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 April 2012, 07:01 PM   #61
tonimxp is offline tonimxp  Italy
diyAudio Member
 
Join Date: Oct 2007
Location: Gallarate (VA)
Quote:
Originally Posted by Zen Mod View Post
toni relax

goal is to have 3-5mA there

you're safe with 2x1k5 if positive voltage is near 15V

so - everything from 750 to 1k5 will keep you in ballpark
Sorry but for an aleph 30 supplyed with +25V 0 -25V what i would be done
I have to change..... o i have to not change.....this is the problem!

Last edited by tonimxp; 2nd April 2012 at 07:11 PM.
  Reply With Quote
Old 2nd April 2012, 07:38 PM   #62
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
for Aleph 30 - just look at usual Masterpiece - Babelfish J



(25-4*)V / 5mA = 4K2

so , say 2 x 2K2 or 2K1 .................... everything from 1k5 to 2k2

*4V is c-e voltage of small bjt
__________________
my Papa is smarter than your Nelson !
tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb ; Papatreasure
  Reply With Quote
Old 2nd April 2012, 07:59 PM   #63
tonimxp is offline tonimxp  Italy
diyAudio Member
 
Join Date: Oct 2007
Location: Gallarate (VA)
Quote:
Originally Posted by Zen Mod View Post
for Aleph 30 - just look at usual Masterpiece - Babelfish J



(25-4*)V / 5mA = 4K2

so , say 2 x 2K2 or 2K1 .................... everything from 1k5 to 2k2

*4V is c-e voltage of small bjt
Ok! my friend now is again clear!
Many thanks!
  Reply With Quote
Old 3rd April 2012, 10:38 AM   #64
vivanco is offline vivanco  Italy
diyAudio Member
 
Join Date: Jan 2011
I am positively shocked

in my mini Aleph I made the following changes :

i state that the power supply is constituted by 18-0-18 VDC with filter CRC 60000uF / five parallel resistors 3.9 ohms 3W

1 - substitution of the value of R14 and R16 with 750 ohms
2 - replacement of C2 (there was a 220uF panasonic FC) with two gold Mundorf silver oil 22uF and two Arcotronics MKP 10uF, mounted in parallel to achieve a total capacity of 64uF (I've assembled them all on a breadboard and with solid core pure silver I connected to pads of the pCB)

result: never heard anything like it so far
  Reply With Quote
Old 3rd April 2012, 10:57 AM   #65
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
1. irrelevant

2. more , the merrier

__________________
my Papa is smarter than your Nelson !
tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb ; Papatreasure
  Reply With Quote
Old 3rd April 2012, 11:51 AM   #66
vivanco is offline vivanco  Italy
diyAudio Member
 
Join Date: Jan 2011
Quote:
Originally Posted by Zen Mod View Post
1. irrelevant

2. more , the merrier

I'm sorry, but I do not understand your answer
  Reply With Quote
Old 3rd April 2012, 12:04 PM   #67
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
1. change of these resistors will not have influence of sonic
your amp was perfectly OK with 2x1k5 - on 18V PSU

2.that cap must be good one ; better cap , better sound
__________________
my Papa is smarter than your Nelson !
tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb ; Papatreasure
  Reply With Quote
Old 3rd April 2012, 12:35 PM   #68
vivanco is offline vivanco  Italy
diyAudio Member
 
Join Date: Jan 2011
Quote:
Originally Posted by Zen Mod View Post
1. change of these resistors will not have influence of sonic
your amp was perfectly OK with 2x1k5 - on 18V PSU

2.that cap must be good one ; better cap , better sound
zen ok, now everything is clear to me,,,,the magnificent sound is obtained by replacing the electrolytic capacitor with polypropylene quality and the removal of C1 and R10.
thank you for all the advice you dispense.

I ask one last thing, if there is any downside in having changed upon 220uF with 64uF,,or for the fact that the 64uF are high quality, do not you feel the decrease in capacity
  Reply With Quote
Old 3rd April 2012, 12:53 PM   #69
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
just put that 220uF back , along with these caps

it's clever to have low impedance AC path there

I;m using 470uF Elna/125C (dunno which series) , bypassed with 100nF MKC

even better - leave 220uF in , and put just one Mundorf in parallel

then listen

then desolder Mundorf and put hefty MKC instead and listen

I think that you'll find better place for Mundorfs , where you need both capacity and high voltage
__________________
my Papa is smarter than your Nelson !
tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb ; Papatreasure
  Reply With Quote
Old 3rd April 2012, 02:52 PM   #70
vivanco is offline vivanco  Italy
diyAudio Member
 
Join Date: Jan 2011
Quote:
Originally Posted by Zen Mod View Post
hefty MKC
What do you mean?
  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
Brian GT Aleph and PS boards mattattnet Swap Meet 2 17th September 2011 02:10 AM
Axials for C1/C2 on SSE? dr0ss Tubelab 5 28th August 2010 08:50 AM
Aleph 5 with Brian GT boards. (help) edoirt Pass Labs 11 31st July 2006 05:15 PM
C1 and C2 in BoSoZ ruangrit Pass Labs 3 29th January 2003 03:06 PM


New To Site? Need Help?

All times are GMT. The time now is 05:16 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