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Buckeye Hypex Nc502mp Multichannel Amp Teardown

amirm

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I recently reviewed the Buckeye Hypex hypex Nc502mp based multichannel amplifier. This is a quick teardown review of the same.

The case is easy to open after which, you see the implementation based on three Hypex stereo NC502MP class D amplifiers with integrated switching power supplies:

Buckeye 6ch Nc502mp Teardown multichannel amplifier.jpg


Overall this is a clean build and I only have a couple of minor issues:

1. I checked the grounding screw on the Hypex amplifiers and two get routed to the safety ground of the IEC outlet but the top module does not. The resistance was under 1 ohm for the two modules but a few hundred ohms for the top module. Assuming this is recommended practice from Hypex, the case anodization needs to be sanded off underneath.

2. The AC cables are nicely routed away from signal lines. But they bend right at the edge of the amplifier PCB which could nick them. Move the tiedown a hair over and it should be fine.

Speaking of #1, I also like to see the anodization sanded off until bare metal shows. Here they are just scuffed:
Buckeye 6ch Nc502mp Teardown Grounding multichannel amplifier.jpg


Here is a zoomed image of the Hypex modules:

Hypex Nc502mp Teardown multichannel amplifier.jpg


Examining the branding of the capacitors we find that the ones in the amplifier are from Aishi and those in the power supply, Sus'con:

Hypex Nc502mp Blue caps AISHI Teardown multichannel amplifier.jpg


Hypex Nc502mp Black caps Sus'conTeardown multichannel amplifier.jpg


Both are second or third tier capacitors. Fortunately they are rated at 105 degree C instead of 85 which should give them longer life.

BTW, I am always surprised by the amount of goop hypex puts on their amps. They are good to keep vibrations down and keep failure during shipping low. But I must confess I had not seen them put on transformer in that manner. I wonder if it is there to keep transformer whining down as a post measure. The goop makes repair more of a pain by the way as you can't just desolder and pull the part out.

Conclusions
As small company builds go, Buckeye's amp here is very well assembled. Per above, I only found a couple of things I would improve. I let others opine as to what else they see. :)

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Doodski

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@Buckeye Amps In this picture the sanding looks amateur and poorly finished as well it might not be into the bare metal. When I was assembling the electrical systems of oil drilling rigs I provided my own tools and found some very nice stuff and this is one that you will maybe like a lot after you use it. It is for burnishing surfaces for a proper electrical connection. It is meant to be used in a drill. It will fix the appearance and the integrity of the connection in this pic.
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sarumbear

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1. I checked the grounding screw on the Hypex amplifiers and two get routed to the safety ground of the IEC outlet but the top module does not. The resistance was under 1 ohm for the two modules but a few hundred ohms for the top module. Assuming this is recommended practice from Hypex, the case anodization needs to be sanded off underneath.
Which is preferable, ground the PCB or let it float?

Also, where does that hundred ohms coming from do you think?
 
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amirm

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Which is preferable, ground the PCB or let it float?
Assuming those are supposed to be connected to safety ground, then that is what I would do. Then again with three modules spread across the whole chassis, it could create some ground imbalance and currents flowing. Fortunately this is a balanced input amplifier so the impact of that should be very low.
 

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Capacitor brand complaints incoming in 3, 2, 1....
 

sarumbear

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Assuming those are supposed to be connected to safety ground, then that is what I would do. Then again with three modules spread across the whole chassis, it could create some ground imbalance and currents flowing. Fortunately this is a balanced input amplifier so the impact of that should be very low.
What about my second question about a few hundred ohms resistance to ground on modules that are not connected to ground. What is the source of resistance do you think?
 
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peniku8

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You say the case is andonized, so it is made of Aluminum?
 
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amirm

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What about my second question about a few hundred ohms resistance to ground on modules that are not connected to ground. What is the source of resistance do you think?
The other two amp's screw must have bit into the case and got past the anodization. This one did not. I am guessing here.
 

sarumbear

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sarumbear

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The other two amp's screw must have bit into the case and got past the anodization. This one did not. I am guessing here.
Thank you.
 

Buckeye Amps

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Regarding the grounding screw for the IEC: It is bare metal directly under where the spade is pressed into the case by the Kep nut. I make sure you can see bare metal when sanding. If it helps I can sand a bigger area so it extends past the contact area a little.
 

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Also, thank you for measuring the grounding of the actual modules. Knowing this I will definitely sand screw holes for the module mounts as well. Apologies this had not been done before.
 

sarumbear

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Regarding the grounding screw for the IEC: It is bare metal directly under where the spade is pressed into the case by the Kep nut. I make sure you can see bare metal when sanding. If it helps I can sand a bigger area so it extends past the contact area a little.
May i ask you to comment on the grounding questions, please?
 

sarumbear

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Also, thank you for measuring the grounding of the actual modules. Knowing this I will definitely sand screw holes for the module mounts as well. Apologies this had not been done before.
Wouldn‘t it be better if all module ground pins and IEC ground pin are all wired to the chassis as a star configuration?
 

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May i ask you to comment on the grounding questions, please?
Was my above post adequate? Easy fix if so. Up until now I had been sanding by hand but now I will probably use my dremel and just sand the necessary holes for cases in bulk.

Actually I will also ask my case manufacturer if I can specify holes to be sanded/bare but not sure if it will add cost (any service that can't be done in bulk adds a heft labor fee which is why I never used flush mount screws as it added nearly $30 per case to have them drilled)
 

sarumbear

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Was my above post adequate? Easy fix if so. Up until now I had been sanding by hand but now I will probably use my dremel and just sand the necessary holes for cases in bulk.

Actually I will also ask my case manufacturer if I can specify holes to be sanded/bare but not sure if it will add cost (any service that can't be done in bulk adds a heft labor fee which is why I never used flush mount screws as it added nearly $30 per case to have them drilled)
Maybe our posts crossed? I was suggesting relying on wires to ground instead of the case metal, which is unreliable. Also, costly.
 
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Doodski

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Was my above post adequate? Easy fix if so. Up until now I had been sanding by hand but now I will probably use my dremel and just sand the necessary holes for cases in bulk.
That aviation burnishing tool that I suggested in post #2 will solve your issues in seconds and the result looks professional. Try it I am sure you'll love the result.
 

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