Help with power supply??? N.Pass A75 - 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 6th July 2001, 04:25 AM   #1
diyAudio Member
 
Join Date: Jun 2001
Location: Chicago
I am building the N. Pass A75 and I have run into a snag. As Nelson suggested I tested the reg. supply and I am getting a steady 50v.

The problem is when I put in the fuses for the unregulated suppy. I get ~44v DC which is what I would expect, but then he says to measure the AC. When I measure the AC across one of the cap using a VOM set on AC I get about 100v!

What could I have possible done wrong? it is such a simple circuit.

I am using a 31v tranny which I doulble checked is wired up correctly. I bought some 30000uf caps surplus they are marked McKintosh, they look good, but I have no way that I know how to test them, other than that the rectifiers are new from digikey. I have also placed bleed resitors across the caps to bleed them down when not in use.

The tranny buzzes for a fration of a secound, as it charges up the caps. Then I get the ac. When I turn it off the caps then beed off through their resistors.

I don't have a clue unless the caps are bad?

ANyone had any experience like this?

TIA

Greg
  Reply With Quote
Old 6th July 2001, 05:26 AM   #2
grataku is offline grataku  United States
diyAudio Member
 
Join Date: Dec 2000
Location: -
Let me get this straight...are you measuring with a voltmeter on AC setting across the + and - of an electrolytic filtering capacitor after the rectifier?
If so you are driving your voltmeter crazy that's all.
  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
power supply schematic with a 6080 used as a "pass tube" jarthel Tubes / Valves 4 9th July 2012 03:25 AM
pass transistor in regulated supply? theAnonymous1 Power Supplies 73 12th May 2009 12:27 AM
Toroid / supply for Pass project???? Zero Cool Swap Meet 10 24th October 2008 09:55 PM
How many supply voltage on Pass X0 rubydac Pass Labs 9 21st August 2008 03:08 AM
Choke power supply for Pass A75 Persig Pass Labs 13 16th July 2002 11:51 PM


New To Site? Need Help?

All times are GMT. The time now is 09:54 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