Is it big enough? - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 2nd September 2005, 07:27 AM   #1
Wombat2 is offline Wombat2  Australia
diyAudio Member
Wombat2's Avatar
Join Date: Nov 2003
Location: Brisbane
Default Is it big enough?

I'm building a tri-amp 5.1 surround system. I'm using ESP P03A for the 12" woofers,(except centre) LM3876 for the mids and LM4752 for the tweeters. ie 4X 60W and 6 x 50W at +/- 35V (the LM4752 run on a single rail 24v supply for which I already have a 3A regulated PSU)

Would a single 600VA toriod be big enough for the 35volt supply? I'm thinking of running a snubberised regulated supply for the LM3876s and and unregulated for the bigger amps. If I split the tranfo I could go for a 42 v supply and get 100w out of the P03As

David L
  Reply With Quote
Old 2nd September 2005, 08:45 PM   #2
rinox is offline rinox  Italy
diyAudio Member
Join Date: Oct 2004
In my opinion the best is to use at lest two transformer, one dedicated for the bass and the other for the mid-high.... they will cost less then a single trasfo and the results will be better.
  Reply With Quote
Old 3rd September 2005, 08:35 AM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
Join Date: Jul 2004
Location: Scottish Borders
42Vac will give a lot more than 100W into 8r. 35Vac should achieve 100W.
Your 600VA transformer will be undersized for 6 * 50W + 4 * 60W.
the rail voltage will sag badly on peaks and make the sound quality suffer. This will be particularly revelevant on long bass notes.
I would recommend a minimum of 2 by 500VA for your loading and further if you can find them cheaply then use a pair of secondaries for each channel. More easily achieved, a pair of secondaries for the bass and the other pair for mid and treble. Then have separate rectifiers for every channel with their own smoothing and snubbers.
regards Andrew T.
Sent from my desktop computer using a keyboard
  Reply With Quote
Old 3rd September 2005, 09:21 AM   #4
Did it Himself
diyAudio Member
richie00boy's Avatar
Join Date: Nov 2003
Location: Gloucestershire, England, UK
He means 42 V DC On the 35 V supply, your output power is 540 W, so a 600 VA transformer would be a bit undersized for continuous duty. Class-b amps typically demand VA = 2x amp power for continuous duty.
__________________ my website for UK diy audio people - designs, PCBs, modules and more.
  Reply With Quote


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 02:30 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2