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

Thread Tools  Search this Thread 
1st February 2007, 06:42 PM  #1 
diyAudio Member

proper design of pifilter for Aleph 30
Hi folks!
When dimensioning the inductor vor this CLCfilter, how is it done properly? Here is a nice schematic, however it is for 180 000uF which is more than I want. I'm more interested in 3x 22 000uF caps, so the inductor would go between the first 2 caps I think. But how to calculate the proper inductor value? 3.9mH won't fit I think. Any ideas? Have fun! Hannes
__________________
fresh matched IRFP240/IRFP9240 fets  AlephJ/JXkits F5 transistor kits  High Octane phono preamp Wiki 
1st February 2007, 06:55 PM  #2 
The one and only

Any value will improve the noise, so just do the largest you
can. 
1st February 2007, 07:00 PM  #3 
diyAudio Member
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain

again............
http://www.duncanamps.com/psud2/index.html download it and play with read help to know more
__________________
my Papa is smarter than your Nelson ! clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM 
1st February 2007, 08:00 PM  #4 
diyAudio Member
Join Date: Sep 2003
Location: quebec

in my aleph 3 68000uF+1.2mH +68000uF
with good result supply ripple = 25mv ac standard value are 2mH to 4mH but inductor has resistance air core = no saturation but maybe more resistance and heat and magnetic induction in your aleph i test my 1.2mH iron core for no saturation @ 10A wire=no 16 resistance=0,15 ohm 
2nd February 2007, 10:21 AM  #5 
diyAudio Member

Thanks for all replies!
Well. so is there no optimum value? Since capacitors cause a phase shift, I thought there's an optimum inductor value that shifts the phase of the remaining ripple perfectly back to 0°  which I guess should be the best. What makes me wonder is if it's only positive to use a CLC, why wasn't it used in the original Aleph30 or Pearl? When it's so nice, I'll add one also to the pearl of course, or is this just of academic value, because the fets contribute far more noise? Interesting subject! Thanks guys! Any input appreciated! Have fun! Hannes
__________________
fresh matched IRFP240/IRFP9240 fets  AlephJ/JXkits F5 transistor kits  High Octane phono preamp Wiki 
2nd February 2007, 11:01 AM  #6 
diyAudio Member
Join Date: Sep 2003
Location: quebec

"thought there's an optimum inductor"
in my book maybe yes? if you look CLC like C +LC for LC fc=1/(6.28 x squareroot( LC) ) for power 50hz ripple=100hz for power 60hz ripple=120hz fc with factor 5 to 10 of ripple hz is good optimum: 1too low L = no effect 2optimum is factor 5 to 10 3too big L = difficult to find with low R and R= voltage drop and heat 
2nd February 2007, 11:22 AM  #7 
diyAudio Member

Ok, I see what's the problem, you'll never get the inductors you would need.
So for a 3.9mH choke you would need just 26 Farads capacitance... Or for 66000 uF only 1.55 Henry inductance... So with what I could get, I'm just a factor 50 off what would be ideal. I see. So better get a 6.8mH inductor then. Have fun! Hannes PS: but why are inductors so rarely used then? Too expensive or less efficient than adding capacitance for the same money?
__________________
fresh matched IRFP240/IRFP9240 fets  AlephJ/JXkits F5 transistor kits  High Octane phono preamp Wiki 
2nd February 2007, 11:30 AM  #8 
diyAudio Member
Join Date: Sep 2003
Location: quebec

?????????
if L=3.9mH C=66000uF fc=9.92hz very good factor 10 and a little more if my calculator hp is rigth or me :) 
2nd February 2007, 11:34 AM  #9 
diyAudio Member

Ah ok I misunderstood you!
You mean fc times 510 to get the 100/120Hz ripple would be ideal! I see, thanks a lot for clarification! Why 510 times? Thanks a lot! Hannes
__________________
fresh matched IRFP240/IRFP9240 fets  AlephJ/JXkits F5 transistor kits  High Octane phono preamp Wiki 
2nd February 2007, 12:27 PM  #10 
diyAudio Member
Join Date: Sep 2003
Location: quebec

why factor 10
thumb law :) for me factor 10 reduction of ripple is already very good to give a good step down on speaker hum factor 20 or 30 is better if and only if : 1big inductor with big wire for low R 2no magnetic saturation @ 10A (also thumb law) 3maybe the money talk also :) in my aleph 3 the factor is 6,8 with good 25mv ac ripple bye 
Thread Tools  Search this Thread 


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Help with filter design  skyraider  Instruments and Amps  3  14th October 2008 12:01 AM 
Article: The Do’s and Don'ts for Proper Design Implementation  Groundloops  Class D  0  26th March 2006 08:07 AM 
Newbie question re: "Proper" cabinet design  Ken C  MultiWay  5  8th June 2004 07:14 PM 
aleph 5 CLC filter  tomchaoda  Pass Labs  35  22nd March 2004 03:11 AM 
New To Site?  Need Help? 