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Old 29th March 2003, 02:41 AM   #541
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Default Newbie listening in...

Interesting topic and discussion. My 2 cents...

Three years ago, I bought some Tannoy Proto-J studio monitors to go with an old Marantz 1530 that I inherited from my grandfather. Needless to say, the shopping experience was a series of in-store demos. I listened to other entry level speakers from a number of makers. I was dead set on another brand when I went into the pro store. Blown away. Good thing I decided to check it out before buying the other set.

Similar experience when I started looking to upgrade my CD player. Ended up with a Sony DVP-NC650V. That surprised me because it is neither "studio" nor "audiophile." One friend (with Brystons, Sony ES and Bose 901s) commented that he was hearing new things on a familiar CD.

My next purchase will probably be a pair of Yorkville YSM1-p active monitors to make my system 4.0 surround and maybe this summer I'll build a subwoofer.

I try not to let the status or price of a component influence my decision, even though it does. I try to A/B when I go shopping, even though I know I can't get the X. I don't have the perfect room and my ears have probably already lost the top 2 or 3 thousand hz. I've tried to be unconventional - for a time, my old truck had a CD portable with a Creative Soundworks sub/sat. (Yes, people were saying that it sounded better than their 6 speaker car systems).

I guess my point is that even though my system isn't "audiophile" and is by no means expensive, it sounds great in my apartment and better than anything most of my friends can put it up against. Maybe in this crowd I'd be another wannabe, but in my circle, my system is king. I enjoy the music and the system impresses my friends. Who cares if one component sounds marginally better or not. I might hear the difference, but if I can't afford it, then it's not part of the decision.

ensen
Vancouver

PS: The key word is "marginally." It's really easy to spot the bad stuff and I do adhere to the basics... amps with supplies big enough to support the peak output, high snr, low thd+n.
 
Old 29th March 2003, 02:58 AM   #542
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Default Carver Challenge Details...

For those who might be interested, I dug up the Carver Challenge article in Stereophile. The brief background is Bob Carver (the man behind Phase Linear, Carver and now Sunfire) made it known to the press he would put his inexpensive amplifiers up against ANY amplifier in a blind test if he had a few days to adjust the transfer function of his amp to match the challenger's amp. Stereophile took him up on the challenge and here are some quotes from the article written by J. Gordon Holt:

"We knew that Carver couldn't possibly pull this off, at least not to the point where none of us would be able to distinguish between his modified 1.0 and our reference amp. After all, some of the most highly trained audio ears in the world would be listening for the differences."

"...the reference unit is a high-powered, very expensive stereo unit with a strong and unique sonic "personality" and a penchant for being very finicky about the loudspeakers it works with. It was, we were gleefully confident, likely to be very dissimilar in sound from Carver's own designs."

"Not surprisingly, the reference amplifier sounded very different [from the Carver] and, in our opinion (shared, in most respects, by Bob), much better."

"Bob didn't have to concern himself about quality capacitors, minimal internal wiring, gold connectors, or any of those things; all he needed to do was duplicate, at the output of his amplifier, the sum of their effects at the output of the reference amp. Once he had obtained the necessarily deep null between those amplifiers, it was his belief that ears were not going to pick up on what was left."

"After the second day of listening to his final design, we threw in the towel and conceded Bob the bout."

"We had thrown some of the most revealing tests that we know of at both amps, and they came through identically. Even on the subliminal level--the level at which you gradually get the feeling that one amplifier is more "comfortable" than another--we failed to sense a difference between the two amps."

"We wanted Bob to fail. We wanted to hear a difference. Among other things, it would have reassured us that our ears really are among the best in the business." (italics emphasis in original article)

"According to the rules of the game, Bob had won."

"The implications of all this are disquieting, to say the least. If, after only four days of work, it is possible for someone--design genius or not--to make a $700 amplifier sound exactly like a state-of-the-art amplifier costing many times as much, what does that say for the cost-effectiveness of the latter?"


The amplifier used was a Carver M1.0 selling for $699. Bob used null difference testing to tweak the M1.0 until he obtained a deep null with the (unnamed) Stereophile tube reference amp. They did not reveal the reference amp because they felt it would be unfair to that manufacture who might ask: "why us?".

It was later revealed the most significant modification Bob made was to simply put some series resistance into the output of the M1.0 to better approximate the much higher output impedance of the tube amp. The other tweaks were supposedly limited to a small R-C network in the feedback loop.

It should be noted that J. Gorden Holt was the Editor-At-Large and Chief Tester at that time. Larry Archibald, the Publisher, and John Atkinson, the International Editor and a frequent reviewer, also participated in the listening sessions.

The challenge showed two things IMHO:

1 - It validates null difference testing with "some of the most highly trained ears in the world". Bob simply nulled his amp to the reference and JGH, JA and LA at Stereophile could not tell them apart.

2 - It shows that you don't need expensive components or exotic techniques to make a very modest amplifier with mainstream parts sound like a much more esoteric amp.

Bob literally bought the components used to modify the stock M1.0 at Radio Shack and worked out of his hotel room in Sante Fe (home of Stereophile). He made a 20 pound (9kg) mass production solid state power amp full of cheap parts (with a rail switching class-G power supply no less) sound so close to a very expensive heavy monster tube design that some of the mightiest GoldenEars couldn't tell them apart.

Considering that Stereophile is mainly filled with ads from high-end vendors hurt by the outcome of the challenge (versus just one advertiser--Carver helped by it), and that everything would point to the editors not wanting to admit a $700 amp can sound the same as a five figure one, I have to assume they wrote an accurate article and were not paying Bob any special favors.
 
Old 29th March 2003, 01:14 PM   #543
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Default Carver Test = Common Sense.

Nw_avphile,

Thankyou for digging up and posting the above article.
There has been much debate recently citing this test, and now I know what the test is about.

As I understand it, his test is all about 'cloning' amplifiers, and in this case Bob Carver modifying his amplifier (improving and/or stuffing it up !) so as to emulate the transfer characteristic of the example reference amplifier.

Of course, this dynamic null testing will by definition produce a 'clone' of the reference amplifier, and by extension the 'clone' ought to be reasonably indistinguishable from the reference amplifier.

It does however say nothing at all about the sonic qualities of either the reference amplifier, or the 'clone' amplifier - all it does show is that they are the same or extremely similar.

On the other hand it ought to be extremely useful for differentiating, understanding and categorising sonics changes due to differing components, values, layouts etc.

In my servicing work, I find it very useful to feed a mono signal into a stereo amplifier with a single speaker across the active outputs and take a listen to tones or music signals - this reveals very much about level and response matching between the two channels, and has been of great assistance in finding defects due to one cause or another - I have been doing the Carver test for years without knowing it !.

Eric.
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Old 29th March 2003, 02:24 PM   #544
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NW, you left out the coda. They ran the test again with a production version of the Carver amp. S'phile claimed (though the text doesn't support it) that they were able to distinguish the production amp from the reference. Unfortunately, the reference amp, a tube one, was in no real sense the same amp that it had been many month previously, as those of us faced with retubing bills are all too painfully aware. The null was less than 30 dB.

S'phile's conclusion: aha! you can't pull this trick off in production! That will satisfy the advertisers (IIRC, Stereophile became the single biggest revenue generator in all of high-end audio, including their advertisers).

Carver's conclusion: if you can make an amp null against a tube amp, don't expect that null to remain high after several months when the tubes are aging and the transistors aren't.
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Old 29th March 2003, 02:38 PM   #545
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Default Re: Carver Test = Common Sense.

Quote:
Originally posted by mrfeedback
Thankyou for digging up and posting the above article.
There has been much debate recently citing this test, and now I know what the test is about.
You're welcome. It's one of the more interesting pieces on the subject of high-end amplifiers versus mainstream ones because it was published in a very high-end magazine. Most of the other articles (such as those by Tom Nousaine) have either been published in more mainstream magazines (like Audio, Sound and Vision, Stereo Review, etc.) or more as scientific papers by the AES, etc.

Quote:
Originally posted by mrfeedback
It does however say nothing at all about the sonic qualities of either the reference amplifier, or the 'clone' amplifier - all it does show is that they are the same or extremely similar.
Well they didn't want to name the reference for obvious reasons but here's another quote where they describe it, this time in the follow-up piece on the production version of the Carver (the M1.0t):

"If Carver had managed to produce an inexpensive solid-state clone of one of the world's most highly respected tube amplifiers, it would seem to expose high-end amplifier manufactures as cynical exploiters, and audiophiles as gullible, if well-heeled, self-deluders."

The words "world's most highly respected" say quite a bit. They praise the reference, and in the first article, the Carver amp frequently. This was the late 80's so I'm guessing the reference amp was either the flagship Audio Research or possibly the flagship VTL? They said "high-powered" so that narrows the field quite a bit when it comes to "most highly respected" tube amps.

Quote:
Originally posted by mrfeedback
On the other hand it ought to be extremely useful for differentiating, understanding and categorising sonics changes due to differing components, values, layouts etc.
Yes, my thoughts exactly. It can be a very valuable tool and the Stereophile article gives it additional credibility.
 
Old 29th March 2003, 02:54 PM   #546
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Quote:
Originally posted by SY
NW, you left out the coda. They ran the test again with a production version of the Carver amp. S'phile claimed (though the text doesn't support it) that they were able to distinguish the production amp from the reference.
I left it out because, as you put it, the text doesn't support it. They ran a couple of very sloppy blind tests against the production version and the results could only be called inconclusive at best. After having much of the high-end world tell them they were crazy, and I'm guessing a lot of behind-the-scenes pressure from advertisers, it very much appeared to be a way for the magazine to try and get back to business as usual with everyone having their proper place in the high-end hierarchy.

Quote:
Originally posted by SY
Unfortunately, the reference amp, a tube one, was in no real sense the same amp that it had been many month previously, as those of us faced with retubing bills are all too painfully aware. The null was less than 30 dB.
Yes, and Bob claimed the production M1.0t they used may not have been biased correctly. He also claimed the ground set-up in their null test was creating a problem (the M1.0t amp, like most Carver "Magnetic Field" amps has one channel inverted in polarity to ease the strain of in-phase bass on the bizarre power supply so it has some special grounding requirements).

The letters to Stereophile in the months following both articles were interesting. I can only imagine what some of their advertisers were saying behind the scenes. The whole thing created quite a stir and it seems fairly obvious Stereophile (and probably the rest of the high-end press) learned a valuable lesson and, sadly, I doubt they'll be accepting any more such challenges.
 
Old 29th March 2003, 03:06 PM   #547
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Default The tube clone...

Quote:
Carver's conclusion: if you can make an amp null against a tube amp, don't expect that null to remain high after several months when the tubes are aging and the transistors aren't.
And don't expect the oposite...that is, to make a tube amp null against a solid state amp...
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Old 31st March 2003, 07:42 AM   #548
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Red face About the Halcros

Jorge,

I listened to them after they closed the door, at the end of the day.
Before thad, it was full of people.
One thing thas was obvious is that the room is not appropriate for equipment like that, but it's the biggest room they have.
If your friend was there on the first day, maby he was with me and Domingos, my friend I talked about.
They are going to close that semi-open left wall, that's what's killing the sound of everything they put there.
They assumed and they were saying to the customers that the room was not ready.
But you have do discount the sound of the room, specially if you heard other things playing there (as I did).
I can only tell you that it plays very well.
Oh, and the B&W 800s were burning-in, they were new.
 
Old 31st March 2003, 08:09 AM   #549
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Default Just a few things

nw,
First of all, I don't read Stereophile.
It doesn't worth the cover price.
I'm not a high-end snob, you know.
I also think there are many good and cheap components.
That's why I have a NAD amp.
There's also many high-end products that don't worth the money they ask for it, it's a robbery.
One good example is a 47 Labs Gaincard.
So much maney for almost nothing inside...
But I understand that a Krell has to be expensive.
But you can't really compare a cheap AV amp with a good stereo amp.
If it was so, why would I bother to have a good stereo amp (mine is tweaked ), a very good dac, etc, if the AV amp has everything inside?
Can you expect an amp with 5 or 6 channels inside, preamp, DACs, DSPs, plays better than a stereo amp of the same price?
As you see, I'm not blinded by high-end, but pleeeeeease...

P.S: Eric, congratulations for your note about women.
I couldn't say it better.
 
Old 31st March 2003, 08:27 AM   #550
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Default THE TEST.

Hi,

Quote:
This was the late 80's so I'm guessing the reference amp was either the flagship Audio Research or possibly the flagship VTL? They said "high-powered" so that narrows the field quite a bit when it comes to "most highly respected" tube amps.
Wasn't the "Reference Amp" the Carver "Silver Seven"?
At least that is what I thought it was, I could be wrong though...

Cheers,
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