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Nord One NC1200DM Signature Stereo Amp Teardown

amirm

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#1
I previously reviewed the Nord One NC1200DM Signature Stereo class-d amplifier. Here is a brief tear down of the same.

The NC1200Dm is a "dual mono" configuration with two power supplies, two hypex NC1200 amplifier modules and two NORD designed "buffer" (preamplifier) stages:

Nord One NC1200DM Signature Stereo Amp teardown.jpg

As I noted in the tear down of the Nord Three Purifi amplifier, I am not happy with the pair of voltage regulators in the buffer boards hanging in the breeze. Those heatsinks should be larger/heavier and soldered to the PC board.

I don't understand why the buffer stages are sandwiched between the noise power supply and power amp. They should be to the back of the unit.

I am pleased that no double stick tape is used to fasten the power cables to the heat sinks.

That's it really. Not much else to critique.

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As always, questions, comments, corrections, etc. are welcome.

It takes a lot of energy and stamina to tear down an amplifier. I have to get the right screwdriver, find all the screws, and undo them without damaging anything. Super delicate work and tiring. Need a pick me up in the form of more cash in my pocket. So please donate generously using : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

Matias

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#2

amirm

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As far as I know these are Sparkos voltage regulators, not Nord's, so they can't be built in the same PC board.
https://sparkoslabs.com/discrete-voltage-regulators/

View attachment 42089
What I said is that the heatsink should be soldered to the PCB. Not the components of the regulator. Or at least be supported by the PCB like these:

1576026604658.png


Dangling them in mid air is just not correct. Vibration can cause fatigue through shipping and such and cause the terminals to potentially fail. They need a larger heatsink anyway. So might as well put a taller one in there that comes down to the main PCB.
 

veeceem

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#4
So ...a known brand doesnt always mean ...proper installation...even when the price is not dirt cheap :/
 

Doodski

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So ...a known brand doesnt always mean ...proper installation...even when the price is not dirt cheap :/
After about 55K units of repair most of what I've seen as a repair technician is broken units. Faults occur in near everything, I expect them and they don't surprise me. The integrity of the equipment generally does get much better with higher end gear but it's not a rule. One thing I dislike about this amplifier is the use of the adhesive under the capacitors. I've confirmed several times that the adhesive there gets baked from heat , it's properties change and it turns conductive and can cause weird intermittent faults to occur or the protection circuitry to engage. I've seen the adhesive turn conductive in audio gear and also when I worked as a QA/QC tech for a down-hole tool company. (Pressure, temperature, torque, strain and tension measuring devices used down-hole at depth when drilling for petroleum.) We where dynamically and thermally qualifying hundreds of IC's at a time in a oven and spec'd them up to about 175C because it gets hot down-hole and the higher the spec the better. Both the 120V AC power and the low voltage square waves in digital circuits have been seen to be shunted by the adhesive used on printed circuit boards that has gone conductive to some degree. We had repeat problem in the down-hole tools, I inspected some used tools that where baked from high heat and after advising the engineers of what I suspected was the issue we stopped using the adhesive on the circuit boards and the issue went away in short order.
 
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restorer-john

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#7
Vibration can cause fatigue through shipping and such and cause the terminals to potentially fail.
@amirm Did you ever see whilst at Sony, the big rotating round steel cage they used to test boxed product in? It rolled around for many minutes and the boxed products would tumble and drop. They'd unpack and test the gear, check damaged interior parts for movement, where to re-design and add securing adhesives/brackets etc.

I saw a corporate video on it once where amplifiers were in the cage in their cartons and it made me cringe.
 

dreite

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#8
I'd like to see more manufacturers bring the mains connections to the opposite side of the chassis from the signal connections. This means that speaker/input connections will be on the "front" and mains on the "back." A much better configuration internally (usually.)
The normal convention of everything on the back is too crowded and doesn't make that much sense anymore.

Dave.
 

restorer-john

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I've confirmed several times that the adhesive there gets baked from heat , it's properties change and it turns conductive and can cause weird intermittent faults to occur or the protection circuitry to engage. I've seen the adhesive turn conductive in audio gear and also when I worked as a QA/QC tech for a down-hole tool company.
To be fair, we've moved on from the conductive Sony Bond Adhesive style issues that were rampant across all brands in the 70s and 80s. The conductive and corrosive issues are rare these days, but I'm still cleaning up the mess from the past... :)
 

Xyrium

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#11
Amir, you know you watched his "How to set up an electronics lab" at least a dozen times. ;)

Kidding of course...
 

trl

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One thing I dislike about this amplifier is the use of the adhesive under the capacitors. I've confirmed several times that the adhesive there gets baked from heat , it's properties change and it turns conductive and can cause weird intermittent faults to occur or the protection circuitry to engage. I've seen the adhesive turn conductive in audio gear and also when I worked as a QA/QC tech for a down-hole tool company. (Pressure, temperature, torque, strain and tension measuring devices used down-hole at depth when drilling for petroleum.)
I don't see any glue or other kind of adhesive tape under the caps, but maybe it's due to the angle of the picture (maybe I'll spot something after I'll drink my morning coffee). However, what else could be used to minimise vibrations induced to the capacitors if adhesive tape and glue are not OK? Just the "old fashion" metallic brackets like here: https://www.capacitorindustries.com/product-category/capacitor-hardware-and-brackets/? Thank you!
 

restorer-john

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#13
I don't see any glue or other kind of adhesive tape under the caps, but maybe it's due to the angle of the picture
The adhesive is around all the electros on the Hypex amplifier boards, and in between the 6 output filter (red) caps.

On the PSU, its slathered all around the 4 main caps, the secondary filter caps, the chokes/filters etc.

I have no problem with it until it a) corrodes the legs of the components and goes conductive or b) gets in my way when repairs are needed. Then I officially hate the stuff. Acetone is no fun and it's about the only thing that will dissolve and clean a PCB covered in dried out adhesive.

I've started a thread about bond glue and capacitors here:
https://www.audiosciencereview.com/forum/index.php?threads/bond-glue-issues-and-pictures.10329/

Considering many of these types of amplifier boards and SMPSs are stuffed into active speakers, it makes a whole lot of sense from a reliability perspective to glue stuff down and stop vibration, noises, and potential dry joints. Gone are the days where large components were properly affixed to metal chassis.

Remember, this is the modern world, where gear is full of double sided tape cable mounts, glued down components, hot melt adhesive- whatever quick fix they can employ. Even our $1500 phones are glued together.

This Nord is pretty good, apart from the strange layout choices Amir has already mentioned.
 
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trl

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The adhesive is around all the electros on the Hypex amplifier boards, and in between the 6 output filter (red) caps.
I see it now, there's also on the electrolytics from bottom-left as well, thanks for pointing it out.
I also found some close-up pics too on manufacturer's website:




It's great that you've started a new thread about this matter, although the glue from the Hypex looks more "gummy" and rubber-like, so doesn't looks like it will cause any troubles in the next 10 years or so.
 

Timbo2

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#15
Acetone is no fun and it's about the only thing that will dissolve and clean a PCB covered in dried out adhesive.
I don't mind working with lots of solvents, but I 100% agree about acetone. It's hard on skin, the smell is awful, it will give you a headache in a closed space and it evaporates quickly so it can be tough to get useful working life with. It's also my solvent of "last choice" as it frequently eats away at things I don't want dissolved like lettering or plastic pieces.
 

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