Please rate this psu design - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 9th October 2007, 07:28 PM   #1
diyAudio Member
 
Groundloops's Avatar
 
Join Date: May 2004
Location: fubar Germany.
Question Please rate this psu design

Im about to build a preamp and want to start with the psu. I came about this design in headwize.com; what do you think of it?

Click the image to open in full size.

Is it suitable to feed various opamps (the common suspects), up to 6 pieces? Or is it simply overkill and a lm317/337 with rc filter after the diodes will do as well?
  Reply With Quote
Old 9th October 2007, 07:57 PM   #2
Khron is offline Khron  Romania
diyAudio Member
 
Join Date: Jul 2005
Location: Finland
Send a message via AIM to Khron Send a message via MSN to Khron Send a message via Yahoo to Khron
I'm no electronics expert, but i do have a couple of ideas/tips, whatever you want to call them:


1) I think that bypassing the adjustment pots with some caps may well help with bringing down the noise (as per the LM317/337 datasheet

2) Arent those 100V caps just a *bit* overkill, given that you have a maximum of 48V DC? I'm thinking that some 63V caps would work just fine before the regs, and some 35-50V ones after, and this would be based on bulk and cost.



Chris
  Reply With Quote
Old 10th October 2007, 07:57 AM   #3
Elvee is online now Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Hi

Have you checked that the OPA548 accepts a capacitive load? Only very few opamps do.
LV
  Reply With Quote
Old 10th October 2007, 08:06 AM   #4
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
the voltage drop across all the regs/Vref are very high.
What about dissipation?
__________________
regards Andrew T.
  Reply With Quote
Old 10th October 2007, 04:35 PM   #5
m-tech is offline m-tech  Serbia
diyAudio Member
 
Join Date: Feb 2006
Location: Belgrade
48Vdc is too high input voltage for LM317. It's OK if ADJ pin floating above ground, but you are using pot on this pin. Be careful.
No need for big capacitor ( 1000u is too much ) at output of LM317.
  Reply With Quote
Old 11th October 2007, 05:36 PM   #6
nonoise is offline nonoise  South Africa
diyAudio Member
 
Join Date: Jun 2006
Perhaps Kevin (it looks like his design) used a LM317HV this
variation of the device could handle the 48V.
  Reply With Quote
Old 12th October 2007, 06:49 AM   #7
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
the floating three pin regs (317 etc) can work at much higher than 35V. That is the input to output pin limit.
The problem is at start up when the output is discharged (zero V) and the input suddenly rises to maximum in a few mS. A big cap on the output makes this worse.
Similarly, the adjustment could take the output pin very low and exceed the differential limit.
__________________
regards Andrew T.
  Reply With Quote
Old 12th October 2007, 11:24 PM   #8
nonoise is offline nonoise  South Africa
diyAudio Member
 
Join Date: Jun 2006
Yes Andrew quite correct,
I also saw that they tend to specify a delta V different to a normal vin
Max. The 317HV will do 60V but the 337 will only do -50 V which is a bit close to the -48V input.
In short the design seems a bit stressed (also considering the not unsubstantial dissipation the pass elements are subjected to).
  Reply With Quote
Old 15th October 2007, 09:46 PM   #9
Gordy is offline Gordy  United Kingdom
diyAudio Member
 
Join Date: Nov 2006
I agree that it needs adjusting as has been stated above (... lower input voltage to regulator for lower volt drop across [and hence lower dissipation in] the regulator, adjust the cap values, add a cap across the adjustment resistor). Also the regulators and op-amps may need heat-sinks.

However, the overall concept is right.
  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
666 Hz Fs tweeters -- how would you rate them? Wavebourn Multi-Way 14 11th April 2008 05:39 PM
Rate my 12v to 19v converter please! cjk2 Power Supplies 12 31st December 2007 02:15 AM
How would you rate the best class-d ruaneg Class D 4 24th September 2006 11:26 PM
dvd spdif fs rate? rlim Digital Source 2 7th January 2006 01:19 AM
Slew rate value Luke123 Chip Amps 5 7th April 2005 12:30 AM


New To Site? Need Help?

All times are GMT. The time now is 07:35 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