[mgalusha]

A small package from the Netherlands arrived yesterday and I spent the evening putting the contents into chassis.

I used some chassis from CoZ Cables, which I have mixed feelings about. They fit together very well, all the holes are the right size and in the right place, there are just too many openings to suit me. Note that I've exchanged some email with Robert Cozart and I believe the next batch are going to be simplified. Robert was kind enough to offer me a new set of back plates but I declined, no reason to cut into his margins.

Anyway, assembling a pair of these as mono blocks is pretty easy. As stated in many other threads, this is not a complicated build. The important things are layout and cable dressing. This is discussed in the data sheets available from Hypex and that ship with the modules.

The only thing I found that causes me concern is not having a safety earth connection. They are designed to be Class 2 safety compliant and the SMPS600 module is supplied with insulated stand offs, though one is metal and meant to bond with the chassis to reduce EMI/RFI. Once I had the amplifiers assembled I decided to measure from line neutral to the chassis. It was 120VAC.

When wiring the PS module I followed the standard color code blue/white = neutral and brown/black = line. This made sense as the line fuse is on the brown wire of the board. Now the voltage I measured may be just leakage with no current but it does bother me. I tried reversing the leads and the neutral to chassis voltage drops to about 1.2VAC. I will almost certainly add a safety earth and hope it still sounds the same; I am exceedingly paranoid about safety.

Not much else to say. All the wiring is tightly twisted, 12GA wire was employed for the speakers with ring terminals on each end. The power wire is 16GA and I found some nice lighted switches at Radio Shack. I will likely build a soft latching power circuit at some point but the current setup works just fine. I connected them up last night and the result was as good as I hoped for.

A few photos.





Mostly built, switch and input not wired yet.





The gap above the IEC is because the cut out was for an IEC with switch module. None of the connectors on the bottom row are connected.

[JohnR]

Neutral to chassis is 120VAC? Um... that's because the chassis is floating?

[mgalusha]

Yes but I'd rather have it float the other way and not be at a high potential to my other components.

[JohnR]

I guess I don't understand why the chassis can't just be grounded.

[Big Red Machine]

That's a 400 watt mono block?

And the 2 circuits are pre-built for the chassis of your choice?

Sounds like a great project Mike.

[mgalusha]

John,

It can, they just suggest that it be built as a class 2 device with no safety earth. Given my level of paranoia, I will almost certainly add that tonight. I ran out of time last night and wanted to listen to a little music after spending the night in the shop.

I guess I don't understand why the chassis can't just be grounded.

[jtwrace]

I guess I don't understand why the chassis can't just be grounded.

It can be according to Bruno as long as you're XLR input and don't get any ground loops from upstream equipment.

http://www.diyaudio.com/forums/vendors-bazaar/190434-hypex-ncore-232.html#post2909634

[JohnR]

Whew. I thought class 2 was for plastic chassis. I was having these memories of vintage amps that gave me a little "tingle" every time I went near them. Anyway, nice work (a bit easy for you though )

[dwk]

Not a bad chassis at the price, but I agree that the rear-panel hole choices are odd. Why 2 speak-ons plus / but only a single pair of binding posts?  It looks like you could rework it into a stereo setup easily with a single SMPS and a pair of NCore boards - 2 xlr ins, 2 speakon outs and maybe fill the binding post holes with some RCA inputs.  I'm thinking of a stereo setup, and this would make for a pretty easy build.

Very tempting, although I'll have to think about timing. My current speaker setup relies on bi-amping, so this doesn't make complete sense until I make my 'next/final' speaker choice (hopefully in a new house in the fall....). On the other hand, my guess is that there is going to be a bit of a run on these so maybe being a bit proactive wouldn't hurt. 

[mgalusha]

Whew. I thought class 2 was for plastic chassis. I was having these memories of vintage amps that gave me a little "tingle" every time I went near them. Anyway, nice work (a bit easy for you though )

Oh yea, I still have vivid memories of being bitten by an old Allied radio ~40 years ago.

This is Mr. Putzeys take on safety earth: http://www.hypex.nl/docs/appnotes/earth_appnote.pdf

[mgalusha]

That's a 400 watt mono block?

And the 2 circuits are pre-built for the chassis of your choice?

Yep, at least into 4 ohms. They rate them 200W/8R, 400W/4R, 580W/2R. Those are for 90 seconds, for continuous sine wave power they are somewhat lower. Like other class D amp, they have a high efficiency and don't require massive heat sinks. And yes, the two modules are built and tested and include the wiring harnesses. I supplied the chassis, connectors, speaker and power wire, that is pretty much it.

[Big Red Machine]

I can't get their webshop page to load.  What are the prices for each module in a mono?

When you get the grounding safely figured out keep posting so we can copy!     This might be a real fun project if the price is right.

[jtwrace]

I can't get their webshop page to load.  What are the prices for each module in a mono?

When you get the grounding safely figured out keep posting so we can copy!     This might be a real fun project if the price is right.

There isn't anything to figure out though.  $1500 for two NC400's and two SMPS's.

[Big Red Machine]

There isn't anything to figure out though.  $1500 for two NC400's and two SMPS's.

That's a no brainer.  Send me a PM on their performance.  I think TomS is getting some as well.

[JohnR]

This is Mr. Putzeys take on safety earth: http://www.hypex.nl/docs/appnotes/earth_appnote.pdf

Yes. I do wonder if the logical conclusion (other than differential connections everywhere) is to have a single chassis - optical (or transformer-isolated) digital from the computer, and then a single box for the electronics.

Sorry - OT/irrelevant. Just been thinking about that one today.

[HT cOz]

Mike,

Very nice build.  I'm a little jealous    If at anytime you change your mind on the simplified rear plate let me know and I will include it in my next series of chassis.  I'm way more concerned about people being happy than margin. 

I have to admit that getting feadback on DIY Audio is somewhat like hearding cats and I'm constantly worried about the rules here at AC regarding Vendors etc. I found that flexibility seems like a good idea but people really prefer simplicity.  I guess we live and learn.

Here is drawing of the simplified rear plate.



By the way which speaker binding posts did you use?

Kind Regards,
Robert

[zybar]

That's a no brainer.  Send me a PM on their performance.  I think TomS is getting some as well.

Pete,

I am listening to them this weekend and will post my opinions.

George

[dspringham]

Robert,

Do you have a stereo chassis available (or any intentions for one)?

Regards,
Dave

[HT cOz]

Robert,

Do you have a stereo chassis available (or any intentions for one)?

Regards,
Dave

Yes as it would be more cost effective and I am mindfull of that being somewhat budget challenged myself.  Monoblocks allow for shorter speaker cable runs which is a plus for people seeking the ultimate system performance. 

Now back to Mikes great build...

[dspringham]

Mike,

Any thoughts on driving the nCores via a passive such as a Bent Audio/Slagle Autoformer? I seem to recall seeing an input Z spec (for non-balanced connection) of 100K. If so, the amps would be passive friendly (at least from Z matching aspect).

Comments from any others appreciated as well.

Dave