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

Planars & Exotics ESL's, planars, and alternative technologies

ESL Diaphragm coating
ESL Diaphragm coating
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 21st July 2018, 07:35 AM   #961
kazap is offline kazap  Australia
diyAudio Member
 
kazap's Avatar
 
Join Date: Apr 2011
Location: Brisbane
Quote:
Originally Posted by MJ Dijkstra View Post
..... In case of an aircapacitor this is neglegible. ...

Would you care to explain?
  Reply With Quote
Old 21st July 2018, 08:16 AM   #962
MJ Dijkstra is offline MJ Dijkstra  Netherlands
diyAudio Member
 
Join Date: Apr 2005
Location: Utrecht
Quote:
Originally Posted by kazap View Post
Would you care to explain?
Roughening the surfaces of a pair of parallel plates does only causes a small variation in the minimum distance the pairs of charges can approach — it is insignificant compared to the large distance between the plates. (unless in case of a megathick graphite coating LOL) The dielectric follows a smooth average line at the boundary.
A higher surface area does work in ultracapacitors as well as in electrolytic capacitors, but not in aircapacitors.
__________________
drs M.J. Dijkstra

Last edited by MJ Dijkstra; 21st July 2018 at 08:20 AM.
  Reply With Quote
Old 21st July 2018, 01:34 PM   #963
wout31 is offline wout31
diyAudio Member
 
Join Date: Feb 2012
Quote:
Originally Posted by gentlevoice View Post
Hi all,
This is a bit off-topic but nevertheless ... I sense that the "tone of voice" in this otherwise very interesting thread (IMO) tends to get somewhat harsh.
Personally I find this to be a pity because I reckon that we all have an interest in this subject - and I think that positive collaboration is supportive of good innovation and ideas - and also because I personally always see people next to the ideas, not just ideas.
And IMHO it is just much more pleasant to exchange positively ...
Felt like saying this.
Jesper
I couldn't agree more. If I contributed or provoked the harshness I sincerely apologize. As you look back on this thread you see that at one point I censored/removed a reply. I was about about to say the same as you are saying now. A bit later I said goodnight and goodbye because I was fed up with kind remarks that we're posted. I came here to learn and share not to be insulted and laughed at. I must say that the culture of the Dutch is more blunt than other cultures, but definitely not like this (I hope). Off-topic? No. Very much to the point.
  Reply With Quote
Old 21st July 2018, 01:46 PM   #964
alexberg is offline alexberg
diyAudio Member
 
alexberg's Avatar
 
Join Date: Oct 2009
Quote:
Originally Posted by kazap View Post
As you point out surface area is pivotal to charge density. An irregular surface increases surface area of the membrane at the micron level. Viola. Potential for increased charge density.
C=eps*eps0*S/d, where eps is permittivity, eps0 vacuum(air) permittivity, S-area, d-distance between plates. Charge is related to the voltage at a given capacitance U=Q/C.
Having hair like structure will not help, unlike lytic capacitors where contact is provided by electrolyte and porous electrode is of a definite advantage.

Last edited by alexberg; 21st July 2018 at 01:54 PM.
  Reply With Quote
Old 21st July 2018, 03:55 PM   #965
gentlevoice is offline gentlevoice  Denmark
diyAudio Member
 
Join Date: Oct 2007
Location: Denmark
ESL Diaphragm coating
Quote:
Hi all,
This is a bit off-topic but nevertheless ... I sense that the "tone of voice" in this otherwise very interesting thread (IMO) tends to get somewhat harsh.
Personally I find this to be a pity because I reckon that we all have an interest in this subject - and I think that positive collaboration is supportive of good innovation and ideas - and also because I personally always see people next to the ideas, not just ideas.
And IMHO it is just much more pleasant to exchange positively ...
Felt like saying this.
Jesper
Hi again ... I would like to emphasize that with the above comment I do not point at anyone in particular ... I see it more as an "invitation" - if I can use this word - to smile at eachother when posting ...

Wishing you a pleasant weekend ...

Cheers,

Jesper
__________________
"... It is always possible to be friendly ..." HH the Dalai Lama.
  Reply With Quote
Old 22nd July 2018, 08:42 AM   #966
alexberg is offline alexberg
diyAudio Member
 
alexberg's Avatar
 
Join Date: Oct 2009
Besides the troll defying law of physics we're got a shrink.
"Mahatma" Gandhi won because he was allowed to.
  Reply With Quote
Old 23rd July 2018, 03:06 AM   #967
bentoronto is offline bentoronto  Canada
diyAudio Member
 
Join Date: Jan 2008
Location: Toronto and Delray Beach, FL
ESL Diaphragm coating
I'm curious about charge density (but ignorant of the physics).

My cells (manufacturers originally to be inside Dayton-Wright speakers), made in the early '70's, charge very slowly as indicated by SPL. They take perhaps 18 hrs to be within maybe 2dB of their final SPL. The increase is uniform across their band, roughly 40-15kHz. There is a substantial resistance, maybe 100 MOhms, not sure, in series with the HW power supply.

What does that mean?

B.
__________________
HiFi aspirations since 1957. Currently working on motional feedback again... the final frontier in audio (and just posted data for a folded 17-foot pipe sub)
  Reply With Quote
Old 23rd July 2018, 04:01 PM   #968
alexberg is offline alexberg
diyAudio Member
 
alexberg's Avatar
 
Join Date: Oct 2009
There is nothing peculiar in regard to sulfur hexafluoride besides density and breakdown voltage, so it's hard to tell. It well might be related to the coating resistance. If it's too high then even distribution will take too much time. It well might be that higher bias voltage means higher leakage thus less current available for charging diaphragm itself.
  Reply With Quote
Old 23rd July 2018, 04:11 PM   #969
bentoronto is offline bentoronto  Canada
diyAudio Member
 
Join Date: Jan 2008
Location: Toronto and Delray Beach, FL
ESL Diaphragm coating
Quote:
Originally Posted by alexberg View Post
There is nothing peculiar in regard to sulfur hexafluoride besides density and breakdown voltage, so it's hard to tell. It well might be related to the coating resistance. If it's too high then even distribution will take too much time. It well might be that higher bias voltage means higher leakage thus less current available for charging diaphragm itself.
Thanks for info. I mounted the DW cells in open air frames, 6 cells to a panel. So the welding gas isn't around.

Yes, takes a while to charge the cells. But is the performance changed? Does the charge need to be re-charged after loud music passages? Can resistance be too large?

Would it be correct to think that if it took 18 hrs to charge, there couldn't be much leakage? Does the large series resistance matter much when talking of charging cells?

And do the amp and matching transformer care about the diaphragm charge?

B.
__________________
HiFi aspirations since 1957. Currently working on motional feedback again... the final frontier in audio (and just posted data for a folded 17-foot pipe sub)
  Reply With Quote
Old 24th July 2018, 07:58 AM   #970
kazap is offline kazap  Australia
diyAudio Member
 
kazap's Avatar
 
Join Date: Apr 2011
Location: Brisbane
Hi Ben
Interesting panels you have but waiting 18hrs plus to hearing full SPL's is a little inconvenient perhaps or do you just keep them charged all the time like giant dust traps. Speaking of which without the gas I imagine youve got no dust covers and wonder if a membrane is leaking charge?



Diagnosis needs a good history:
Is this a change or have the panels always taken >18hrs?
What coating do you use? If its the original whats the consensus on what the coating is and how long it lasts?

Whats your high voltage source and specs - kV and mA, mono or stereo chargers?
Assuming your running stereo pairs are the SPLs similar ie playing a mono track is dead centre?
Have you tried the old neon bulb indicator trick to gauge charging rate?


If its a sudden change a panel or resistor may have shortened out with excessive leakage affecting the entire system, if you only have a single HV source for all panels.


If its been a slow change over years but is better on rainy days it might be time to re-coat.



Im no expert but others here certainly are so lets see what they think of:



Given your high panel count and the possibility just one leaky panel could degrade charging all the rest, there might be merit in trying the neon bulb indicator trick so each panel can be easily monitored. Neon lamps are still available and cheap or dirt cheap so maybe try paralleling a few for better current pass and faster panel charging. The neon bulbs are about $2 for twenty so you can wire each panel up and identify any gone bad. No flashing means no charge eg stray connection, resistor on open, coating discontinuity etc. Rapid flashing means a short or leakage.



You might want test and if need be upgrade your resistors at some stage. There might be merit in using multiple resistors eg two in series x two parallel for lowering voltage and current loads, purchase costs and to provide redundancy if one fails either way.



If you re-coat your panels you could do a really cool trial of different coatings given for have 2x8 panels. How about using four different coating, one coating then would be used on four panels. Then do SPL measurements and start a new thread.



Stay safe around all those kV's.
  Reply With Quote

Reply


ESL Diaphragm coatingHide 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Diaphragm coating Bazukaz Planars & Exotics 24 9th October 2016 10:41 AM
ESL Diaphragm Coating - HELP GlidingDutchman Planars & Exotics 12 11th October 2014 08:04 PM
PCB coating rs1026 Parts 10 2nd December 2011 11:08 PM
Help with diaphragm coating furly Planars & Exotics 6 17th January 2006 08:23 PM
ESL diaphragm coating I_Forgot Planars & Exotics 58 4th April 2005 05:54 AM


New To Site? Need Help?

All times are GMT. The time now is 05:41 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki