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John Curl's Blowtorch preamplifier part III
John Curl's Blowtorch preamplifier part III
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Old 19th February 2018, 02:14 AM   #101
Tournesol is offline Tournesol  Belgium
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Quote:
Originally Posted by scott wurcer View Post
Both the picking capacitors and Bateman's articles were self published or published in hobby magazines with no technical peer review. Were there blind listening tests that would pass any serious review? I don't know, but I don't think so.
Don't know about the Bateman's article, but "Picking capacitors" had the advantage, at the time it was published, to enlight a lot of people, including me, about the capacitance's problems in audio.
Enough to inspire me to undertake measurements and listening sessions on the same subject. Leading to the same conclusions.

I believe-you when you understate you should had been more "scientific" if you had done this work, but, unfortunately, I had not read anything about this subject under your name at this time or after. Self published or not.
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Old 19th February 2018, 02:15 AM   #102
TheGimp is offline TheGimp  United States
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Well, I screwed the pooch on my measurements.

I found that if I increased the capacitance over 1uF I would get the IM distortion. Something about my test set I suspect.

So, I need to go do some reading and try to approach this in a more consistent manner.

I've loaded a bunch of pdfs to my amazon fire, so I'm off to take a shower and read till I fall asleep. Thanks for all the recommendations for articles.

Night all, and thanks for the input.
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Old 19th February 2018, 02:43 AM   #103
nezbleu is offline nezbleu  Canada
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John Curl's Blowtorch preamplifier part III
Quote:
Originally Posted by RNMarsh View Post
SY was rude and annoying and I never learned anything useful from him.
I never found him rude. I have no doubt you found him annoying. If you never learned anything from him, then you weren't paying attention. He is an accomplished scientist with much to offer.

FWIW I read "Picking Capacitors" when it was published in Audio magazine, which I read every month back then. It was a game changer, very informative, challenged received wisdom, and was based on some serious research. It was not rigorous nor peer reviewed. It spawned an industry that mischaracterized your findings and preyed on the gullible. Not your fault, but you also never really challenged the snake oil charlatans that used your work to justify their BS. Or maybe you did, but I never saw it. Surely even you would recognize the disingenuousness of the beeswax and unobtanium capacitor purveyors.

Now SY would actually measure (as you and Walt did) and dismiss the more ridiculous claims (about caps, wires, digital, Bybees, etc). I know you and he wound up on different sides of many arguments. When he makes a claim he backs it up with repeatable data, and he expects the same from those who challenge his findings. That can be really annoying, but it's called science.

I think, or hope, that you know that I hold you in very high regard, and I have admired your contributions to the audio state of the art over many decades. I also admire SY's contributions; he wasn't just hanging out here bothering people, he applied science, measured, designed, listened, measured again, published his work, etc. If half the folks here did half as much, we would have a richer forum.
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Old 19th February 2018, 02:59 AM   #104
RNMarsh is offline RNMarsh  United States
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Nezbleu -- I agree about most everything you said, above. You have to realize that I was not working in audio and had little contact with those who were/are - except those who were more interested in T&M, design and how and why's. Not consumer markets.

I never then nor now feel what others do with the information that is not related to me - be some how my responsibility - like selling over priced capacitors. Not my concern about listener only audiophiles who dont know BS when they hear it. I would assume the industry would police itself.

As for SY - I came to DIYaudio to help people who wanted to build my minimalist headphone amp. But got jumped/blind-sided on the snake oil capacitor sales people selling remarked caps at high prices to unsuspecting audiophiles. WTF ? So, I dont know SY but only thru his position towards me. But, he isnt alone. Somehow, I get blamed for all these other people selling over priced caps and it is My fault? Amazing. More stupid thinking from otherwise good technical minds.


THx-RNMarsh

Last edited by RNMarsh; 19th February 2018 at 03:11 AM.
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Old 19th February 2018, 03:49 AM   #105
anatech is offline anatech  Canada
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John Curl's Blowtorch preamplifier part III
Hi Richard,
I think most appreciate the knowledge you bring. There will always be a peanut gallery of mostly noise. If you can let that slide off your back.

As for SY, you two would probably get along in person. I also think the two of you would respect each other. I'm saying this from knowing SY and going off exchanges between you and I. Could be wrong, but I don't think so. SY is very direct and I can see this coming off as rude. That would probably be the biggest issue to get beyond.

I do miss SY around here.

-Chris
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Old 19th February 2018, 03:56 AM   #106
john curl is offline john curl  United States
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Chris, I replaced some caps in this Sony tuner that appear to be ceramic. What do you think. C101, C102,C202
Attached Images
File Type: png Picture 37.png (238.4 KB, 384 views)
File Type: png Picture 38.png (294.6 KB, 386 views)
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Old 19th February 2018, 04:16 AM   #107
anatech is offline anatech  Canada
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John Curl's Blowtorch preamplifier part III
Hi John,
How about C201? That looks like a nasty one.

Not having seen one of these on my bench, I can't say much about the original capacitors, but what you have done is what I would do if forced to try and upgrade one of these. At $100, trying to improve it is silly unless it belongs to you. Also, the gain stages shown are not very good for thermal stability. I wouldn't be too surprised to see huge variations in operating point. It has other problems that make it a poor candidate for improvement.

At this moment, on my bench is a Marantz 2325 that is undergoing a complete series of improvements. Capacitors are one part of the job. I'm matching transistors, making some minor circuit changes and aligning the tuner, among other things. It will come off the bench an entirely new piece of equipment. The changes result in both audible and measured improvements.

I can do better with other models, but this will sound pretty darned good, and make someone extremely happy. There is no point in doing this otherwise.

-Chris
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Old 19th February 2018, 05:11 AM   #108
RNMarsh is offline RNMarsh  United States
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Chris.... what are you using to do the FM alignment?

Which one(s) should I get aligned?

Marantz 20
Yamaha T-2
Sony ST-444 ES
Magnum Dynalab MD 102
Sangean HDT-1X
Kenwood KT 5500

?

-Richard

Last edited by RNMarsh; 19th February 2018 at 05:32 AM.
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Old 19th February 2018, 05:16 AM   #109
john curl is offline john curl  United States
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I chose this Sony tuner, because Richard Sequerra told me it was the best design out there today. However, there were a few compromises, and I had to change the caps. Of course, most of you would be perfectly happy with it as it was.
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Old 19th February 2018, 05:21 AM   #110
anatech is offline anatech  Canada
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John Curl's Blowtorch preamplifier part III
Hi Richard,
A really cool piece of gear called a Sencore SG80, and an HP 8656B. The Sencore refuses to sit on even frequencies, just odd ones. That forces me to use another generator as well. Overall, very happy with the SG80 and it continues to operate nicely as long as it's used.

-Chris
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