Few questions about Linkwitz' mic amp circuit - Page 2 - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, 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 8th February 2009, 06:20 AM   #11
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
If low ESR is optimal, should I parallel two 120 uF caps?

I think 25V caps should work here...
  Reply With Quote
Old 8th February 2009, 06:27 AM   #12
diyAudio Member
 
Join Date: Jan 2008
If you aren't short of space, that's a perfectly good solution, just get them as close to each other as possible.

25V would be fine.
  Reply With Quote
Old 8th February 2009, 06:52 AM   #13
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Thanks for your help. It's greatly appreciated.
  Reply With Quote
Old 8th February 2009, 10:49 AM   #14
infinia is offline infinia  United States
diyAudio Member
 
infinia's Avatar
 
Join Date: May 2005
Location: Californication
Default Keep it simple

I wouldn't worry too much about batteries being unbalanced in that preamp circuit. Starting with fresh batteries the current draw is balanced so....not a problem here as with some other circuits. The opamp can deal with uneq V's esp with the output being very low swing (tens of mV). it's really a non issue.

Just use 2 batteries and add the ceramic 0.1uF caps (generic, not NPO)

OT comments below
Dielectric microphonics for supply bypassing not an issue esp with microphones in use. Caps used in a high gain, high impedance feedback network would be a concern tho. Then I would use film instead of NPO for anything larger than 500pF due to cost.
__________________
like four million tons of hydrogen exploding on the sun
like the whisper of the termites building castles in the dust
  Reply With Quote
Old 8th February 2009, 05:17 PM   #15
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Default Re: Keep it simple

Quote:
Originally posted by infinia

Just use 2 batteries and add the ceramic 0.1uF caps (generic, not NPO)
Crud. I already soldered MKTs to the legs.

What will the difference be? I've got to do some parts shopping anyway.
  Reply With Quote
Old 9th February 2009, 03:34 AM   #16
infinia is offline infinia  United States
diyAudio Member
 
infinia's Avatar
 
Join Date: May 2005
Location: Californication
MKT should be OK for bypasses. Here close placement is a little more important than dielectric type. I just prefer ceramic bypass caps because they are smaller for a given value and offer a lower impedance at MHz, where the opamp errant oscillations tend to occur.
__________________
like four million tons of hydrogen exploding on the sun
like the whisper of the termites building castles in the dust
  Reply With Quote
Old 9th February 2009, 04:59 AM   #17
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Well, I'm open to replacing them. I want this thing to give me great sound right when I power it up.
  Reply With Quote
Old 9th February 2009, 01:16 PM   #18
infinia is offline infinia  United States
diyAudio Member
 
infinia's Avatar
 
Join Date: May 2005
Location: Californication
Default these arn't that critical sound wise

Quote:
Originally posted by 454Casull
I want this thing to give me great sound right when I power it up.

This is a for speaker test rig right. Should be ok for recording but with selectable gains maybe.

MKT you are using is OK
AVX box caps 0.1u 10% 50V or similar. (post your complete PL before clicking buy if you are worried)
__________________
like four million tons of hydrogen exploding on the sun
like the whisper of the termites building castles in the dust
  Reply With Quote
Old 9th February 2009, 01:30 PM   #19
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
I'm actually hoping to use this for recording as well as for speaker testing.

I've bought most of the parts already; I can supply a list when I get home.
  Reply With Quote
Old 9th February 2009, 02:49 PM   #20
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
All resistors are 1% metal film
OPA2134PA op-amp
Input (?) polar cap is a general-purpose tantalum
Op-amp power supply decouplers are currently 0.1 uF MKT box caps
  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
Linkwitz Transform Circuit skogs Subwoofers 1 26th October 2006 11:03 PM
Linkwitz transform circuit? Dxvideo Subwoofers 5 30th August 2005 02:20 PM
Linkwitz eq circuit The Dudster Subwoofers 5 3rd November 2004 05:29 PM
Linkwitz lm3886 circuit srfranci Chip Amps 1 30th October 2004 11:28 AM
linkwitz transform circuit pkgum Multi-Way 8 14th December 2001 12:08 PM


New To Site? Need Help?

All times are GMT. The time now is 02:13 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