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

Solid State Talk all about solid state amplification.

mica capacitors in amplifier
mica capacitors in amplifier
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
Thread Tools Search this Thread
Old 4th May 2004, 05:13 AM   #11
sam9 is offline sam9  United States
diyAudio Member
sam9's Avatar
Join Date: Jun 2002
Location: Left Coast
I have used ploystyrene for small values ( 75pF -300pF), but those may be almost as expensive as silver-mica unless you can find good source.

One alternative would be to decide which of the silver-micas are the most critical to sound of the amp and bear the cost for those while sustituting film or ceramic for the others. Although I have not built a Leach, I have faced this dilema with other amps. The rule i used, (which may be not entirely valid) was that very, very small values 1p-20p are passing signals so far above the audible range so they couold be replaced by ceramic (I'm not sure there are film caps with such low values) and anything not in the signal NFB return can be replaced (film being prefereable to cermic, if possible). This is strictly a cost strategy, if cost were not an issue I would just order SMs.
  Reply With Quote
Old 4th May 2004, 03:58 PM   #12
pooge is offline pooge  United States
diyAudio Member
Join Date: May 2003
Location: Northern Va.
Exactly. The silver micas in the Leach amp are very small lag compensation caps. Probably won't have much, if any, impact on sound. In a correspondence I had with Dr. Leach, he said that microphonics of ceramic disks gave the amp problems. NP0s don't have as big a problem with microphonics, since they aren't made of the same piezoelectric ceramic. However, I have found difficulty finding any good data on NP0s and microphonics. But other than that possible problem, they should be an excellent cap in that application.
  Reply With Quote
Old 4th May 2004, 07:26 PM   #13
Eva is offline Eva  Spain
diyAudio Member
Eva's Avatar
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
The Miller [C-B] compensation capacitors on the leach amp determine open loop frequency response of the circuit above 1Khz [first pole] but these suffer some degree of distortion correction due NFB

Capacitor nonlinearities on the split-feedback network may also start to show some contribution to overall THD at high frequencies but here there is no NFB to correct that
  Reply With Quote
Old 6th May 2004, 02:12 PM   #14
Jocko Homo is offline Jocko Homo  United States
Join Date: Feb 2002
Location: As far from the NOSsers as possible
Default Micas are cheaper???

Only at the surplus stores...........!

  Reply With Quote


mica capacitors in amplifierHide 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
what is the difference between silver mica capacitors and ceramic capacitors ?? prorms Solid State 1 6th May 2008 12:38 PM
Help with identifying codes for Glass and Mica Axial Capacitors cvtrig Parts 1 16th July 2007 10:16 AM
Can you help me choose capacitors for my amplifier's power supply? Kuja Power Supplies 3 12th March 2007 04:03 PM
FS: Rifa Polystyrene & some Silver-Mica Capacitors tubemike Swap Meet 0 20th December 2005 04:02 PM

New To Site? Need Help?

All times are GMT. The time now is 06:20 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio