Protection circuitry and sound quality.

[Chr1]

Still curious as to why NAD has their "Soft Clipping" switch if there is nothing in the signal path?

Also, surely decent amps are similar to decent DACs in that due to different design and components there are audible and measurable differences, and like DACs sometimes the differences are subtle and most likely down to either better components and a simpler, less "noisey" signal path?

 

[MakeMineVinyl]

Still curious as to why NAD has their "Soft Clipping" switch if there is nothing in the signal path?

Also, surely decent amps are similar to decent DACs in that due to different design and components there are audible and measurable differences, and like DACs sometimes the differences are subtle and most likely down to either better components and a simpler, less "noisey" signal path?

A soft clipping circuit is more likely to be directly in the audio path, or at least have elements which control the audio signal in the audio path. An example is a light dependent resistor which changes value at a pre-determined output from the amplifier channel, constraining output to below clipping levels. However even these are unlikely to make a measurable, much less audible, difference in performance as long as the circuit is not in operation.

Perhaps NAD simply wanted to give the option to bypass soft clipping for those people who don't run the amplifier anywhere near full output. I don't believe there's some grand conspiracy going on there.

As I mentioned before, other protection circuits such those to detect short circuits, excessive current, and high frequency oscillation are not typically in the audio path, but are rather in a side loop, and cannot affect the audio directly in any measurable way.

 

[Chr1]

Thanks again. Now wondering if there is any advantage to be the NAD protection system, if it is in the signal path?

 

[MakeMineVinyl]

Thanks again. Now wondering if there is any advantage to be the NAD protection system, if it is in the signal path?

Do you mean the soft clipping? I don't consider soft clipping to be 'protection' per se.

In any event, you would need to see a schematic to determine exactly what's going on, or at least a PCB to study.

 

[Chr1]

Okay. But if so, surely it is then just a way to prevent an under powered amp from damaging speakers... whilst also adding unwanted components to the signal path?

 

[MakeMineVinyl]

Okay. But if so, surely it is then just a way to prevent an under powered amp from damaging speakers... whilst also adding unwanted components to the signal path?

I can't speak for what NAD's logic is, but in the few amplifiers we make which use clip limiters, these are all high powered units producing hundreds of watts, and most are for professional use. These types of amplifiers are most likely to be driven hard, and you don't want the amplifiers to be blowing out compression drivers and such. Someone unplugging an input cable to a mixer can send a strong transient through the power amplifiers, and they could clip without intervention. In these amplifiers, all that is in the signal path is a single variable resistor, and it is a shunt rather than a series component to the audio path. When inactive, the resistor is multiple meg-ohms in value.

 

[Chr1]

Indeed. I guess, again I am still trying to figure out what makes amplifiers different and why I prefer one to another. My Lazarus H-1A is listed as 50w per channel. My NAD C372 at 175w per channel. The NAD has a soft clipping switch and the Lazarus doesn't. The Lazarus seems more powerful than the NAD. Better bass, "grip" on the woofer and a cleaner sound at the higher frequencies. To my ears. I am just trying to figure out why. Thanks.

 

[MakeMineVinyl]

Indeed. I guess, again I am still trying to figure out what makes amplifiers different and why I prefer one to another. My Lazarus H-1A is listed as 50w per channel. My NAD C372 at 175w per channel. The NAD has a soft clipping switch and the Lazarus doesn't. The Lazarus seems more powerful than the NAD. Better bass, "grip" on the woofer and a cleaner sound at the higher frequencies. To my ears. I am just trying to figure out why. Thanks.

If there are differences, it is almost certainly in the dozens, if not hundreds, of other electronic components which make up the amplifying bits, and how they are designed and put together.

 

[Chr1]

Thanks. Have to say that I figure given there are many differences in design and components, and that amplifiers are still being built in this way... then surely there are bound to be subtle differences, audible and otherwise in some of them. To suggest they all sound the same, for a given power application, implies that any variation in design, cost, implementation from the cheapest good measuring design is pointless and I am not quite sure that I buy into that personally.

 

[MakeMineVinyl]

Thanks. Have to say that I figure given there are many differences in design and components, and that amplifiers are still being built in this way... then surely there are bound to be subtle differences, audible and otherwise in some of them. To suggest they all sound the same, for a given power application, implies that any variation in design, cost, implementation from the cheapest good measuring design is pointless and I am not quite sure that I buy into that personally.

Are you talking about variations in performance and sound based on the protection circuitry? If so, you will find that the vast majority of amplifiers you are likely to buy (i.e. sub 5-6 figure cost) have very similar protection schemes because this technology is very mature and the options focus on a limited number of proven solutions. There will always be outliers, mostly in smaller brands with limited production, but even then there are only so many ways to do protection, and the chance that any of them could be designed to change sound quality are pretty slight.

If you're referring to amplifier topology in general, these are going to be more similar than different with established manufacturers (like my own). You can always find really bad examples from small brands with no reputation, but I wouldn't buy that stuff to begin with.

 

[Chr1]

Sorry, no I should have said that I am no longer taking about protection circuitry.
I am referring to one of the few things that I find slightly problematic with the this forum: the widely held opinion that all properly implemented amplifiers sound the same. I have to say that I this is not my view and I am trying to figure out what causes the differences that I perceive between my amplifiers. Anyway, many thanks for the help and apologies for my ignorance re electronics! Much appreciated.

 

[MakeMineVinyl]

Sorry, no I should have said that I am no longer taking about protection circuitry.
I am referring to one of the few things that I find slightly problematic with the this forum: the widely held opinion that all properly implemented amplifiers sound the same. I have to say that I this is not my view and I am trying to figure out what causes the differences that I perceive between my amplifiers. Anyway, many thanks for the help and apologies for my ignorance re electronics! Much appreciated.

I would say the major culprit is amplifiers, both solid state and tube, with higher than normal output impedance. This will act as a voltage divider which modulates frequency response in sympathy with the impedance variations of speaker systems.

 

[Chr1]

Thanks. Presumably ideally a minimal signal path, with high quality components and a minimal design, given the power (and protection) requirements makes for optimal sound quality and possibly subtle audible differences. Cheers.

 

[Chrispy]

You might also actually do some level matched double blind abx tests to further explore what you think you hear.....

 

[Chr1]

I am merely saying that I do not believe that there are no audible differences between the miriad of well designed amplifiers. Apologies, but I don't really have the inclination to spend a whole lot of time doing tests that would most likely be be deemed flawed in some way. I suspect that there are a lot of folks on this forum that share this opinion about amplifiers but are probably reluctant to voice it as it appears to be unpopular here. Anyway, I enjoy continuing to learn. Thanks.

 

[Chrispy]

I am merely saying that I do not believe that there are no audible differences between the miriad of well designed amplifiers. Apologies, but I don't really have the inclination to spend a whole lot of time doing tests that would most likely be be deemed flawed in some way. I suspect that there are a lot of folks on this forum that share this opinion about amplifiers but are probably reluctant to voice it as it appears to be unpopular here. Anyway, I enjoy continuing to learn. Thanks.

But what do you and those others base that "belief" on particularly? The very word belief is bothersome. Are these conclusions based on well conducted comparisons or shopping/anecdotal experiences? Magazine/blog reviews? Hifi salespeople? Whether you or others find differences on a personal subjective level just isn't very interesting let alone conclusive. Why would a well done test be deemed flawed unless it is?

 

[Chr1]

No. I base my belief on the fact that if it was that if they all sounded the same then there would not be the diversity. I do not believe that everything beyond a certain point is snakeoil. If I was to equate it to motorcycle engines (my other hobby). It is like saying that as long as the motor makes x horsepower, y Nm torque, with z gears and weighs no more than such and such kg, they are all the same. There are subtle differences. With engines, all manor of things make them different in the way that they make power. Ie Two stroke, four stroke. Configuration ie v twin, in line etc. The fact that certain measurements are the same does not mean that there are not differences.

 

[Doodski]

The fact that certain measurements are the same does not mean that there are not differences.

How do you know this? Of course some amps sound different. Far and few in between but they do exist.

 

[Chr1]

I absolutely agree with you when you say that "Of course some amps sound different".
I am just curious as to why this point of view seems to be so unpopular here...

 

[Chr1]

Apologies, slightly inebriated due to bourbon...
But to continue the tenuous motorcycle analogy : the transducers are all important.

Audio : Mikes, speakers. Motos: rider, tyres.