Burning Amp BA-3 - Page 103 - 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 4th July 2013, 12:17 AM   #1021
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Make sure you measure offset before the output cap. Other than that, it is pretty straightforward. Ask any questions you have. Jfets are good if you have between 6-7ma across jfet Rs.
__________________
...Shape the sound , Man!
  Reply With Quote
Old 4th July 2013, 12:38 AM   #1022
6L6 is offline 6L6  United States
diyAudio Member
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
Quote:
Originally Posted by bcmbob View Post
Is there a published build and/or initial start-up/test/adjustment procedure for the BA-3 front end somewhere on the forum? I haven't located one yet. Would be good to confirm proper operation before I hook it up to something else.
It's essentially an F5 in topology, so treat it like an F5 ---

Turn down the bias pots, neutralize the 2nd harmonic pot.

Get out your three meters just like an F5. Turn up the bias pots equally until there is some voltage across R10 and R11.

Increase bias about 20% at a time, and null your offset at each increase.

Lather, rinse, repeat until you have 1V across the output source resistors and zero offset.

That should be good.
  Reply With Quote
Old 4th July 2013, 12:45 AM   #1023
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
Thanks All !
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."
  Reply With Quote
Old 4th July 2013, 03:28 AM   #1024
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
He's Back

Does anyone have a part number(s) for P1/2 P3 on the BA-3 FE board. I ordered these and received standard vertical three pin trimmers. From the traces, I'm assuming all four leads on those pads are necessary. I spent some time at Mouser but can't put my finger on the exact combination of orientation and pins.
Attached Images
File Type: jpg TMRS.jpg (51.7 KB, 348 views)
File Type: jpg 20130703_232601.jpg (46.8 KB, 310 views)
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."
  Reply With Quote
Old 4th July 2013, 03:37 AM   #1025
evanc is offline evanc  United States
diyAudio Member
 
Join Date: Sep 2009
Location: New Jersey. About 1 hour from NYC and 1 min. from the beach
Only three pins needed. I used regular vishay multitude trimmers.
__________________
http://www.evancotler.com
  Reply With Quote
Old 4th July 2013, 03:57 AM   #1026
6L6 is offline 6L6  United States
diyAudio Member
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
The offset pin and the in-line pin are there for convenience, to fit various types/brands of pots.

The ones you have are great.
  Reply With Quote
Old 4th July 2013, 10:37 AM   #1027
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
Good to hear that.

Moving on - Thanks.
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."
  Reply With Quote
Old 15th July 2013, 01:21 AM   #1028
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
Due to some space requirements, I would like to have a single row of caps in the power supply. Does this look correct?

And - if I wanted additional caps they would be inserted to the right of the purple ones ?
Attached Images
File Type: jpg BA Wires.jpg (189.5 KB, 227 views)
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."
  Reply With Quote
Old 15th July 2013, 09:48 AM   #1029
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Yes.
The green T junction away off to the right hand side is your MAG.

The R of the CRC is a little unconventional in that both appear in the +ve side of the cap banks. I think that theoretically they perform just as well as doing one in +ve and one in -ve.

Remember to keep twisted pairs/triplets to as close as the PCBs allow.
__________________
regards Andrew T.
  Reply With Quote
Old 15th July 2013, 01:55 PM   #1030
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
Thanks Andrew.
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."
  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
Burning Amplifier BA-3 Nelson Pass diyAudio.com Articles 34 27th June 2014 04:36 AM
Burning Amplifier BA-1 Variac Pass Labs 340 27th May 2014 08:03 AM
Burning Amplifier BA-1 Nelson Pass diyAudio.com Articles 3 24th October 2011 02:53 AM
WTB: Burning Amp BA-1 or BA-2 jdubs Swap Meet 0 23rd March 2011 03:16 AM
FS: two burning amps (one each BA-1 and BA-2) without drivers Eric Weitzman Swap Meet 15 17th February 2010 02:35 AM


New To Site? Need Help?

All times are GMT. The time now is 03:23 AM.


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