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John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
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Old 15th January 2014, 05:28 PM   #46821
PMA is offline PMA  Europe
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Quote:
Originally Posted by jneutron View Post
Agreed. In addition, for this specific system the source and load impedance are very important as well.

jn
Sure, that's why we analyze a cable driven from almost zero impedance and terminated by a speaker - complex impedance with series inductance (almost infinite impedance at high frequencies) and why we speak about possible R-C termination to reduce high frequency reflections. I thought this was the goal.
 
Old 15th January 2014, 05:29 PM   #46822
rsavas is offline rsavas  Canada
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Stupid me, forgetting, Au wire was not to be left out, yes I'll get me some 14-16awg gold wire on my next Mouser order, gotta PN for me as well?
If you can lend me some, I'll be sure to return it to you ;-) Maybe I'll show it off as my new jewelry, as well, I hope it has a transparent sheath, so I can get the full effect. Maybe wrapping it around my head neck will help me hear the BIG difference ;-) I am a silly a$$. It will be the only jewelry I have. Okay back to code, really, I have said enough already today.
Cheers
 
Old 15th January 2014, 05:34 PM   #46823
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Originally Posted by jneutron View Post
By converting to 10 pieces of 10 ohm units, and arranging them on a ground plane in a spoked arrangement, I was able to get the parasitic L out, and the subsequent 250 picosecond risetime was flat topped.
I understand you, in the eighties I was designing high voltage dividers to measure fast transients like 1.2/50us wave and 1.2/50us chopped wave (dielectric breakdown). Groundplane (floor = plane) + series damping. Even the reflections on the high voltage input line (wire) must have been damped.

Last edited by PMA; 15th January 2014 at 05:41 PM.
 
Old 15th January 2014, 05:53 PM   #46824
john curl is offline john curl  United States
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Actually I was told by Jack Bybee that gold wire is exceptional. Too much for me, however, AND all of my cables that I use today are copper or copper-aluminum. Silver wire is on the inside of the CTC Blowtorch, only. I did Blowtorches with both quality copper and quality silver wire. Silver won for me, but it is quite a hassle to break in, so most of my designs use quality copper wire, and aluminum cases.
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Old 15th January 2014, 06:13 PM   #46825
hhoyt is offline hhoyt  United States
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John Curl's Blowtorch preamplifier part II
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Originally Posted by brianco View Post
With over 46,000 posts on this the second thread, one would imagine that continuing the debate regarding uncontrolled subjective testing versus strictly controlled testing is a futile pursuit. Those who do so are totally wasting their time.....

That being so, why not attempt to keep this topic somewhere near pre-amp design and implementation?
Thank you for re-stating what makes many of us roll our eyes along with unsubstantiated comments on subjective quality...I've been involved in both forms of evaluation and neither is without problems...maybe there is a different thread more appropriate for these kinds of comments?

Howie

Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
 
Old 15th January 2014, 06:15 PM   #46826
jneutron is offline jneutron  United States
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Originally Posted by PMA View Post
Sure, that's why we analyze a cable driven from almost zero impedance and terminated by a speaker - complex impedance with series inductance (almost infinite impedance at high frequencies) and why we speak about possible R-C termination to reduce high frequency reflections. I thought this was the goal.
There are several goals.

Termination to reduce hf reflections is a stability concern especially if the line is low z. and the load lets go at hf. But that's where you guys already excel.

I'm also concerned about image reconstruction and what compromises it.

Quote:
Originally Posted by PMA View Post
I understand you, in the eighties I was designing high voltage dividers to measure fast transients like 1.2/50us wave and 1.2/50us chopped wave (dielectric breakdown). Groundplane (floor = plane) + series damping. Even the reflections on the high voltage input line (wire) must have been damped.
Oh man, that musta been ugly. HV and low inductance are almost mutually exclusive.

jn
 
Old 15th January 2014, 06:17 PM   #46827
jneutron is offline jneutron  United States
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Originally Posted by rsavas View Post
Stupid me, forgetting, Au wire was not to be left out,
You owe me 4 quatloos. I take paypal..

jn
 
Old 15th January 2014, 06:27 PM   #46828
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Old 15th January 2014, 06:54 PM   #46829
scott wurcer is offline scott wurcer  United States
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Originally Posted by a.wayne View Post
There's a big difference sonically between silver and copper , one would have to be tone deaf not to notice ...
Or in the wrong kitchen.

http://www.youtube.com/watch?v=hWi3NwDrQok
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Last edited by scott wurcer; 15th January 2014 at 07:00 PM.
 
Old 15th January 2014, 07:00 PM   #46830
canyoncruz is offline canyoncruz  United States
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Laser distortion analog. For directly modulated the worst we have seen is -130 dB. Externally modulated about 59 dB lower. This at 100 kilometers.

Linearity is really depend and on the package. Laser run class A because there is no such thing as negative photons. With out cooling there will be a point were you get thermal roll off ( the high end of the amplitude). I will have to get current numbers but it is very good.

The noise we are interested in is RIN, and that is pushing -180 dB.


Foe to slink, get a grin lens and some 50 um multi mode or smf28 single mode Fiber. Make sure everything is angle polished. Hack a to slink connector And stuff the grin lens ( without alignment use a multi mode fiber) get the right pitch lens so you can but it up. Single mode sources are still available that can be swapped out for to slink, but the run at 1300 Nam so you will need a receiver too.

In the analog mode , one thing of interest is the laser acts very much like a tube. You can tube a harmonic profile. Clipping is similar though asymmetrical.

My apologies for the phone typing.
 

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