Apollon Hypex NC2K Monoblock Amplifier Review

[Chromatischism]

Individual instruments will have their own spectral makeup, but music creators can do whatever they want in the studio, especially once everything is put together:

 

[CDMC]

People aren't here to put an effort into answering ill-informed questions. Instead of asking these arbitrary questions based on lack of information, given the new information above on the frequencies produced by musical instruments why don't you think/research why any recording would arbitrarily limit itself to 17khz and if you think there is a reason for it, make the case.

When you make nonsensical ill-informed statements like "anything above some arbitrary frequency is not part of musical content and not what the musician intended" which isn't supported by logic let alone knowledge, the onus is on you to support your thesis than simply say because so far I haven't seen anything on Google, prove me otherwise.

Otherwise, you are just wasting people's time.

I think you are being a bit harsh. He asked a question and did so nicely. I agree with his premise, that there is no real musical information above 17k and were there, the vast majority of people lack the physical capability to hear it. As such, a .5 db rolloff at 20k is inaudible.

 

[Vasr]

I think you are being a bit harsh. He asked a question and did so nicely. I agree with his premise, that there is no real musical information above 17k and were there, the vast majority of people lack the physical capability to hear it. As such, a .5 db rolloff at 20k is inaudible.

Good example of interpreting with a confirmation bias.

 

[pjug]

It is easy to experiment in audacity to get an idea if the rolloff is something you can hear Just use pink noise and apply EQ similar to what the amp does to a section of the track. For me (can't hear above 14KHz) the difference is not noticeable.

 

[pjug]

More than high frequency rolloff, I wonder what happens at lower frequencies when these (or any amp) drive real speakers. Here are stereophile measurements of a Bel Canto nCore. The simulated speaker curve does not look bad, just 0.2dB or so of wiggle, but I imagine this could be worse with some speakers. So then an A/B test with different amps might show an audible issue.

from https://www.stereophile.com/content/bel-canto-e1x-power-amplifier-measurements

Fig.1 Bel Canto e1x, frequency response at 2.83V into: simulated loudspeaker load (gray), 8 ohms (left channel blue, right red), 4 ohms (left cyan, right magenta), 2 ohms (green) (1dB/vertical div.).

 

[pjug]

It could, but it's a lot easier to just choose all neutral electronics and then go shopping for loudspeakers.

That sounds good, but if a couple few tenths of a dB is coloration then the choices are really narrowed. Purifi, Accuphase, I'm sure some others. But you rule out nCore, AHB2, and other really good amplifiers.

 

[CDMC]

Good example of interpreting with a confirmation bias.

I resemble that remark. I still think it was a bit harsh, he was being nice and asking a genuine question.

 

[Chromatischism]

That sounds good, but if a couple few tenths of a dB is coloration then the choices are really narrowed. Purifi, Accuphase, I'm sure some others. But you rule out nCore, AHB2, and other really good amplifiers.

I would contend that NCore is more than good enough for most people.

Those seeking perfection need not apply...

 

[Deleted member 19195]

I would contend that NCore is more than good enough for most people.

Those seeking perfection need not apply...

I agree, and would go one further; the UCD is more than good enough for most people. NCore takes it to another level but has no appreciable audible difference to most people. We have surpassed ludicrous low levels of distortion.

 

[restorer-john]

More than high frequency rolloff, I wonder what happens at lower frequencies when these (or any amp) drive real speakers.

Do you mean lower than the AP's plot limit at 10Hz? There's an HPF to prevent DC offsets playing havoc with the ADC.

The low end response of a decent amp varies little in the low end with increasing power output until you get close to clipping and power supply limitations kick in. The top end is a different story however.

With real speakers attached to an amplifier, doing frequency response measurements at the speaker terminals is limited to low powers, unless you want to vaporize tweeters or deafen everyone within earshot.

 

[pjug]

Do you mean lower than the AP's plot limit at 10Hz? There's an HPF to prevent DC offsets playing havoc with the ADC.

The low end response of a decent amp varies little in the low end with increasing power output until you get close to clipping and power supply limitations kick in. The top end is a different story however.

With real speakers attached to an amplifier, doing frequency response measurements at the speaker terminals is limited to low powers, unless you want to vaporize tweeters or deafen everyone within earshot.

No, I wasn't thinking about very low freqs. I was just thinking about A-B comparison of amps, and if you can get at whether the rolloff is audible that way. How do you separate hearing rolloff from hearing dips resulting from output impedance?

 

[restorer-john]

How do you separate hearing rolloff from hearing dips resulting from output impedance?

With most amplifiers being DC coupled (to the speaker) and offering very low output impedances at low frequencies, it's really not an issue. Capacitor coupled designs from the long distant past, when coupled with modern speakers (bass reflex designs) can do some interesting things at or near the resonance impedance peak.

Bass can become big and woolly (uncontrolled) and either sound awesomely good or the complete opposite with such vintage amplifiers.

 

[pjug]

With most amplifiers being DC coupled (to the speaker) and offering very low output impedances at low frequencies, it's really not an issue. Capacitor coupled designs from the long distant past, when coupled with modern speakers (bass reflex designs) can do some interesting things at or near the resonance impedance peak.

Bass can become big and woolly (uncontrolled) and either sound awesomely good or the complete opposite with such vintage amplifiers.

I'm not communicating very well today. I said lower frequencies, but I was still talking about treble frequencies (like the dip at 5K in the simulated loudspeaker curve in the plot that I copied). Maybe in an A-B test you think you are hearing the top end rolloff but really you are hearing the dip due to output impedance. Now I'm getting a bit sheepish about going on about it because it doesn't seem too important, and maybe polluting a review thread.

 

[restorer-john]

@pjug It's all good mate.

 

[pjug]

@pjug It's all good mate.

Phew!

I think I was thrown by the curve of the Bel Canto that I copied. nCore amps should have very high damping factor but the Bel Canto does not. What's up with that?

Anyway, the rolloff on the Apollon doesn't bother me. I don't need this kind of power as long as I'm on good terms with my neighbors but I'll keep this Apollon in mind in case that changes.

 

[andreasmaaan]

Phew!

I think I was thrown by the curve of the Bel Canto that I copied. nCore amps should have very high damping factor but the Bel Canto does not. What's up with that?

Are you sure that amp actually uses an nCore module? The entire suite of measurements look completely unlike any nCore I've seen.

EDIT: ok, it's a lot more complicated. Here's Bel Canto's description of how the amp works:

"The first stage delivers most of the gain, either 14dB or 20dB depending on an internal switch setting and operates in class-A mode in the e1X amp. The second stage is the Ncore modulator that delivers all of the current to the speaker load and has a gain of 4.5× or 13dB. The first stage amplifier is our proprietary discrete Single Stage High Current class-A amplifier and uses selected resistors and capacitors for best performance. The signal path from the input stage through the Ncore modulator stage is fully discrete. There's more than 50dB of loop gain throughout the audio band in both the input and the Ncore modulator stages. The result is a constant low-distortion signature throughout the audio band and none of the coloration that can occur when feedback is used without adequate bandwidth or loop gain in the amplifier stages."

 

[pjug]

Are you sure that amp actually uses an nCore module? The entire suite of measurements look completely unlike any nCore I've seen.

No not really sure as I am not really familiar with the Bel Canto amp, but from the linked measurement page:
"Removing the top cover to reset the gain revealed the two Hypex Ncore class-D output modules and the switch-mode power supply"

 

[andreasmaaan]

No not really sure as I am not really familiar with the Bel Canto amp, but from the linked measurement page:
"Removing the top cover to reset the gain revealed the two Hypex Ncore class-D output modules and the switch-mode power supply"

Yes, sorry, I edited my previous post, which now explains why it measures so differently.

 

[pjug]

Yes, sorry, I edited my previous post, which now explains why it measures so differently.

Thanks very much for that. I'm sorry that I didn't notice that this is a different animal.

 

[Chromatischism]

I'm not communicating very well today. I said lower frequencies, but I was still talking about treble frequencies (like the dip at 5K in the simulated loudspeaker curve in the plot that I copied). Maybe in an A-B test you think you are hearing the top end rolloff but really you are hearing the dip due to output impedance. Now I'm getting a bit sheepish about going on about it because it doesn't seem too important, and maybe polluting a review thread.

Some actual measurements here: http://archimago.blogspot.com/2020/01/measurements-hypex-ncore-nc252mp.html

Amplifier Damping into 4Ω load is high: Impressive! We're looking at an average of 340x, with high damping consistently across the audible spectrum. Above a damping factor of 100, measurement precision becomes very important so I had to perform a few readings and average things out to get that graph above. To have an even more accurate look at the output impedance, check out page 13 of the data sheet. Remember that we don't necessarily need very high values (something like >50x average would be great) but the stronger the damping factor, the more "load invariant" the amplifier becomes and we can show this when we look at the frequency response of an actual reactive speaker load: