Buckeye Amps: Hypex NCx500 Official Thread

[Rick Sykora]

Because I know that Buckeye made his gain option choices by asking for input from the forum members and you know that I assist him. He is busy getting builds for others done, so think you can appreciate that. Rehashing history will not change the amplifier.

As I already stated, the amp has many choices and beyond that, if you want help, simply need more context. This is how design problems are solved.

 

[goryu]

I would go for the medium so I can take advantage of the better SNR of the DAC.
It might also be a good idea if the VC before the amp is not some rock-solid solution but a digital one susceptible to max to 0db for it's own reasons.

Thanks for offering a helpful comment. Using the medium setting of 5.8V at 4 ohms would mean the amp wouldn't reach it's rated output at the 4V input max of the dac if I understand this correctly so one would expect a peak output of less than rated power. Roughly 30% less voltage would mean quite a bit less it would seem.

 

[Sokel]

Thanks for offering a helpful comment. Using the medium setting of 5.8V at 4 ohms would mean the amp wouldn't reach it's rated output at the 4V input max of the dac if I understand this correctly so one would expect a peak output of less than rated power. Roughly 30% less voltage would mean quite a bit less it would seem.

You could use one of the high settings with a voltage divider carefully calculated for your needs if you insist about an exact match.
But it had to be a very good quality one so you won't add any noise,etc.

 

[goryu]

Because I know that Buckeye made his gain option choices by asking for input from the forum members and you know that I assist him. He is busy getting builds for others done, so think you can appreciate that. Rehashing history will not change the amplifier.

As I already stated, the amp has many choices and beyond that, if you want help, simply need more context. This is how design problems are solved.

Rehashing history? Not sure what you are on about. Amp has many choices? Did someone say it lacked choices? My comment wasn't about the lack of choices, rather the lack of a choice which would seem to better meet the typical XLR standard of 4V.

 

[goryu]

You could use one of the high settings with a voltage divider carefully calculated for your needs if you insist about an exact match.
But it had to be a very good quality one so you won't add any noise,etc.

Don't think I need an exact match but leaving 30% of the amp's capability out of reach is unfortunate.

 

[Sokel]

Because I know that Buckeye made his gain option choices by asking for input from the forum members and you know that I assist him. He is busy getting builds for others done, so think you can appreciate that. Rehashing history will not change the amplifier.

As I already stated, the amp has many choices and beyond that, if you want help, simply need more context. This is how design problems are solved.

To tell the truth the obvious choices should be 2,4 and 5V as that's what the majority of today's devices output.
On the other hand I like the 10V one .

 

[Rick Sykora]

Rehashing history? Not sure what you are on about. Amp has many choices? Did someone say it lacked choices? My comment wasn't about the lack of choices, rather the lack of a choice which would seem to better meet the typical XLR standard of 4V.

How many other vendors have you asked? If there is a better alternative buy it. Another Buckeye customer will be happy to have your amps.

 

[goryu]

How many other vendors have you asked? If there is a better alternative buy it. Another Buckeye customer will be happy to have your amps.

Why would I ask another vendor about this amp? Again, your comments are inappropriate and of zero utility.

 

[Rick Sykora]

Why would I ask another vendor about this amp? Again, your comments are inappropriate and of zero utility.

Ok.

 

[DonH56]

My 3 channel NCx500 amps have arrived at long last.

Here's a question...The variable gain is given as:

*Gain settings, if using the Buckeye buffer stage:
4ohm - 24.2dB/3.2Vrms (High), 19.2dB/5.8Vrms (Medium), 14.2dB/10.3Vrms (Low)
8ohm - 24.2dB/3.4Vrms (High), 19.2dB/6.0Vrms (Medium), 14.2dB/10.8Vrms (Low)
*Gain setting, if using the Hypex onboard buffer stage:
4ohm - 26.8dB/1.88Vrms
8ohm - 26.8dB/1.95Vrms


Curious, since this amp has XLR inputs, and my understanding is that the standard for such is 4Vrms, why there isn't a gain option that matches? Seems with my Octodac, which outputs the standard 4Vrms, I can either choose the High setting, and take care not to go near full output on the dac, or go to the Medium setting, and not have access to full power. Do I have that right?

Yes, you have it right. I am not aware of a specific standard using 4 Vrms (not that I have looked hard). For many years standard levels were -10 dBV ().316 Vrms) for consumer products and +4 dBu (1.228 Vrms) for professional products. Higher output voltage from DACs has become popular IMO to provide ever-higher SINAD/SNR numbers. They are typically limited by their noise floor so higher output voltage provides better SINAD (or at least SNR) numbers.

Note using the 8-ohm numbers and your 4 Vrms DAC's output, 3.4 Vrms on the high setting is a difference of -1.4 dB, so you would only overdrive by 1.4 dB max. That is a pretty small overdrive. If you choose the 6 Vrms setting, then you give up about 3.5 dB in headroom (or max output), a little over one-half the power. I would use the high gain setting if noise is not an issue. What are you using for a volume control? I would normally expect a volume control within the DAC or between DAC and amp, and would be surprised if you drove the amp to near maximum output in a typical listening environment (i.e. had the volume all the way to max).

HTH - Don

 

[Rick Sykora]

Yes, you have it right. I am not aware of a specific standard using 4 Vrms (not that I have looked hard). For many years standard levels were -10 dBV ().316 Vrms) for consumer products and +4 dBu (1.228 Vrms) for professional products. Higher output voltage from DACs has become popular IMO to provide ever-higher SINAD/SNR numbers. They are typically limited by their noise floor so higher output voltage provides better SINAD (or at least SNR) numbers.

Note using the 8-ohm numbers and your 4 Vrms DAC's output, 3.4 Vrms on the high setting is a difference of -1.4 dB, so you would only overdrive by 1.4 dB max. That is a pretty small overdrive. If you choose the 6 Vrms setting, then you give up about 3.5 dB in headroom (or max output), a little over one-half the power. I would use the high gain setting if noise is not an issue. What are you using for a volume control? I would normally expect a volume control within the DAC or between DAC and amp, and would be surprised if you drove the amp to near maximum output in a typical listening environment (i.e. had the volume all the way to max).

HTH - Don

Agree and in the active speaker case, input gain will be varied to deal with different driver sensitivities (and other needs). These are often larger gain concerns than the one cited, but that is not being discussed. Full amplifier power will not be utilized but see little point in bemoaning it.

 

[goryu]

Yes, you have it right. I am not aware of a specific standard using 4 Vrms (not that I have looked hard). For many years standard levels were -10 dBV ().316 Vrms) for consumer products and +4 dBu (1.228 Vrms) for professional products. Higher output voltage from DACs has become popular IMO to provide ever-higher SINAD/SNR numbers. They are typically limited by their noise floor so higher output voltage provides better SINAD (or at least SNR) numbers.

Note using the 8-ohm numbers and your 4 Vrms DAC's output, 3.4 Vrms on the high setting is a difference of -1.4 dB, so you would only overdrive by 1.4 dB max. That is a pretty small overdrive. If you choose the 6 Vrms setting, then you give up about 3.5 dB in headroom (or max output), a little over one-half the power. I would use the high gain setting if noise is not an issue. What are you using for a volume control? I would normally expect a volume control within the DAC or between DAC and amp, and would be surprised if you drove the amp to near maximum output in a typical listening environment (i.e. had the volume all the way to max).

HTH - Don

Thank you very much for a very useful reply.

The Oktodac outputs 4.2V max RMS. My speakers are a nominal 4ohms but will dip to 2Ohms. One channel will be used with multiple subs that will present a 2Ohm load. The dac has an internal volume control of each channel. Alternatively, I could set the dac at full output and control the volume in software since I will be actively amping with dsp crossovers, room correction, etc. Giving up half the power is not desirous. High setting seems to be the best alternative.

 

[Rick Sykora]

To tell the truth the obvious choices should be 2,4 and 5V as that's what the majority of today's devices output.
On the other hand I like the 10V one .

As I mentioned, there are lots of gain options on this amp and they were chosen with member input. As @DonH56 pointed out, there may be some special consideration for noise in some applications. Each channel on this amp has 3 gain options. Unlikely you would vary gain per channel for home theater, but you might for an active speaker. This is why I like to get the problem stated before we all start answering only to find out that our answers are not solving the actual problem. 

 

[Buckeye Amps]

Another large batch of the 2kW SMPS' have arrived and will be filling pending 2023 orders for the 3ch NCx500.
My hope is to have all 2023 orders for the 3ch NCx500 filled within the next 2-3wks (mid March goal).

Then we will be working on the 2024 orders and finally carrying a consistent inventory of the SMPS so there will no longer be back order delays.

 

[Dr. Cyrax]

Another large batch of the 2kW SMPS' have arrived and will be filling pending 2023 orders for the 3ch NCx500.
My hope is to have all 2023 orders for the 3ch NCx500 filled within the next 2-3wks (mid March goal).

Then we will be working on the 2024 orders and finally carrying a consistent inventory of the SMPS so there will no longer be back order delays.

Hope my order is in there somewhere, and ships soon... Very exited!

 

[Heyu]

Any advantage using the Ncx500 for Magnepan LRS that demand power vs my parasound hca 1500a amp?

 

[amper42]

No matter how much power I put to my Magnepan LRS they sounded like a tiny bit of reverb was added to the music and lacked definition. I got rid of mine and went with Revel. That's probably not what you are looking for but it really improved my listening sessions. The Revels offer superb definition and punch that my LRS couldn't provide no matter which amp I used. Buckeye amps didn't change that in my listening room.

 

[Heyu]

No matter how much power I put to my Magnepan LRS they sounded like a tiny bit of reverb was added to the music and lacked definition. I got rid of mine and went with Revel. That's probably not what you are looking for but it really improved my listening sessions. The Revels offer superb definition and punch that my LRS couldn't provide no matter which amp I used. Buckeye amps didn't change that in my listening room.

In my case my LRS sound amazing in my room. I just wonder is I'm missing out with the Parasound hca 1500a vs another amp like the Ncx500.

 

[NegativeEntropy]

In my case my LRS sound amazing in my room. I just wonder is I'm missing out with the Parasound hca 1500a vs another amp like the Ncx500.

I realize those LRS love power, but assuming your Parasound is not choking on the easy phase angle but sometimes 3 ohm load of these speakers then I doubt you would notice a difference - specs on the Parasound show 315 watts into 4 ohm stereo.

 

[Dundas]

Another large batch of the 2kW SMPS' have arrived and will be filling pending 2023 orders for the 3ch NCx500.
My hope is to have all 2023 orders for the 3ch NCx500 filled within the next 2-3wks (mid March goal).

Then we will be working on the 2024 orders and finally carrying a consistent inventory of the SMPS so there will no longer be back order delays.

Now all we need is the 14" SpeakOn case!