Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 12th October 2004, 04:55 AM   #1
Greg F is offline Greg F  Australia
diyAudio Member
 
Join Date: Oct 2004
Default Help please Sub Amp P68 from ESP

Hi Guys,

Hope you can help ...

Have assembled P68 from ESP
http://sound.westhost.com/project68.htm

I'am using two 12Vdc 500mA plug packs to reach 21v +/- for testing with 22ohm 10w W/wound resistors ...

Get 16.8Vdc before resistors when hooked up to Amp
Current return is 6.7 + & - rail ??

But the main problem is - 4v @ output, lifted resistors R18,19,20,21 still getting - 4v then lifted R16,17 got - 6.7v

Not shore If this is do damage to other components ??

So the only power is from Q3 base if possible or D2,3 through C5 to the output ??

Also D1 always lights up but where is the current coming from ?? Q1 base ??

Any suggestion

Greg ...

Click the image to open in full size.
  Reply With Quote
Old 12th October 2004, 09:30 AM   #2
diyAudio Member
 
Join Date: Jul 2001
Location: The Netherlands
What is the voltage drop over the two 1 Ohm resistors.. is there any bias current flowing?
  Reply With Quote
Old 12th October 2004, 12:15 PM   #3
hjelm is offline hjelm  Sweden
diyAudio Member
 
hjelm's Avatar
 
Join Date: Nov 2003
Location: Västerås
D1 lights up since the current goes from ground, r23, r8, D1, to -12V
__________________
Hjelm
  Reply With Quote
Old 13th October 2004, 12:11 AM   #4
Greg F is offline Greg F  Australia
diyAudio Member
 
Join Date: Oct 2004
tschrama,

Didn't check that, I power down once output & return current was measured ...
Would it help to locate problem If I hooked everything back up and check that current ??

hjelm,

So LED can be power from - rail, that explains it ... thks ...

Greg ...
  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



New To Site? Need Help?

All times are GMT. The time now is 01:07 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