Anyone use Wall warts to run a gainclone - Page 2 - diyAudio
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 29th May 2003, 07:25 PM   #11
diyAudio Member
 
Join Date: Jan 2001
Location: Scandinavia
Quote:
Originally posted by JCoffey
Interesting. I have quite a few compaq laptop power supplies laying around. Something to look into. Build a couple Monoblocks with laptop cords connected to them.......

If you use a balanced topology (and "create your own ground"), you can get by with one PSU and won't have to worry about interference between the supplies (beating comes to mind since they are NOT running at the same frequency, but probably close).

I would add filtering at the output of the Compaq unit. Try it with a resistive load first to verify that you don't get oscillations with your chosen filter (LC or just C?). It would probably be opportune to look at the waveform to see how "bad" the output is.

Petter
  Reply With Quote
Old 29th May 2003, 07:59 PM   #12
mikelm is offline mikelm  England
diyAudio Member
 
Join Date: May 2003
Location: England
Send a message via Yahoo to mikelm
Quote:
Originally posted by Petter



If you use a balanced topology (and "create your own ground&quot, you can get by with one PSU and won't have to worry about interference between the supplies (beating comes to mind since they are NOT running at the same frequency, but probably close).

I would add filtering at the output of the Compaq unit. Try it with a resistive load first to verify that you don't get oscillations with your chosen filter (LC or just C?). It would probably be opportune to look at the waveform to see how "bad" the output is.

Petter
after trying different single rail voltages for balanced working ( with a resistor divider and cap to define the centre point for the i/p earth ) I came to the conclusion that 36V was about optimum.
I'm not sure if computor supplies come this high. And yes, LF common mode noise will cancel but this does not apply to higher frequencies so filtering will be necessary

cheers

mike
  Reply With Quote
Old 29th May 2003, 11:36 PM   #13
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Quote:
Originally posted by JCoffey
Interesting. I have quite a few compaq laptop power supplies laying around. Something to look into. Build a couple Monoblocks with laptop cords connected to them.......
[QUOTE]Originally posted by Petter
[B]

I blew a Compaq supply and replaced with a linear one with Pass transistor for the extra juice -- CPQ wanted $90 for a new supply! Apple, btw, is worse and their laptop supplies have short half-lives.

With regard to filtering -- it's the switching transients you want to eliminate in addition to the ripple. Thus, I use a small surplus torroid on the DC line. Without it you get interference eminating back from the computer into the power line.
  Reply With Quote
Old 29th May 2003, 11:53 PM   #14
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
Quote:
Originally posted by jackinnj

Apple, btw, is worse and their laptop supplies have short half-lives.]
Hmmm, I have been running mac laptops for years, and I have had no problems with PSUs... CDrom drives yes, but PSUs...no
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 29th May 2003, 11:57 PM   #15
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Default it's the connector

the connector which they use can become "undone" with a lot of use, mine became intermittent and sparked -- we have 2 Mac laptops in the house, 1 dell and 1 compaq. The Mac connector is "quirky" to say the least, incorporating ferrite shielding into the body of the casing. Compaq just uses a standard plug, Dell's is proprietary, but not as complex as the Mac to replace.
  Reply With Quote
Old 30th May 2003, 01:26 AM   #16
diyAudio Member
 
Join Date: Oct 2002
Location: south amboy nj
Send a message via AIM to zx3chris
what about using 4 of these??

http://www.brigarelectronics.com/Mer...ategory_Code=T

12vdc each, so 2 in series for 24v then the other 2 with a center ground for +/- ????
  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
Designing for on-wall/near-wall speaker placement morbo Multi-Way 4 27th November 2010 04:52 PM
in-wall/on-wall speaker? (axiom w-22 clone?) Scott_fx Multi-Way 0 22nd February 2007 02:08 AM
In-wall vs bookshelf spk flush with wall darascott Multi-Way 3 1st October 2005 03:16 PM
Opinions on wall to wall subwoofer array jmiyake Subwoofers 35 19th July 2003 11:26 PM
"wall-warts" is this cheap junk from USA? peranders Everything Else 15 27th January 2003 10:51 AM


New To Site? Need Help?

All times are GMT. The time now is 04:25 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