John Curl's Blowtorch preamplifier part II

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#19,801
My listening experience in touring both The Show and the CES. Years before, Waviac had a really good sound, a few years ago, LAMM had great sound, this year, I found nothing that 'knocked me out' Even JBL failed to show what they showed, last year, which was pretty darn good.
 
#19,802
Okay, so maybe all the speakers sucked and the preamps were awesome. Or maybe the people setting up the systems forgot how. Or maybe the rooms were bad. Well, lots of possibilities ...

At a Stereophile show I once heard a setup with the Thiel speakers and a particular amp which I didn't think was good, for whatever reason. Being a Thiel fan I blamed the amp, of course. Months later I read a glowing review of the amp in Stereophile ... a bargain at it price.

Well, who knows why the system sounded bad. Lots of possibilities.
 
#19,807
My phono input uses matched 4 x 2SK147 and 4 x 2SJ72 per channel plus cascodes - bought them from Erno 20 years ago in the golden age of jfets. What is left for designers today ? BF 852 and waiting for Linear Devices to make a P channel device or do we go over to the dark side and use bipolars. Any sign of a surface mount N or P dual low noise jfet pair or is it all cell phone and computer chips and we are doomed to trolling Hong Kong Ebay sites for fake jfets forever?
 
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#19,808
I am failing to see why you could not parallel 2 times 2SK170 and 2SJ74 each to replace one 2SK147 and 2SJ72 respectively. According to the datasheet I end up with the same total gm / input capacitance ratio. What am I overlooking, other than that k170/J74 are also becoming rare? Are there other parameters where they differ still?
 
#19,809
2sj74 is also discontinued device. While diy guys can find, beg, borrow, steal, unsolder from a neighbour's amp while he sleeps, enough for a personal project not enough around to match IDSS for a manufacturer to build a new design from unless you are Nelson, Charles, or Constellation and were wise enough to stock up on singles and dual jfets to last a few years (hopefully).
 
#19,814
I remember hearing my first 'special' Strad. I had heard many world class violins during the previous year, while working at IHEM in Switzerland.
However, one evening, while attending a recital from one of the 'master teachers', I just could not believe my ears. I was in shock! I whispered to my future wife, a violinist herself, what was happening? It was so OUTSTANDING a violin sound. She said: 'That's your first 'Strad', John". After the concert, I bored the owner of the Strad, (I can't even remember his name) with my enthusiasm over his instrument for what seemed 1/2 an hour.
To me, this is were it's at, and WHY I don't do double blind tests. It would be the same with wine, amps or preamps, for me at least. The differences would disappear during the test, only to reappear afterward.
 
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#19,817
"Double-Blind Violin Test: Can You Pick The Strad? : Deceptive Cadence : NPR"

I saw this on line a few days ago as well.

What all this also says is that we should not make claims about our creations that in the final analysis do not stand up to objective scrutiny. Before I get shot down, this does NOT mean I diss any of the people on this forum, or their design choices. What I am saying is that there are many design options that produce credible subjective results (and I mean high end John, not mid-fi ;-). If you take all of the Stereophile A+ rated products, I doubt many would say some of them sound crap. They will sound different, and those differences will attract some dedicated customers. As a designer, those are the people you have to look after!

🙂
 
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