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.

AlephJ Mimi! (Mini)
AlephJ Mimi! (Mini)
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 6th January 2017, 10:43 PM   #91
lykkedk is offline lykkedk  Denmark
diyAudio Member
 
lykkedk's Avatar
 
Join Date: Dec 2002
Location: Denmark, Fredericia
Quote:
Originally Posted by maiko View Post
Hello Jesper, seems like a nice build!
One question though, what is the function of adding C3 and C6??
I cant tell; but the 220uF is in original schematic.

Jesper.
__________________
DCG3 Dual DCSTB, AK4490 Dual SuperDAC
AlephJ Mimi! http://www.diyaudio.com/forums/pass-...mimi-mini.html
  Reply With Quote
Old 6th January 2017, 11:49 PM   #92
didiet78 is offline didiet78  Indonesia
diyAudio Member
 
Join Date: Mar 2007
Location: Bandung
C3 , C7 functin : fill empty space of pc board
__________________
Didiet
Usb I2S + AK4490 / WM8805+ESS9023 / SDHC Card I2S audio player + AD1860
  Reply With Quote
Old 7th January 2017, 12:32 AM   #93
maiko is offline maiko  Finland
diyAudio Member
 
maiko's Avatar
 
Join Date: Jul 2016
Location: Stella Polaris Vicinitas
Ok, I think I found the schematics in Jespers earlier post.
http://www.diyaudio.com/forums/pass-...ml#post4933856

It is a schematics of First Watt Aleph J (C)2005, there is Q4, if I understand the function of it, is to current limit the output transistors to roughly ~1,5A, but C3 seems to modulate the current limit?
I am lost, maybe you are right Didiet haha...

Mr. Pass, please explain C3!
Attached Images
File Type: jpg aleph_j_sch.jpg (106.4 KB, 242 views)
  Reply With Quote
Old 7th January 2017, 01:41 AM   #94
Zen Mod is online now Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
AlephJ Mimi! (Mini)
Aleph current source
__________________
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 7th January 2017, 02:23 AM   #95
maiko is offline maiko  Finland
diyAudio Member
 
maiko's Avatar
 
Join Date: Jul 2016
Location: Stella Polaris Vicinitas
Thanks ZM!
I found a good description how it works, easier reading than patents (# 5,710,522).
https://www.passdiy.com/project/ampl...n-variations-9
  Reply With Quote
Old 7th January 2017, 07:53 AM   #96
lykkedk is offline lykkedk  Denmark
diyAudio Member
 
lykkedk's Avatar
 
Join Date: Dec 2002
Location: Denmark, Fredericia
I assume -In have to be connected to GND for test/best performance?

Jesper.
__________________
DCG3 Dual DCSTB, AK4490 Dual SuperDAC
AlephJ Mimi! http://www.diyaudio.com/forums/pass-...mimi-mini.html
  Reply With Quote
Old 7th January 2017, 09:06 AM   #97
Zen Mod is online now Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
AlephJ Mimi! (Mini)
when testing/setting - ground both inputs , no load on output

when singing - if you use RCA , ground neg input
__________________
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 7th January 2017, 10:25 AM   #98
lykkedk is offline lykkedk  Denmark
diyAudio Member
 
lykkedk's Avatar
 
Join Date: Dec 2002
Location: Denmark, Fredericia
Quote:
Originally Posted by Zen Mod View Post
when testing/setting - ground both inputs , no load on output

when singing - if you use RCA , ground neg input
Ohh yea! i remember now... thanx.

Jesper.
__________________
DCG3 Dual DCSTB, AK4490 Dual SuperDAC
AlephJ Mimi! http://www.diyaudio.com/forums/pass-...mimi-mini.html
  Reply With Quote
Old 7th January 2017, 10:51 AM   #99
lykkedk is offline lykkedk  Denmark
diyAudio Member
 
lykkedk's Avatar
 
Join Date: Dec 2002
Location: Denmark, Fredericia
Default Testing

Hello.

I assume that this is the right procedure, when testing/powering up ::

Short -IN and +IN to GND

Plug in mains (Variac, lightbulb is only for Sissy )
PSU is +18 - "0" -18 VDC

Meassure voltagedrop across R16 (Source resistor Q5)
This is BIAS, but howto calculate this ???
I expect this voltage to be around 0.5V for Bias >1A ???

Bias is adjusted with R27 trimmer.

When everything is good, also adjust DC-offset with R7 trimmer.

Normal procedure after that, let amp. warm up and settle, then readjust and see if everything is stable and temperature is not to hot (>55C)

Jesper.
Attached Images
File Type: png Mini AJ non UMS sch.png (43.7 KB, 213 views)
__________________
DCG3 Dual DCSTB, AK4490 Dual SuperDAC
AlephJ Mimi! http://www.diyaudio.com/forums/pass-...mimi-mini.html
  Reply With Quote
Old 7th January 2017, 12:34 PM   #100
lykkedk is offline lykkedk  Denmark
diyAudio Member
 
lykkedk's Avatar
 
Join Date: Dec 2002
Location: Denmark, Fredericia
So everything is stuffed up now...

Just have to prepare my PSU... maybee test this betabuild in next few days?

Have a good weekend all.

Jesper.
Attached Images
File Type: jpg Populating_pcb_2.jpg (318.9 KB, 214 views)
__________________
DCG3 Dual DCSTB, AK4490 Dual SuperDAC
AlephJ Mimi! http://www.diyaudio.com/forums/pass-...mimi-mini.html
  Reply With Quote

Reply


AlephJ Mimi! (Mini)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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
FS: Babelfish J Mini version acamilicko Swap Meet 3 7th August 2017 05:09 PM
FS: PreAmp with Complimentary JFET Diff input & JFET ouput USAcircuits Vendor's Bazaar 12 21st June 2011 12:02 PM
Jfet input for Aleph 60? Dansk Pass Labs 14 22nd January 2011 02:34 PM
Aleph Mini with JFET input? Arie Pass Labs 11 21st March 2008 06:42 PM
A chopped Mini-A with Jfet input stage Fuling Pass Labs 12 15th November 2006 08:45 PM


New To Site? Need Help?

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


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki