My Aleph3/5-BA-2-Semisouth-J2 Clone Monster - Page 11 - 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 17th January 2011, 11:33 AM   #101
Banned
 
Join Date: Nov 2006
Just wondering whether you increased the quiescent current up to 3.2 A yet (1.6 A per device)
  Reply With Quote
Old 17th January 2011, 02:23 PM   #102
generg is offline generg  Germany
diyAudio Member
 
generg's Avatar
 
Join Date: Jul 2009
Location: Near Frankfurt
hi Melon Head,

Nelson was so friendly to send me the service manual of Aleph60.

6 stages deep, every stage with 0,4 A at +-35V.

later I will try the modification Zen Mod suggested in this thread some time ago.....


Jfet input for Aleph 60?
__________________
and the First Wtt is......a really First Class PSS Idea
  Reply With Quote
Old 17th January 2011, 02:44 PM   #103
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally Posted by Nelson Pass View Post
You might allow for referencing the cascodes to ground. Try it
both ways and see what you like.



ZM weiss Bahnhof .....

__________________
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
  Reply With Quote
Old 17th January 2011, 03:22 PM   #104
generg is offline generg  Germany
diyAudio Member
 
generg's Avatar
 
Join Date: Jul 2009
Location: Near Frankfurt
ZM knows not only one "bahnhof". He knows many and he often knows where the journey goes to.....
__________________
and the First Wtt is......a really First Class PSS Idea
  Reply With Quote
Old 18th January 2011, 02:10 AM   #105
Banned
 
Join Date: Nov 2006
Quote:
Originally Posted by generg View Post
hi Melon Head,

Nelson was so friendly to send me the service manual of Aleph60.

6 stages deep, every stage with 0,4 A at +-35V.

later I will try the modification Zen Mod suggested in this thread some time ago.....


Jfet input for Aleph 60?
I honestly believe you will get better sound with your speakers (4 Ohms) by increasing the bias (quiescent) current further than 2.4A. If you cant achieve it with 35V rails (heatsinks too small etc) than consider dropping the voltage (eg 28V).
3A to 4A is where it's at or even higher if you can manage it.
I am assuming you will be building monoblocks.
There is one thing I remember Nelson saying was that, if you bias at the maximum expected peak current (take into account reactive nature of speaker) than you can set the current gain to even higher levels and get good results.
Not as efficient but you might find the results are to your liking
  Reply With Quote
Old 19th January 2011, 06:25 PM   #106
generg is offline generg  Germany
diyAudio Member
 
generg's Avatar
 
Join Date: Jul 2009
Location: Near Frankfurt
Hi Melon Head,

thanks for suggestion, unfortunately my heatsinks do not allow more than 2,4 A at 35V.
So I have at the moment not the possibility to omit the aleph ccs and drive pure class A.

At the moment A60 delivers a very good bass with the small Thiel speakers, in a way the First Watt amps could not do of course....
__________________
and the First Wtt is......a really First Class PSS Idea
  Reply With Quote
Old 19th January 2011, 08:25 PM   #107
Banned
 
Join Date: Nov 2006
If you drop the rails to 28V then you can increase the bias to 3A.

I was not suggesting removing the Aleph current source. I was suggesting increasing the bias further so that the peak current never exceeds the quiescent current.
The thing I like about the Aleph current source is not that it allows greater efficiency than a standard SE design, it is the fact that it reduces distortion levels even at current demands lower than the quiescent current.

If you don't have time or energy to do further mods and are happy with the sound then just sit back and enjoy the music.

Last edited by Melon Head; 19th January 2011 at 08:34 PM.
  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
FirstWatt J2 Blues Pass Labs 830 28th October 2014 01:01 AM
F3 vs J2 for a SET guy Paul Folbrecht Pass Labs 24 27th May 2010 10:16 PM
FS: two burning amps (one each BA-1 and BA-2) without drivers Eric Weitzman Swap Meet 15 17th February 2010 03:35 AM
The simplified schematic of J2 what I suppose to be. wensan Pass Labs 9 16th November 2009 10:09 AM
Adcom J2 8934m Ardvaark Parts 0 23rd July 2009 06:30 PM


New To Site? Need Help?

All times are GMT. The time now is 08:26 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