AC where it shouldn't be. - 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 7th February 2006, 09:06 PM   #1
diyAudio Member
 
Join Date: Dec 2004
Location: Sweden
Default AC where it shouldn't be.

Connecting to the Aleph-X pcb. I have AC on the pwr supply. Is this ok? Also I have to much voltage on Q2 and Q11. Measured about 12V without turning on the variac to 220V.
  Reply With Quote
Old 7th February 2006, 10:14 PM   #2
diyAudio Member
 
BobEllis's Avatar
 
Join Date: Sep 2003
Location: Upstate NY
How much AC is on the rails? a few volts or a few millivolts?

Do you have the DC that you expect when the PSU is not connected to the amp? describe your psu - CRC? how much C and R?

What is your expected rail voltage?

What voltage do you get over R23 and R25? If less than ~4V you won't turn on Q2/Q11 and their drains will be close to the positve rail.
  Reply With Quote
Old 7th February 2006, 10:28 PM   #3
diyAudio Member
 
Join Date: Dec 2004
Location: Sweden
Several volts AC.
I have 18VDC as expected. I'm using this power supply: http://www.kk-pcb.com/power-x.html

As Im using this board http://www.kk-pcb.com/alephx.html I have to come back tomorrow for the voltage over R23 and R 25
  Reply With Quote
Old 7th February 2006, 10:56 PM   #4
diyAudio Member
 
BobEllis's Avatar
 
Join Date: Sep 2003
Location: Upstate NY
If you're getting that much AC then something is seriously wrong. Something is drawing a ton of current, you should be seeing millivolts with that filter. check for a solder bridge to ground or across the rails, backwards electrolytic or backwards FET.

The part numbering I was using refers to Grey's schematic. R23/25 are the 390R in the legs of teh LTP.
  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
AC where it shouldn't be. anders.a Power Supplies 34 14th February 2006 08:55 PM
The price issue: Why shouldn't I just get an integrated receiver? Fryguy Solid State 1 8th August 2003 06:07 AM


New To Site? Need Help?

All times are GMT. The time now is 08:05 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