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Old 20th May 2011, 02:47 PM   #12271
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Quote:
Originally Posted by simon7000 View Post
L's consisting of just an air core coil of copper wire fused with polymers are at least 2 orders of magnitude worse than R or C at low levels. Some were 5 orders worse. I only tried a few aimed at the audio market. But as individual components vary that is a lot of range. You also left out the bit about the high gain stage.

But as someone posted it is rated at .3% for phone which is pretty much what I would have expected.
Not by my measurements, air core #12 wire coil >-150dB as an LC low pass.
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Old 20th May 2011, 02:57 PM   #12272
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I've built up a 7.1kΩ line level LCR network. I guess it's time to do some measurements. It may be awhile, though. My next door neighbor works for a calibration firm and he is going to check my test equipment for me. My upgrade to modern computer based testing has stalled so I'm still stuck with old school.

Maybe I'll be in a position to discuss this subject in a better light at a later time. Until then I'll stick by my assertion that the Allnic and Ypsilon phono stages sound better than anything else I've heard.

John

Last edited by jlsem; 20th May 2011 at 03:01 PM.
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Old 20th May 2011, 03:17 PM   #12273
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Poor me, just a guy who tells 'stories' and doesn't know which and why good designs are good, and bad designs are bad. For the record, the HCA3500 suffered a similar problem with 'Stereophile' reviewers, YET it did NOT have an IC op amp at the input. What was their cause to reject it THEN? Threw me for awhile, too!
I think there are two ways of coming to a conclusion, in order to fix something: To guess what might be a problem, remove or change it, then try again.
OR blame the reviewer, based on the 'fact' the the AD712 IC is virtually perfect (even though it is not made anymore) and COMPLETELY adequate for audio use, even against the more exotic designs.
The problem is: I still have to get a good rating in 'Stereophile' to sell enough product to make it economically successful. Which way works, especially when 'fixing it' also sounds 'better' to ones own ears and those of one's associates?

Last edited by john curl; 20th May 2011 at 03:44 PM.
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Old 20th May 2011, 03:19 PM   #12274
jlsem is offline jlsem  United States
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Quote:
what advantage (other than fashion)
I don't understand what you mean by fashion. LCR networks have been used by diy-ers for many, many years. As far as a few high-end companies following suit, I believe that most if not all of them began as diy guys. It was the diy community that began to question the philosophy of eliminating bulk and cost disadvantages while searching for the advantage of a more satisfying sound.

John

Last edited by jlsem; 20th May 2011 at 03:25 PM.
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Old 20th May 2011, 03:21 PM   #12275
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An air core inductor used as a low pass filter will filter its own harmonics. Therefore, not so perfect a comparison.
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Old 20th May 2011, 03:37 PM   #12276
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Quote:
Originally Posted by jlsem View Post
I don't understand what you mean by fashion. LCR networks have been used by diy-ers for many, many years.
That fashion started around the same time as the fashion for other bulky iron. You don't even see it mentioned in standard treatments of RIAA (e.g., Crowhurst, Lipshitz) published before the early to mid '90s; I don't know this, but if I were to guess, it probably had the same origin as other irrational fashions in "high end" audio- Jean Hiraga.

Since it carries no performance advantage, costs more, but looks impressive, I think you'll have a hard time coming up with an engineering justification.
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Old 20th May 2011, 03:57 PM   #12277
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Default Huh?

Quote:
Originally Posted by john curl View Post
...
OR blame the reviewer, based on the 'fact' the the AD712 IC is virtually perfect (even though it is not made anymore) and COMPLETELY adequate for audio use, even against the more exotic designs.
.....
Huh?
Product Status: production
AD712 | Precision, Low Cost, High Speed, BiFET Dual Op Amp | Operational Amplifiers (Op Amps) | All Operational Amplifiers | Analog Devices

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Old 20th May 2011, 04:08 PM   #12278
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John the point was WE didn't hear it and they refused a face to face listening test (claiming they didn't have a listening room!!!!). It's one of the biggies.
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Old 20th May 2011, 04:20 PM   #12279
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While I am here on this subject, I would like to talk about a specific way of believing in the world, what works, and what is 'possible'.
I call this: 'Leading with a conclusion' (and working backward)
This is what I find is directed against the 'chip', removal of the IC from the HCA2200, and 100 other choices that I have made over the decades, even though the 'solutions' have given me some success.
The best example that I can give, if you will carefully examine it, is based on an incident, over 400 years ago, between two very intelligent people, one, a try-everything kind of guy, and another, a distinguished professor. Here goes:
Galileo, first getting telescopes as spy glasses for the Venice military establishment so that they can spot for warships from their higher towers, sort of an early warning system, decides to point his telescope at the sky and see what he can see. You know, just for the heck of it. He looks at the planet Jupiter and to his astonishment, he sees four little lit spots near it that appear over the days to change position. What a concept! So he tries to get an official to look into his telescope to see what he has found. It is 1610.
This is Francisco Sizzi's (professor of astronomy) answer to Galileo:
"Jupiter's moons are invisible to the naked eye and therefore can have no influence on the earth, and therefore would be useless, and therefore do not exist." 'The Experts Speak', p.295
Now consider professor Sizzi's comment seriously. He is a learned man, he has been told (by church doctrine) that certain things are possible, and all other things are error. The church has invested more than 1000 years investigating what is possible and impossible in their studies of previous writings and they are pretty darn sure of themselves.
Well, we have some people around here who are also pretty sure of themselves due to their educational background and what it allows for something to be or not to be. But do they have 'the' answer to that question, in every case? I think not.
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Old 20th May 2011, 04:34 PM   #12280
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I was referring to the use of the AD712 as MY CHOICE as the input IC chip in the initial HCA2200, not Adcom's problems with the chip. I was not informed by them, at the time, or you for that matter, that there was a problem. I had to go through the reviewing process, myself, before the problem was found.
Now, why didn't I pick up on the problem, myself? Because I NEVER listened the the ORIGINAL HCA2200 in my own hi end system. I had WATT-PUPPIES at the time and I was afraid that I might damage the tweeters with such a large amp, so I never took it home to listen to. Was my boss mad at me for that! He blamed ME for selecting the chip, based on my association with you, and allowing it to be put into the power amp input. I should have not JUST measured it, but tried it out personally.
Did I learn my lesson? Partly. Yet, just yesterday, I got a report that the phono stage that we sent to the Munich show, also sounded just fine, AND I have never listened to it in my home system, so I took another chance. (and I had my fingers crossed, because you never know for sure, until you try it yourself) at least, in my opinion, if it sounds OK in MY listening room then it will be OK for others too. This is how I selected IC's for the JC-3 and made other last minute changes. Thank goodness that I did.
It started out as a 'dog'. So much for all IC's, etc sound the same.
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