DIY - Adjustable Power Supply Design - 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 19th March 2002, 04:28 AM   #1
diyAudio Member
 
Join Date: Mar 2001
Location: Seattle
Default DIY - Adjustable Power Supply Design

Hello All,

I want to build an adjustable +/- 100V power supply. Nothing particularly fancy, but would like to use my toroid with dual 120v secondaries.

Any designs (that are not terribly involved) out there within the reach of a DIYer?

Regards,

Vinay
  Reply With Quote
Old 19th March 2002, 07:50 AM   #2
diyAudio Member
 
Join Date: Oct 2001
I suggest the use of an autotransformer (Variac) and an ordinary bridge+capacitor approach.
  Reply With Quote
Old 19th March 2002, 12:05 PM   #3
ralf is offline ralf  Germany
diyAudio Member
 
Join Date: Dec 2001
Location: Germany
Default further question

hi,

when i use a variac as transformer, with a bridge- from where do i get the ground, which will be connected to the mid of the capacitors?

When i use a "normal" transformer, it`s symmetrical, that means the ground i need is the connection of two cables, coming out of the transformer, plus the two ac - cables, which are connected to the bridge.

But on a variac i have only two cables -ac !

Ralf
  Reply With Quote
Old 19th March 2002, 12:22 PM   #4
diyAudio Member
 
Join Date: Oct 2001
Always use a Variac in combination with a 'normal' transformer since the Variac output is NOT ISOLATED from the mains.
Then you already solve the problem mentioned above.
  Reply With Quote
Old 19th March 2002, 12:38 PM   #5
UrSv is offline UrSv  Sweden
diyAudio Member
 
UrSv's Avatar
 
Join Date: Jan 2002
Location: Sweden
You say you have a toroid with dual 120 V secondaries. Use the Variac to feed the primary of your toroid and take the dual secondaries as the "normal" supply with bridges and caps.

Something like this:


/UrSv
Attached Images
File Type: png psu.png (662 Bytes, 227 views)
  Reply With Quote
Old 19th March 2002, 04:40 PM   #6
grataku is offline grataku  United States
diyAudio Member
 
Join Date: Dec 2000
Location: -
Vinay
what do you want to do exactly? 2X120VAC to +/-100VDC? If so that is going to involve a lot of power dissipation. How much current do you plan to draw?
If it's more than 200mA you better buy a new transformer. The variac alternative will work but it's awfully clunky. Plus you would be limited in the A of your VA rating.
To get +/- 100DC unregulated you will need a trafo more in the order of 2x60VAC.
  Reply With Quote
Old 19th March 2002, 05:15 PM   #7
diyAudio Member
 
Join Date: Mar 2001
Location: Seattle
Default More details

The transformer is about 300VA.

I would like to get about 300 to 500 ma.

I have to check, but i think I can set up for +/-60V (+/- 84V rectified).

I want a general purpose (with at least some regulation) power supply, although I would like to use for the Balanced Zen Line Stage, when not using for other activities.

Regards,

Vinay
  Reply With Quote
Old 20th March 2002, 05:46 PM   #8
grataku is offline grataku  United States
diyAudio Member
 
Join Date: Dec 2000
Location: -
Look in Geoff site he's got one adjustable regulator circuit that kind of works.
Actually you just need to adjust the voltage prior to loading and it's fine.
You could change a few components to make it siutable for your application.
If you really want to drop from ~170 rect. to 100 regulated and get 500mA out of it you are going to need some big mama transistors. 500mA at 70 V is probably dangerously close to the SOAR limit of the 2N3055. You should be able to do it with more transistors in parallel followed by a 0.33 ohm emitter resistor or with a MJ150XX-type transistors. In any case, the transistor on each side of the PS should be equipped with a heatsink able to dissipate ~50W continuously.
  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
Adjustable power supply questions rendisha Parts 28 10th June 2013 09:57 AM
Power Supply Design Defbrett Tubes / Valves 28 9th October 2009 11:54 PM
Adjustable power supply to replace volume control Leolabs Solid State 8 11th July 2007 04:43 PM
Power supply design LeakSt20 Parts 0 16th August 2005 03:06 PM
Adjustable regulated power supply Ford_V6 Solid State 2 1st April 2003 05:03 PM


New To Site? Need Help?

All times are GMT. The time now is 02:08 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