Review and Measurements of Hypex NC400 DIY Amp

[Julf]

I have a couple of Nc400 monoblocks coming next week and I have never really thought about this gain-stuff. For the time being I will be driving them with Minidsp 4x10hd using balanced output. According to the manual, I have a choice between 4v output voltage and 8v through a dipswitch on the board. How does this stuff work, what should I pick?

Go for 4 V, and even that is 6 dB too high for 400 W full output into 4 Ω, so make sure you don't turn up gain too much on the minidsp.

 

[Absolute]

Ok. The volumecontrol in Minidsp goes from - "some high number" to 0. Are those numbers usable in any sense relative to the gain numbers/volts?

 

[Julf]

Ok. The volumecontrol in Minidsp goes from - "some high number" to 0. Are those numbers usable in any sense relative to the gain numbers/volts?

Not really.

 

[Jinjuku]

Huh, www.hypexshop.com is looking like it's down

 

[Dion_Sinewave]

Huh, www.hypexshop.com is looking like it's down

That’s weird, as I just bought a few more modules a couple of days ago.
I hear that some people have difficulty with availability from DIYclassd.com but I’ve certainly never experienced it- and I have made severa separate purchases from there

 

[Julf]

https://www.diyclassd.com/ and https://www.hypex.nl/ work fine.

 

[JimB]

Go for 4 V, and even that is 6 dB too high for 400 W full output into 4 Ω, so make sure you don't turn up gain too much on the minidsp.

I needed to match mine to other amps (AHB2 at mid gain) for active three-way speakers, so I reduced the gain per standard Hypex advice. It's a little tricky, depending on your equipment and skills, but it worked perfectly for me.

 

[Julf]

I needed to match mine to other amps (AHB2 at mid gain) for active three-way speakers, so I reduced the gain per standard Hypex advice. It's a little tricky, depending on your equipment and skills, but it worked perfectly for me.

Yes, those small SMD resistors require a stable hand...

 

[rajapruk]

I needed to match mine to other amps (AHB2 at mid gain) for active three-way speakers, so I reduced the gain per standard Hypex advice. It's a little tricky, depending on your equipment and skills, but it worked perfectly for me.

Did you do any subjective comparison ncore vs AHB2? What is your opinion?

 

[JimB]

Yes, those small SMD resistors require a stable hand...

Right. And, unfortunately, reducing gain meant replacing resistors. If only I could have just added resistors in parallel.

 

[JimB]

Did you do any subjective comparison ncore vs AHB2? What is your opinion?

No. I need 6 channels of amplification to run my speakers (Linkwitz Lab Orions). I used to use 10 channels! The two NC400 monoblocks drive just the woofers - crossed over 4th-order at 120 Hz . I wanted them for their power, low output impedance and reduced cost from doing them on my own for that. The mids and tweeters got the AHB2s.

BUT!! See here!
https://www.audiosciencereview.com/...f-benchmark-ahb2-amp.7628/page-70#post-270177

 

[phoenixdogfan]

Possible? Sure. No performance benefit (other than heat sinking to the case). I use an SMPS1200A400 for two NC400s, using the Hypex connector kit, as intended.

Is there a benefit (power, reliability, or sonic) to using the SMPS1200A400 with connector in a stereo application(like the Ghent 300mm case) over say dual SMPS600N400s in the same case?

 

[Julf]

Is there a benefit (power, reliability, or sonic) to using the SMPS1200A400 with connector in a stereo application(like the Ghent 300mm case) over say dual SMPS600N400s in the same case?

Two separate power supplies are probably slightly less efficient (and thus generate a little more heat) than one single one, but that would have to be verified with measurements.

 

[pos]

Two separate power supplies are probably slightly less efficient (and thus generate a little more heat) than one single one, but that would have to be verified with measurements.

What you gain on the SMPS side (around 8W idle IIRC, depending on the revision) you loose on the nc400 side as they will dissipate 5W more each when fed with the SMPS1200.

 

[Julf]

What you gain on the SMPS side (around 8W idle IIRC, depending on the revision) you loose on the nc400 side as they will dissipate 5W more each when fed with the SMPS1200.

Ah, yes. Good point!

 

[JimB]

Two separate power supplies are probably slightly less efficient (and thus generate a little more heat) than one single one, but that would have to be verified with measurements.

Right. That is what the specs indicate. I also like that the 1200 has real heatsinking to the case, so in addition to slightly less heat produced, it gets out better.

 

[JimB]

What you gain on the SMPS side (around 8W idle IIRC, depending on the revision) you loose on the nc400 side as they will dissipate 5W more each when fed with the SMPS1200.

Yes, but the question was about a two channel case, not two mono cases. So the options are two SMPS600s, or one SMPS1200. I chose the 1200. Also costs a little less. Win/Win for me. I have made two channel amps with both the Ghent Ncore-SE(200) and Ncore-SE(300). The 300 is a bit easier to work on and has better heat dissipation (of course). It calculates out to be about the same as two mono cases with SMPS600s. The -SE(200) is smaller and is a spare, general purpose amp for me. I used the SMPS1200 in both cases (pun intended).

Or have I missed something. Are you saying an NC400 dissipates more power when supplied by an SMPS1200A400 than from an SMPS600N400? Why would that be? The 1200 outputs 63V to the 65V of the 600. Both provide Vdr. Where is the extra 5W coming in?

 

[pos]

I was specifically referring to a stereo SMPS1200 scenario here.

According to current specs, a stereo setup with one SMPS1200 and two nc400 should dissipate around 28W idle, whereas a dual mono SMPS600+nc400 setup should end up at around 25W total. Not a huge difference but still notable, and the additional heat comes right from the nc400 modules.

 

[JimB]

I was specifically referring to a stereo SMPS1200 scenario here.

According to current specs, a stereo setup with one SMPS1200 and two nc400 should dissipate around 28W idle, whereas a dual mono SMPS600+nc400 setup should end up at around 25W total. Not a huge difference but still notable, and the additional heat comes right from the nc400 modules.

Ahhh. Because the Vdr supply from the SMPS1200 does NOT work as intended for the NC400s, which I didn't know. Thanks.

(I still like the SMPS1200 for this application.)

 

[rajapruk]

SMPS1200 is cheaper. I think that is the only pro of that alternative.
I did the same decision in my first ncore build. In the second (current) build I use SMPS600.
I have a gut-feeling that the longevity of the SMPS600 is higher than on the SMPS1200.
One of my SMPS1200 acted up.