• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Hypex NC250MP monoblock build with eval board

Rick Sykora

Major Contributor
Forum Donor
Joined
Jan 14, 2020
Messages
2,419
Likes
4,461
Location
Stow, Ohio USA
While I awaited the repair of my QA451 programmable load, was working with temporary substitute and still not sure what happened, but my NC500 eval board went bad and so needed a replacement. Since it was one of a pair of monoblocks, decided to move to a single case. This left the old Ghent cases open for repurposing and had some NC250MP modules around so decided would put give them a try.

I had been struggling with the Mogami cable/IDC connector combination for the MP series Hypex and had come up with another approach to improve how the XLR connections would be made. I found that the MP series eval board was fairly inexpensive and came with nice set of premade cables too. After toying around with a couple of different layouts, here is the layout:
DFE0D9AD-C8DF-4E1B-A7D0-28DF1365D2EB.jpeg


The eval board does a nice job of adapting the ribbon cables to a nice, shielded cable terminating with a locking connector to bring in the input signal from the XLR. Was somewhat concerned about its length but allowed it to be routed along the edge of the case. The supplied speaker wire was not as generous and as shown is a bit precariously run over the large caps. With my measurement rig back in action, checked to see if either routing introduced noise, and was pleased to find it measured just fine.

The eval board has 4 plastic mounting posts in the corners and so used vents along the case edge to secure the board in place. You get a nice array of status LEDs including clipping ones. Could have added some light pipes to improve visibility but did not feel it necessary for my use. This left the front panel LED and with all the other LEDs, seemed appropriate that it simply be a power indicator. So shortened the wires and solder to the Vaux and ground pads on the eval board. Here is a look with power applied:
F71F1768-5E80-436B-9F19-324DDA575575.jpeg


In case you are wondering which LEDs are available, the first two (from the top) are the clipping LEDs. The next 3 are auxiliary power indicators (all ON), DC error is OFF and the last one is the POWER GOOD indicator.
 
Last edited:
OP
Rick Sykora

Rick Sykora

Major Contributor
Forum Donor
Joined
Jan 14, 2020
Messages
2,419
Likes
4,461
Location
Stow, Ohio USA
As I mentioned, my QuantAsylum measurement rig is back in action. I ran a full battery of test just to verify the build. Here is the THD+N vs Power for the new amp...

1663106522699.png

This is about as good as it gets for these amps. This one is pushing 300 watts into 4 ohms at .1% THD+N :)

Here is a look at the noise spectra (A weighted at just under 5 watts):

1663107181674.png
 
Last edited:
OP
Rick Sykora

Rick Sykora

Major Contributor
Forum Donor
Joined
Jan 14, 2020
Messages
2,419
Likes
4,461
Location
Stow, Ohio USA
Completed the second monoblock and redid the layout. Pics are updated in the first post to show. A quick noise check says it is good to go.

Future build will use spade connectors on the binding posts. Have to fight to get them hot enough to solder due to thermal mass. Did not help that they had solder on them from previous use.
 
Top Bottom