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John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
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Old 3rd January 2014, 03:14 AM   #46321
simon7000 is offline simon7000  United States
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JN

PM me a shipping address. I will send you a few coils to measure so we can compare notes. I think you are drifting off the issue of disagreement.

We both understand there is more than one issue affecting signals in a cable. The issue is inductance and if it changes in a coiled cable.

So inductance bridges at high noon, stranger!

ES
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Old 3rd January 2014, 04:54 AM   #46322
elektroj is offline elektroj  Europe
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I have a question to those who might know the details better - John, Scott, Brad..

What's the difference, if there is any, in Jfet manufacturing process that makes the transistors from the same process (say 51, National semi) switching ones in one case (J111) and low noise in other case (PF5101)? Quality control? Some ommited or extra process? Different wafers? Cleaninness? Different manufacturing line?

Thanks!
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Old 3rd January 2014, 07:29 AM   #46323
Bonsai is offline Bonsai  Europe
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Interesting article here about PCB material and very high data rates. One for JN and the physicists here to get their teeth into I guess!

Glass weave skew problems may be solved | EDN
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Old 3rd January 2014, 11:15 AM   #46324
DF96 is offline DF96  England
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Will we now find 'high-end' people claiming that glass weave skew destroys stereo imaging and creates smear? After all, 2ps of skew must be audibly better than 6ps of skew.
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Old 3rd January 2014, 11:24 AM   #46325
Bonsai is offline Bonsai  Europe
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LOL. Let's wait and see
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Old 3rd January 2014, 11:44 AM   #46326
PMA is offline PMA  Europe
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John Curl's Blowtorch preamplifier part II
Default Channel separation measurement for JN

I have made one more channel separation measurement, especially for JN. Now, the whole chain of Preamplifier + PA4 power amplifier was measured. With cables and everything, of course. Then, a measurement of Preamplifier alone was done. One may see that the power amplifier has not changed the measurement result! Finally, as a reminder, channel separation of power amplifier PA4 alone is shown. The conclusion is that it is a preamp that defines channel separation, in case that power amplifier has a proper dual-mono layout and proper wiring.
Attached Images
File Type: png channel separation Preamp + PA4.PNG (22.2 KB, 234 views)
File Type: png channel separation Preamp only.PNG (21.0 KB, 232 views)
File Type: png channel_separation PA4.PNG (21.8 KB, 229 views)
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Old 3rd January 2014, 01:02 PM   #46327
scott wurcer is offline scott wurcer  United States
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Quote:
Originally Posted by simon7000 View Post
JN

You can take everything out of context as much as you want to. Anyone can go back and read forward.
Ed, I don't have the energy right now but I distinctly remember you stating that someone left the wire coiled and his measurements were "all wrong" implying that uncoiled would have been OK.
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Old 3rd January 2014, 01:09 PM   #46328
scott wurcer is offline scott wurcer  United States
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Quote:
Originally Posted by elektroj View Post
I have a question to those who might know the details better - John, Scott, Brad..

What's the difference, if there is any, in Jfet manufacturing process that makes the transistors from the same process (say 51, National semi) switching ones in one case (J111) and low noise in other case (PF5101)? Quality control? Some ommited or extra process? Different wafers? Cleaninness? Different manufacturing line?

Thanks!
You need more information, the noise can depend on channel length within the same process. Other things, gettering could be left out, starting matierial maybe, different fab maybr too, but I don't think anyone can afford diirty fabs today.
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Old 3rd January 2014, 01:55 PM   #46329
scott wurcer is offline scott wurcer  United States
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Quote:
Originally Posted by scott wurcer View Post
You need more information, the noise can depend on channel length within the same process. Other things, gettering could be left out, starting matierial maybe, different fab maybr too, but I don't think anyone can afford diirty fabs today.
I can't find PF5101 DS so can't tell if it is actually same die. Seriously cold here, SY must be experiencing real winter for once.
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Old 3rd January 2014, 02:07 PM   #46330
Bonsai is offline Bonsai  Europe
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My brother lives in Nantucket. Just got pics through of the snow. Unbelievable. Stay indoors
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