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Buckeye Nc502mp Review (6 Channel Amplifer)

rdenney

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What is the real power output of the nc502mp at 8 and 4 ohms? On the Hypex website they are measuring the power at 1khz only.

You have to look at the data sheets. They provide distortion vs. power at 100, 1000, and 6000 Hz.

Measured the way amps are traditionally measured (power at specified distortion across the band), I interpret their data to mean about 220 wpc into 8 ohms and 440 wpc into 4 ohms. “Peak” power is measured at 1% distortion, and as I recall that’s in the 350/600 range.

Rick “look at the graphs in the data sheets downloadable in the Hypex site” Denney
 

tonycollinet

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Thanks but Amir measured 313 watts at 4 ohm on the review.
Amir doesn’t measure power at the 1% distortion level, he rates power as the point at which the amp starts to clip, not once it has reached 1% distortion from clipping.
 

rdenney

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Thanks but Amir measured 313 watts at 4 ohm on the review.
That was to a different distortion level. One number out of context is not illuminating.

Rick “understanding why manufacturers usually don’t provide detailed test data as Hypex has done” Denney
 

EJ3

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Amir doesn’t measure power at the 1% distortion level, he rates power as the point at which the amp starts to clip, not once it has reached 1% distortion from clipping.
Which I believe is more telling than 1% distortion (if it clips before 1% distortion then, to me, the clipping point is the max power point).
 

tonycollinet

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Which I believe is more telling than 1% distortion (if it clips before 1% distortion then, to me, the clipping point is the max power point).
Which is a perfectly fine definition.

However the definition which many (not all) manufacturers use for their max power point, is when distortion has reached 1%**. Which is why a manufacturers specified max power is often higher than that given by Amir's test.

**Not totally unreasonably - still -40db and only just starting to become audible for many people, and then only on the absolute peaks of the music.
 

rdenney

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It depends.
I like the look of a CNC alloy case myself… but it adds to the cost.
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
 

Buckeye Amps

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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
The final tweak to my business is the wait times. The input boards are coming along well (sending the Hypex NCxxxMP official protoype build out for full testing this week). Once in full swing, my goal is 1-2wk lead time on 2 and 4ch builds, 2-4wks on 6/8ch builds max
 

Holmz

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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.


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

MrOtto

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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

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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

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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

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At some power outputs THD+N is actually lower in BTL than stereo:
NC502MPStereovsBTL.png


Which amp with this power output can compete?
 

mdsimon2

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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
 
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