NCx500 vs Purifi 1ET6525SA vs ICEpower 1200AS2 for a long-term “end game” home system

[Lando]

Hi everyone,

I’m trying to choose a power amplifier that I can keep for many years, ideally through future speaker upgrades, and I’d like to hear opinions from people who have more experience with these platforms.

My use is purely domestic: music, movies and gaming. I’m not a studio engineer, but I do care a lot about clean sound, low noise, reliability, thermal behavior and avoiding unnecessary upgrades every few years.

My current/future chain will be roughly:

PC → miniDSP Flex Balanced → power amplifier → passive speakers
miniDSP Flex → active SVS subwoofer

Current speakers are Wharfedale Diamond 12.1i the new version, but these are not the speakers I’m choosing the amplifier around. In the future I’d like to move to high-quality floorstanders or other serious passive speakers, possibly in a larger room, so I want reasonable compatibility with lower sensitivity and/or more demanding loads.

These are the main amplifiers I’m considering:

1. Audiophonics HPA-S600NCX — 2× Hypex NCx500
https://www.audiophonics.fr/en/powe...lass-d-ncore-ncx500-2x600w-4-ohm-p-17591.html

Roughly:

• 2×600 W / 4 Ω in the Audiophonics implementation
• 2×300 W / 8 Ω
• around 7 µV module output noise unbuffered
• very low THD+N
• shared Hypex SMPS1200A700
• switchable gain
• passive cooling

2. Audiophonics HPA-S450ET — 2× Purifi 1ET6525SA
https://www.audiophonics.fr/en/power-amplifiers/audiophonics-hpa-s450et-p-20205.html

Roughly:

• 2×450 W / 4 Ω
• 2×230 W / 8 Ω
• ~510 W / 2 Ω
• ~6.6 µV output noise
• extremely low THD+N
• extremely low output impedance
• frequency response specified around ±0.01 dB through the audio band across different loads
• shared Hypex SMPS1200A400
• switchable gain

3. TC Rastrs TCR1200S PRO — ICEpower 1200AS2
https://tcrastrs.com/

This one is considerably cheaper, around €700, and uses the mature ICEpower 1200AS2 platform.

The attraction is:

• very high available power
• integrated amplifier + PSU module
• active cooling in the PRO version
• mature platform
• much lower price

The trade-offs seem to be higher idle consumption/heat and less extreme measurements than NCx/Purifi, although still far below what I would expect to be an audible limitation in normal use.

There is also the new ICEpower SC400A2 / “Super Conductor” platform appearing in 2026, which looks technically much closer to Purifi/NCx in efficiency, distortion and load-independent frequency response. I’m aware that finished commercial implementations are only now starting to appear, so I’m not necessarily waiting for it, but it does make the timing interesting.

The part I’m struggling with is this:

The Purifi is clearly the most “mathematically ideal” of the three in terms of distortion, output impedance and frequency-response invariance.

The NCx500 gives up a small amount of that extreme performance but provides more voltage/power headroom into typical 4–8 Ω speakers.

The ICEpower 1200AS2 is much cheaper and more than good enough on paper, but is an older and less efficient design.

The NCx500 and Purifi Audiophonics units are also very close in price, so this is not really a budget question.

What I would especially like opinions on:

• For a long-term domestic system, is there any practical reason to prefer the 1ET6525SA over NCx500 other than the last few dB/decimals of measured performance?
• Does the extra NCx500 power meaningfully broaden future speaker compatibility, or is ~450 W/4 Ω from the Purifi already effectively “enough for almost anything sensible”?
• Are there important differences in current capability, behavior with difficult impedance/phase loads, clipping behavior or protection that are easy to miss by just comparing headline wattage?
• Which platform would you prefer from a long-term reliability/serviceability perspective?
• Would you personally pay roughly twice the price of a good 1200AS2 implementation for NCx/Purifi in a normal home system?
• Is there another amplifier/platform in Europe around this price range that I should seriously consider before buying?

I’m less interested in subjective claims like “warmer”, “more musical” or “better soundstage” unless there is a technical reason behind them. I’m mainly trying to understand whether there are engineering differences that could matter with future speakers, or whether I’m simply entering the territory of diminishing returns.

Thanks — any measurements, technical arguments or long-term ownership experience would be very welcome.

 

[staticV3]

Helpful formulas when dealing with output power:

1. Power factor to dB difference:

10*log10(600W/450W)= 1.25dB difference

2. dB difference to perceived loudness factor

2^(1.25dB/10dB)= 1.09 -> 9% louder

If you have Equalizer APO installed somewhere, or any other software with precise decibel input (Audacity, Audition etc.), try applying a 1.25dB boost and get a feel for how much louder the Hypex could actually play.

 

[Sokel]

All though I use 2 1200as2 (as monos) and there are truly workhorses, your rig probably does not justify it, unless you want to evaporate your mains at some time.

I would get the Purifi or the Conductor if I were you and I would also take care of a safeguard scheme about delivered power, to the point of speaker's max SPL or your listening habits (whichever is lower) .

 

[Kravi4ka]

I had an amp based on the 1200as2, never liked the sound of it no matter how good the measurements or data is. I love my 1ET9040. Just an opinion.

 

[Redacted]

You're probably overthinking the amp thing.
They are all good and way more than loud enough to get the police round. And all transparent.
As to reliability, all we have (AFAIK) is anecdotes. And anecdotes are not data.

I'm in the camp of being most fussy about how the speakers sound in your room* - the rest of the kit, I tend to think, is increasingly about functionality and looks. Pick any of the amps, or maybe the cheapest. Or whichever has a local office, or reputable dealer or local repair centre, where you live. You don't want to get into export/import for repairs.

*Although I don't follow my own advice, since I'm hoping to stay married.

 

[Keith Flanker]

Practical differences beyond the measurements: the 1ET6525SA has the flattest response into varying loads and the lowest output impedance of the three, which only really matters with long speaker runs or speakers with wild impedance swings; the NCx500 gives you roughly 1.25dB more headroom and is more forgiving if you later pick low-sensitivity floorstanders in a large room. For a domestic setup with a miniDSP Flex in front, 450W into 4 ohms is effectively enough for almost anything sensible — the extra NCx500 power is a nicety, not a requirement. I’d also check input sensitivity and gain matching against the Flex’s output level, since that affects the noise floor more than the module’s headline specs. Reliability-wise both platforms are mature, so I’d buy whichever has the better local warranty or service. And since you said price isn’t really the question, I’d skip the 1200AS2 — it’s fine, just not worth the trade-offs when the other two are that close in cost.

 

[Multicore]

I’m trying to choose a power amplifier that I can keep for many years, ideally through future speaker upgrades, and I’d like to hear opinions

Bryston.

All the amps you suggested are more than excellent in terms of capability and signal hygiene. But none are, in my view, products designed to last a lifetime with a warranty to convince.

I have a Buckeye Amps Hypex that we enjoy nearly every day and I'm proud of. It's been out of warranty for 2 or 3 years. If it died now I wouldn't feel cheated because I know it wasn't specifically engineered to last much longer than typical consumer electronics. If it were it would cost a lot more and I wouldn't have bought it.

So what do you want @Lando :

• long-term “end game”, "keep for many years, ideally through future speaker upgrades",
• SOTA performance and loads of power at low, low prices?

 

[amper42]

It's hard not to be happy with a Purifi amp.

Energy efficiency and low heat generation are measurably superior. Most amps run significantly warmer. Even if you are deaf you can tell which one is the Purifi amp after they have run for an hour. Simply place your hand on top of the case. The coolest running amp is always the Purifi design.

 

[Ruediger]

In the end it comes down to what you want as they are both great amps and the measurements look superb.

And with them from Audiophonics workshop the features are basically the same.

Personally I'd get the Purifi if the budget is around the same.

 

[Mark609]

You're overthinking this. Buy the best value, bang for the buck. All of them are highly efficient and will do the trick.

Having said that owner Dylan is building this for me as I write to drive Ascend Acoustics ELX towers and a Horizon center crossed over to subs around 80 Hz. WAY over kill (especially because the bass is being yanked out and sent to the subs) but I've got money to burn. https://www.buckeyeamp.com/shop/amplifiers/hypex/ncx500/3_channel

That's about $2.36/watt into 4 ohms.

 

[Lando]

Bryston.

All the amps you suggested are more than excellent in terms of capability and signal hygiene. But none are, in my view, products designed to last a lifetime with a warranty to convince.

I have a Buckeye Amps Hypex that we enjoy nearly every day and I'm proud of. It's been out of warranty for 2 or 3 years. If it died now I wouldn't feel cheated because I know it wasn't specifically engineered to last much longer than typical consumer electronics. If it were it would cost a lot more and I wouldn't have bought it.

So what do you want @Lando :

• long-term “end game”, "keep for many years, ideally through future speaker upgrades",
• SOTA performance and loads of power at low, low prices?

Probably somewhere in between What I really want is excellent performance, plenty of power, solid engineering, and something I can keep through future speaker upgrades. I’m also planning to start building and experimenting with different DIY speakers, so having an amp that can comfortably handle a wide range of designs is important to me.

 

[Lando]

Thanks everyone for taking the time to reply and share your thoughts. I really appreciate it — there are several points here I hadn’t considered, and the discussion is helping me better define what I actually need from this amplifier. ♫♪.ılılıll|̲̅̅●̲̅̅|̲̅̅=̲̅̅|̲̅̅●̲̅̅|llılılı.♫♪

I was also considering building the amplifier myself, which would be a fun project, but after looking at the cost of the modules and components, it’s a bit of a shame that DIY can actually end up more expensive than buying a complete amp.

 

[Multicore]

Probably somewhere in between What I really want is excellent performance, plenty of power, solid engineering, and something I can keep through future speaker upgrades. I’m also planning to start building and experimenting with different DIY speakers, so having an amp that can comfortably handle a wide range of designs is important to me.

In that case I have a solution for you: get a Purifi amp, any of the builds other people list will do, and change your speakers every year.

See what I did there? I'm practical, me!

 

[perceptionist]

No need to worry about it until you see Amir's SC400A2 review. Also by avoiding hard-to-drive speakers, there is no need to buy endgame amplifiers. Avoid those speakers that dig into low ohms or have sharp impedance swings in the bass region.

 

[Ruediger]

Isn't it nice that you can have all in one package. Great measurements, a lot of power and the ability to drive every low impedance/low sensitivity speaker with ease.

 

[Pareto Pragmatic]

the 1ET6525SA has the flattest response into varying loads and the lowest output impedance of the three, which only really matters with long speaker runs or speakers with wild impedance swings;

When I made a similar choice for an amp, "least likely to cause issues in future equipment selection" was a factor. Speaker impedance and swings was part of that.

Me, I would say for long term, lower temperatures is a pretty good reason to choose any electronic device if a tie breaker is needed.

 

[xaxxon]

Probably somewhere in between What I really want is excellent performance, plenty of power, solid engineering, and something I can keep through future speaker upgrades. I’m also planning to start building and experimenting with different DIY speakers, so having an amp that can comfortably handle a wide range of designs is important to me.

"solid engineering" isn't really a single thing. You're going to sacrifice repairability when you optimize for size/cost. These mass produced class D options do great and are priced right. But if they die, you often can't take them to the local electronics repair place to have a few components replaced.

That said, you can often just replace them a few times vs the up front cost of the "good stuff" that weighs 50x more and is built by hand part by part.

Engineering is all about tradeoffs and you have to pick the tradeoffs that make the most sense for you. But in general the low cost COTS class D amp modules are the way to go in almost every scenario.

However, if you're going to be throwing silly loads at them (or making mistakes in designing your own stuff), some of these amps can damage themselves. The benchmark AHB2 amp is probably the most rock solid amp in terms of monitoring the inputs/outputs and just shutting itself off in any abnormal situation. It basically doesn't clip and you can short the output lines and it doesn't care. It'll just turn itself off and you fix whatever and try again. It has a lot of self-monitoring tech built into it. I have 5 and I love them. I'd trust them to not blow up my tweeters with square wave clipping, for example, if I did something silly.

I also have 8 channels of buckeye amp hypex amplification. That's all fine and I've run subwoofers off of two channels bridged on it and it's done fine work putting out near 1kw when I mess up with my digital volume control. Though now I use a behringer DSP amp for that subwoofer (with modified fans to not be loud) and I prefer that setup just because of the DSP.

 

[rjp]

I own a Purifi 6525 and like it very much. However, I think the future will be active speakers with multiple built-in amps and custom dsp for each driver.
The giant power amps of today with all their interconnects and heavy speaker wire will be obsolete and hard to resell in the future.

For now, Purifi or Hypex are good options to tide you over.

 

[Ruediger]

That sounds like a choice, not an advantage.

The speaker still needs a signal cable and on top of that then a power cable. One passive speaker cable is cleaner. I don't see why it must be heavy. Unless you are doing separate cables per driver or oversized star quad cabling?

I think active speakers with wireless options will gain more fans in the future. And there will be a choice of high bandwidth solutions with good coverage.

 

[staticV3]

I don't see why it must be heavy.

External Amps require longer speaker wire and passive speakers draw more current due to the analog filter circuitry.

Both drive up the required cable diameter and hence, weight.