Choke input PSU... - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 22nd December 2010, 01:57 PM   #11
diyAudio Member
 
Join Date: Feb 2010
Location: London
Can anybody in the UK, or elsewhere, recommend an air cored choke suitable for a monoblock F5 that does not cost an arm and a leg, as I'll need four? I get very confused when faced with the range available and would appreciate some expert advice. Most inductors seem designed for crossover use rather than power supplies and might be adequate, but I'd rather not risk stressing them or causing a bonfire!
  Reply With Quote
Old 22nd December 2010, 09:26 PM   #12
DougL is offline DougL  United States
diyAudio Member
 
Join Date: Feb 2004
Location: Wheaton IL.
Blog Entries: 30
To design a choke input supply, here are some of the required equations:
To get the Q required (1 or less) = 1/Rdc *(sqroot(L/C))
L (minimum) = Vin rms / Imin = .01 H= 30V rms / 2600 mA
For 1 channel using a LL1694 Q = 1/.9R (Sqrt(.08H/.18F)) = .73
Minimum Choke goes to .02H for a single channel F5.

The required capacitance and inductance is truly enormous. I would hate to see a .02H air core with a low dcr. CLC are much more practical. What fun is that?

Doug
__________________
Scienta sine ars nihil est - Science without Art is nothing. (Implies the converse as well)
Mater tua criceta fuit, et pater tuo redoluit bacarum sambucus
  Reply With Quote
Old 23rd December 2010, 10:33 AM   #13
diyAudio Member
 
Join Date: Feb 2010
Location: London
Many thanks for your rapid response DougL. I now realize that my question might have been misleading. I intend to use around 90,000 uF capacitance per rail, but having read some of the discussions would very much prefer to employ an inductor (as well as some resistance) to couple them CLCCRC..... Using PSUD to model the PSU shows that a very low ripple can be achieved this way. I had innocently assumed that 2mH would have been the required inductance, but clearly have a lot to learn. Any suggestions for a suitable inductor at a realistic price?
  Reply With Quote
Old 23rd December 2010, 02:32 PM   #14
DougL is offline DougL  United States
diyAudio Member
 
Join Date: Feb 2004
Location: Wheaton IL.
Blog Entries: 30
For a CLC or CLCRC type supply, you have a lot of flexibility in choosing inductor values. in an LC or LCRC, having a high enough inductance is critical for success. The equations I posted are for LC, not CLC.
For a CLC, a standard crossover air core will melt before it saturates, and it would take a lot more current than you are using to melt even a 20 gauge one. From looking at parts express, you are looking at $8 to $12 each. Not insignificant, but not outrageous.

HTH

Doug
__________________
Scienta sine ars nihil est - Science without Art is nothing. (Implies the converse as well)
Mater tua criceta fuit, et pater tuo redoluit bacarum sambucus
  Reply With Quote
Old 26th December 2010, 07:37 AM   #15
diyAudio Member
 
Join Date: Feb 2010
Location: London
Thanks Doug - you have reassured me a lot. There are many coils available, but they all seem to be for use in crossovers or SMPS so I was anxious that they could be dangerous in an F5 even in monoblock form. Do you have any advice on value in this format or is it simply bigger is better as elsewhere 2mH seems to be the preferred choice for two channel F5 power supplies? Nick
  Reply With Quote
Old 26th December 2010, 09:39 PM   #16
diyAudio Member
 
Join Date: Dec 2009
All you need is a Jantzen 2 mH 15 ga aircore inductor.
  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
Help replacing a PSU choke - How to choose choke Hubba Tubes / Valves 2 10th September 2010 02:33 PM
Help for choke input regulated PSU inertial Tubes / Valves 5 1st September 2008 07:05 PM
Choke input PSU, drawbacks? dsavitsk Tubes / Valves 12 4th May 2007 11:52 PM
Design of Resonant Input Choke PSU Yugo Tubes / Valves 29 20th April 2007 11:25 PM


New To Site? Need Help?

All times are GMT. The time now is 03:36 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