Go Back   Home > Forums > Amplifiers > Power Supplies

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 28th November 2005, 04:03 AM   #1
diyAudio Member
 
Join Date: Sep 2005
Default Power supply for LM4702

I recently ordered the LM4702 audio driver from National; it has a maximum supply voltage of +/-75V.


My current power supply will put out +/-80V. Is there any way I can drop about 10V for the 4702 in an efficient and cheap way?
  Reply With Quote
Old 28th November 2005, 08:00 AM   #2
Tweeker is offline Tweeker  United States
diyAudio Member
 
Join Date: Dec 2004
Location: Cincinnati, Ohio
Cheapest way is a couple strings of diodes, not necessarily the best way.
__________________
Be sure your foil hat has a good low impedance ground.
  Reply With Quote
Old 20th December 2005, 12:51 PM   #3
alexcd is offline alexcd  United States
diyAudio Member
 
alexcd's Avatar
 
Join Date: Sep 2004
Location: US - Boston
Send a message via AIM to alexcd Send a message via Yahoo to alexcd
A resistor and zener diode will hold it at 75V... of course they would need to eat up dV*I = MASSIVE POWER.
  Reply With Quote
Old 21st December 2005, 03:41 AM   #4
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
Default Re: Power supply for LM4702

Quote:
Originally posted by rtarbell
I recently ordered the LM4702 audio driver from National; it has a maximum supply voltage of +/-75V.


My current power supply will put out +/-80V. Is there any way I can drop about 10V for the 4702 in an efficient and cheap way?

depends on the power transformer you'll be using, and the final config of your lm4702 amps, could be that the +/-80volt rails will sag to 75volt levels once your amps is powered up and idling!
  Reply With Quote
Old 21st December 2005, 12:17 PM   #5
alexcd is offline alexcd  United States
diyAudio Member
 
alexcd's Avatar
 
Join Date: Sep 2004
Location: US - Boston
Send a message via AIM to alexcd Send a message via Yahoo to alexcd
Not to doubt you Tony but it would be pretty unwise to design anything around where the power supply may be in a sag. It doesn't take much time at all to kill an IC with high voltage. Be safe and either find a way to unwind your trans or buy another one. Sorry.
  Reply With Quote
Old 30th December 2005, 03:07 AM   #6
amp_cy is offline amp_cy  Cyprus
diyAudio Member
 
Join Date: Dec 2005
Location: Nicosia
If your power supply consists of a toroid transformer, you could add several more turns on the transformer core and connect these to the primary windings. The wire should be of the same thickness as the primary. You should then insulate these turns with some insulation tap.

This is a non distructive alteration which will change the transformer turns ratio. NOTE make sure the new windings are in phase with with the primary.
  Reply With Quote
Old 25th June 2006, 07:18 PM   #7
ahrsix is offline ahrsix  United Kingdom
diyAudio Member
 
Join Date: Jun 2006
Default Power Supply for LM4702

Have a peek at the LM338K 5amp regulator data sheet, there not cheap but I'v used them on PSUs for over 20yrs never regretted it. There are circuits on the forums, a good amps worth it.
arrsix





Always cut towards your friend
Old RN saying
__________________
arrsix
  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
XDA-1 -- A symmetrical power amp utilizing LM4702 Russ White Chip Amps 35 24th September 2007 09:44 PM
something with LM4702 and Power FET FastEddy Chip Amps 58 20th December 2006 05:30 PM
Lm4702 on pure dc power steven344 Chip Amps 1 14th December 2006 02:34 PM


New To Site? Need Help?

All times are GMT. The time now is 08:26 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