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Classe Sigma AMP5 Multichannel Amplifier Review

PeteL

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Well, if we go there, can't really compare the price of a used warranty-less amp and new one. Not saying that it's horrible, but the retail price makes it look bad. What could make it look a bit better is a weighted THD metric, as there's nothing after the 3rd.
That frequency response drop and SNR are still a shame, though.
Do you hear a 1 db attenuation at 20K? The situation where this noise floor would become an audible concern are very very edge cases too, again, not saying it's the purchase of the century, I'm saying it's not a laughable effort for what they where trying to accomplish at the time. It's a high end brand, low volume It's obvious that they couldn't come with something like that for much cheaper. It's debatable if they should have even tried, in my opinion, no, they should have stuck to their main market.
 

q3cpma

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Do you hear a 1 db attenuation at 20K? The situation where this noise floor would become an audible concern are very very edge cases too, again, not saying it's the purchase of the century, I'm saying it's not a laughable effort for what they where trying to accomplish at the time. It's a high end brand, low volume It's obvious that they couldn't come with something like that for much cheaper. It's debatable if they should have even tried, in my opinion, no, they should have stuck to their main market.
Those are indeed mostly unimportant issues, as far as sound quality goes. But my impression is that people spending that much money want the cream of the crop, with audibility concerns being considered as "mostly solved" at a lower price point anyway.
 

levimax

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I think the best thing to do with this amp would be ABX testing it against the Benchmark. This amp checks all the boxes for the "class D amps don't sound good" theorists: High output low headroom, bandwidth limited, lots of ultrasonic noise, strange distortion vs frequency curves. I think the results would be very interesting.
 

CDMC

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NAD M27 was available in 2015 as were other options such as ATI, Emotiva.
 

PeteL

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Those are indeed mostly unimportant issues, as far as sound quality goes. But my impression is that people spending that much money want the cream of the crop, with audibility concerns being considered as "mostly solved" at a lower price point anyway.
I don't know man, I'll admit that I may be biased and like to vouch for fellow Montrealers. I also as an engineer gets it that a designer would develop its own thing, even in it means compromise in term of raw measurments, if it achieve the taarget sonically and in term of specs. Now of cours it's not a cost efficient approach, RnD's a bitch. ASR is a tough crowd, what matters here is not necessarîy what matters to the engineer who designed it, ans not necessarily what matter to their target market neither. designing your own amp is not just about pride, but brand recognition as well. Now, as I said, this product symbolize a lot to the fall of Classé that almost killed the brand. Almost impossible for North American Audio Brands to compete in pricing. It's unfortunate, but there's nothing left but luxury brands. litterally, no one else than Schiit achieved to do so. They're the only, it's not even worth trying.
 

LTig

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Am I to deduce that pairing the Classé pre- og power amp with an analogue input source then you end up digitizing twice? And at different samplerates?
The Classé preamp digitizes analog signals only when you enable room EQ or use the tone controls. In this case yes, the signal passes 2 AD/DAC stages, 1 in the preamp and 1 in the power amp.
 

Kal Rubinson

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What I know about Classe products comes from reading online customer reviews. The Sigma line has received many complaints.

I don't have first hand knowledge, but I suspect some decisions were driven by B&W and EVA Automation management.
AFAIK, EVA had no involvement with Classé except to close it.
 

PeteL

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You paid way too much for those. NC400's go for €700 each and include everything you need to make them. Even outperforms the NC500 in terms of distortion. So that's €3500 for the easy DIY solution that is pretty overpriced compared to OEM pricing for NC500's. 5 channel NC500 should be around €2500.
Yes, I know NC400 kits are the better deal, the Idea was not for me to buy a Kit, at the time I wanted to try to make a pair of monobloc that look and behave like a real amp, to get a feel of what it involves and perhaps build amps that could potentially be commercialized. I scratched that out, for me there was no way to be competitive and not lose money. I know that some small manufacturers where apparently able to, maybe, I obviously don't know their books, but You would still need the infrastructure first, which I didn't have, and then obviously the first few are more expensive than the 100th, but even then amp based on NCore modules don't come cheap. NC400 kits are indeed a great deal for someone into DIY. It's far from being overpriced if you just build a few, You can't achieve that low of a number with NC500 in small quantity, but with volume and proper equipment yes.
 

Koeitje

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Yes, I know NC400 kits are the better deal, the Idea was not for me to buy a Kit, at the time I wanted to try to make a pair of monobloc that look and behave like a real amp, to get a feel of what it involves and perhaps build amps that could potentially be commercialized. I scratched that out, for me there was no way to be competitive and not lose money. I know that some small manufacturers where apparently able to, maybe, I obviously don't know their books, but You would still need the infrastructure first, which I didn't have, and then obviously the first few are more expensive than the 100th, but even then amp based on NCore modules don't come cheap. NC400 kits are indeed a great deal for someone into DIY. It's far from being overpriced if you just build a few, You can't achieve that low of a number with NC500 in small quantity, but with volume and proper equipment yes.
How does the NC400 not look and behave like a real amp? Its construction is exactly the same as the OEM modules apart from the built-in buffer stage I believe. You still got a separate SMPS power supply (Hypex even has options that include it on one board) and the amplifier board.

NC400's are overpriced compared to OEM pricing, the NC500 is much cheaper, not in terms of DIY market pricing. The performance of the NC400 is better apart from maximum power output, that is true. But the NC500 beats this Classé amplifier with ease.
All that is hard to quantify, can we just focus on comparing apples to apples? DIY is a niche, we are entousiasth here, and like that suff, but we should compare to commercial, FCC and CE regulated products. I find that even boutique online only craftmans Amp builders are a bit of a stretch in term of comparison base. I'm just saying that it was hard to find a 5 channel 450 w amp 5 years ago, and the price thety go now in the used market is fair, as per amir conclusion
The price is fair if you can match the performance of products in the same price range. That product would be the NAD M27, which is a far better amplifier.

Generally speaking DIY amplifiers are actually more expensive than commercial amplifiers. My 5 NC400 example is a good example of that because NC500's are cheaper and you would get a single big chassis instead of 5 small cases.
 

restorer-john

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The AHB2 is also from 2015, and remains the undisputed design champ.

Says who? It's not a high powered power amplifier, in fact it's barely qualifing as a "power" amplifier in my book. Generally anything over 120wpc@8R is low end "power" amplification. It doesn't even make that.

It's a truly excellent performing mid powered amplifier. 100wpc is still integrated territory and hardly worth the moniker of "power". It's much easier to get wonderful figures with lower rails, less EMR, fewer output devices and less gain. Build a big PSU with huge current capability and a ton of SOA in silicon and noise will be a by-product.

Benchmark have picked a sweet spot for a low-medium powered amplifier. Facts are, a ton of people need two (or more) in BTL to get what they need.

The lowest powered power amp in my collection is 135wpc@8R. Most start around the 150wpc and 200wpc is where power amps get remotely serious. A big power amplifier is 500wpc@8R. Even the new McIntosh integrated amplifier is 350wpc@8R.

Don't get me wrong, most of the 100-120wpc integrateds I own are also what I call "sweet spot" amplifiers. They offer almost pre/power performance in one box. Especially the high gain, no active front end designs from the late 80s and early 90s.
 

PeteL

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How does the NC400 not look and behave like a real amp? Its construction is exactly the same as the OEM modules apart from the built-in buffer stage I believe. You still got a separate SMPS power supply (Hypex even has options that include it on one board) and the amplifier board.

NC400's are overpriced compared to OEM pricing, the NC500 is much cheaper, not in terms of DIY market pricing. The performance of the NC400 is better apart from maximum power output, that is true. But the NC500 beats this Classé amplifier with ease.

The price is fair if you can match the performance of products in the same price range. That product would be the NAD M27, which is a far better amplifier.

Generally speaking DIY amplifiers are actually more expensive than commercial amplifiers. My 5 NC400 example is a good example of that because NC500's are cheaper and you would get a single big chassis instead of 5 small cases.

I think you misread my post, You can't go and resell a NC400 monobloc. My NC500 was more expensive mainly because, after buying a good quality generic case, that don't look cheap, I had to find someone that had the equipment to do the piercing on the front and back panel, for connection and switches. Yes I could have just drilled them but that's what I mean by looks and feel professionally made. I gave up before having silkscreen and laser engraving, but if I went there it would have been even more. I also did engraved brass tags with the logo of my company I had at the time,but I don't even count that. I also wanted the option to be able to accept both rca and xlr, and I went for quality Neutrik ones. I wanted the power switch on the front panel and I wanted a nice and heavy duty one that had the led integrated on the button. the OEM pricing for a NC500, for singles quantity is when you convert euro to us dollars Is:
module:
buffer:
SMPS:
The price goes down a bit if you buy multiples, but not as much as one might think.
But It's not a completed amp, the bulk of the price is on The chassis, connectors, etc. The NC400 is not overpriced, of course they take a margin.. Also note that this wouldn't fit in the Hypex own diy case, that they sell for 195$. OEM is cheaper, but not if you build just 2 units!

edit:removed the pricing, since they don't show without login in with an account, I do not know if it's ok to publish them here
 
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anmpr1

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It's not a high powered power amplifier, in fact it's barely qualifing as a "power" amplifier... 200wpc is where power amps get remotely serious.
1) If the criteria/definition for a 'power' amp is 200 w/ch or more in to 8 ohms then you are correct.

2) If more power is needed then, as you say, two (or more) are an option. Which still will be difficult for any other brand to match, spec-wise. And two (or more, in multiamp configurations) will still be cheaper than many competing models offering similar power.

3) However, if you need five hundred to a thousand watts in to a one or two ohm load, then Benchmark cannot be recommended. Either that, or your loudspeakers cannot be recommended.
 

peng

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I hadn't heard anything about them for decades, when they were in the business of recreating that old Mark Levinson ML-2 magic--i.e., low voltage with lots of class A current. Their latest and greatest mono amplifier looks to be some sort of 'sliding' class A design. 35 initial 'A' watts, then the rest delivered in something more traditional.

At these prices it's going to be up to a dealer to convince the naive customer that 'the sound' is somehow better than the competition. They will have their work cut out for them. Classe design, industrial grey with a fan sticking out in front, paired with a black on white meter, is a bit on the limited appeal, streamlined modernist side. My guess is once the dealer lowers the lights for the demo, and the blue metered hue and green tubes start to do their thing from behind the backlit glass, and once that reflects off the oiled rosewood of those expensive B&W speakers--well, at that point most customers are buying the Mac.

Your point about the evolution (devolution?) of Denon and Marantz, and luxury branding, is an interesting marketing lesson. When Saul started out, his amp and preamp were decidedly luxury. Top of the line pricing. More expensive than anything out there. And his tuner was completely over the top. Even his first receiver. Once Superscope bought the company all that changed. Denon Japan has a history of some very high end products, but they were never exported to the US. My guess is that under SU, none of that will ever return. Personally, if I was in the market for big iron, I'd much rather have the Denon pictured below than anything from Classe.

View attachment 87293

It looks like they gave up on separates, but are still working on their higher end integrated amps. For some reasons though, only Marantz are marketing the higher end integrated amps in North America while Denon would only cater to Japan and may be a few places in the far East.
 

Mosfet

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I hadn't heard anything about them for decades, when they were in the business of recreating that old Mark Levinson ML-2 magic--i.e., low voltage with lots of class A current. Their latest and greatest mono amplifier looks to be some sort of 'sliding' class A design. 35 initial 'A' watts, then the rest delivered in something more traditional.

At these prices it's going to be up to a dealer to convince the naive customer that 'the sound' is somehow better than the competition. They will have their work cut out for them. Classe design, industrial grey with a fan sticking out in front, paired with a black on white meter, is a bit on the limited appeal, streamlined modernist side. My guess is once the dealer lowers the lights for the demo, and the blue metered hue and green tubes start to do their thing from behind the backlit glass, and once that reflects off the oiled rosewood of those expensive B&W speakers--well, at that point most customers are buying the Mac.

Your point about the evolution (devolution?) of Denon and Marantz, and luxury branding, is an interesting marketing lesson. When Saul started out, his amp and preamp were decidedly luxury. Top of the line pricing. More expensive than anything out there. And his tuner was completely over the top. Even his first receiver. Once Superscope bought the company all that changed. Denon Japan has a history of some very high end products, but they were never exported to the US. My guess is that under SU, none of that will ever return. Personally, if I was in the market for big iron, I'd much rather have the Denon pictured below than anything from Classe.

View attachment 87293



1602512661279.png


I own the Classé CA-200 power amp. It has been rock solid for over 20 years. Quiet as a mouse.
 

anmpr1

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I own the Classé CA-200 power amp. It has been rock solid for over 20 years. Quiet as a mouse.
If you can get 20+ trouble-free years out of gear that's a good thing. It really should be expected. That it doesn't always happen is a sad commentary. From my experience, stuff with moving parts is the first to go. Motorized volume controls and such. I've had capacitors leak. And lightening attacks blow stuff up. But unusual electrical surges are not really the fault of the equipment, I don't suppose.
 

levimax

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If you can get 20+ trouble-free years out of gear that's a good thing. It really should be expected. That it doesn't always happen is a sad commentary. From my experience, stuff with moving parts is the first to go. Motorized volume controls and such. I've had capacitors leak. And lightening attacks blow stuff up. But unusual electrical surges are not really the fault of the equipment, I don't suppose.
After buying several "high end" AVR's that broke after 3-5 years and were unrepairable due to lack of parts (not moving parts) I went vintage and DIY and have not looked back. That Classe' CA-200 looks nice inside and I can see why it lasted 20 years.... probably has a lot more in it. Modern AVR's with all the "features" (overly complicated) are a joke when it comes to reliability and reparability.... reading Amirs reviews many are even broken when new.
 

Mosfet

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Yes, it was made in Canada, Quebec to be precise. And the electrolytic caps are all Nichicon, they used the top of the line model of Nichicon at the time of manufacture. I just pulled the top cover off last month and currently, there are no leaks, no bulging from any of the caps. I did notice that they are all 85 degrees C though. I prefer 105 degrees C for longevity.
 

RichB

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Most amplifiers do not have clip indicators so it is easy over-estimate the need for power. I always did, opting for the ATI AT6000's over the AT4000s. In reality, there was only a 1 dB advantage.

Critical listening will occur at 1 watt and below, that is if you think amps can and do sound differently, of course.

- Rich
 
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