Silver Mica caps VS Polystyrene caps - Page 2 - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

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 13th September 2003, 12:13 PM   #11
mcp is offline mcp  United States
diyAudio Member
 
Join Date: Jul 2002
Location: Vacation Land
Here's a simple experiment where any forum members can try. Take a power amp, replace the feedback cap with a ceramic and listen to the amp. Take note of the mids and highs. Then replace it with a silver mica.

BTW make sure the caps are the same values as the original.
__________________
Michael Chua
  Reply With Quote
Old 14th September 2003, 03:01 AM   #12
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
Graham (Circlotron),

Interesting info on the silver micas. I like 'em.

Very nice likeness on your avatar!

Cheers,

Hugh
__________________
Aspen Amplifiers P/L (Australia)
www.aksaonline.com
  Reply With Quote
Old 14th September 2003, 04:36 AM   #13
sam9 is offline sam9  United States
diyAudio Member
 
sam9's Avatar
 
Join Date: Jun 2002
Location: Left Coast
I think I recall from somewhere that the principle application of silver mica caps is in thr RF industry. That would seem consistent with Circlotron's post.
  Reply With Quote
Old 15th September 2003, 08:59 PM   #14
diyAudio Member
 
richwalters's Avatar
 
Join Date: Sep 2003
Location: Alps:Tube amp designs over 150W, SMPS guru.
Default polystyrene _S mica caps

Nice to hear Silvered Mica still in active audio despite being far more expensive than polystyrene. Despite most of the "plusses" going to both types, I've repaired too many crowded amp chassis where users have complained of flagging power output leading to tube meltdown. PLEA.... don't solder polystyrene direct to the tube sockets i.e a-g2 via damper resistor for stability where a KT88 is blazing above in UL class A........the heat will eventually lead to cap failure and tube meltdown.
Check the upper temp ratings of polystyrene.......some types are quite restrictive,whereas mica excels.
Now do the sums...we've had 35C ambient this summer, some polystyrenes upper limit is only 70C, that allows 35C rise on a tube pin quite likely.att'n:
  Reply With Quote
Old 15th September 2003, 09:35 PM   #15
haldor is offline haldor  United States
diyAudio Member
 
Join Date: Aug 2001
Location: Columbus, Ohio
Might also have something to do with the fact that silver mica caps with larger than 1 nF are just about impossible to find. That would tend to limit their use in audio.

Phil
  Reply With Quote
Old 15th September 2003, 10:05 PM   #16
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
Strange enough I can get Richard Jahre 32.4 nF 125 V silver mica caps more easily than I can find polystyrene caps ...

This reminds me of someone on this forum that claimed all low voltage silver mica's have to be tested before being used as reliability seems to be an issue. When I don't forget I'll search tomorrow for that.

IIRC it had something to do with the way the leads are connected to the mica ( mechanical stability ). When sealed with resin the caps should be better in that aspect.
__________________
It's only audio. Official member of the Norske Brillegeit Gang.
  Reply With Quote
Old 15th September 2003, 10:19 PM   #17
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
I've used both silver mica and polystyrene caps in tube preamps (for RIAA eq and RF suppression) and power amps (compensation cap). If there was any sonic difference, it escaped me. Reliability points strongly in the direction of silver micas. Never lost one, whereas I've replaced bunches of polystyrenes that went to join Jesus.

If you want to be ultra-cool, use the old flat-pack silver micas with the six dot color code.
__________________
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
Old 15th September 2003, 10:24 PM   #18
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
Quote:
I've replaced bunches of polystyrenes that went to join Jesus.
Didn't know He was into caps too.

Did the polystyrenes fail from overheating or what ? I never had one that failed till now ( knock knock on table ). I used NSF of german origin mostly. Never liked the english ( forgot the brand, sorry ) polystyrenes with the ultrathin wires as they suffered from overheating quite fast.

To make things even more unclear here were polypropylene caps from Siemens sold as polystyrene caps. Even a trained eye couldn't see the difference. Fortunately they were OK both soundwise and technically.
__________________
It's only audio. Official member of the Norske Brillegeit Gang.
  Reply With Quote
Old 15th September 2003, 11:02 PM   #19
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
It's a combination of heat and voltage, I'd suspect. I'll bet the rated WVDC is degraded quite a bit in a 50-75 C environment.
__________________
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
Old 15th September 2003, 11:07 PM   #20
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
I only used them in relative cool ( both meanings ) solid state equipment, maybe that's why they didn't fail more than other caps. I had my share with electrolytics in Quad amps, but that's another story.
__________________
It's only audio. Official member of the Norske Brillegeit Gang.
  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
silver mica caps doktor Parts 14 26th April 2006 01:08 AM
silver mica and pp caps ronardi Parts 3 24th March 2005 02:06 PM
silver mica caps code tubbytwo Parts 2 1st December 2004 11:58 PM
Replacing ceramic disc caps with silver mica caps? G Solid State 5 18th November 2002 01:02 PM


New To Site? Need Help?

All times are GMT. The time now is 01:34 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