MCH-K38 - Reliability, Warranty, Detailed Specs?

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JimW

  • Jr. Member
  • Posts: 6
MCH-K38 - Reliability, Warranty, Detailed Specs?
« on: 9 Sep 2016, 07:13 pm »
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".

Questions:
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.

Answers to these questions and any comments will be welcomed and greatly appreciated.

Thanks

J

rustydoglim

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #1 on: 9 Sep 2016, 07:54 pm »
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".

Questions:
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


srb

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #2 on: 9 Sep 2016, 09:37 pm »
The warranty should be two years. It has an error in the manual.

In another topic on the MCH-K38 back on September 5 you also said "I think MCH-K38 warranty should be 2 years, the manual has an error".

I keep several websites up to date and find I can update a webpage or PDF and replace it on the website all in just a couple of minutes, yet I see the manual has not been updated and it does seem like a very important distinction.

JimW

  • Jr. Member
  • Posts: 6
Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #3 on: 9 Sep 2016, 09:41 pm »
In another topic on the MCH-K38 back on September 5 you also said "I think MCH-K38 warranty should be 2 years, the manual has an error".

I keep several websites up to date and find I can update a webpage or PDF and replace it on the website all in just a couple of minutes, yet I see the manual has not been updated and it does seem like a very important distinction.

I agree, if it's 2 years, commit to it and put it in writing! I'm waiting.

Eric Gustafsson

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  • Posts: 67
Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #4 on: 10 Sep 2016, 08:29 pm »
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.

This was strange as my MCH-K38 has chassis ventilation at both top and bottom.  :o

I.Greyhound Fan

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #5 on: 10 Sep 2016, 10:53 pm »
I agree, if it's 2 years, commit to it and put it in writing! I'm waiting.

Why not 5 or 10 years like companies such as Pass and Parasound?  If I am going to drop $3K on a product the company should have confidence that it will last.

I have some interest in this amp and the Ref 20.

rustydoglim

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #6 on: 11 Sep 2016, 08:07 am »
We are all too busy with stuff and I admit, updating the manual and uploaded it to the website is a low priority.
Here's what you guys need to know about NuPrime business model and warranty in general.  See the About Us on the website. We price our product almost like factory direct pricing but with high-end service.  Come on, who sells a reference class mono/stereo amp like STA-9 for $649 ?
It is without question that our products are a fraction of what similar performing products would have cost you.
So, we could raise the price of a product by 15%, and increase the warranty coverage to 3 or 5 years. But if we are not expecting to have any problem down the road, and we keep our service and parts cost very low, why should we ask every customers to pay for the few who might ended up with failure?

We have never thought about this issue until now. I think it will be a good idea to offer extended warranty coverage for those who want a peace of mind.

Oh, I was thinking about the other amps that have heatsink attached to the chassis. For MCH-K38, it is too tall and the module placement doesn't allow to conduct heat directly. So ventilation is the next best option.

rustydoglim

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #7 on: 11 Sep 2016, 09:10 am »
I added the "Warranty: 2 Years" to MCH-K38 product page.

Eisener Bart

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #8 on: 11 Sep 2016, 11:07 am »
Come on, who sells a reference class mono/stereo amp like STA-9 for $649 ?

Nobody:D

Eisener Bart

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #9 on: 11 Sep 2016, 11:08 am »
Oh, I was thinking about the other amps that have heatsink attached to the chassis. For MCH-K38, it is too tall and the module placement doesn't allow to conduct heat directly. So ventilation is the next best option.

Active ventilation? Not good idea.

JimW

  • Jr. Member
  • Posts: 6
Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #10 on: 12 Sep 2016, 11:33 pm »

Oh, I was thinking about the other amps that have heatsink attached to the chassis. For MCH-K38, it is too tall and the module placement doesn't allow to conduct heat directly. So ventilation is the next best option.

I was just going by the pictures of the MCH-K38 on primeaudio.com, no vents.

On the faith that you are a man of your word and there is a 2 year warranty I ordered one from Sonic Unity not knowing that it would ship from Taiwan. Looks like I'll probably have to pay United States duty/customs taxes and fees too  :( .

JackD

  • Full Member
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Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #11 on: 12 Sep 2016, 11:43 pm »
I've received three Nuprime pieces from Taiwan and no fees on any of them

srb

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #12 on: 13 Sep 2016, 12:13 am »
On the faith that you are a man of your word and there is a 2 year warranty I ordered one from Sonic Unity not knowing that it would ship from Taiwan.

Although the online user manual hasn't been changed yet, as mentioned in a previous post, the 2-year warranty has been noted and added to the MCH-K38 product page Specifications section.  You can take a screenshot if you want to "have it in writing".

http://www.nuprimeaudio.com/index.php/products/amplifiers-and-preamps/multi-channel-amps/mch-k38.html

 

John Casler

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #13 on: 13 Sep 2016, 12:39 am »
I was just going by the pictures of the MCH-K38 on primeaudio.com, no vents.

On the faith that you are a man of your word and there is a 2 year warranty I ordered one from Sonic Unity not knowing that it would ship from Taiwan. Looks like I'll probably have to pay United States duty/customs taxes and fees too  :( .

As above, no "additional" fees other than shipping.


rustydoglim

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #14 on: 15 Sep 2016, 05:18 pm »
I was just going by the pictures of the MCH-K38 on primeaudio.com, no vents.

On the faith that you are a man of your word and there is a 2 year warranty I ordered one from Sonic Unity not knowing that it would ship from Taiwan. Looks like I'll probably have to pay United States duty/customs taxes and fees too  :( .

No, you should not have to, Rick probably told you already.

JimW

  • Jr. Member
  • Posts: 6
Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #15 on: 15 Sep 2016, 08:46 pm »
I received the MCH K-38 and while unboxing I noticed what sounded like a screw or something metallic rattling around loose inside the chassis. I of course don't dare plug it in and I don't want to open it and void the warranty.

I will say that shipping from TW to the Dallas, TX area was pretty fast and got here without any apparent damage. And, unlike the pictures it does have vents in the top and bottom. Too bad I can't use it.

 

rustydoglim

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #16 on: 19 Sep 2016, 04:26 am »
JimW has kindly decided to open the cover and put the loose screw in.

smishsmorshen

  • Jr. Member
  • Posts: 3
Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #17 on: 22 Oct 2016, 03:20 am »
@JimW

Just curious if you've had a chance to give it a good listen since it's been a few weeks. Would love to hear your thoughts/impressions.

Getting my unit next week ^_^


sonicxtc

  • Full Member
  • Posts: 302
Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #18 on: 27 Dec 2016, 10:21 pm »
Hi,
Is the warranty on NuPrime products transferable?
If so, what's involved in the process? Please explain.

Thank you.

rustydoglim

Re: MCH-K38 - Reliability, Warranty, Detailed Specs?
« Reply #19 on: 31 Dec 2016, 12:40 am »
I answered in his email but for others, it is transferable. Keep the receipt. Without the receipt, we can use the serial number to locate the ship date from the factory.