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Old 5th March 2013, 11:56 AM   #8541
SY is offline SY  United States
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Quote:
Originally Posted by vacuphile View Post
What could explain this?
Looks, price tag, prestige, and a general insensitivity to distortion. Don't know about Wavac, but Jadis offers the extra benefit of regularly emitting smoke.
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Old 5th March 2013, 12:11 PM   #8542
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Quote:
Originally Posted by vacuphile View Post
Agree with Dave, but it doesn't answer the question why in this case, like for example with the WAVAC, the distortion is euphonic. Because usually, gear with such distortion figures would sound plain horrible. What could explain this?
It would be interesting to listen the same speakers used in the tests but driven by a normal cheap amp .. like the T-amp for instance
Maybe there will be some kind of surprise
For me distorted is synonym to deformed ... not a nice sensation
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Old 5th March 2013, 12:21 PM   #8543
DF96 is offline DF96  England
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It could be the name 300B. When applied to any amplifier, including at least one which does not contain the said valve, it appears to affect listeners' perceptions.

30-40 years ago a similar effect was common in IT: anything labelled IBM was regarded as good, no matter how expensive or inappropriate it was.

I'm not knocking the 300B or IBM, as both are capable of good results. However, neither guarantees good results when misapplied.
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Old 5th March 2013, 12:27 PM   #8544
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My experiments with SE amps suggested < 1 % at 5W is possible without feedback . I am unwilling to say the tricks I used as they took time and were not the cliched versions . They are all easy enough to work out . More importantly after many attempts I got the harmonics to reduce on a near exponential graph . The argument put up by Jean Hiraga in the 1980's was that the exponential curve seems to be of zero perceived distortion if the 2 nd doesn't exceed 1 % . His argument being that the the comparative harmonics please the ear and is taken to be neutral . He seems to argue that nothing except zero distortion would be taken to be as neutral . For example 0.05% 5 th and nothing else would be taken as less neutral . I suspect to make a 300 B or 211 version of my amp would not be difficult ( I have 77 V rms drive if required at > 10 mA ) . I did have 211 in mind . Conventional amps of this type usually are about 5 % THD if the religious route is taken ( sad that it is ) . The other valve I have just received is Gu 50 . These are called the poor mans 300 B by some .

Jardis is a strange word in French as the S is sounded , it means something like " once upon a time " or when time was .

I feel I do well for a man with almost zero interest in valves .

Last edited by nigel pearson; 5th March 2013 at 12:40 PM.
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Old 5th March 2013, 03:26 PM   #8545
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These are the days of perceived value.

High price is assumed to mean better, famous moniker also, and so forth. And it's not just audio, it's everywhere. If you own a say Kia hatchback, chances are you'll run up against at least one guy who will explain why your car is a moving pile of junk. But if you were to switch the monikers from Kia to say Porsche, your car would be revered without any additional change. Ditto TV set, ditto everything.

It's a shallow world out there. And it ain't getting better.
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Old 5th March 2013, 03:55 PM   #8546
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Quote:
Originally Posted by DF96 View Post
30-40 years ago a similar effect was common in IT: anything labelled IBM was regarded as good, no matter how expensive or inappropriate it was.
"Nobody ever got fired for buying IBM", was the slogan they advertized with; straight for the guts. They planted this mneme of implicit trustworthiness with great succes.

Another great way IBM fjukked with the collective mind was the "Think" thing. I have always felt this was a misappropriation of Timothy Leary's "Think for yourself, question authority". They blanked out the bits obviously unacceptable to any power hungry organization, and by butchering Leary's slogan, they perversely snuck in the notion that to Think is what IBM does, and that you can safely leave it up to them.
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Old 5th March 2013, 09:10 PM   #8547
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I work on the 5% rule: 95% of human activity is rubbish - repetitive, mindless, ego-driven, ritualistic, fit only to be dropped into a shredder. But, that small 5% is where the action is, this is where the human race inches forward, fractional bit by fractional bit, so that after some time period one can actually look over one's shoulder and say, "Yes, we have made some progress there ..."

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Old 5th March 2013, 11:04 PM   #8548
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Quote:
Originally Posted by DF96 View Post
It appears to have 15% 2nd and perhaps 5% 3rd (which means similar levels of IM). At 1.6W I can only assume this is some sort of joke. Have you shown the wrong plot?
Note the 50Hz, many SET designs are entering core saturation at a few Watts below 100 Hz. The measurement at 1 kHz would be much better.

HiFi shows always seem to demo SET amps with tinkly piano and female vocals, not drums and bass
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Old 6th March 2013, 09:20 AM   #8549
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From memory my cheap and reasonable Danbury transformer gave 2W at 18 Hz 8 R . The output valve is KT 88 . At 50 Hz it will give 8W at about double the 1 kHz distortion . The graphs below are before I introduced any transistors to the mix . 2 valves , 8 R and good to about 50 kHz . No loop feedback . EL 34 was almost as good with nicer clipping spectrum . EL 34 mostly double the distortion at lower wattage's . Although in theory KT88 is more powerful , in practice there is not much in it . The EL34 is run hard to get that . The design was inspired by the PYE Mozart . In the end it had nothing in common with the PYE apart from SE . I tried the RH34 by Alex Kitic . I didn't get far with that . I did use an LM317 as a current sink for the EL 34 next . I had to work very hard to beat that .
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Old 6th March 2013, 09:31 AM   #8550
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Originally Posted by fas42 View Post
I work on the 5% rule: 95% of human activity is rubbish - repetitive, mindless, ego-driven, ritualistic, fit only to be dropped into a shredder. But, that small 5% is where the action is, this is where the human race inches forward, fractional bit by fractional bit, so that after some time period one can actually look over one's shoulder and say, "Yes, we have made some progress there ..."

Frank
< 0.00000000005 % ?
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