pi-filter Power supply for Alephs - 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 2nd May 2007, 01:18 PM   #1
diyAudio Member
 
Stefanoo's Avatar
 
Join Date: Apr 2006
Location: italia - ora USA -WI
Default pi-filter Power supply for Alephs

I would like to have your support guys, some hints about CLC pi power supply.
I'm actually building the pre Aleph P1.7 and i'm trying to evaluate the possibility of having a more refined power supply stage.
I was thinking on building a PI CLC stage.

Would it be better of a regulated power supply?

is this type of power supply always better in absolute or a regulated power supply is better for pre stage and a clc pi filter is better for a power amplifier?

Could you guys give me some hints on how to build an efficient pi-clc power supply?

Thanks in advance.

Best,
Stefano.
__________________
Stefano
  Reply With Quote
Old 2nd May 2007, 04:09 PM   #2
diyAudio Member
 
Join Date: Nov 2006
I am just finishing rebuilding the PS for my Aleph mini.

I first tried a regulated supply, then I went back to the CLC. But this is for a power amp. Looking at the experiences from the above and the PS I had for my BOsOZ, I believe the regulated supply, slightly modified, shown in the BOSOZ article is best.

The differences I had were:

1) I used a single transformer, 350 VA, 55v secondaries.
2) I used a regular amp PS board (with rectifiers) and 6800 X 3 microfarad 80V caps (panasonic) for each rail. (this is a Marchand electronics PS15 board).
3) Output from board above is fed into the regulated PS board shown in the BOSOZ article.
4) I put much larger output caps on the BOSOZ board.

This PS showed absolutely no ripple or noise spikes that I could see on my scope. I think I was using about 100 ma current all told from the PS.

Of course, this is kind of the big stupid way to do it, I am sure there are more succint methods for getting no ripple. And it may not even be necessary for the aleph p 1.7, but this was really easy to implement and worked exceedingly well.

I think you will still have ripple with a CLC.

JJ
  Reply With Quote
Old 2nd May 2007, 04:29 PM   #3
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
CLC filtering is used for;

-glasswork amplifiers, where the high voltages makes a regulator expensive and bulky.
-(Class A) power amps, for very effectively reducing ripple voltage at the high bias levels.
-digital stuff, for high frequency filtering.

Where does that leave a P1.7 ?
Already thought of what the values for the coil and the lytics will be like if you desire it to be "efficient" ?

regulated
__________________
No More Mr Nice Guy
  Reply With Quote
Old 2nd May 2007, 06:41 PM   #4
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
A regulated supply is appropriate for a preamp, where the
current is quite low. I like to follow the reulated supply with a
big RC filter of a few ohms and many thousands of uF.

(or even F)

  Reply With Quote
Old 2nd May 2007, 08:35 PM   #5
diyAudio Member
 
Stefanoo's Avatar
 
Join Date: Apr 2006
Location: italia - ora USA -WI
thanks a lot.

just thought: why would you let follow the regulated part with RC filter of few ohm? (i mean in the schematic you are using an R=3.3)

Just another though passes through my head right now:

I would like to build a separate box with the power supply that ...stayed on what you guys and Nelson have just said to me here.... will be regulated.......and...the thought is:

since after the regulated part (let's say after Q23 quoted from the Power supply sheet) i would place a large amount of uF ...or better...F ..........

is it true that it is always a good rule of thumb to place the filtering as close as possible at the board?
Although, should i place another filtering directly on the box containing the pre board or it doesn't matter?

I don't know if i was clear by eplaining my thoughts and if not, i'm sorry ...but this is not my language and sometimes it's difficolt to explain what passes as a lightening on my mind...


One more question: where can i find very good and fine power tranformer? i did read on the forum something about piltron transformers, but i don't know what they are made researches but without results.

Can anybody give me some good advice on where to find a very high qulity 60V transformer (i will need 2 of them)

As the my very last thought...if anybody may give good hints on how to improve at the maximum state the power supply stage...i don't know replacing the zener in series...or something....

every good suggestion is welcome...
__________________
Stefano
  Reply With Quote
Old 2nd May 2007, 08:53 PM   #6
diyAudio Member
 
apassgear's Avatar
 
Join Date: Nov 2002
Location: Viña del Mar, Torreon
I have use for A4 plain C, CRC, CLC and LC.

I like it best with chokes has excellent regulation and one can definitely hear the difference
  Reply With Quote
Old 2nd May 2007, 09:10 PM   #7
diyAudio Member
 
Stefanoo's Avatar
 
Join Date: Apr 2006
Location: italia - ora USA -WI
sorry i haven't understood what you meant with A4 plain.

But i did understand that up to your experience the chocke (pi-LCL) filter sounds better than a regulated supply? is that correct?

could you share in more detail your experience with CLC power supply...i mean... what have you tried to compare the different supplies on? pre amp-power amp-pre phono....and so on?
__________________
Stefano
  Reply With Quote
Old 2nd May 2007, 09:48 PM   #8
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
Quote:
Originally posted by Stefanoo

just thought: why would you let follow the regulated part with RC filter of few ohm? (i mean in the schematic you are using an R=3.3)

I would like to build a separate box with the power supply
is it true that it is always a good rule of thumb to place the filtering as close as possible at the board?
Although, should i place another filtering directly on the box containing the pre board or it doesn't matter?

One more question: where can i find very good and fine power tranformer? i did read on the forum something about piltron transformers, but i don't know what they are made researches but without results.

Can anybody give me some good advice on where to find a very high qulity 60V transformer (i will need 2 of them)

As the my very last thought...if anybody may give good hints on how to improve at the maximum state the power supply stage...i don't know replacing the zener in series...or something....


--The 3.3 Ohm resistor reduces inrush current (not really a big problem in this case) and provides a bit of extra isolation.
--An external power supply is a fine idea. My feeling is that you should have some capacitance in the power supply and next to the circuit. If it comes down to a choice of one or the other, put the capacitance next to the circuit.
--If you put the term Plitron into Google, you will find that they have a website at www.plitron.com. There are plenty of good transformers out there. That said, I have used Plitron many times and like them.
--I don't understand your last question. Give it another try.

Grey

P.S.: I suspect you will find that A4 is being used to mean Aleph 4.
  Reply With Quote
Old 2nd May 2007, 10:09 PM   #9
diyAudio Member
 
apassgear's Avatar
 
Join Date: Nov 2002
Location: Viña del Mar, Torreon
Quote:
Originally posted by Stefanoo
sorry i haven't understood what you meant with A4 plain.

But i did understand that up to your experience the chocke (pi-LCL) filter sounds better than a regulated supply? is that correct?

could you share in more detail your experience with CLC power supply...i mean... what have you tried to compare the different supplies on? pre amp-power amp-pre phono....and so on?
A4 means Aleph 4

Haven’t tested a regulated supply to compare with, what I said is that a CLC or LC has very good regulation -and very clean supply at it- and think it would be similar to using a regulated supply, if not better soundwise.

Building a regulated supply for this type of amp - taking in consideration the amount of current draw and power required – would be a nice challenge and to my opinion not worthwhile having the alternative of a choked Pi filter.
All the power Pi filters mentioned were tested on the Aleph 4. But I have also tested CLC and LC on preamps with nice results too.
  Reply With Quote
Old 3rd May 2007, 06:24 AM   #10
diyAudio Member
 
Stefanoo's Avatar
 
Join Date: Apr 2006
Location: italia - ora USA -WI
sorry my question was really confusing, i'll try again:

may anybody give some idea on how to improve the original power supply for the PREAMPLIFIER Aleph P 1.7?

I would like to have the best supply as possible.

About the filtering: yes, i was thinking on having capacitor filter on the separate box and another block close by the main board.
__________________
Stefano
  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
Power supply filter mod Ty_Bower Tubes / Valves 3 21st July 2007 01:50 AM
how to filter a switching power supply? space-cake Class D 1 11th March 2007 01:56 AM
Dimensioning LC power supply filter Stefano Power Supplies 7 17th December 2005 07:44 PM
How do I diy Hi-End filter power supply and power cord? bmpa Parts 6 24th April 2004 12:12 AM
Why not put filter caps in power supply? Joshua Layne Chip Amps 7 31st January 2004 03:50 PM


New To Site? Need Help?

All times are GMT. The time now is 12:19 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