Classe Sigma SSP

[BWguy]

Has anyone listened to this new processor? It is 7.1 but sounds like it is geared more for 2.1 audio. Impressions?

 

[BoredSysAdmin]

http://www.audioholics.com/av-preamp-processor-reviews/classe-sigma-series-interview-with-dave-nauber .
as for me, pre-pro with amp for $10k minus auto room configure, minus dynamic eq.
Sorry, I'll pass

 

[AcuDefTechGuy]

I think a $2K Denon or Yamaha AVR sound just as good in 2.0 Pure Direct.

 

[Seth=L]

Has anyone listened to this new processor? It is 7.1 but sounds like it is geared more for 2.1 audio. Impressions?

I have not listened to it. While I will sort of agree with the above posts, which is to say I believe in the law of diminishing returns, I also don't think you'd be making a poor decision necessarily. However, if 2 channel perfection is your bag, I don't recommend high dollar multichannel processors in the least for another reason entirely. That reason is residual value. A 2 channel preamp from Classe will retain a significant portion of its value for years to come, the home theater processor will not. The majority of people that would buy the Sigma SSP don't consider it for it's 2 channel properties. It may well be a great 2 channel preamplifier, but I'm willing to bet you can get a better 2 channel preamp for less and that will be worth more 5 years from today.

I had a B&K Reference 20 multichannel processor which cost over a grand new in the late 90's early 2000's, now it's not hardly worth $100. Much like computers, they become outmoded very quickly by new technology, software, and marketing.

I would tend to avoid esoteric processors, but I have no problem with high end preamplifiers.

 

[BWguy]

I love both, 2 channel sound, as well a 5.1 for Blu Ray concerts and movies. However music is my focus. But your right, it is hard to invest in a high end processor as they become outdated 6 months after your purchase one. But if the Sigma, or another processor, would give me music nirvana, I would surely keep it for many years. I really have no interest in atmos, although 4k might be of interest in a few years.

 

[slipperybidness]

The Sigma amps have SMPS. I'm assuming the Preamps do too?

If yes, then I would personally steer clear. Especially at the $.

 

[Seth=L]

The Sigma amps have SMPS. I'm assuming the Preamps do too?

If yes, then I would personally steer clear. Especially at the $.

Any particular reason why this would be a factor?

 

[slipperybidness]

SMPS have many disadvantages, especially in amps.

For an amp, unregulated symmetrical DC P/S is by far the best approach.

Disadvantages:
*SMPS switching action on the AC mains creates RF noise. You must deal with eliminating the RF that it creates
*Virtually no headroom on SMPS.
*SMPS are more complex circuitry. Thus, they are more likely to fail.

Advantages:
*SMPS are lighter and more efficient
*SMPS are cheaper to build on a large scale (R&D is much greater, but once you ramp up production the SMPS is much cheaper)
*Mostly, these advantages are due to not needing a hulking transformer.


Slap SMPS in a Classe, leaves higher profit margins.

 

[Seth=L]

SMPS have many disadvantages, especially in amps.

For an amp, unregulated symmetrical DC P/S is by far the best approach.

Disadvantages:
*SMPS switching action on the AC mains creates RF noise. You must deal with eliminating the RF that it creates
*Virtually no headroom on SMPS.
*SMPS are more complex circuitry. Thus, they are more likely to fail.

Advantages:
*SMPS are lighter and more efficient
*SMPS are cheaper to build on a large scale (R&D is much greater, but once you ramp up production the SMPS is much cheaper)
*Mostly, these advantages are due to not needing a hulking transformer.


Slap SMPS in a Classe, leaves higher profit margins.

Would it be incorrect to assume that like most things there's poor implementation and good implementation of like power supplies? What I mean is, isn't it possible that the SMPS found in Classe components may not be the norm and may be every bit as good as a linear supply? I'm not saying I know them to be as good or better, but it is possible right? Classe has been using SMPS for years now if that makes a difference.

 

[RichB]

Very good interview:

From Class:

It’s the interaction between the output filter and the speaker load, which changes with frequency, and how they may or may not influence the sound of a given speaker that matters. For a resistive load in a test setup, the amps measure best just above 4 ohms, but that’s not indicative of anything in particular as it’s the reactive performance with a real speaker that tells the story. Have a listen and see how well it works with whatever speaker you choose.

I would rather have an amp that is invariant to load.
The new Theta Class-D is claims to be and so does the Benchmark AHB2.

Failure to maintain the voltage when amplifying a signal is not good. Unfortunately, this is not characterized as distortion but it is clearly not an accurate multiple of the source.

- Rich

 

[slipperybidness]

Would it be incorrect to assume that like most things there's poor implementation and good implementation of like power supplies? What I mean is, isn't it possible that the SMPS found in Classe components may not be the norm and may be every bit as good as a linear supply? I'm not saying I know them to be as good or better, but it is possible right? Classe has been using SMPS for years now if that makes a difference.

Nope.

You simply cannot beat the laws of physics! SMPS create RF noise, end of story. So, now you have to deal with filtering out the RF that they generate.

SMPS is more complex. Simple statistics will tell you that the more parts in a system, the more likely for system failure!

Plain and simple, if PERFORMANCE is your end goal, then the BEST choice for an amp power supply is un-regulated DC supply.

If LIGHT WEIGHT, EFFICIENCY, LOW COST are the end goals, then SMPS is the BEST choice for an amp power supply.

I can point you towards these arguments in literature if you want. G. Randy Sloan is the main expert that I have been reading. Douglas Self is another good resource.

 

[slipperybidness]

Very good interview:

From Class:



I would rather have an amp that is invariant to load.
The new Theta Class-D is claims to be and so does the Benchmark AHB2.

Failure to maintain the voltage when amplifying a signal is not good. Unfortunately, this is not characterized as distortion but it is clearly not an accurate multiple of the source.

- Rich

+1

http://www.signaltransfer.freeuk.com/invarint.htm

 

[Seth=L]

I wonder how a triple darlington stacks up to this load invariant offering.

I will use mine as an example (well not mine, the one in the pic is dirtier). This Niles SI-275 is marketed as being 2.66 ohm stable and is touted as being designed specifically for reactive loads. The transformer is a double wound 3kva per side, so the current is there, but what about the output stage? I hope I'm not entirely derailing this thread.

 

[RichB]

I measured the Parasound single and bi-amped to the Salons. The crossover to the 3 woofers is at 125hz. At 100Hz the Salons are a 4 ohm load with about 20 degree phase angle (according to Stereophile).

100hz Tone:

Single: 2.48
Bi-amp Upper: 2.51
Bi-Amp Lower: 2.45

Its a Radio Shake meter, but it does show some sag under load.
I am not sure this math makes sense, but at ,05 * 80DB = 4DB.
That does not make sense giving the review measurements.
I might have to measure again.

- Rich

 

[Patrick Butler]

Hi BWguy,

If you are interested in knowing more about the SMPS used by the Sigma SSP, you can read this white paper on the CP-800, which uses the same SMPS.

In general the observations made about SMPS on this thread are correct. They tend to be efficient, cheap and noisy. Anybody who has heard a CP-800, or looked at the measurements knows that what is true for most SMPS is not true as it applies to the CP-800, and the Sigma SSP (also the CA-D200, AMP2, AMP5) which all use the same SMPS.

Regards,

Patrick Butler
B&W Group North America

I love both, 2 channel sound, as well a 5.1 for Blu Ray concerts and movies. However music is my focus. But your right, it is hard to invest in a high end processor as they become outdated 6 months after your purchase one. But if the Sigma, or another processor, would give me music nirvana, I would surely keep it for many years. I really have no interest in atmos, although 4k might be of interest in a few years.

 

[slipperybidness]

Hi BWguy,

If you are interested in knowing more about the SMPS used by the Sigma SSP, you can read this white paper on the CP-800, which uses the same SMPS.

In general the observations made about SMPS on this thread are correct. They tend to be efficient, cheap and noisy. Anybody who has heard a CP-800, or looked at the measurements knows that what is true for most SMPS is not true as it applies to the CP-800, and the Sigma SSP (also the CA-D200, AMP2, AMP5) which all use the same SMPS.

Regards,

Patrick Butler
B&W Group North America

Thanks for the links!

I will read up when I have some time.

However, you did not address the fact that SMPS are more complex and have more components than an un-regulated DC supply. More components = more likely to have a single component fail.

This is good stuff! I like that vendors like to weigh in with their own points of view, etc! It shows that they do indeed have the end customer in mind.

 

[slipperybidness]

Hi BWguy,

If you are interested in knowing more about the SMPS used by the Sigma SSP, you can read this white paper on the CP-800, which uses the same SMPS.

In general the observations made about SMPS on this thread are correct. They tend to be efficient, cheap and noisy. Anybody who has heard a CP-800, or looked at the measurements knows that what is true for most SMPS is not true as it applies to the CP-800, and the Sigma SSP (also the CA-D200, AMP2, AMP5) which all use the same SMPS.

Regards,

Patrick Butler
B&W Group North America

OK. I read through the white paper.

Not a surprise, but 2 disadvantages of SMPS were completely omitted:

*More complex = more likely to fail
*Lack of headroom using SMPS (probably not much of a factor for a pre-amp, but different story for a power amp).

But, the article does discuss some of the other advantages and disadvantages. It certainly looks like a lot of thought went into the R&D on this one. That's just another piece of the SMPS puzzle, huge R&D demands, but once you have a viable design the production is cheap.

To be clear, I suspect that SMPS will be the future of audio, and the un-regulated DC supplies will become a niche, much like pure class A topology is today. And, it looks like each generation is getting better. So, I do give Classe a pat on the back for looking towards the future and doing something to improve upon the past!

Now, I think the PFC on this SMPS may be the real star of that show! That seems to be neglected in consumer level amps, and in many situations it can have huge benefits.

Dunno why Classe doesn't play that up more? Maybe it's over the heads of the average consumer?

 

[Patrick Butler]

Hi slipperybidness,

SMPSs are definitely more complicated. Not sure about them being more likely to fail. Headroom can certainly be an issue. The one in the CP-800, and Sigma SSP is capable of delivery 1000W, so there is plenty of power to be had for those designs (which is why it is also used in our Class D amps.)

Classé is a pretty modest company. I would agree that what makes Classé a great engineering company should be talked about more, and you are correct that many consumer's eyes roll back in their heads when tech is talked about in general. However, many are quite sophisticated in their understanding of electronics and it is important to engage them on that level.

Regards,

Patrick
B&W Group North America

OK. I read through the white paper.

Not a surprise, but 2 disadvantages of SMPS were completely omitted:

*More complex = more likely to fail
*Lack of headroom using SMPS (probably not much of a factor for a pre-amp, but different story for a power amp).

But, the article does discuss some of the other advantages and disadvantages. It certainly looks like a lot of thought went into the R&D on this one. That's just another piece of the SMPS puzzle, huge R&D demands, but once you have a viable design the production is cheap.

To be clear, I suspect that SMPS will be the future of audio, and the un-regulated DC supplies will become a niche, much like pure class A topology is today. And, it looks like each generation is getting better. So, I do give Classe a pat on the back for looking towards the future and doing something to improve upon the past!

Now, I think the PFC on this SMPS may be the real star of that show! That seems to be neglected in consumer level amps, and in many situations it can have huge benefits.

Dunno why Classe doesn't play that up more? Maybe it's over the heads of the average consumer?

 

[slipperybidness]

Hi slipperybidness,

SMPSs are definitely more complicated. Not sure about them being more likely to fail.

Patrick
B&W Group North America

Just assume that a particular part has a 1 in 1000 failure rate.

My design uses 1 part, so I have a 1 in 1000 chance of failure.

My competitor uses 10 parts, so his design now has a 10 in 1000 chance of failure.

Same reasoning applies when determining the number of OP transistors. More transistors means each one is worked less. But, more transistors also means that it is more likely to get one that will fail.

Simple statistics.

 

[Scottsol]

Just assume that a particular part has a 1 in 1000 failure rate.

My design uses 1 part, so I have a 1 in 1000 chance of failure.

My competitor uses 10 parts, so his design now has a 10 in 1000 chance of failure.

Same reasoning applies when determining the number of OP transistors. More transistors means each one is worked less. But, more transistors also means that it is more likely to get one that will fail.

Simple statistics.

Mark Twain is credited with saying, "There are three types of lies. Lies, damn lies, and statistics." You have added support to this.

Suppose the average part has a 10 year failure rate of 1 in 100,000, now the 10 part unit has a 1 in 10,000 chance of failing in ten years. Given that an item like the SSP in not likely to achieve even 5000 unit sales there is no meaningful difference between a 1 in 10,000 and 1 in 100,000 failure rate.

Simple statistics.