Hypex NCx500 Class D Amplifier Review

[antcollinet]

Good to know, thanks! I never ordered audio gear from outside the EU, so no experience. But nevertheless good to know that I wouldn't have any unpleasant surprises.

You will still pay VAT on import. Customs duty and VAT are separate taxes. And that will be on stuff ordered within EU or outside of it.

 

[ommadusk]

I received the Audiophonics stereo amp today. It sounds wonderful. I'm wondering if anyone knows what the input sensitivity for maximum power is on a bufferless NcoreX?

 

[staticV3]

I'm wondering if anyone knows what the input sensitivity for maximum power is on a bufferless NcoreX?

sqrt(500*2)*10^(-11.5/20)=8.41Vrms at 2Ω
sqrt(600*4)*10^(-11.5/20)=13.0Vrms at 4Ω
sqrt(300*8)*10^(-11.5/20)=13.0Vrms at 8Ω

 

[Julf]

I've just received my Audiophonics HPA-S600NCX and I've put it on 19dB gain. That means it reaches maximum power at 5.33v. I'm using a 4v output DAC, the DX7 Pro+, which happens to be very good as my source and pre amplifier. I've realised that I'm not going to turning up the volume past -20-25dB when listening to music and it will be lower when watching TV. The Audiophonics Purifi HPA-S400ET has a 20dB gain which gives maximum power at 4.19v. I also ordered that amp and I'm going to compare the two with my DAC.

When you compare, you have to start by matching levels. 1 dB level difference is not perceived as a volume difference, but often perceived as "better" in terms of things like "clarity".

 

[Tom22]

I was in touch with Martin Logan on the issue of impedance of electrostats (ESL 11A in my case), issue of „hard to drive“…the amp module they refer to is the Ncx500 that I mentioned in my mail to them.

Just wanted to share their reply with you:

„Unfortunately we are unable to share impedance charts to the public.

In the case of the ESL 11A, the woofer section is of course self amplified so the customers amplifier is really of no concern for frequencies around 300Hz and below. The minimum impedance of the panel is .6 Ohms @ 20kHz. At first glance that may seem very difficult to handle, but we also need to remember that there is very little content at that high of a frequency range so it isn’t nearly as difficult as it may sound.

Contrary to common belief the panel is not difficult to drive as we have done extensive testing with anything from a modest AV Receiver up to reference level mono amplifiers. The amp module the customer is looking at is extremely capable and should handle this speaker with no issue.

On paper a dual mono design is superior, but the panel doesn’t necessarily NEED that much to function properly as most customers aren’t using an amp setup like that. The difference would just come down to which version sounds better which is a subjective answer only the listener can decide. That being said, there is a certain piece of mind knowing that the amp is the most capable version and this way there is no regret or second guessing.“

 

[SIY]

I was in touch with Martin Logan on the issue of impedance of electrostats (ESL 11A in my case), issue of „hard to drive“…the amp module they refer to is the Ncx500 that I mentioned in my mail to them.

Just wanted to share their reply with you:

„Unfortunately we are unable to share impedance charts to the public.

In the case of the ESL 11A, the woofer section is of course self amplified so the customers amplifier is really of no concern for frequencies around 300Hz and below. The minimum impedance of the panel is .6 Ohms @ 20kHz. At first glance that may seem very difficult to handle, but we also need to remember that there is very little content at that high of a frequency range so it isn’t nearly as difficult as it may sound.

Contrary to common belief the panel is not difficult to drive as we have done extensive testing with anything from a modest AV Receiver up to reference level mono amplifiers. The amp module the customer is looking at is extremely capable and should handle this speaker with no issue.

On paper a dual mono design is superior, but the panel doesn’t necessarily NEED that much to function properly as most customers aren’t using an amp setup like that. The difference would just come down to which version sounds better which is a subjective answer only the listener can decide. That being said, there is a certain piece of mind knowing that the amp is the most capable version and this way there is no regret or second guessing.“

My ESLs (disclaimer: not Martin Logan) are being driven by a few different Hypex NCORE modules and now an AXIGN. Exactly zero problems, the combos are flawless and all sonically identical, the minor differences in bench measurements notwithstanding.

It's curious that "Unfortunately we are unable to share impedance charts to the public" since that's a trivially easy measurement for anyone to make. What in the world are they thinking?

 

[soerenssen]

Please help me choose between 3 mono blocks and a 3-channel NCx500, cosidering different gain "requirements":

Inputs:
- Denon x4800h with 2V RCA pre-outs for LCR
- Denon LR pre-outs connected to Topping A70 Pro (8V XLR out) for LR via RCA
- 2-channel DAC (Sabre D70 Pro) connected to Topping A70 Pro for music via XLR
- Denon Center pre-out connected directly to an NCx500 amp (RCA-RCA)

Using the Topping pre-amp, the input gain of the stereo modules could be set to 19V (for low-gain 8V is not sufficient). The third amp should be set to high gain because of the RCA connection. But, correct me if I'm wrong, using a multi-channel amp I'll have only one gain setting applied to all the 3 amps, making it difficult to match gain across mixed RCA/XLR inputs.

The idea is to us 3 mono blocks, have the one volume level saved in the Topping pre-amp for HT, another volume level saved for music, and I'd use the pre-amp to switch inputs. Is this a good idea to match gain like this between XLR and RCA sources or am I overlooking something?

 

[Sokel]

Please help me choose between 3 mono blocks and a 3-channel NCx500, cosidering different gain "requirements":

Inputs:
- Denon x4800h with 2V RCA pre-outs for LCR
- Denon LR pre-outs connected to Topping A70 Pro (8V XLR out) for LR via RCA
- 2-channel DAC (Sabre D70 Pro) connected to Topping A70 Pro for music via XLR
- Denon Center pre-out connected directly to an NCx500 amp (RCA-RCA)

Using the Topping pre-amp, the input gain of the stereo modules could be set to 19V (for low-gain 8V is not sufficient). The third amp should be set to high gain because of the RCA connection. But, correct me if I'm wrong, using a multi-channel amp I'll have only one gain setting applied to all the 3 amps, making it difficult to match gain across mixed RCA/XLR inputs.

The idea is to us 3 mono blocks, have the one volume level saved in the Topping pre-amp for HT, another volume level saved for music, and I'd use the pre-amp to switch inputs. Is this a good idea to match gain like this between XLR and RCA sources or am I overlooking something?

You must also calculate the XRL-RCA voltage drop.

 

[soerenssen]

You must also calculate the XRL-RCA voltage drop.

Center mono block with RCA 2V input from the Denon (RCA-to-RCA).
LR stereo with 8V XLR input from the pre-amp: XLR-to-XLR between the pre-amp and the amp, but indeed, the Denon will connect via RCA to the same pre-amp - did you mean the voltage drop there? If yes, it means that an even higher volume level would be saved for HT usage in the pre-amp, but if possible, I would not change the gain settings on the LR mono blocks back and forth each time.
Is this the proper way to match them, using the volume knob on the pre-amp?

 

[Sokel]

The setup your thinking about is over complex.I can imagine lots ans lots of ways for things to go wrong and a result far from optimal.

I would simplify it a lot by getting a device that can handle everything (I know nothing about HT but there must be devices that are fit for both HT and 2-channel).

That's the only way I can think of so to maintain integrity and noise-free results all the way to the speakers,otherwise you are likely to get to the rabbit hole of grounds loops (thinking only about different gains and mixing RCA-XLR,etc) as we have seen countless times.

 

[soerenssen]

The setup your thinking about is over complex.I can imagine lots ans lots of ways for things to go wrong and a result far from optimal.

I would simplify it a lot by getting a device that can handle everything (I know nothing about HT but there must be devices that are fit for both HT and 2-channel).

That's the only way I can think of so to maintain integrity and noise-free results all the way to the speakers,otherwise you are likely to get to the rabbit hole of grounds loops (thinking only about different gains and mixing RCA-XLR,etc) as we have seen countless times.

I know it's complex. So, if I connect the Denon to the NCx500 via RCA and in parallel to the pre-amp via RCA, this would have a higher risk for a ground loop? But then why do AVR manufacturers sell devices with RCA pre-outs? Would it be a better approach to use only RCA-RCA or only XLR-XLR everywhere in the chain?

Edit: Some manufacturers offer XLR pre-outs for LR or LCR and the surround pre-outs are RCA. If balanced and unbalanced interconnects are truly incompatible with each other, then I don't understand why they do it.

 

[Julf]

Edit: Some manufacturers offer XLR pre-outs for LR or LCR and the surround pre-outs are RCA. If balanced and unbalanced interconnects are truly incompatible with each other, then I don't understand why they do it.

They are not incompatible. RCA to XLR is no problem, other way around depends on the gear and their ground/earth structure.

 

[soerenssen]

They are not incompatible. RCA to XLR is no problem, other way around depends on the gear and their ground/earth structure.

In my setup it would be a mixture of RCA-RCA (or RCA-XLR if that's better) and XLR-XLR, initially. Definitely no XLR-RCA.
The idea is to re-use the LR speakers, without having to buy a second stereo amp them (driven by the AVR pre-outs).

 

[soerenssen]

The power supply used in these designs is a very significant contributor to the overall audio performance. In multichannel designs, be sure that the power supply has adequate total power to perform its job.

The reason we only carry the Hypex NCx500 mono block version is primarily due to the power supply limitation of the SMPS1200A700. This power supply module can put out approximately 1,000 watts, which when driving loads that dip down to 4 Ohms would limit the specified output power from 700 watts to 500 watts.

Deer Creek Audio is an authorized Hypex dealer. We sell Hypex amplifiers that are pure Hypex designs with proven performance and reliability. Check us out at deercreekaudio.com

I am trying to decide between a stereo and dual mono setup, but having contradicting information from different assemblers is a bit confusing for someone who is not educated in this. If the SMPS1200 can put out 1000W only, it seems undersized for two amps on paper or under load it leads to audible(?) distortion sooner. I would like to avoid clipping (and extra distortion) with my Kef Reference 3 speakers for sure. If someone can tell me that the only way to avoid that is to go with two mono blocks, I'm happy to click the buy button anytime. On the other hand, I worked hard for that money so if a stereo amp does the job too without dropping a sweat, why would someone spend extra for the monos?

I opened a ticket at Hypex directly, hoping to clarify this and also help others who are trying to decide.

 

[Julf]

In my setup it would be a mixture of RCA-RCA (or RCA-XLR if that's better) and XLR-XLR, initially. Definitely no XLR-RCA.
The idea is to re-use the LR speakers, without having to buy a second stereo amp them (driven by the AVR pre-outs).

Then you should be more than fine.

 

[soerenssen]

Are there any crosstalk measurements available for the stereo version, to compare with the mono block?

 

[Killingbeans]

Didn't we already drive a stake through the heart of that on page 55?

 

[soerenssen]

Didn't we already drive a stake through the heart of that on page 55?

Yes I know, but without available measurement data.

 

[peng]

Didn't we already drive a stake through the heart of that on page 55?

I think he knows, but he just want to have the numbers so he can pick the one with the highest numbers regardless.

 

[soerenssen]

I think he knows, but he just want to have the numbers so he can pick the one with the highest numbers regardless.

Whatever can justify paying double for the dual mono config (or aiming for even more grunt if required).
But I'm not so worried about crosstalk, more about the power. It's not even a question of having some extra power reserve and less strain on the PSU (compared to the stereo version) at this point. Sandu from soundnews is using a dual bridged AHB2 setup for the Kefs. That's 500W into 4ohm (at 0.00026% distortion) before protection kicks in. The speakers go well below 4 ohm between 40Hz and 300Hz. He even mentions the NC1200 as a good alternative. According to the comparison of a single PSU powering one vs. two amps (from @Rick Sykora), the NCx500 puts out 390W or 470W at 0.002%. This makes me wonder if these speakers require even more than 2x NCx500. On the other hand, the AHB2 has 18A output current per channel, the NCx500 offers 27/28A.

Edit: Both of them are overkill? Probably. In what circumstances can these figures drop, for any reason? Are there any alternatives in this price segment at all?
Edit 2: KEF recommends an amp that has 60-110% of the power rating of the speaker.