John Curl's Blowtorch preamplifier part II - Page 18 - diyAudio
Go Back   Home > Forums > Member Areas > The Lounge

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

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 3rd July 2009, 05:39 PM   #171
PMA is offline PMA  Europe
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
Jacco, he was afraid of quality of a cap used in a feedthrough, so I suggested to make own with a good cap
  Reply With Quote
Old 3rd July 2009, 05:46 PM   #172
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Pavel,
Given the values you are looking at with a feedthrough capacitor, any low K ceramic material should be fine. Talking about power supply feeds and amplifier outputs, they are low impedance circuits, so even a high K ceramic shouldn't represent any problems. Input circuits should be easy to deal with as well. Wouldn't a length of shielded RF wire act as a feedthrough capacitor the shield was grounded at the point of entry through the casing?

I have used these off and on, usually when dealing with higher frequency circuits. RF amplifiers and switching power supplies certainly rate here.

Hi stoolpigeon, Demian,
A new thread for this would be the best. It would be a shame to confuse two designers and their ideas, and Demian deserves a thread of his own to discuss his ideas, if desired.

-Chris
__________________
"Just because you can, doesn't mean you should" © my Wife
  Reply With Quote
Old 3rd July 2009, 05:49 PM   #173
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
Quote:
Originally posted by Magura


It's actually not all that to shield an inductor. With some help from Dimitri, I made a 5mH shielded inductor for a power amp PSU, some time ago.

It's a mix of ferritic stainless steel and copper shield.

Magura
Whoa! High "sex" value to those slick lookin' shields!!

by "ferritic" do you mean non-magnetic?

_-_-bear


Edit: oh, where are we on internal PS vs. external PS, especially WRT that choke shielding issue? Do we want only DC sent through the embilical connecting cord, and what about ground if we go external??
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 3rd July 2009, 05:55 PM   #174
PMA is offline PMA  Europe
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
Chris, I use professional HF feedthroughs, they are also a part of my current preamp design, to clean DC PSU output wires thru an Al wall.
  Reply With Quote
Old 3rd July 2009, 05:55 PM   #175
Magura is offline Magura  Denmark
diyAudio Member
 
Magura's Avatar
 
Join Date: Oct 2003
Location: Denmark, Viborg
Quote:
Originally posted by 1audio


Did you characterize the effect on the inductor of shielding it? You would see the inductance change and it would have a saturation point as well. When saturated the shield effectively vanishes so you need to be sure you stay below that limit. Also it will affect the HF performance but the coil pictured will not have the best HF performance anyway.

The inductance stayed the same, due to the mix of copper and ferrittic stainless steel.

I have not had a need to push it past 10A, till that point no saturation occurred.

Magura
__________________
Everything is possible....to do the impossible just takes a little while longer.
www.class-a-labs.com
  Reply With Quote
Old 3rd July 2009, 05:57 PM   #176
Magura is offline Magura  Denmark
diyAudio Member
 
Magura's Avatar
 
Join Date: Oct 2003
Location: Denmark, Viborg
Quote:
Originally posted by bear


Whoa! High "sex" value to those slick lookin' shields!!

by "ferritic" do you mean non-magnetic?

_-_-bear
Thanks Bear.

Ferrittic stainless steel is the type that is magnetic. It's rather rarely used, but for this it made sense.


Magura
__________________
Everything is possible....to do the impossible just takes a little while longer.
www.class-a-labs.com
  Reply With Quote
Old 3rd July 2009, 06:00 PM   #177
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
Quote:
Originally posted by nicoch46
yes ,I find no other explanation: whay if I swap on borbely design caps or diode the sound change a lot ?

ok cooking parts is not like a design....shunt can be audio psu



This is an interesting question, but this is the Blowtorch thread, not the Borbely thread. Erno has some interesting design ideas, and it deserves its own thread, imho. You might want to start a thread on Borbely designs, post the schematic you are referring to, along with a jpeg of your implementation and a block diagram of your wiring/ground scheme??

_-_-bear
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 3rd July 2009, 06:04 PM   #178
PMA is offline PMA  Europe
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
You will have almost nothing to discuss here, then, maybe cars and wines.
  Reply With Quote
Old 3rd July 2009, 06:06 PM   #179
expert in tautology
diyAudio Member
 
bear's Avatar
 
Join Date: Apr 2002
Location: New York State USA
Quote:
Originally posted by Magura


Thanks Bear.

Ferrittic stainless steel is the type that is magnetic. It's rather rarely used, but for this it made sense.


Magura
Wondering if the alloy is one of the ones with a high hardness - making it difficult to machine??

_-_-bear
__________________
_-_-bear
http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- [...2SJ74 Toshiba bogus asian parts - beware! ]
  Reply With Quote
Old 3rd July 2009, 06:07 PM   #180
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
Epcos B85321, metallized polyprop foil capacitors.
Manufactured in values up to 4.7uF, and subsequent 6''x2'' sizes.

(= what i use to go through 10mm Alu walls)
Attached Images
File Type: jpg filly.jpg (48.1 KB, 812 views)
__________________
2015 : World Cup Cat Hacky Sack
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 10:25 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2