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

Pass Labs This forum is dedicated to Pass Labs discussion.

Aleph questions
Aleph questions
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
Old 28th October 2001, 03:11 PM   #1
dynt is offline dynt
diyAudio Member
Join Date: Oct 2001
Sorry if these are trite questions!
I am thinking about building one of the Alephs (maybe the 4, I love extra power). I would like to know why the 0.47 ohms resistors on the drain of the output mosfets are paralleled after the output mosfet cluster instead of each mosfet having its own resistor. Wouldn't that help with matching issues?
Another question what is the function of C11, the 220uf electrolytic on the -pole of the balanced input? Isn't this cap on the signal path? How important are its sonic characteristics?

  Reply With Quote
Old 28th October 2001, 08:00 PM   #2
Orgonom is offline Orgonom
diyAudio Member
Join Date: Oct 2001
Hi dnyt,
the paralleled 0.47R Resistors form the feedbackloop for
the aktive currentsource and the whole amp. The use of more then one resistor makes it easier to have an low value
resistor cheaply and akkurate tolerance.
The 220uF Cap is in the signal path.I think it depends
if you are using sym or asym input. When using sym, take
an MKP Cap with 47nF parallel.
Remember, my opinion - would be nice to hear other comments.
  Reply With Quote
Old 29th October 2001, 06:20 PM   #3
Nelson Pass is offline Nelson Pass  United States
The one and only
Nelson Pass's Avatar
Join Date: Mar 2001
Aleph questions
The cap gives the amplifier unity gain at DC and
is used to give low DC offset to the output and
protect the speaker against DC at the input of the
amp. You can safely remove it, but you will find
yourself making adjustments to the offset as the
temperature. The best place for adjustment would
be either R3 or R24 on the Aleph 4 (ref Left channel).

The Aleph 0 had a pot at this location, and no capacitors at all, but there was simply too much field adjustment
required to keep the offset low, and too many users had
DC coming out of preamps.
  Reply With Quote
Old 15th October 2004, 11:51 AM   #4
promitheus is offline promitheus  Europe
diyAudio Member
promitheus's Avatar
Join Date: Jan 2001
Location: Germany
Aleph questions
Does a tantalum cap sound better or worse? I didnīt use a normal electrolytic here.
  Reply With Quote
Old 15th October 2004, 01:27 PM   #5
wuffwaff is offline wuffwaff  Netherlands
diyAudio Member
wuffwaff's Avatar
Join Date: Aug 2001
Location: Ingolstadt Germany
Hi Promitheus,

a real tantalum cap distords quite heavily and should NOT be used here. Read the other thread on Aleph Cap for more information.

een ooievaar is geen konijn want zijn oren zijn te klein!
  Reply With Quote


Aleph questionsHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
questions about aleph 3 pinial26 Pass Labs 12 19th November 2007 09:53 PM
New Aleph 5, questions gianc Pass Labs 6 23rd February 2006 12:30 AM
Aleph 30 questions needtubes Pass Labs 15 2nd November 2005 06:22 PM
Aleph p 1.7 questions? bbakota2000 Pass Labs 11 14th March 2004 01:50 AM
Aleph 2 questions loovet Pass Labs 2 3rd February 2003 12:04 AM

New To Site? Need Help?

All times are GMT. The time now is 06:46 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio