help with rail voltages - 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 24th June 2004, 01:10 AM   #1
diyAudio Member
 
Join Date: Oct 2003
Location: Christchurch
Question help with rail voltages

I am able to get some 2nd hand transformers that would give me 36vac--0--36vac.....maybe around +/- 46vdc??

Is that going to be to high when using irfp044s in an aleph x??
  Reply With Quote
Old 24th June 2004, 04:09 AM   #2
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Without a load this will come out about +/- 50V. With a load
it will be less, but how much depends on the hardware.

This is high, even for an Aleph X. How big are they (VA rating)
and do they have 240 V primaries? for that matter, what is
your voltage?
  Reply With Quote
Old 24th June 2004, 05:13 AM   #3
diyAudio Member
 
Join Date: Oct 2003
Location: Christchurch
Mains Voltage here is ~240VAC.

There are several avaible, D55-449M Fuji Electric Co Ltd, 3.55KVA for $120 each.

The primary is 240vac with several tappings.

The lowest possable sec voltage is a taped 36vac, I was thinking of using two transformers, one for each rail.

I am guessing the highest possable sec voltage is probably no more than 40vac, possably still too low to give me much power.

They only weigh 19kg, is that a bad thing?
  Reply With Quote
Old 24th June 2004, 07:50 AM   #4
uli is offline uli  Austria
diyAudio Member
 
Join Date: Dec 2002
Location: Vienna, Austria
Default 3.55kVA

Go ahead with those monsters


Only thing to be aware of:

Buy enough aluminium


Uli

__________________

'Jazz is not dead, it just smells funny' F.Zappa
  Reply With Quote
Old 24th June 2004, 09:02 AM   #5
diyAudio Member
 
Join Date: Oct 2002
Location: Holland, The Hague
Large second hand 3550 VA trafo that only weigh 19 kg

HHUMMMMMMMMM (50 hz)...

__________________
Is that all there is?
  Reply With Quote
Old 24th June 2004, 10:00 AM   #6
uli is offline uli  Austria
diyAudio Member
 
Join Date: Dec 2002
Location: Vienna, Austria
Default hummm

I think, they will be ok since they won´t be loaded that much

Uli

__________________

'Jazz is not dead, it just smells funny' F.Zappa
  Reply With Quote
Old 24th June 2004, 10:28 AM   #7
diyAudio Member
 
Join Date: Oct 2003
Location: Christchurch
Supposing the hum wasnt too bad, the irfp044 being a 60volt device, and the rails being +/- ~48V ......am I going to cook my 044's?
  Reply With Quote
Old 24th June 2004, 10:38 AM   #8
diyAudio Member
 
Join Date: Dec 2002
Location: Houston
Quote:
Originally posted by Svetlana
Supposing the hum wasnt too bad, the irfp044 being a 60volt device, and the rails being +/- ~48V ......am I going to cook my 044's?
I think yes, the 044's will not last very long. Also some are only rated at 55 volts.
Since these transformers are 120.00 each, why not contact a winder about getting a pair that give you 25 volt outputs. 240.00 should buy what you need, just not in a 3.5kVA unit.

George
  Reply With Quote
Old 24th June 2004, 11:52 AM   #9
diyAudio Member
 
Join Date: Oct 2003
Location: Christchurch
So whats the highest safest voltage I can run these parts..maybe 1/3 of their stated voltage ratings? maybe a half? why cant I run them at their full 60 volts?
  Reply With Quote
Old 24th June 2004, 12:04 PM   #10
Luke is offline Luke  New Zealand
diyAudio Member
 
Join Date: Sep 2001
Location: Wellington NZ
Send a message via AIM to Luke
Hi Svetlana,

you could parallel two 40 volt windings and use them as plus minus 20 volt rails and just ground the centre where they meet.
I think you need resistors in series to ground though to keep the rails the same?
With 6 amps bias that should give abut 120watts class A and dissipate close to 300 watts per channel
BTW are there any more of these, im slowly getting bits together for my aleph-X. A company name or phone number of who is selling these would be nice

cheers arthur
  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
modern day rail voltages Clipped Car Audio 3 28th September 2007 04:38 AM
Rail voltages from 15-0-15 volt transformer Bama Slamma Power Supplies 3 26th November 2006 10:27 AM
the best transformer rail voltages for gainclone? araven Chip Amps 2 30th September 2006 10:31 PM
bosoz rail voltages EANDERS Pass Labs 2 25th March 2005 04:19 PM
Amp supply rail voltages.... Xicarius Everything Else 2 4th August 2004 12:38 AM


New To Site? Need Help?

All times are GMT. The time now is 07:41 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