Review and Measurements of Hypex NC400 DIY Amp

[pos]

There have been several SMPS 1200 and 600 design iterations over the years, so maybe current offering is more durable.
For one thing the thermal design of the SMPS1200 is better with the heatsink in contact with the case, but with some tweaks the same can be made for the SMPS600.
Maybe a simple DC-DC converter could be used to raise the VDR a bit on the SMPS1200...

 

[rajapruk]

In the test Amir did of nc400, 1 channel driven from a single SMPS measured better than 2 channels driven from the same SMPS.
Some kind of interference.
I do not know if it proves anything, but it could indicate that a separate smaller SMPS per nc400 is better than sharing a larger SMPS.

 

[rajapruk]

Btw pos, your face is starting to look old, I think you need a recone??

 

[JimB]

In the test Amir did of nc400, 1 channel driven from a single SMPS measured better than 2 channels driven from the same SMPS.
Some kind of interference.
I do not know if it proves anything, but it could indicate that a separate smaller SMPS per nc400 is better than sharing a larger SMPS.

Caution here. That was with a single SMPS600, which is rated to match the maximum output of a single NC400, not two of them. The SMPS1200 has twice the output, and so is a match for two NC400s.

 

[DDF]

There have been several SMPS 1200 and 600 design iterations over the years, so maybe current offering is more durable.

From earlier in the thread that will shed more light on the differences between PSUs, and the SMPS1200 reliability:

https://www.audiosciencereview.com/...-hypex-nc400-diy-amp.5907/page-17#post-134259
https://www.audiosciencereview.com/...-hypex-nc400-diy-amp.5907/page-21#post-135016
Hypex changed cap brands on SMPS1200:
https://www.audiosciencereview.com/...-hypex-nc400-diy-amp.5907/page-17#post-134314

 

[pos]

Btw pos, your face is starting to look old, I think you need a recone??

Sagging?
What about your double voice coils?

 

[rajapruk]

Caution here. That was with a single SMPS600, which is rated to match the maximum output of a single NC400, not two of them. The SMPS1200 has twice the output, and so is a match for two NC400s.

It was not driven hard, if I remember correctly. Just some watt per channel.

 

[rajapruk]

Sagging?
What about your double voice coils?

I can still maintain pistonic motion without breakups at a high frequency.

 

[JimB]

It was not driven hard, if I remember correctly. Just some watt per channel.

True. There was measurable improvement at 5W at 1KHz. The big difference was a drop in 3rd harmonic from -113dB to -133dB. A big drop (in a small number). Running two NC400s from a single SMPS600 does not provide best performance.

 

[phoenixdogfan]

True. There was measurable improvement at 5W at 1KHz. The big difference was a drop in 3rd harmonic from -113dB to -133dB. A big drop (in a small number). Running two NC400s from a single SMPS600 does not provide best performance.

I think the real question is whether two Mc400s would run better with a single SMPS1200 or dual SMPS600s. Based on the discussion, I don't think there's a definitive answer here. Certainly with the SMPS600s VDR, the NC400s will have cooler running, and considering, they're the most expensive components in the box, I would now personally lean toward dual SMPS600s, b/c if I needed to replace anything I'd rather it be a single 120EU SMPS than a 275EU NC400.

 

[DDF]

I think the real question is whether two Mc400s would run better with a single SMPS1200 or dual SMPS600s.

As mentioned in my second link, from what I could find from Hypex:

I went with SMPS1200 to help avoid possibility of current limiting:
- SMPS1200A400 specs qty 3 UCD4000 delivering 240W/ea into 8 ohms @ 1%/1kHz
- SMPS600 specs qty 1 NC400 delivering 240W into 8 ohms @ 1%/1kHz

 

[Filio45]

Thinking about buying two NC400 monos from audiophonics, who offer a two-year parts and labour warranty. Hopefully not..but if the smps malfunctioned outside of the warranty period, is it an easy swap over without any soldering or other adjustments? Speaking as a non diy'er, that is.

Shame that the air vent is above the module rather than smps.

https://www.audiophonics.fr/en/powe...ono-amplifier-ncore-1x400w-4-ohm-p-14155.html

 

[Julf]

Thinking about buying two NC400 monos from audiophonics, who offer a two-year parts and labour warranty. Hopefully not..but if the smps malfunctioned outside of the warranty period, is it an easy swap over without any soldering or any other adjustments? Speaking as a non diy'er, that is.

Yes, it is very easy - no soldering or adjustments needed.

 

[arboleda]

I just ordered the hpa-s400nc from audiophonics. It’s the dual 600 power supply model. Can’t wait.

 

[batfunk]

Hi Arboleda! Second! I hesitated between audiophonics nc122 based stereo amp and this one, but bad french reviews about nc122 module reliability ( power module included in causes buzz) and lack of thermal dissipation of the nc122 tight box helped me to choose.
The HPA-S400NC is way too powerful for my needs, but nc400 has slight better thd+n performance at 1 watt. Probably inaudible but who cares?
I bought the topping dx7pro too(509 euros) on Amazon france.
Somebody on the forum told me about maybe adjusting the gain of the amp and dac. What is the purpose? How I do that? My loudspeakers are 93 db sensitive, 4 ohms, 200 w max input and i listen at 70 db max 2 m away from the speakers.
Stupid noobs question: I see that nc400 works best beetween 30 and 50 watts. Can I modify this gain to use 40 watts instead of 0.133 watts(all power I need for 80 db)?
Dx7pro+nc400 stereo amp+pw link, I think I touch my hifi holy graalforev... For a few years

 

[arboleda]

Sweet. I’m away from home this week, expect my unit to arrive the day before I get back so that will be fun.

Like you, I’ll usually only use a small amount of the amps potential power.

I think if your preamp output and gain (determined by resistors in the amp?) were high enough to produce 40 watts of output then you’d get far higher decibels from the speakers than you want. But I’m still learning a lot too.

 

[arboleda]

hopefully other people can chime in on your gain questions

 

[Julf]

Somebody on the forum told me about maybe adjusting the gain of the amp and dac. What is the purpose? How I do that? My loudspeakers are 93 db sensitive, 4 ohms, 200 w max input and i listen at 70 db max 2 m away from the speakers.
Stupid noobs question: I see that nc400 works best beetween 30 and 50 watts. Can I modify this gain to use 40 watts instead of 0.133 watts(all power I need for 80 db)?

The nc400 works just fine at any power below clipping, but yes, some of us have adjusted the gain - mainly those of us who use sources with high signal levels (so signal would have to be attenuated to avoid clipping). It does require desoldering (and possibly resoldering, depending on the gain you want) a surface-mounted resistor, so you need to have nimble hands and a good magnifying glass.

See this application note from Hypex.

 

[batfunk]

Thanks, but I'm no way a technician, I barely know how to use a screwdriver.

 

[HeavyMantra]

All good here? Bought this used and I don't really know what I'm looking at