Back to Back Polarized Electro's - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 15th November 2003, 01:04 AM   #1
diyAudio Member
 
EchoWars's Avatar
 
Join Date: Dec 2002
Location: Left of the Dial
Default Back to Back Polarized Electro's

I thought that if you wanted to make a bipolar out of two back-to-back polarized electrolytics that you connected the negs to each other, and the positives to the outside..

device > + - - + > device

However, working on a few old amps where they have the positives together, and the negs to the outside...

device > - + + - > device

Perhaps it doesn't matter. Is that the case?
  Reply With Quote
Old 15th November 2003, 01:17 AM   #2
diyAudio Member
 
Join Date: Nov 2003
Location: flyover country
To me, thinking about the workings of back to back or nonpolar 'lytics (same thing) is like thinking about how sausages are made or politicians do their thing. Whatever is supposed to happen sorta does, even though the hidden details are fairly gruesome. So connecting the pluses vs the minuses to make a nonpolar probably works equally unwell. If you want to improve the situation, try adding a low current dc bias (through a highish value series resistor) in excess of the peak value of the signal to be passed to the tied together node of the 'lytics.
  Reply With Quote
Old 15th November 2003, 01:30 AM   #3
EE_Mark is offline EE_Mark  United States
diyAudio Member
 
Join Date: Nov 2003
Location: Los Angeles
Default Nonpolarized electrolytics

It doesn't matter whether the + terminals join or the - terminals join. It makes absolutely no difference whatsoever. I either case one of the caps will be reverse biased and will look lie a low impedance so the voltage will dropn across mthe capacitor that is seeing the correct polarity.
__________________
Mark
  Reply With Quote
Old 15th November 2003, 01:32 AM   #4
EE_Mark is offline EE_Mark  United States
diyAudio Member
 
Join Date: Nov 2003
Location: Los Angeles
Default I should try proofreading my massages!

It doesn't matter whether the + terminals join or the - terminals join. It makes absolutely no difference whatsoever. In either case one of the caps will be reverse biased and will look like a low impedance so the voltage will drop across the capacitor that is seeing the correct polarity.

__________________
__________________
Mark
  Reply With Quote
Old 15th November 2003, 02:00 AM   #5
Cobra2 is offline Cobra2  Norway
DIY !
diyAudio Member
 
Cobra2's Avatar
 
Join Date: Apr 2002
Location: Stavanger, Norway
Send a message via Skype™ to Cobra2
But since negative terminal is often connected to the can, it would be more practical to connect the negative terminals.
(just a good idea if they are close or naked...)

Arne K
__________________
Don't believe everything you think...
  Reply With Quote
Old 15th November 2003, 03:55 AM   #6
jcx is offline jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
Cyril Bateman talked about al electros in his "Capacitor Sound" series in Electornics World mag last year, with a recent amp re-cap distortion measurement follow up just this month

basically he claims the thin spontaneous film on one electrode in a polar cap causes large distortion, for lowest distortion he recomends bipoalr electros which are made with full thickness oxide on both foils, further lowering V stress on the oxide by series connecting bipolar electros is his strong recomendation for lowest distortion in large value cap applications
  Reply With Quote
Old 15th November 2003, 05:49 AM   #7
EE_Mark is offline EE_Mark  United States
diyAudio Member
 
Join Date: Nov 2003
Location: Los Angeles
Default In plain English

Quote:
Originally posted by jcx
Cyril Bateman talked about al electros in his "Capacitor Sound" series in Electornics World mag last year, with a recent amp re-cap distortion measurement follow up just this month

basically he claims the thin spontaneous film on one electrode in a polar cap causes large distortion, for lowest distortion he recomends bipoalr electros which are made with full thickness oxide on both foils, further lowering V stress on the oxide by series connecting bipolar electros is his strong recomendation for lowest distortion in large value cap applications
I think what he's trying to say is I'm right. If you're really worried about it drop $5 and buy some Sanyo SG Series Os-Con caps.

http://www.bdent.com/
__________________
Mark
  Reply With Quote
Old 15th November 2003, 08:07 AM   #8
Banned
 
Join Date: Dec 2001
Location: Zamboanga, City of Flowers, Mindanao
Send a message via Yahoo to Elso Kwak
Cool Re: Back to Back Polarized Electro's

Quote:
Originally posted by EchoWars
I thought that if you wanted to make a bipolar out of two back-to-back polarized electrolytics that you connected the negs to each other, and the positives to the outside..

device > + - - + > device

However, working on a few old amps where they have the positives together, and the negs to the outside...

device > - + + - > device

Perhaps it doesn't matter. Is that the case?

HiEchoWars,
Better use bipolar electrolytics if you have to use elco's.
  Reply With Quote
Old 15th November 2003, 10:03 AM   #9
diyAudio Member
 
EchoWars's Avatar
 
Join Date: Dec 2002
Location: Left of the Dial
Naaa....not really doing anything to this amp, it runs fine...just saw the back to back electrolytics with positive sides connected wheras I've always seen the negatives connected.

Thanks for the reply guys...always learning something.
  Reply With Quote
Old 15th November 2003, 03:39 PM   #10
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
EW, we had a long thread about this a few months back which included some experimental resuts (including my clumsy attempts at scope photography). It's probably worth doing a quick search.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Back to Back transformers and safety ground dsavitsk Tubes / Valves 1 9th February 2009 10:10 PM
back to back isolation transformers: maxlorenz Parts 30 27th March 2006 03:15 AM
back to back coupling capacitors reddog Solid State 5 3rd January 2006 06:59 AM
Back to Back transformers to get +B of 200V ?? Shoog Tubes / Valves 5 23rd September 2005 03:58 AM
(Attn Planet 10!) active xo & 2.5 way back to back Vifa P13 mids - questions paulspencer Multi-Way 9 15th August 2004 05:34 AM


New To Site? Need Help?

All times are GMT. The time now is 03:20 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