folks at Rogue are great to deal with as well. 

Let me add that I've always respected Yamaha products.  Great value for the money.  Back in the VHS days, I would only buy Yamaha players.  More recently I purchased a Yamaha sound bar for my family room's Sony TV.  However, I'd be somewhat shocked if one of their $300 amps can best the Sphinx.  A model number would be helpful...  

Best to all - Michael