SSLV1.1 builds & fairy tales - Page 194 - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 25th November 2012, 07:31 PM   #1931
diyAudio Member
 
Join Date: Jan 2011
Location: sitting down
yes same buf3.

I tried interchanging cables with same problem.
  Reply With Quote
Old 25th November 2012, 07:33 PM   #1932
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Does it drift on a dummy?
  Reply With Quote
Old 25th November 2012, 07:36 PM   #1933
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Is the 0.1V drift stop end and is it positive or negative when it gets hotter beyond 300mA?
What your Vref array consists of? (parts in "see text" area).
  Reply With Quote
Old 25th November 2012, 07:41 PM   #1934
diyAudio Member
 
Join Date: Jan 2011
Location: sitting down
tried dummy load with 2 12r 5w so tesetd with 24,12 and 6r load but the 6r load has too much current so the V out on both bibs drop by half.

bib power resisters are 2 x 3.9r with bjt version

seems to start drifting at about 400 so I think I'm on the edge with the current setting resisters. I may add another to get more current to see effect.

see text has 1 red led, 27r and 1 k trimmer with rest jumpered. I can play with voltage without problem

everything well sinked so nothing gets hot.

Last edited by necplusultra; 25th November 2012 at 08:05 PM.
  Reply With Quote
Old 25th November 2012, 08:15 PM   #1935
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Is the drift negative or positive, and does it stop at 0.1V?
  Reply With Quote
Old 25th November 2012, 08:23 PM   #1936
diyAudio Member
 
Join Date: Jan 2011
Location: sitting down
drift is up and down but not stable at 5.25v like the functional bib. Also,it seems that turning the wiper does not change the V either when hooked up to buf3. I will perform more testing to try to figure this out. Since buf3 should consume about 450ma, I may be just on the threshold with those 2x3.9r power resisters. I started with 1 but that was not enough for the buf3 so I added another 3.9r and now one is perfect but the other is straying.

I'll try to post pictures later
  Reply With Quote
Old 25th November 2012, 08:28 PM   #1937
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Looks like its on threshold. Normally V1.1 will drift (depending on Vref combination and temp) only a little negative. If with enough current it will still do the same weird stuff, then first suspect is the trimmer.
  Reply With Quote
Old 25th November 2012, 08:31 PM   #1938
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Verify your current by measuring the voltage across the setting resistors and dividing by their combo value.
  Reply With Quote
Old 25th November 2012, 08:54 PM   #1939
diyAudio Member
 
Join Date: Jul 2010
Default Yeah...

For the Buffalo you will want about 550-600 mA in the BiB CCS. This is a lot easier to achieve with 4 leds. Also, make sure you have adequate sinking. I relieved some heat in my set up by using an 8 VAC transformer so there is a little less voltage drop.

V/R in the current set resistor gives you the CCS current...
  Reply With Quote
Old 25th November 2012, 08:56 PM   #1940
diyAudio Member
 
Join Date: Jan 2011
Location: sitting down
Thanks Salas,

This is indeed a learning experience for me.

So I added an extra 3.9r on the failing bib and now I get a constant 5.25 V. I'll measure the voltage accross these R's and calculate but it seems that the comnsumption would fall between 2x3.9 and 3 x 3.9. The functional bib is at 2x3.9r. I had to add an extra 3.9r on the other bib to make it work properly. It seems that my current setting R's should fall somewhere between 1.3 and 1.95R.

V accross one bib .72v / 1.3 = .553
V accross other bib is .93 /1.95 = .476



If I understand this correctly, previously I had .72/1.95 = .369 which is not enough for the buf3.


Also, if the b3 consumes 450, I should be adding an extra 150 for the bib for a total of 600ma. I would have to reduce the r on both to attain 600ma given that one v reads .72 and the other reads .93

Hope I got this right

So my question is why do I get so different voltages (.72 vs .93) on identical builds?

Last edited by necplusultra; 25th November 2012 at 08:59 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
GB Thread for Salas SSLV1.1 BiB shunt reg Tea-Bag Group Buys 1458 3rd July 2014 04:28 PM
WTB : Salas SSLV1.1 BiB shunt CaNNA3IS Swap Meet 1 24th November 2013 09:43 AM
FS : 2 x Salas SSLV1.1 BiB PCB + 6 x IRF MiniKits korben69 Swap Meet 6 2nd July 2013 09:32 AM
Some VX.2 Builds CSS/XBL CSS 0 11th April 2013 05:34 PM
so who here builds amps amp builder jb Tubes / Valves 29 15th July 2005 08:23 PM


New To Site? Need Help?

All times are GMT. The time now is 07:31 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