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Apollon NCx500ST Stereo Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 5 1.1%
  • 2. Not terrible (postman panther)

    Votes: 6 1.3%
  • 3. Fine (happy panther)

    Votes: 32 7.1%
  • 4. Great (golfing panther)

    Votes: 408 90.5%

  • Total voters
    451
Why fight since we have all we need at hand:


(all the math included)

Find the real estate, get the numbers from amp's and PSU's efficiency charts and you're there.
 
That's never been my understanding. Very few Class AB amps are stable @ 2ohms, whereas Class D is almost exclusively used to power 2ohm high current subwoofer loads for HT, Car and Professional applications.
One of those stable at 2 ohm load is the Mark Levinson #27. 100W @ 8ohms, 200W at 4 ohms, 350W at 2 ohms. And it can be bridged.
 
I tried them both and I just prefer Purifi. I can't blast high volumes and I prefer the lower distortion.
 
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I tried them both and I just prefer Purifi. I can't blast high volumes and I prefer the lower distortion.
Do you think the difference in distortion is audible?
 
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I tried them both and I just prefer Purifi. I can't blast high volumes and I prefer the lower distortion.
From Hi-Fi Classics:
NAD 2200 test at 2 Ohms (did not test the distortion at full power):
The 2-ohm distortion was also very low at most power levels, reaching 0.0225 percent at 300 watts.
The results were very impressive. With the standard 20-millisecond test signal, the maximum output was 450 watts into 8 ohms (for a dynamic headroom of 6.5 dB), 685 watts into 4 ohms, and 870 watts into 2 ohms.
We repeated these measurements with 4-ohm loads and with longer-duration tone bursts.
If that is not enough, the amplifier can also be operated in a bridged (mono) mode, in which it is rated to deliver up to 400 watts of continuous output into 8 ohms—or, in terms of dynamic power, 1,200 watts into 8 ohms and 1,600 watts into 4 ohms! It is also said to have a wide “dynamic power envelope,” which means that it can maintain these high levels for longer than the standard 20-ms bursts.
Using the “lab” inputs, the lower — 3-dB frequency was below our 5-Hz measurement limit, and the upper — 3-dB frequency was 135 kHz. The A-weighted noise of the amplifier was 93 dB below 1 watt, or 113 dB below its rated output. The amplifier was stable when driving simulated reactive speaker loads, and its reactive load factor was 1.6 dB at 63 Hz. The slew factor exceeded our measurement limit of 25.

You might be amazed (perceptions MAY be altered):

Vintage NAD 2200 Power Envelope Audio Amplifier Dyno Test​


Williston Audio Labs
371K subscribers
 
I think this is the one
 

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There's a chart somewhere I'll see if I can find it. Above and beyond I just preferred the sound of the Purifi for some reason.
The chart doesn't actually go into audibility in any way. Preference is of course subjective and has very little to do with sound quality these days.
 
I hope NAD will upgrade their next Hypex NCore amps with the new NCX modules.
 
I received my Apollon amp yesterday, their implementation of the Hypex NCx500 ST NCOREx Stereo Amp. No owner's manual nor power cord (I need 117VAC, US). It's probably OK since connecting to it is similar to other amps. I am using a 14 gauge cord that's good for up to 15 amps. But it is a bit strange.


I bought it as the backup for the ML #27, which is 30+ years old. The Apollon will fill this role nicely and for a fraction of the cost of a class A or A/B amp with a similar drive, $1.2K vs ??? Amir's findings are so good, I had to give it a try.


I listened to this amp today with my SP-6 preamp and Revel f108 speakers (full range). I sit about 2m from the speakers. I normally listen about 85-90 dB at listening position. I've measured the voltage on the speakers in real time. I found the max power I'm calling for is around 10 watts. Not much. Comparison amp is my old and trusty ML #27 with new blue can capacitors in the PS.


Here's my impressions after only an hour of critical listening... The Apollon sounds airier than the ML, but there's no sibilance or accentuated highs. It doesn't have the same bass impact. But male voices were very clear and human-sounding. It's a good break from the darker ML sound. I'm running boh amps at the same gain, which is about 26dB. More listening definitely needed as the differences are quite small and may moderate after longer listening. I am assuming that there's no "break-in" involvbed. My overall impression is that this is a very clear and clean amp with a quite neutral presentation, but not cold and clinical.


I did have to pay an additional $140 for the new US tariff. This is a big concern as a lot of gear is more expensive than the Apollon amp. Speakers for example.
I've been listening to this amp for about 12 days as I alternated it with my ML #27. Here are my impressions from this longer listening period.

- Runs as cool as the ML#27 at the same power output.
- No extraneous noises like on/off pops, clicking relays, grunts and groans. It is ready to go right after turn-on. The #27 is noisier and lets out a tiny thud through the right speaker on turn-off.
- Balanced connections are straightforward and easy to make and break. I didn't try the RCA inputs.
- Very small and lightweight compared to the #27.
- Quite neutral. I couldn't detect any sound signature. It does not seem to have the "weight" that the #27 has. This is clearly a personal, vague and very subjective feeling but it it the best description I can come up with. I never heard even the slightest indication of distortion from the amp.
- Long listening sessions weren't "fatiguing".
- No deficiencies in any part of the audio spectrum. None. It is not particular about genre.
- The four gain choices are a very good feature as they allow one to adjust the gain so that the preamp is operating at its quietest and least distorted setting.
- I always ran at normal listening level at an output of 20 watts or under. I can't comment on higher power operation.
- Great back-up for my aging #27.

Am I now going to replace the ML #27 with this guy? No, not right now. I am too emotionally attached to it. Unless I decide I want a tube amp when the #27 fails for good, this little Apollon beast is my next amp.
 
I've been listening to this amp for about 12 days as I alternated it with my ML #27. Here are my impressions from this longer listening period.

- Runs as cool as the ML#27 at the same power output.
- No extraneous noises like on/off pops, clicking relays, grunts and groans. It is ready to go right after turn-on. The #27 is noisier and lets out a tiny thud through the right speaker on turn-off.
- Balanced connections are straightforward and easy to make and break. I didn't try the RCA inputs.
- Very small and lightweight compared to the #27.
- Quite neutral. I couldn't detect any sound signature. It does not seem to have the "weight" that the #27 has. This is clearly a personal, vague and very subjective feeling but it it the best description I can come up with. I never heard even the slightest indication of distortion from the amp.
- Long listening sessions weren't "fatiguing".
- No deficiencies in any part of the audio spectrum. None. It is not particular about genre.
- The four gain choices are a very good feature as they allow one to adjust the gain so that the preamp is operating at its quietest and least distorted setting.
- I always ran at normal listening level at an output of 20 watts or under. I can't comment on higher power operation.
- Great back-up for my aging #27.

Am I now going to replace the ML #27 with this guy? No, not right now. I am too emotionally attached to it. Unless I decide I want a tube amp when the #27 fails for good, this little Apollon beast is my next amp.
I bet adding a 20 lbs base to this amp will add the 'weight' you are missing from the ML #27.
 
I bet adding a 20 lbs base to this amp will add the 'weight' you are missing from the ML #27.
Yeah, I'm sure it would help. But the #27 weighs about 90 lbs, so I'd need to add about 80 lbs. Then it won't move when I press the on/off button.
 
And for this who are curious, the "basic" design is pretty damn luxurious in itself. One of the best looking case work for "basic."
Just getting to grips with all the various choices... so I guess the "Lux" is the same as the basic model with a fancy case, making it quite heavier? Any benefits apart from looks?
 
Just getting to grips with all the various choices... so I guess the "Lux" is the same as the basic model with a fancy case, making it quite heavier? Any benefits apart from looks?
Pride of ownership? Lol
No, just fancier case really.
 
Pride of ownership? Lol
No, just fancier case really.
might it affect the temperature of the case? I saw this from Apollon

"For those who are skeptical about the heat dissipation of this amplifier, we offer a Lux version featuring a 10mm thick aluminum enclosure with large ventilation openings on both the top and bottom."
 
Got the Apollon 1ET6525SA amplifier a month ago. Can't fault it in any way, and it doesn't run hot at all in my setup (my model only have side ventilation). Was shipped from Apollon earlier than the stated lead time, and overall I am very satisfied with both the product and the service.
 
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