Has everyone forgotten besides the more famous challenge with the Conrad Johnson amp Carver did the same thing with a Mark Levinson amp for a different publication? As I recall he did have to change out some electrolytic decoupling caps in his amp to polypropylene caps to manage this.
We had a brief discussion about two of the challenges in the "meet Bob Carver Tomorrow" thread:
http://audiosciencereview.com/forum/index.php?threads/meeting-bob-carver-tomorrow.1255/page-3
But i´ve only read about the other challenges after the stereophile published the event and the letter by Harvey Rosenberg and had totally forgotten about it until you mentioned it in that thread.
The stereophile challenge version is a regular topic in forum discussions, while the audio critic is not, presumably due to the reason Rosenberg mentioned in his letter.
Carver's thinking was quite simple though it still is not believed by audiophiles. He knew he had built a powerful, fairly wide bandwidth, low distortion amplifier that should be quite high fidelity to the input signal. Any amplifier that sounded different than his had to have some coloration which meant a smaller performance envelope. The challenge was to color his amp to match. A challenge and requiring some skill and knowledge on his part, but in principle a lead pipe cinch.
Unfortunately i don´t know about the details of the (possibly) parts exchange, but if Carver really replaced an electrolytic by a polypropylen then chance are quite high that the assertion "the challenge was to color his amp to match" wasn´t correct.
I've written before how I loaded down a triode amp at the output, tapped the output and fed a good clean SS amp, and the result sounded like the tube amp.
Who could i know that is really sounded like the tube amp? Without a description of the controlled listening tests done to corrobate that impression it is impossible to evaluate.
They take the real gear, and work out all the interactions even down to cross coupling among circuitry and transformers due to physical layout. You buy the plug in and have the sound. If audiophiles would quit being ridiculous half a** mystics they could benefit from this with much less expense. No one is going to invest time or effort in it however, because the goofy folks in this hobby would never agree it is possible. And that includes no matter how much you demonstrate to them it is so. Despite the old catch phrase, no one distrusts their ears as much as audiophiles.
It´s really amazing that "audiophiles" don´t trust in these attempts despite all the ridicule and belitteling that routinely takes place....
But maybe it´s the inconsistency that is evident by using the Carver challenges as evidence. As said in the other thread/posts, if taken seriously, the audio critic people were convinced that perceptable differences existed between solid state amplifiers, because that was the starting point for the challenge (all according to the then published material). As long as there at the end a "hah those dumb audiophiles" possible to express, nobody seems to challenge the premise. What about the measured differences compared to the known thresholds of hearing?
At the end the audio critic people wrote to have done a "blind listening" and came to the conclusion that there wasn´t a perceptable difference (not anymore?), as usual the documentation of those "blind tests" was ....let´s say sparse.
In the stereophile challenge there was presumably a measureable difference partly above the know hearing thresholds, but the stereophile crew only did sighted listening (althoug prepared to do "blind" as well) and concluded that the amplifiers sounded the same after the modifications.
So what are the possible conclusions:
-) sighted listening works as a charm, first to detect the audible differences below the known hearing thresholds and at the end to detect the "sameness" , but why then all this blaming of subjective reviews, that stereophile and the like do?
-) there never were audible differences and everything else was much ado about nothing to present a good show and have a nice marketing story to tell at the end
-) the "nongolden ear brigade" doesn´t take their own arguments serious when presenting the challenge results