Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

The Lounge A place to talk about almost anything but politics and religion.

John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 14th July 2011, 09:54 PM   #14041
simon7000 is offline simon7000  United States
diyAudio Member
 
Join Date: Nov 2008
Location: Oakmont PA
OK my gear for this measurement was bought new by me, but has never been recalibrated so there may be some error, but I am certain it is only a few percent.

The small diode measured .123 l x .064 d, the larger diode .203 x .104! (Inches!)
  Reply With Quote
Old 14th July 2011, 10:09 PM   #14042
john curl is offline john curl  United States
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
Could be mircorgaps! Whatever it is, it is.
__________________
"Condemnation without Examination is Prejudice"
  Reply With Quote
Old 14th July 2011, 10:45 PM   #14043
scott wurcer is offline scott wurcer  United States
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: dorchester ma
John Curl's Blowtorch preamplifier part II
Quote:
Originally Posted by simon7000 View Post
Actually long ago I was in a group working on a semi-high power laser It ran at 22kv 200a around 3 pps. The trigger used a krytron for the first stage switch. I had not only never seen one before, but had never heard of one. Of course that was because they were I think still classified as secret (Lower Level).

So yes during that project I also learned a bit about the breakdown of air. One fellow got his PHD photographing how punch through in air actually happened! Really neat pictures!

I am less worried about air gaps as I am oxide formations on the surfaces of what should be mechanically connected components. How do you make a variable resistor without a wiper and associated problems?
There are no metal oxide/metal junctions that change from conducting to not over a 1 or 2 milli-volt span. Fermi levels, activation energies, bandgaps, whatever they all often have those pesky exponential relationships with temperature as well as values in the volt range.
__________________
"The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important."
  Reply With Quote
Old 14th July 2011, 10:49 PM   #14044
simon7000 is offline simon7000  United States
diyAudio Member
 
Join Date: Nov 2008
Location: Oakmont PA
Quote:
Originally Posted by scott wurcer View Post
There are no metal oxide/metal junctions that change from conducting to not over a 1 or 2 milli-volt span. Fermi levels, activation energies, bandgaps, whatever they all often have those pesky exponential relationships with temperature as well as values in the volt range.
Ever see a guy tap a dead microphone to get it to work?
  Reply With Quote
Old 14th July 2011, 11:05 PM   #14045
scott wurcer is offline scott wurcer  United States
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: dorchester ma
John Curl's Blowtorch preamplifier part II
Quote:
Originally Posted by simon7000 View Post
Ever see a guy tap a dead microphone to get it to work?
Your plot shows about 50mV per div, a typical microphone has 20mV at 94dB SPL so why is there no output? You grind a bad connection back together by working the two halves around, no need for any exotic explaination. Same thing with corroded batteries.
__________________
"The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important."

Last edited by scott wurcer; 14th July 2011 at 11:09 PM.
  Reply With Quote
Old 14th July 2011, 11:54 PM   #14046
john curl is offline john curl  United States
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
I meant to say: microgaps. Sorry, still sort of blind.
__________________
"Condemnation without Examination is Prejudice"
  Reply With Quote
Old 15th July 2011, 01:23 AM   #14047
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
John Curl's Blowtorch preamplifier part II
All, please try to stay technical. All cheap shots will be deleted.
  Reply With Quote
Old 15th July 2011, 04:24 AM   #14048
magnoman is offline magnoman  United States
diyAudio Member
 
Join Date: Nov 2010
Location: The City, SanFrancisco
Thanks everyone for the insights into ferromagnetic case effects (my nickel plated aluminum cases' self respect appears to have returned as well).

-Antonio
  Reply With Quote
Old 15th July 2011, 05:38 AM   #14049
john curl is offline john curl  United States
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
Magnoman, going to the hi fi show? If you do, be sure to stop by Constellation Audio and look at the aluminum cases (with damping) that we are designing with. Mine weighs over 90lb, I am told. (Only rich guys need apply '-)
__________________
"Condemnation without Examination is Prejudice"
  Reply With Quote
Old 15th July 2011, 01:11 PM   #14050
jneutron is offline jneutron  United States
diyAudio Member
 
jneutron's Avatar
 
Join Date: Jan 2004
Location: away
Quote:
Originally Posted by simon7000 View Post
OK my gear for this measurement was bought new by me, but has never been recalibrated so there may be some error, but I am certain it is only a few percent.

The small diode measured .123 l x .064 d, the larger diode .203 x .104! (Inches!)
Several things confuse me.

1. Was your caliper calibrated? Digital or analog.
2. What was room temperature? Is the caliper TCE the same as the diode TCE? stainless is 166 ppm/C, silicon about 4, molybdenum 3.3, copper 16, aluminum 25..if ya gonna measure, do it right...
2. Why do you call a diode that is .123 inches by .064 diameter small??? A 1N4148 chip is .008 inches thick, and .012 by .012 inches..
3.. Why do you call .203 by .104 big?? The one on my desk is 3.5 inches wide and 8 inches long, weighs 11 lbs. ""you call that a knife??...now...that's a knife...""

Any schematic of the setup??

Cheers, John
  Reply With Quote

Reply


John Curl's Blowtorch preamplifier part IIHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


New To Site? Need Help?

All times are GMT. The time now is 03:43 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki