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Buckeye Nc502mp Review (6 Channel Amplifer)

Mxman

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What's your AVR model? and most importantly the room size? , 350W @ 8ohms is max ... and that's not a good way to go about it, as per my understanding.

The MiniDSP specs meet what you are stating,
IN: Unbalanced: 2Vrms or 0.9Vrms
Balanced: 4Vrms
OUT: Unbalanced: 2Vrms or 0.9Vrms
Balanced: 4Vrms or 8Vrms
Unfortunately it's my 12 wide x 30 x~7h foot basement. I was hoping to go class d to maximize availability of wall current. Minimize heat and noise and unlike 96 pound amps like the nad m25 or monolith 7 would ship easier. I'm open to suggestions though. :)

Oh it's an onkyo txrz810 sorry... Nothing too fancy
 
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peng

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Dylan has been tolerating me my email a bit... I'm a newbie

I've got a onkyo txrz that's supposedly 1v out... I'm thinking of going mini dsp to bump the voltage say the 10x10hd

Mini dsp say the hd boxes have a 12db boost which... Should get me (hopefully) ~1v boost without clipping... I'm pretty sure I'm going to order one as i went to process the signal. I'm not opposed to something like a drv134 to go RCA to xlr

Going off the hypex specs for the nc502 350w @ 8 ohms it needs ~2.7x volts to hit ~350w...?

Does anybody have some suggestions for bumping the voltage? I'm just trying to make a build of materials. Thanks in advance.

I don't think you have to bump it up. Usually if the specs say 1 or 1.2 V rated they mean the voltage for the internal power amp to reach its rated output and the maximum pre out would likely be 2 V or higher. The minidsps are typically rated 2 V maximum unbalanced (depends on the specific model, may be higher, you need to check the fine print in the specs)so there may be no gain at all, the Onkyo may actually do better.

Edit: As post#240, if it is the 10X10 HD then you get 4 V max balanced but still only 2 V max for unbalanced.

Which Onkyo model will you be using? It may be find for the NC502MP. Like the Denon/Marantz AVRs, they all say 1.2 V but you know they can do higher than 3 V, even 4 V.
 
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amper42

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Unfortunately it's my 12 wide x 30 x~7h foot basement. I was hoping to go class d to maximize availability of wall current. Minimize heat and noise and unlike 96 pound amps like the nad m25 or monolith 7 would ship easier. I'm open to suggestions though. :)

Amp Weight/Energy Comparison:
Monolith 7x200 - 93 pounds - 156W idle - 165-185W range in stereo mode = 81dB with BMR monitors
Buckeye NC502MP Stereo - 5.5 pounds - 23W idle - 23-25W in stereo mode = 81dB with BMR monitors
Purifi P452 March Audio - 8.75 pounds - 16W idle - 16-18W in stereo mode = 81dB with BMR monitors

The data above is what I measured when comparing Monolith 7x200 to Buckeye NC502MP and the Purifi P452 March Audio amp. That Monolith 7x200 class A/B amp takes considerably more effort to move than the two Class D amps listed above. :D
 

Mxman

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Yeah
I don't think you have to bump it up. Usually if the specs say 1 or 1.2 V rated they mean the voltage for the internal power amp to reach its rated output and the maximum pre out would likely be 2 V or higher. The minidsps are typically rated 2 V maximum unbalanced (depends on the specific model, may be higher, you need to check the fine print in the specs)so there may be no gain at all, the Onkyo may actually do better.

Edit: As post#240, if it is the 10X10 HD then you get 4 V max balanced but still only 2 V max for unbalanced.

Which Onkyo model will you be using? It may be find for the NC502MP. Like the Denon/Marantz AVRs, they all say 1.2 V but you know they can do higher than 3 V, even 4 V.
Yeah it's a txrz810, again nothing too fancy. But it has a 'full compliment' of preouts. The onkyos seem to all be beheaded by Amir
 

rdenney

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Yeah

Yeah it's a txrz810, again nothing too fancy. But it has a 'full compliment' of preouts. The onkyos seem to all be beheaded by Amir
Most AVRs are beheaded by Amir. DACs are not as good as they could be, and amps usually share a smallish power supply amongst all channels.

But if you drive external amps and watch movies, it will be more than good enough.

The spec to consider is not the rated output, but rather the maximum line-level output at the pre-outs. The rated output is at minimum distortion and is often at unity gain (1-2 V), but the maximum output is commonly some multiple of that. Even if distortion is a bit higher, you won’t notice.

Rick “not that Oinko publishes the maximum pre-out level” Denney
 
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peng

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Yeah

Yeah it's a txrz810, again nothing too fancy. But it has a 'full compliment' of preouts. The onkyos seem to all be beheaded by Amir

The SM for the TX-RZ810 is available and you can search for it.

The volume control IC has the following specs:

Maximum output voltage: Min. 3.8 Vrms, Typ. 4.2 Vrms, that's for RL=10kΩ

For DAC, the chip used is the AK4458, same as Denon/Marantz (those made before the spring of 2021).

I could not find any review on it with measurements, but based on the datasheets for the volume control chip and the DAC chip I think you should have enough voltage to take advantage of the NC502MP's rated output.
 

Hcg76

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Hi folks,

I recently became a member of the Buckeye amp family, having ordered a 4 channel nc252mp based amp and a 4 channel NC502MP based amp. In a 7.1.4 system the stronger 502 amp is for side and rears and the 252 amp is for my Atmos channels.

Long story short, when I hook up the amp with 2 nc252mp modules to my bed layer speakers they’re super quiet and all that’s heard is the amp. Basically it sounds amazing and perfect. But when I hook up my amp with the 2 nc502mp modules there‘s immediately very loud noise coming from the speakers they’re hooked up to. Unfortunately I can’t up a video with the noises but it sounds like electrical interference mixed with high pitched noises and such. It’s very distracting! Futhermore the sounds ONLY come on when sides and/or rear speakers are hooked up and it doesn’t go away regardless if I have the xlr cables connected or not? My side and rear speakers are JTR Noesis 110HT‘s btw.

Is there any kind of a fix to this noise from the nc502mp amp? I’m assuming it had to do with the distance to my side and rear speakers (~20 feet away) since none of my LCRs have the sound when connected to that amp. I figured I’d ask before returning the amp for a refund. I’ve posted this question on the other Buckeye amp thread as someone may have a simple solution I haven’t thought of. :)

TIA
-John
 

Buckeye Amps

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I'll add in (as I have been working with him): I replaced both NC502 modules with brand new ones. Both the original modules and the new ones worked fine on my test setup and even on my personal setup.

And as he said, the issue is there if just the speakers are connected (no source connected on the XLRs). I have advised him to try ferrite cores, as I have had one customer nearly a year ago have a similar issues with just his surround speakers and the maker of the speakers suggested ferrite cores as a last effort and it fixed the issue.
 

Rottmannash

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In using the pre outs on my RZ810 and having no issues driving either a Purifi, 252MP or a Class A/B Rotel.
 

Spkrdctr

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I'll add in (as I have been working with him): I replaced both NC502 modules with brand new ones. Both the original modules and the new ones worked fine on my test setup and even on my personal setup.

And as he said, the issue is there if just the speakers are connected (no source connected on the XLRs). I have advised him to try ferrite cores, as I have had one customer nearly a year ago have a similar issues with just his surround speakers and the maker of the speakers suggested ferrite cores as a last effort and it fixed the issue.
Thanks for being a great amp maker with fantastic customer service!
 

Mxman

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The SM for the TX-RZ810 is available and you can search for it.

The volume control IC has the following specs:

Maximum output voltage: Min. 3.8 Vrms, Typ. 4.2 Vrms, that's for RL=10kΩ

For DAC, the chip used is the AK4458, same as Denon/Marantz (those made before the spring of 2021).

I could not find any review on it with measurements, but based on the datasheets for the volume control chip and the DAC chip I think you should have enough voltage to take advantage of the NC502MP's rated output.
Oh wow I've checked every piece of documentation and couldn't find that. I was originally concerned as i was using an old peavy cinemacoustic to run some subs and had to crank the gain.

I guess now i have to put in an order!

Thanks also to @Rottmannash for that!
 

Hcg76

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Anyone see anything that looks off here? I figured I’d ask you experts before sending it back to exchange for an amp with nc252mp modules. Thanks.
 

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Sal1950

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I'll add in (as I have been working with him): I replaced both NC502 modules with brand new ones. Both the original modules and the new ones worked fine on my test setup and even on my personal setup.
How very strange? Appears to yet be a ghost or two in the Hypex modules
 

rdenney

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If you replaced the modules in the amp enclosure, and having eliminated an effect outside of the amp, then I would investigate the items in the box you did not replace. Maybe there is a stray strand of wire where it doesn’t belong, or a defective connector with an insulation leak.

I certainly cannot believe that there’s something about the 502’s design that would cause such a thing, and you’ve eliminated a production/execution issue by replacing the modules.

Here’s a pic of the interior of my 502 if you want to make a comparison. But I’m betting the issue won’t be visible at this level.

Buckeye-502-interior.JPEG


Rick “even a weird ground loop caused by a flaky internal case ground” Denney
 

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I looked over all the wiring when I hade it back in my possession and tested it on two different systems I have.
 

peng

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I looked over all the wiring when I hade it back in my possession and tested it on two different systems I have.

I know something similar happened to someone with the 502 but not yours. Regardless, I think you can ask Hypex tech support about this as I do believe the design of the 502MP (probably has to do with the specific switching frequency of that model) likely make it prone to interference (even harmonic resonance..) between the amp's output filter and the speaker's crossover network. If I am right, the fix could be quite simple, and Hypex should know how obviously. I think it would be extremely rare for such interaction to result in some weird noise with only certain speakers. Did you hear back from him if the ferrite cores fix it?
 

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He did try the ferrite cords and shorter speaker wire runs.
What's even more strange is the amp works fine on his Front LCR speakers
 

Spkrdctr

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His speakers are probably wonky. When in doubt, buy new!
 

peng

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He did try the ferrite cords and shorter speaker wire runs.
What's even more strange is the amp works fine on his Front LCR speakers

Yep, same with the other member's, again it wasn't a Buckeye amp. His also got the NC502MP modules replaced but the issue persisted, he eventually got the NC500 and problem solved. I would love to discuss such issue with Hypex but the won't talk to me because I am not a dealer. They will talk to you though.
 

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Yep, same with the other member's, again it wasn't a Buckeye amp. His also got the NC502MP modules replaced but the issue persisted, he eventually got the NC500 and problem solved. I would love to discuss such issue with Hypex but the won't talk to me because I am not a dealer. They will talk to you though.
I am messaging them soon here to see their thoughts
 
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