Is this Challenge still Good?

[KEW]

Would >90% suffice?

I don't have a dog in this hunt, but if I was the guy setting up the challenge, believed anyone would be guessing at random, and it was my $10K, my first question would be "How many challenges would it take before it would be won by pure chance?" He has had thousands of people take the challenge. I'd bet that at 90% the challenge would have been won by now, even if there is no difference.

Maybe a statistics dude will read this and figure out the likelihood of someone winning the 24/24 challenge (assuming random guesses).

However, the statement of the challenge that got my attention is:
"The listener can take as long as they want to switch back and forth between A, B, and X at will. "
With that rule, someone can take their time and be thorough. Obviously, it would be best to bring in your favorite amp and a $100 Best Buy special. If there is a significant difference (which doesn't have to be "night and day"), and especially given familiar music and enough time, it should be easy enough to consistently home in on it! To miss even once is not saying there is no difference, it is saying that the poor amp sounded better!

 

[mtrycrafts]

That THD won't begin until pretty close to the cutoff point, though and until that point, they sound pretty nice. I'm kind of surprised that I haven't seen SET amps with parallel output tubes (although I haven't really looked, either).

I have a couple of SE guitar amps and while I don't use the one with 6V6 much, the one with the 6L6G is what I have been playing most, lately. At about 70 years old, original transformers and all of the tubes except the 80 rectifier (I found three that work on ebay for $18.50), it's very clean sounding.

Yes, maybe. Sets do start with a much higher THD to begin with, like the LAMM ML2. And, when they have only a few watts, it get to 3% or more rather quickly and frequently. Not to mention the amps high output impedance that will make its FR the same as the speakers. Unless you are driving a 100dB spl sensitive speakers, or higher

 

[Robof83]

That would be cool if a statististics person could clarify that. It took me just 3 tries to get 83%, but I have no idea how lucky I was.

 

[mtrycrafts]

....
It's not like you would believe me if I said that my SET's have better transparency and far better detail retrieval than the Emo, Crown, and NADs recently used in the same system, but they do, at least to these ears. ....

Belief has nothing to do with this. What can be demonstrated does and what can be properly measured. SETs just don't measure up. Ancient poor designs, certainly not one you could call a 'well designed' amp.

 

[mtrycrafts]

24/24 shouldn't be that hard at all if there is truly a night and day difference like some people suggest.

I know I certainly would be 24/24 for distinguishing between pictures of the night sky and pictures of the day sky.

With your eyes closed? LOL

 

[Robof83]

That might be a little harder, probably the same difficulty as Richard Clark's Test

 

[WmAx]

Yes, maybe. Sets do start with a much higher THD to begin with, like the LAMM ML2. And, when they have only a few watts, it get to 3% or more rather quickly and frequently. Not to mention the amps high output impedance that will make its FR the same as the speakers. Unless you are driving a 100dB spl sensitive speakers, or higher

Looking into Stereophile's database, many SETs have 3-4 percant THD in normal operation, with it increasing to 5 percent or higher near clipping(which is not far away when you have so few watts to begin with.....)

-Chris

 

[Lordoftherings]

How will he make sure of that?

I read quite a bit about it, and he uses his own set of rules with very precise volume level balance between the different amplifiers.
And you cannot make a guess, it have to be honest and true, based on your own set of ears.
And you need a certain very high percentage of right answers.

Tough test for sure.

 

[Lordoftherings]

He can make sure of it just by making it a fair test. Humans do not have superhuman hearing, regardless of whatever delusions they have about such matters.

+1 Got that one right.

 

[Lordoftherings]

My op was questioning if LOTR thought the test were rigged I completely concur that the test is valid and correct

Oh, it is rigged, but it is rigged properly, very properly in fact, too much properly.

That's the problem; when everything is set up correctly and with great validity, we all fail.

 

[WmAx]

Even tube amps are allowed to be compared against SS amps, as long as the tube amp does not produce so much noise or very high levels of distortion as to be differentiated. Frequency response does not matter, he will apply EQ to the 'poor SS' amp to match the high-end tube amp's frequency response.

Good luck finding those 'huge' differences in sound.... because those differences have yet have been proven to exist in a test eliminating knowledge of the device you are listening to.

Thus... my preference for high quality pro amps with high power, ability to handle any load, and very fairly priced.

-Chris

 

[mtrycrafts]

...It took me all of 3 tries and I got 20/24 tails. ....

Maybe that coin is not a fair coin? Favors the tails more?

 

[Robof83]

Or maybe it's scared of heads

 

[highfigh]

Yes, maybe. Sets do start with a much higher THD to begin with, like the LAMM ML2. And, when they have only a few watts, it get to 3% or more rather quickly and frequently. Not to mention the amps high output impedance that will make its FR the same as the speakers. Unless you are driving a 100dB spl sensitive speakers, or higher

But, at what point does the THD become a problem, in terms of sound quality? It's not hard clipping or the same orders as a SS amp and with low power output, using speakers with 86dB/W/M sensitivity really doesn't make sense, to me.

 

[Robof83]

But, at what point does the THD become a problem, in terms of sound quality? It's not hard clipping or the same orders as a SS amp and with low power output, using speakers with 86dB/W/M sensitivity really doesn't make sense, to me.

What about in a small room? There are some pretty good sounding speakers at that sensitivity.

 

[mtrycrafts]

But, at what point does the THD become a problem, in terms of sound quality? It's not hard clipping or the same orders as a SS amp and with low power output, using speakers with 86dB/W/M sensitivity really doesn't make sense, to me.

Well, that would depend on the FR where it happens. At the sub band, 10% and even much more is not objectionable. Try that at mid Fr and upper it is objectionable in a hurry. Not to mention the potential or rather the great potential of that SET to follow the FR curve of the speaker right off the bat

May want to check this out
http://www.axiomaudio.com/distortion.html#

 

[mtrycrafts]

What about in a small room? There are some pretty good sounding speakers at that sensitivity.

SETs just don't have enough output for any margins.

 

[ski2xblack]

It is your speakers failing you, it seems, if you need rely upon the extreme coloration that is present in the average SET amplifier.

You get far more control, and better fit to your preferences, if you use proper equipment to dial in your coloration to your preference(s). From the most precision of response changes to the insertion of even order harmonic distortion at controlled levels, you can insert the proper professional studio gear into your system to dial in the desired coloration(s); a far more prudent way to approach things rather than putting up with a fixed level of coloration(s) that you can not precisely control, such as is the case with a SET amplifier.

-Chris

I smell what your steppin' in, Chris, but I've actuall tried the processor approach and frankly didn't like it as much as 'putting up with' the fixed coloration of the SETs. Personal choice and all. Specifically (at least as specifically as a highly subjective description can be), the processor approach couldn't replicate the holographic effect of using the SET amp.

Now, would this 'holographic effect' hold up under dbt? Not sure. Given the differences between SETs and other amp topologies, maybe. I do know that Steve Deckert (who made my amps) accepted the amp challenge years ago and invited Richard Clark to test against any of his amps, but it never actually took place. I suspect it was due to Steve balking at the restrictions of the challenge.

 

[mtrycrafts]

the processor approach couldn't replicate the holographic effect of using the SET amp.
.

Ah, so the amount of phase shifting and time delays taking place causing that effect is what you are after? Certainly not present on the master tapes

 

[ski2xblack]

SETs just don't measure up. Ancient poor designs, certainly not one you could call a 'well designed' amp.

Well, I never claimed my SETs were state of the art technological tour de foces, or whatever. They certainly have no pretentions in that regard. What they are is an excellent example of the minimalist school of thought, about as close to 'wire with gain' as you can get. And they sound marvelous (or so my subjective, subliminal biases tell me).