OPA2132 bypass - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 3rd December 2004, 07:18 PM   #1
Radian is offline Radian  Germany
diyAudio Member
 
Join Date: Jun 2004
Location: Wiesbaden
Default OPA2132 bypass

Hi,
I put this post in the chip amp forum because Carlos and some others mentioned using this OpAmp.
Please ignore any wrong grammar and spelling, this is my second language.
I have a very limited understanding of electronics, so forgive me if my questions seem to be silly.

I want to upgade my Marchand XM1 active crossover with the OPA2132.
As Carlos mentioned a wile back this is one of his favorite OpAms if it is bypassed with 47-100uf cap and a smal ceramic cap.
As I understant, this bypass is to be done on the negative and the positive rails of the OpAmp.
Each crossover bord uses three OpAms: one for the buffer and two for filtering. This makes all together 12 OpAmps for a three way stereo unit.
Since all the OpAmps are fed by one psu, do I need to use a cap after the psu with 12 times the requierd capacitence for one chip, or is it better to still have 12 induvidual caps close to the chips. The other question would be, if I already used plenty of capacitence for filtering at the psu, does that spoil the induvitual bypassing.

I appreciate any help,


Klaus
  Reply With Quote
Old 3rd December 2004, 08:02 PM   #2
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
No worries about your english. It's good!

Good engineering pratice is to have 100 nF/63 V polyester or ceramic close to each supply pin of the opamps and down to ground. You can also have for instance 10 nF + 10 uF electrolytic capacitors but this OPA2132 or OPA2134 aren't so sensitive. It becomes more sensitive the faster the opamp gets.

Your last question: Strive alsways to have decouplings caps as close as possible to the "current consumer".

Doesn't your filter already have sufficient decoupling?
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 4th December 2004, 07:40 PM   #3
Radian is offline Radian  Germany
diyAudio Member
 
Join Date: Jun 2004
Location: Wiesbaden
Thank you P-A
  Reply With Quote
Old 12th December 2004, 09:29 PM   #4
Banned
 
Join Date: Mar 2003
Location: Lisbon, Portugal
Quote:
Originally posted by peranders
You can also have for instance 10 nF + 10 uF electrolytic capacitors but this OPA2132 or OPA2134 aren't so sensitive. It becomes more sensitive the faster the opamp gets.
....
Doesn't your filter already have sufficient decoupling?
Who told you so?
Just by looking at the datasheet?
Since I've registered here that I've been insisting on how these op-amps must be used.
The way you are "advicing" this member to use them they sound very bad.
Thanks for that.
This is also one of the major flaws of your "SMD Gainclone".
The way you use op-amps I should advice that the best results you can have is with the NE5532, they are very happy this way and when used this way they sound much better than modern and much superior op-amps.
Keep up the good work.
Oh, and please use the AD8620, a much inferior op-amp than the OPA2132, but sounds better the incorrect way you use it in audio applications, of course.
  Reply With Quote
Old 13th December 2004, 02:39 PM   #5
macboy is offline macboy  Canada
diyAudio Member
 
Join Date: Oct 2003
Location: Ottawa, Canada
Quote:
Who told you so?
Just by looking at the datasheet?
Since I've registered here that I've been insisting on how these op-amps must be used.
The way you are "advicing" this member to use them they sound very bad.
Thanks for that.
This is also one of the major flaws of your "SMD Gainclone".
...
Carlosfm,
Your post could have been more constructive. Instead of just telling others that you think they are doing something wrong, you could tell them how you think they are doing it wrong. That is, tell them what you think is the right way. You could have saved yourself a lot of typing by just saying, "In my experience, the OPA2132 sounds better to me when I used 100 uF bypass caps instead of much smaller ones.". That would be a constructive addition to the thread.
  Reply With Quote
Old 13th December 2004, 03:23 PM   #6
diyAudio Member
 
moving_electron's Avatar
 
Join Date: Jan 2004
Location: Where the rain does fall but the trees grow tall
I'm trying some different op amps but keeping the same bypass caps before changing the cap values again.

OPA2132 sounds rather good to me and is the current winner with 47uF bypass caps per power pin. Has 22uf between rails though at a single point on the board and 22uF from each power rail to ground where power comes on board. Each has a 100nF ceramic as well. 100nf ceramic between each op-amp supply pin.

I may leave this bypassing alone for a while though as I am quite happy with it for now. Sounds good in the preamp and the phono preamp. Crisp, clean but not harsh or "clinical".

Other opamps to try though.
  Reply With Quote
Old 13th December 2004, 09:49 PM   #7
Radian is offline Radian  Germany
diyAudio Member
 
Join Date: Jun 2004
Location: Wiesbaden
Default What to do now?

Hello Carlos,

Please tell me how you would go about in my case.
Since I have 12 OpAmps on one power supply do I still need to put 47uf close to each pin of the OpAmps or can I use 12X 47uf at the PSU and just 100nf close to the chips?
I actually don't have the 2132 but the 2134.

Cheers,
Klaus
  Reply With Quote
Old 13th December 2004, 10:08 PM   #8
Banned
 
Join Date: Mar 2003
Location: Lisbon, Portugal
Default Re: What to do now?

Quote:
Originally posted by Radian
Hello Carlos,

Please tell me how you would go about in my case.
Since I have 12 OpAmps on one power supply do I still need to put 47uf close to each pin of the OpAmps...
Yes.

Quote:
Originally posted by Radian
... or can I use 12X 47uf at the PSU and just 100nf close to the chips?
No!

Quote:
Originally posted by Radian
I actually don't have the 2132 but the 2134.
The same.
Enjoy.
  Reply With Quote
Old 13th December 2004, 10:11 PM   #9
Banned
 
Join Date: Mar 2003
Location: Lisbon, Portugal
Quote:
Originally posted by moving_electron
OPA2132 sounds rather good to me and is the current winner with 47uF bypass caps per power pin.
You are getting there.
You are on the right path.
Take those 47uf caps and put just 100nf caps.
You will be shocked.
You will say: **** op-amp!
  Reply With Quote
Old 13th December 2004, 11:58 PM   #10
diyAudio Member
 
moving_electron's Avatar
 
Join Date: Jan 2004
Location: Where the rain does fall but the trees grow tall
Quote:
Originally posted by carlosfm


Take those 47uf caps and put just 100nf caps.
You will be shocked.
You will say: **** op-amp!
Are you saying to take off the 47uF and just use the 100nf caps?

My experience with the OPA2604 was that things got better as I added capacitance on the power pins although at that point I only had 10uF on them.

The OPA2132 sounded better to me than the OPA2604 when I tried them at 47uF. I made a number of changes to the system as I went from 10uF to 47uF.

Looking forward to being shocked! Mentally, not physically.
  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
8v single supply, OPA2132 or LME49720 ? 100db Digital Line Level 1 12th February 2009 11:08 AM
OPA2132 and 2134 ctong Digital Source 5 14th May 2007 09:12 PM
Wtb: Opa2132 mantisory Swap Meet 6 17th February 2006 03:36 PM
swapped OPA2132 for AD8620... dorkus Digital Source 15 22nd January 2006 09:01 PM
Lm6172, Opa2132, Ad827 TPC Parts 2 1st June 2003 01:39 PM


New To Site? Need Help?

All times are GMT. The time now is 04:38 PM.


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