Buckeye Nc502mp Review (6 Channel Amplifer)

[Holmz]

It also depends on where you are. If in the US, buying from Buckeye is much easier (notwithstanding the wait time) and the shipping is routine. I don't know where KJF and Nord are both in the UK. Shipping will be far more expensive and more likely subject to unanticipated delays without the vastly expensive expedited courier service. (I checked KJF's web page on that.)

Rick "seeing the advantage of being able to by Hypex-equipped amps from various suppliers around the world" Denney

Yeah specifically thinking of Alan’s implementation, which would be good for people in Au/Nz Singapore, etc.

Basically the same as the others but with a CNC case.
Biing a bicycle ride away, it is an options.
In I was in Cornhusker’s land, then Buckeye gets easier on a bicycle, or UPS.

Amplifiers - March Audio

March Audio Amplifiers feature the stunning class D technology developed by Purifi and Bruno Putzeys. Exceptional technical performance and sublime sound quality.

www.marchaudio.com

Holmz, “who is specifically thinking of supply chain woes, and shipping costs,“ Holmz

 

[MrOtto]

Bridged mode performance looks slightly better than stereo, so if you upgrade with another board and run monoblocks you get more power and better performance?
View attachment 196740

Any thoughts on using two NC502MP in BTL-mode as an upgrade to only one in stereo mode? On upgrade in power, and performance? This or use another amp? BTL mode is not recommended for 2 ohm-application, but no speaker I'm considering has this low impedance plot.

 

[DonH56]

The obvious question is if you need the extra power?

Bridging will theoretically quadruple the power. In practice I tend to see closer to a doubling in spec sheets (I do not know what the NC502MP claims for bridged operation). The extra power is the benefit that attracts most to a bridged design.

Distortion depends upon implementation, mainly how well the two amps are matched which may decrease or increase the distortion. IME distortion is usually a wash. Gain is usually doubled. Noise and output impedance will be a little higher with two amps (bridged) driving each speaker -- noise by roughly 1.4x (sqrt(2) and output impedance by 2 (damping factor is halved). Providing twice the voltage swing also means the amp effectively "sees" half the load impedance, so your 8-ohm speaker "looks like" a 4-ohm speaker to a bridged amp. That has implications for thermal management as well as power supply demands and amplifier stability, thus the typical requirement that minimum load in bridged operation be twice that of normal operation.

HTH - Don

 

[mdsimon2]

Any thoughts on using two NC502MP in BTL-mode as an upgrade to only one in stereo mode? On upgrade in power, and performance? This or use another amp? BTL mode is not recommended for 2 ohm-application, but no speaker I'm considering has this low impedance plot.

What is better to you about BTL? You get more power but the trade off is higher noise and higher gain which will result in worse system SNR compared to stereo.

The only reasons to use BTL are power related. For example if you have a source that outputs less than 2.35 V you will not be able to drive a stereo NC502MP to full power, here the 6 dB extra gain from BTL will give you more power. Similarly if you were driving a stereo NC502MP to full power but needed more output (and your speakers could handle the extra power) a BTL NC502MP could give you a bit more output.

Overall given the rather healthy power output of the NC502MP I can't imagine much of reason to use BTL. The one case that does come to mind are power hungry 8 ohm subwoofers where going to BTL gives 1200 W compare to 350 W in stereo.

Michael

 

[MrOtto]

At some power outputs THD+N is actually lower in BTL than stereo:

Which amp with this power output can compete?

 

[mdsimon2]

At some power outputs THD+N is actually lower in BTL than stereo:
View attachment 198024

Which amp with this power output can compete?

I guess it depends on what you care about.

In all cases BTL has higher noise than stereo. You can see this by looking at lower power output where THD+N is dominated by N.

8 ohm - stereo: 1 W THD+N = 0.0012% (-98 dB), residual noise = sqrt(1 x 8) x (0.0012/100) = 34 uV
8 ohm - BTL: 1 W in to 8 ohm THD +N = 0.0025% (-92 dB), residual noise = sqrt(1 x 8) x (0.0025/100) = 71 uV

4 ohm - stereo: 1 W THD+N = 0.0019% (-94 dB), residual noise = sqrt(1 x 4) x (0.0019/100) = 38 uV
4 ohm - BTL: 1 W THD+N = 0.004% (-88 dB), residual noise = sqrt(1 x 4) x (0.004/100) = 80 uV

I personally care a lot about noise because unlike distortion it is always present.

The other issue with noise is that the BTL nominal gain is 31.5 dB compared to 25.5 dB for stereo. This means that with BTL upstream noise from your source will be multiplied by double compared to stereo.

I will admit that for 8 ohm loads THD+N from 30+ W is a bit better for BTL, however the opposite is true for 4 ohm loads. Overall this region of the THD+N plot does not worry me much as at higher power levels distortion from your speakers will certain dominate compare to distortion from your amplifier especially when that amplifier distortion is in the 0.001-0.002% range.

Michael

 

[pras1011]

Buckeye are you building a diagnostic board similar to the one that KJF uses?

 

[ruzun]

I have an old, circa 2007 Halcro MC70 Class D amp that was rated at 200 watts per channel x 7 with all channels driven. It was well reviewed at the time, and still works fine. Are these new modules a big step up from that older Class D Halcro Design? The amp still works fine but I'm tempted to update to an 8 channel NC502MP Buckeye just because it's been so many years.

 

[Sal1950]

I have an old, circa 2007 Halcro MC70 Class D amp that was rated at 200 watts per channel x 7 with all channels driven. It was well reviewed at the time, and still works fine. Are these new modules a big step up from that older Class D Halcro Design? The amp still works fine but I'm tempted to update to an 8 channel NC502MP Buckeye just because it's been so many years.

2007, Hell that's a spring chicken. I've got Adcoms here that are circa 1995.

 

[Doodski]

2007, Hell that's a spring chicken. I've got Adcoms here that are circa 1995.

I used to provide Adcom warranty service and the stuff was a joy to work on. I had zero ideas that the stuff would last this long. There was not very much to repair and when we got a piece in it was my responsibility to service it so I got all of it. Mostly pre-amps with a broken solder joint or a pot that needed a squirt of cleaner and lube. Nothing really serious.

 

[antcollinet]

I have an old, circa 2007 Halcro MC70 Class D amp that was rated at 200 watts per channel x 7 with all channels driven. It was well reviewed at the time, and still works fine. Are these new modules a big step up from that older Class D Halcro Design? The amp still works fine but I'm tempted to update to an 8 channel NC502MP Buckeye just because it's been so many years.

Ncore is probably a step up in measurements - just from the tech. Whether you will hear any benefit though is another matter : the MC70 is already rated pretty well for THD+N.

I would try to resist that itch. If you can't it is definitely one for try before you buy - being careful not to do what I did, and believe it sounds better because you want to upgrade.

 

[ruzun]

I think I will stick with the Halcro MC70 until it starts to wear out in some noticeable way. There are new Hypex modules due out soon I think the NCx500. So maybe in a year or three I will revisit the issue. I noticed the 8 channel NC502 based Monolith just went on sale for $2149 though, which seems pretty cheap. I'm not having any issues though so I'll stick with the Halcro for now since it might not be a noticeable difference getting a newer amp.

 

[Sal1950]

I noticed the 8 channel NC502 based Monolith just went on sale for $2149 though,

That includes free shipping, a very good price!
But do you need it? Your call. LOL

 

[Angsty]

I think I will stick with the Halcro MC70 until it starts to wear out in some noticeable way. There are new Hypex modules due out soon I think the NCx500. So maybe in a year or three I will revisit the issue. I noticed the 8 channel NC502 based Monolith just went on sale for $2149 though, which seems pretty cheap. I'm not having any issues though so I'll stick with the Halcro for now since it might not be a noticeable difference getting a newer amp.

The Halcros were formidable. I think your decision to stick with it is a good call. They might outlive these Hypex modules and it’s not likely you’d hear a difference.

 

[Rottmannash]

Who made the modules in the Halcro amp?

 

[Labjr]

Who made the modules in the Halcro amp?

They were designed by Bruce Candy of Halcro.

 

[Head_Unit]

It might also be interesting to see 6x600W supplied from wall outlet plug …..

I had the same thought, but it's just not going to happen unless your speakers are quite inefficient or your neighbors really far away. Or everyone is really drunk. Even playing with a mere 6 dB of dynamic range would make the power 900W* = probably wouldn't blow a breaker.

*mmm but if the peaks...something seems off about the exact math, can't figure it due to Mexico/Colombia taking up too much mental bandwidth. Arriba coqueros! Anyway unclipped would not blow the breakers methinks.

 

[pras1011]

The measured watts are terrible compared to what hypex state they are.

 

[Jdunk54nl]

The measured watts are terrible compared to what hypex state they are.

Do you mean the 500w spec. Iirc that number is at 1% (40db line on the graph) and then this exceeds it by 100w to achieve nearly 600w. Amir looks for the “knee” and uses that for max spec where as most manufacturer amp specs are at 1% unless otherwise noted.

 

[pras1011]

I thought using 1% thd to measure watts was cheating? Just like using a 1khz instead the entire frequency from 20hz to 20khz.