Buckeye Hypex NC252MP Amplifier Teardown

[Labjr]

What a great value for home theater!

 

[gene_stl]

I agree, about not using the red and black for the AC line. However, in the USA, it is customary for the line hot, to be black, and the neutral to be white, and the ground green or green/yellow. Blue and brown are seen in "international gear" but since it is likely that Buckeye will sell the majority of his products here in the USA, if that happens I would recommend for domestic consumption, he use the USA color scheme.

I would suggest either running a tap into the place where the screws will self tap or if it is a sheet metal screw (you may still be able to get such a tap) use a waste screw to form the threads prior to assembly. That will make it easier to blow things out.

 

[Buckeye Amps]

Parts update:

- Switching to a 2-conductor 16awg Black/White power wire that also has an outer insulating coat, so it can be run next to the LED wiring
- Switching to a Green/Yellow striped 16awg for Ground
- Switching to a serrated/teethed washers for the ground connection
- Will use Red and Black 20awg for Power LED
- Will also use Red 20awg for the Vout Standby coming off the first module going to the 12v Relay
- Switching to a Green 20awg wire for the PS Enable wiring coming off the relay (Not entirely the correct wire color for DC, but it does denote Power Enable for ATX wiring scheme....I wanted Purple but it wasn't available)

Still looking for best way for securing cables without needing to worry about drilling more holes (but if it is necessary will go that route)

 

[Billy Budapest]

Parts update:

- Switching to a 2-conductor 16awg Black/White power wire that also has an outer insulating coat, so it can be run next to the LED wiring
- Switching to a Green/Yellow striped 16awg for Ground
- Switching to a serrated/teethed washers for the ground connection
- Will use Red and Black 20awg for Power LED
- Will also use Red 20awg for the Vout Standby coming off the first module going to the 12v Relay
- Switching to a Green 20awg wire for the PS Enable wiring coming off the relay (Not entirely the correct wire color for DC, but it does denote Power Enable for ATX wiring scheme....I wanted Purple but it wasn't available)

Still looking for best way for securing cables without needing to worry about drilling more holes (but if it is necessary will go that route)

To secure the cables, perhaps some sort of Techflex-type cover to bundle the cables together. You wouldn’t really need to worry about securing the cables to the bottom or sides of the amp.

https://www.grainger.com/product/2RLR6

 

[Buckeye Amps]

Looking at a build in front of me, I think the solution is simple: there is only one spot I need a very secure hold and that's at the front of the case when the cables do a 90 degree bend. Luckily one of the case feet screws is located here so it will be easy to use a screw tie down. Other than that, the remaining double sided cable tie downs I use are mainly for "cleanliness" and I can accomplish the look with a few properly placed zip ties.

Should have all issues solved now. Just in time for the large batch of NC252's I am receiving for quite a few orders to fulfill over the holidays.

 

[Francis Vaughan]

Are you saying on top of this wiring scheme, I should also be connecting Pin 4 (GND) of J6 of each module together as well?

Yes, but I left an important bit out. If you just connect them together you will create a ground loop via the signal shields. This may make things worse. Maybe Hypex could (indeed should) provide the definitive answer. But at it core, whenever I see a single wire with no apparent reference/ground return it sets off alarm bells. Control of return current is critical in getting the best performance and is one of the things that makes or breaks the PC and internal layout of almost any design. The return current path for PS enable on the second and third amps is the common ground of all the amplifier modules. Which is currently the chassis via the signal shield. Since it is a balanced input this isn't the disaster it would be it if were an unbalanced input, but when we are eking out the last slivers of performance, it is always important to be clear what is happening. It depends on how the PCB is laid out.

There is a basic principle - every wire and every PCB trace is a resistor. Any current flowing in any wire or trace results in a voltage drop. Ground references can cease to be clean, as can any other part of the circuit. A ground loop is a particularly evil variant of this, as any loop is an inductor, and any nearby oscillating magnetic field will induce current in the loop. Current flowing in any loop that has been created results in a voltage drop around the loop, and the typical result is mains hum appearing. Even the ground traces in an amplifier module can (and usually do) have a voltage drop across them. It depends where on the PCB you are picking up the reference. My worry is that the signal shield is going to an assumed quiet ground in the PCB. If it is, and there it has become the return path for the PS enable signal, that relatively dirty standby power may add noise to the amp as it returns through the quiet part. This may not actually be an issue. It is quite possible that the signal shield is tied to the same bit of PCB as the standby power ground pin is. In which case it matters little. Hypex should provide guidance. Indeed they should provide clear guidance on how multiple modules can be set up and interconnected in a single chassis.

OK, after writing the above I did a bit of a search, and they do provide most of the guidance, and happily, they design their amplifiers the right way. So they don't have some notion of an internal quiet ground. Yay!

https://www.hypex.nl/img/upload/doc/an_wp/AN_Legacy_pin_1_problems.pdf

The take away? The current layout is probably OK.
There is no clear defined external ground for the amplifier modules - currently it is via the signal shield. Since this is the ground return for PS enable, this may not be optimal, but given Hypex's documentation is less likely to cause issues than it might with other designs. The optimal answer would be to use a multi-throw relay, and individually switch each amp using its own standby PS. But that may be unnecessary overkill. I would check with Hypex on what the recommended wiring is. They will probably say that what you have is the best answer. But it is an evil and vexed problem in general, and the right answer is not always the obvious one.

 

[Buckeye Amps]

Thank you @Francis Vaughan I really appreciate the write-up. I definitely understand what you are saying now and it makes sense.

 

[Buckeye Amps]

Anyone have a recommendation for a wire stripper that works on outside insulation without "hurting" the inside wiring? I've found a few on Amazon but it seems hit and miss.

 

[gattaca]

^^^^ I tend to stick with these brands for various hand tools now-a-days: Ideal, Irwin, Milwaukee or Klein.
Judge from the legit Amazon reviews.
Judge from what Grainer sells.
Do you want "automatic" or "manual"
Anyone here in the electrical servicing trades with long-time daily experience, jump in. I'm mostly hobbyist and DIY PoV.

https://www.bobvila.com/articles/best-wire-stripper/
https://www.archfoundation.org/best-wire-strippers/
https://www.grainger.com/category/t...an-s-hand-tools/wire-strippers-cable-slitters

Later.

 

[DWPress]

Drat, now I'm going to have to send mine back for properly colored wires.

Nice review @amirm and congratulations @Buckeye Amps!

 

[Jason Shep]

Congrats @Buckeye Amps & great to see such pride taken in the construction of your products.

These must be the best value amps around for multi channel systems & with Atmos etc systems using more & more channels, I can see these being extremely popular, shame they aren’t available in the UK.

 

[maxxevv]

Anyone have a recommendation for a wire stripper that works on outside insulation without "hurting" the inside wiring? I've found a few on Amazon but it seems hit and miss.

I use something very similar to these for work.

There are different variations of the stripper blade for AWG sizing as well as wire core diameter in millimeters. Make sure you buy the version with the appropriate core diameter size that you need.

https://www.amazon.com/Stripper-Ele...child=1&keywords=wire+stripper&qid=1608629961

 

[Labjr]

These must be the best value amps around for multi channel systems & with Atmos etc systems using more & more channels, I can see these being extremely popular, shame they aren’t available in the UK.

This amp seems perfect for most users. I would think six channels is more than enough for home theater. The Atmos thing is getting ridiculous.

 

[Matias]

This amp seems perfect for most users. I would think six channels is more than enough for home theater. The Atmos thing is getting ridiculous.

Yes, I was just watching Star Wars episode 9 on Dinsey+ and was curious, it is delivered as 5.1. A 2019 movie in a 2020 streaming service. So 6 quality channels is very much adequate.

 

[Tks]

 

[Xyrium]

To secure the cables, perhaps some sort of Techflex-type cover to bundle the cables together. You wouldn’t really need to worry about securing the cables to the bottom or sides of the amp.

https://www.grainger.com/product/2RLR6

Man, I love techflex. I used to use it on every home brew cable I made, whether it was needed or not (never in my case). I think it's a great way to not only add a little integrity to the install, but also a little flair to differentiate your product from others.

 

[dorirod]

Anyone have a recommendation for a wire stripper that works on outside insulation without "hurting" the inside wiring? I've found a few on Amazon but it seems hit and miss.

Maybe this one https://www.amazon.com/Knoweasy-Aut...-75inch/dp/B07WFL122J/ref=as_li_qf_asin_il_tl

 

[MrPotatoHead]

I use this one (or version of with larger gauge wire) which is great. Just watch the snap-back!

Ideal Industries Stripmaster Wire Stripper, 16 to #26 AWG - - Amazon.com

 

[Billy Budapest]

This amp seems perfect for most users. I would think six channels is more than enough for home theater. The Atmos thing is getting ridiculous.

Atmos sounds pretty incredible but there is no need for a ridiculous amount of speakers. I have a 5.1.2 system with the .2 being two dinky little Atmos speakers hidden on stands behind my display and angled to bounce off the ceiling. Sounds awesome with overhead effects.

 

[Buckeye Amps]

If someone is building a nice dedicated theater, object based audio is definitely worth it if speaker placement is done right. For most home theater in a living room or semi-dedicated room setup, I find 5.1.4 the best.