I was seriously considering the MCH-K38 until I dug deeper into the specs and also find it only has a one year warranty so now I'm not so sure... so convince me.
For us this is a BIG purchase and will be an integral part of our daily TV watching, music and home theater, in this household you could almost call it "mission critical".
1. The Power specs on the MCH-K38 are very vague, vague specs like these immediately makes me suspicious.
From the manual:
Power: 8 X 210W at 8 & 4 Ohms / 4 X 400W @ 8 & 4 Ohms
Is that 1 channel driven at 1kHZ or all channels driven from 20Hz to 20kHz, or something in between and at what THD???
2. In the pictures I can't see any visible chassis ventilation. Is air fan forced out the bottom or something?
3. With only a one(1) year warranty I wonder how reliable this thing is going to be.
How long repairs take?
The cost of out of warranty repairs?
4. The manual states "Music emerges from a pristine background..." but with Signal to Noise Ratio: > 80dB doesn't sound like a quiet amp to me.
Please refer to the users's feedback no the long MCH-K38 topic in this forum about the sound quality etc etc.
The warranty should be two years. It has an error in the manual.
Long time NuForce customers (and now NuPrime) know that our repair cost is extremely low. Typically $50 to $75 labor plus parts at cost+
We don't use air vent which is an ineffective way to circulate (it doesn't) heat. All Nuprime products conduct heat directly to the top of the chassis. So yes, top cover getting hot is a very good thing.
THD rating is independent of channel, it is the distortion of the amp. For new generation of amps, THD spec has practically become irrelevant. Anything below 0.1% is not meaningful. The reason is that we can't hear it, and for some amp's design, to provide warmth or tube sound, even order harmonics is added and that increase THD measurement (even harmonics is pleasing) by tiny amount (perhaps from 0.005% to 0.01% for example). In the early days of Class D amp, around 2005 to 2012, we still publish THD plots vs power (0.5W to max power), and THD vs freq. But with these new generations of amp, we stop publishing the plots. I think we will probably publish something just for completeness. Typically THD spec is @1kHz. The THD vs power plot will show the continuous THD changes with respect to power. Typically THD could be at 0.5% at 0.5W, and lowered to 0.01% at 10W and slowly go up to 1% at max power. The Max Power rating is always at 1% THD but a lot of consumer audio spec it at 10% (that will be awful). For these new generation of amps from NuPrime, the THD remains very low at < 0.1% throughout the listening frequency.
MCH-K38 has a 1000W power supply and the typical power rating for multi channel amp is 2 channel fully driven with other channels partially driven. But a lot of companies spec the full power for just one channel driven. In any case, with the 1KW power supply, there is sufficient power for the spec.
Read this FAQ about why the same power for 4 and 8 ohm: http://www.nuprimeaudio.com/index.php/guides/faq.html#faq_18